MT
in Non-Road Mobile Machinery (Amendment) Regulations, 2013
Table of Provisions (10)
Statutory Text (10 Articles)
Suppliment tal-Gazzetta tal-Gvern ta’ Malta, Nru. 19,044, 8 ta’ Marzu, 2013
L.N. 108 of 2013
PRODUCT SAFETY ACT
(CAP. 427)
Measures Against the Emission of Gaseous and Particulate
Pollutants from Internal Combustion Engines to be Installed
in Non-Road Mobile Machinery (Amendment) Regulations, 2013
IN exercise of the powers conferred by article 38 and 40 of the
Product Safety Act, the Minister for Fair Competition, Small
Business and Consumers, on the advice of the Malta Competition and
Consumer Affairs Authority, has made the following regulations:-
The title of these regulations is the Measures Against the Citation.
Emission of Gaseous and Particulate Pollutants from Internal
Combustion Engines to be Installed in Non-Road Mobile Machinery
(Amendment) Regulations, 2013, and these regulations shall be read S.L. 427.85.
and construed as one with the Measures Against the Emission of
Gaseous and Particulate Pollutants from Internal Combustion Engines
to be Installed in Non-Road Mobile Machinery Regulations,
hereinafter referred to as the "principal regulations".
Immediately after regulation 16 of the principal Adds new
schedules to the
regulations there shall be added the following new schedules
principal
regulations.
Schedule I
SCOPE, DEFINITIONS, SYMBOLS AND ABBREVIATIONS, ENGINE
MARKINGS, SPECIFICATIONS AND TESTS, SPECIFICATION OF
CONFORMITY OF PRODUCTION ASSESSMENTS, PARAMETERS
DEFINING THE ENGIN E FA MILY, CHOICE OF THE PARENT
ENGINE
1. Scope
These regulations apply to all engines to be installed in non-road mobile
machinery and to secondary engines fitted into vehicles intended for
passenger or goods transport on the road.
These regulations does not apply to engines for the propulsion of
- vehicles as defined by Directive 70/156/EEC, and by Directive 92/61/
EEC,
- agricultural tractors as defined by Directive 74/150/EEC.
Additionally, in order to be covered by these regulations, the engines
have to be installed in machinery which meets the following specific
requirements
intended and suited, to move, or to be moved with or without road, and
with
(i)a C.I. engine having a net power in accordance with section 2.4. that is
higher than or equal to 19 kW but not more than 560 kW and that is
operated under intermittent speed rather than a single constant speed; or
(ii)a C.I. engine having a net power in accordance with section 2.4. that
is higher than or equal to 19 kW but not more than 560 kW and that is
operated under constant speed. Limits only apply from 31 December
2006; or
(iii)a petrol fuelled S.I. engine having a net power in accordance with
section 2.4. of not more than 19 kW; or
(iv) engines designed for the propulsion of railcars, which are self
propelled on-track vehicles specifically designed to carry goods and/or
passengers; or
(v)engines designed for the propulsion of locomotives which are self-
propelled pieces of on-track eq uipment designed for moving or
propelling cars that are designed to carry freight, passengers and other
equipment, but which themselves are not designed or intended to carry
freight, passengers (other than those operating the locomotive) or other
equipment. Any auxiliary engine or engine intended to power equipment
designed to perform maintenance or construction work on the tracks is
not classified under this paragraph but under A (i).
These regulations are not applicable for the following applications
B.ships, except vessels intended for use on inland waterways;
D.
aircraft;
E.recreational vehicles, e.g.
snow mobiles,
off road motorcycles,
all-terrain vehicles
2. DEFINITIONS, SYMBOLS AND ABBREVIATIONS
For the purpose of these regulations,
compression ignition (C.I.) engine shall mean an engine which works on
the compression-ignition principle (e.g. diesel engine);
gaseous pollutants shall mean carbon monoxide, hydrocarbons
(assuming a ratio of C 1 : H 1.85 and oxides of nitrogen, the last named
being expressed in nitrogen dioxide) NO 2 equivalent;
particulate pollutants shall mean any material collected on a specified
filter medium after diluting C.I. engine exhaust gas with clean filtered air
so that the temperature does not exceed 325 K (52 o C);
net power shall mean the power in ‘EEC kW’ obtained on the test bench
at the end of the crankshaft, or its equivalent, measured in accordance
with the EEC method of measuring the power of internal combustion
engines for road vehicles as set out in Directive 80/1269/EEC, except
that the power of the engine cooling fan is excluded and the test
conditions and reference fuel specified in these regulations are adhered
to;
rated speed shall mean the maximum full load speed allowed by the
governor as specified by the manufacturer;
per cent load shall mean the fraction of the maximum available torque at
an engine speed;
maximum torque speed shall mean the engine speed at which the
maximum torque is obtained from the engine, as specified by the
manufacturer;
intermediate speed shall mean that engine speed which meets one of the
following requirements
- for engines which are designed to operate over a speed range on a full
load torque curve, the intermediate speed shall be the declared maximum
torque speed if it occurs between 60 % and 75 % of rated speed,
- if the declared maximum torque speed is less than 60 % of rated speed,
then the intermediate speed shall be 60 % of the rated speed,
- if the declared maximum torque speed is greater than 75 % of the rated
speed then the intermediate speed shall be 75 % of rated speed,
- for engines to be tested on cycle G1, the intermediate speed shall be 85
% of the maximum rated speed (see section 3.5.1.2 of Schedule IV);
volume of 100 m 3 or more with regard to a vessel intended for use on
inland waterways means its volume calculated on the formula LxBxT, ‘L’
being the maximum length of the hull, excluding rudder and bowsprit,
‘B’ being the maximum breadth of the hull in metres, measured to the
outer edge of the shell plating (excluding paddle wheels, rubbing strakes,
etc.) and ‘T’ being the vertical distance between the lowest moulded
point of the hull or the keel and the maximum draught line;
valid navigation or safety certificate shall mean
(a) a certificate proving conformity with the 1974 International
Convention for the Safety of Life at Sea (SOLAS), as amended, or
equivalent, or
(b) a certificate proving conformity with the 1966 International
Convention on Load Lines, as amended, or equivalent, and an IOPP
certificate proving conformity with the 1973 International Convention
for the Prevention of Pollution from Ships (MARPOL), as amended;
defeat device shall mean a device which measures, senses or responds to
operating variables for the purpose of activating, modulating, delaying or
deactivating the operation of any component or function of the emission
control system such that the effectiveness of the control system is
reduced under conditions encountered during the normal non-road
mobile machinery use unless the use of such a device is substantially
included in the applied emission test certification procedure;
irrational control strategy shall mean any strategy or measure that, when
the non-road mobile machinery is operated under normal conditions of
use, reduces the effectiveness of the emission control system to a level
below that expected in the applicable emission test procedures;
adjustable parameter shall mean any physically adjustable device,
system or element of design which may affect emission or engine
performance during emission testing or normal operation;
after-treatment shall mean the passage of exhaust gases through a device
or system whose purpose is chemically or physically to alter the gases
prior to release to the atmosphere;
spark ignition (SI) engine shall mean an engine which works on the
spark-ignition principle;
auxiliary emission control device shall mean any device that senses
engine operation parameters for the purpose of adjusting the operation of
any part of the emission control system;
emission control system shall mean any device, system or element of
design which controls or reduces emissions;
fuel system shall mean all components involved in the metering and
mixture of the fuel;
secondary engine shall mean an engine installed in or on a motor vehicle,
but not providing motive power to the vehicle;
mode length means the time between leaving the speed and/or torque of
the previous mode or the preconditioning phase and the beginning of the
following mode. It includes the time during which speed and/or torque
are changed and the stabilisation at the beginning of each mode;
test cycle shall mean a sequence of test points, each with a defined speed
and torque, to be followed by the engine under steady state (NRSC test)
or transient operating conditions (NRTC test);
Symbols and abbreviations
Symbols for test parameters
2.18.2
Symbols for chemical components
CH 4 Methane
C 3 H 8 Propane
C 2 H 6 Ethane
CO Carbon monoxide
CO 2 Carbon dioxide
DOP Di-octylphthalate
H 2 O Water
HC Hydrocarbons
NO x Oxides of nitrogen
NO Nitric oxide
NO 2 Nitrogen dioxide
O 2 Oxygen
PT Particulates
PTFE Polytetrafluoroethylene
2.18.3
Abbreviations
CFV Critical flow venturi
CLD Chemiluminescent detector
CI Compression ignition
FID Flame ionisation detector
FS Full scale
HCLD Heated chemiluminescent detector
HFID Heated flame ionisation detector
NDIR Non-dispersive infrared analyser
NG Natural gas
NRSC Non-road steady cycle
NRTC Non-road transient cycle
PDP Positive displacement pump
SI Spark ignition
SSV Subsonic venturi
ENGINE MARKINGS
3.1.3
the EC type-approval number as described in
Schedule VIII;
3.1.4
labels in accordance with Schedule XIII, if the
engine is placed on the market under flexible
scheme provisions.
3.2
Spark-ignition engines approved in accordance
with these regulations must bear
3.2.1
the trade mark or trade name of the
manufacturer of the engine;
3.2.2
the EC type-approval number as defined in
Schedule VIII.
3.3
These marks must be durable for the useful life
of the engine and must be clearly legible and
indelible. If labels or plates are used, they must
be attached in such a manner that in addition
the fixing is durable for the useful life of the
engine, and the labels/plates cannot be
removed without destroying or defacing them.
3.4
These marks must be secured to an engine part
necessary for normal engine operation and not
normally requiring replacement during engine
life.
3.4.1
These marks must be located so as to be readily
visible to the average person after the engine
has been completed with all the auxiliaries
necessary for engine operation.
3.4.2
Each engine must be provided with a
supplementary movable plate in a durable
material, which must bear all data indicated
under section 3.1, to be positioned, if
necessary, in order to make the marks referred
to under section 3.1 readily visible to the
average person and easily accessible when the
engine is installed in a machine.
3.5
The coding of the engines in context with the
identification numbers must be such that it
allows for the indubitable determination of the
sequence of production.
3.6
Before leaving the production line the engines
must bear all markings.
3.7
The exact location of the engine markings shall
be declared in Schedule VII, Section 1.
SPECIFICATIONS AND TESTS
4.1
CI engines
4.1.1
General
The components liable to affect the emission of gaseous and
particulate pollutants shall be so designed, constructed and
assembled as to enable the engine, in normal use, despite the
vibrations to which it may be subjected, to comply with the
provisions of these regulations.
The technical measures taken by the manufacturer must be
such as to ensure that the mentioned emissions are effectively
limited, pursuant to these regulations, throughout the normal
life of the engine and under normal conditions of use. These
provisions are deemed to be met if the provisions of sections
4.1.2.1, 4.1.2.3 and 5.3.2.1 are respectively complied with.
If a catalytic converter and/or a particulates trap is used the
manufacturer must prove by durability tests, which he himself
may carry out in accordance with good engineering practice,
and by corresponding records, that these after-treatment
devices can be expected to function properly for the lifetime of
the engine. The records must be produced in compliance with
the requirements of section 5.2 and in particular with section
2.3. A corresponding warranty must be guaranteed to the
customer. Systematic replacement of the device, after a certain
running time of the engine, is permissible. Any adjustment,
repair, disassembly, cleaning, or replacement of engine
components or systems which is performed on a periodic basis
to prevent malfunction of the engine in context with the after-
treatment device, shall only be done to the extent that is
technologically necessary toassure proper functioning of the
emission control system. Accordingly scheduled maintenance
requirements must be included in the customer's manual, and
be covered by the warranty provisions mentioned above, and
be approved before an approval is granted. The corresponding
extract from the manual with respect to maintenance/
replacements of the treatment device(s), and to the warranty
conditions, must be included in the information document as
set out in Schedule II to these regulations.
All engines that expel exhaust gases mixed with water shall be
equipped with a connection in the engine exhaust system that is
located downstream of the engine and before any point at
which the exhaust contacts water (or any other cooling/
scrubbing medium) for the temporary attachment of gaseous or
particulate emissions sampling equipment. It is important that
the location of this connection allows a well mixed
representative sample of the exhaust. This connection shall be
internally threaded with standard pipe threads of a size not
larger than one-half inch, and shall be closed by a plug when
not in use (equivalent connections are allowed).
Specifications concerning the emissions of pollutants
The gaseous and particulate components emitted by the engine
submitted for testing shall be measured by the methods
described in Schedule VI.
Other systems or analysers may be accepted if they yield
equivalent results to the following reference systems
- for gaseous emissions measured in the raw exhaust, the
system shown in Figure 2 of Schedule VI,
- for gaseous emissions measured in the dilute exhaust of a full
flow dilution system, the system shown in Figure 3 of Schedule
VI,
- for particulate emissions, the full flow dilution system,
operating either with a separate filter for each mode or with the
single filter method, shown in Figure 13 of Schedule VI.
The determination of system equivalency shall be based on a
seven-test cycle (or larger) correlation study between the
system under consideration and one or more of the above
reference systems.
The equivalency criterion is defined as a ± 5 % agreement of
the averages of the weighted cycle emissions values. The cycle
to be used shall be that given in Schedule III, section 3.6.1.
For introduction of a new system into these regulations the
determination of equivalency shall be based upon the
calculation of repeatability and reproducibility, as described in
ISO 5725.
The emissions of the carbon monoxide, the emissions of
hydrocarbons, the emissions of the oxides of nitrogen and the
emissions of particulates obtained shall for stage I not exceed
the amount shown in the table below
Oxides of
Carbon
Net power (P)
Hydrocarbons
Particulates (PT)
nitrogen
monoxide (CO)
(HC) (g/kWh)
(g/kWh)
(NO x )(g/kWh)
(g/kWh)
130 ≤ P ≤ 560
5,0
1,3
9,2
0,54
5,0
1,3
9,2
0,70
6,5
1,3
9,2
0,85
The emission limits given in point M2 4.1.2.1 are engine-out
limits and shall be achieved before any exhaust after-treatment
device.
The emissions of the carbon monoxide, the emissions of
hydrocarbons, the emissions of the oxides of nitrogen and the
emissions of particulates obtained shall for stage II not exceed
amounts shown in the table below
Oxides of
Carbon
Net power (P)
Hydrocarbons
Particulates (PT)
nitrogen
monoxide (CO)
(HC) (g/kWh)
(g/kWh)
(NO x )(g/kWh)
(g/kWh)
130 ≤ P ≤ 560
3,5
1,0
6,0
0,2
5,0
1,0
6,0
0,3
5,5
1,3
7,0
0,4
5,5
1,5
8,0
0,8
The emissions of carbon monoxide, the emissions of the sum
of hydrocarbons and oxides of nitrogen and the emissions of
particulates shall for stage III A not exceed the amounts shown
in the table below
Engines for use in other applications than propulsion of inland
waterway vessels, locomotives and railcars
Sum of
hydrocarbons
Category
Carbon
and oxides of Particulates (PT)
Net power (P)
monoxide (CO)
nitrogen
(g/kWh)
(kW)
(g/kWh)
(HC+NO x )
(g/kWh)
H:130 ≤ P ≤ 560
3,5
4,0
0,2
I: 75 ≤ P < 130
5,0
4,0
0,3
J:37 ≤ P < 75
5,0
4,7
0,4
5,5
7,5
0,6
K:187≤ P<37
Engines for propulsion of inland waterway vessels
Sum of hydro-
Category: swept
Carbon
carbons and
volume/net
Particulates
monoxide
oxides of
power
(PT)
(CO)
nitrogen
(SV/P )
(g/kWh)
(g/kWh)
(HC+NO x )
(litres per
(g/kWh)
cylinder/kW)
V1:1 SV < 0,9
5,0
7,5
0,4
and P ≥ 37 kW
V1:2 0,9 ≤ SV <
5,0
7,2
0,3
1,2
V1:3 1,2 ≤ SV <
5,0
7,2
0,2
2,5
V1:4 2,5 ≤ SV <
5,0
7,2
0,2
V2:1 5 ≤ SV < 15
5,0
7,8
0,27
V2:2 15 ≤ SV <
5,0
8,7
0,50
20 and
V2:3 15 ≤ SV <
5,0
9,8
0,50
V2:4 20 ≤ SV <
5,0
9,8
0,50
V2:5 25 ≤ SV <
5,0
11,0
0,50
Engines for propulsion of locomotives
Sum of hydrocarbons and oxides
Carbon
Particulates (PT)
of nitrogen (HC+NO x )
Net power (P) monoxide (CO)
(g/kWh)
(g/kWh)
(g/kWh)
RL A: 130 kW P
3,5
4,0
0,2
Oxides of
Carbon
Hydrocarbons
Particulates (PT)
nitrogen
monoxide (CO) (HC)
(g/kWh)
(g/kWh)
(NO x )(g/kWh)
(g/kWh)
3,5,
0,5
6,0
0,2
RH A: Engines
with P> 2000 Kw
3,5,
0,4
7,4
0,2
Engines for propulsion of railcars
Sum of
hydrocarbons
Category
Carbon
and oxides of
Particulates (PT)
Net power (P)
monoxide (CO)
nitrogen
(g/kWh)
(kW)
(g/kWh)
(HC+NO x )
(g/kWh)
RL A: 130 kW <
3,5
4,0
0,2
P
The emissions of carbon monoxide, the emissions of
hydrocarbons and oxides of nitrogen (or their sum where
relevant) and the emissions of particulates shall, for stage III
B, not exceed the amounts shown in the table below
Engines for use in other applications than propulsion of
locomotives, railcars and inland waterway vessels
Particulates (PT)
Oxides of
Carbon
Hydrocarbons
(g/kWh)
nitrogen
Net power (P) monoxide (CO)
(HC) (g/kWh)
(NO x )(g/kWh)
(g/kWh)
L:130 ≤ P ≤ 560
3,5
4,0
2,0
0,025
M:75 ≤ P < 130
5,0
0,19
3,3
0,025
N: 56 ≤ P < 75
5,0
0,19
3,3
0,025
Particulates (PT)
Oxides of
Carbon
Hydrocarbons
(g/kWh)
nitrogen
Net power (P)
monoxide (CO)
(HC) (g/kWh)
(NO x )(g/kWh)
(g/kWh)
Sum of hydrocarbons and oxides
of nitrogen (HC+NO x )
(g/kWh)
P:37kW ≤ P <
5,0
4,7
0,025
Engines for propulsion of locomotives
Sum of
hydrocarbons
Category
Carbon
and oxides of Particulates (PT)
Net power (P)
monoxide (CO)
nitrogen
(g/kWh)
(kW)
(g/kWh)
(HC+NO x )
(g/kWh)
RC:130 kW < P
3,5
4,0
0,025
The emissions of carbon monoxide, the emissions of
hydrocarbons and oxides of nitrogen (or their sum where
relevant) and the emissions of particulates shall for stage IV
not exceed the amounts shown in the table below
Engines for use in other applications than propulsion of
locomotives, railcars and inland waterway vessels
Particulates (PT)
Oxides of
Carbon
Hydrocarbons
(g/kWh)
nitrogen
Net power (P) monoxide (CO)
(HC) (g/kWh)
(NO x )(g/kWh)
(g/kWh)
Q:130 kW≤ P ≤
3,5
0,19
0,4
0,025
R:56 kW≤ P ≤
5,0
0,19
0,4
0,025
The limit values in sections 4.1.2.4, 4.1.2.5 and 4.1.2.6 shall
include deterioration calculated in accordance with Schedule
III, Appendix 5.
In the case of limit values standards contained in sections
4.1.2.5 and 4.1.2.6, under all randomly selected load
conditions, belonging to a definite control area and with the
exception of specified engine operating conditions which are
not subject to such a provision, the emissions sampled during a
time duration as small as 30 s shall not exceed by more than
100 % the limit values of the above tables. Where reference is
made to this paragraph, Article 5a(1) to (4) and Article 7 of
Decision 1999/468/EC shall apply, having regard to the
provisions of Article 8 thereof.
Where, as defined according to Section 6 in conjunction with
Schedule II, Appendix 2, one engine family covers more than
one power band, the emission values of the parent engine (type
approval) and of all engine types within the same family (COP)
must meet the more stringent requirements of the higher power
band. The applicant has the free choice to restrict the definition
of engine families to single power bands, and to
correspondingly apply for certification.
SI engines
General
The components liable to affect the emission of gaseous
pollutants shall be so designed, constructed and assembled as
to enable the engine, in normal use, despite the vibrations to
which it may be subjected, to comply with the provisions of
these regulations.
The technical measures taken by the manufacturer must be
such as to ensure that the mentioned emissions are effectively
limited, pursuant to these regulations, throughout the normal
life of the engine and under normal conditions of use in
accordance with Schedule IV, Appendix 4.
Specifications concerning the emissions of pollutants
The gaseous components emitted by the engine submitted for
t e s t i n g s h a l l b e m e a s u r e d b y t h e m et h o d s d e s c r i b e d i n
Schedule VI (and shall include any after-treatment device).
Other systems or analysers may be accepted if they yield
equivalent results to the following reference systems
- for gaseous emissions measured in the raw exhaust, the
system shown in Figure 2 of Schedule VI,
- for gaseous emissions measured in the dilute exhaust of a full
flow dilution system, the system shown in figure 3 of Schedule
VI.
The emissions of carbon monoxide, the emissions of
hydrocarbons, the emissions of oxides of nitrogen and the sum
of hydrocarbons and oxides of nitrogen obtained shall for stage
I not exceed the amount shown in the table below
Stage I
Sum of
Oxides of
hydrocarbons
Carbon
nitrogen
and oxides of
Hydrocarbons
monoxide (CO)
(NO x )
nitrogen
(HC) (g/kWh)
(g/kWh)
(g/kWh)
(g/kWh)
HC+NO x
5,36
5,36
5,36
16,1
13,4
The emissions of carbon monoxide and the emissions of the
sum of hydrocarbons and oxides of nitrogen obtained shall for
stage II not exceed the amount shown in the table below
Stage II(*)
Sum of
Carbon
hydrocarbons
monoxide (CO)
and oxides of
Class
(g/kWh)
nitrogen
(g/kWh)
HC+NO x
SH:1
SH:2
SH:3
SN:1
50,0
SN:2
40,0
SN:3
16,1
SN:4
12,1
(*) See Schedule 4, Appendix 4: deterioration factors included.
The NO x emissions for all engine classes must not exceed 10 g/
kWh.
Notwithstanding the definition of ‘hand-held engine’ in
regulation 3 of these regulations two-stroke engines used to
power snowthrowers only have to meet SH:1, SH:2 or SH:3
standards.
Installation on the mobile machinery
The engine installation on the mobile machinery shall comply
with the restrictions set out in the scope of the type-approval.
Additionally the following characteristics in respect to the
approval of the engine always must be met
intake depression shall not exceed that specified for the
approved engine in Schedule II, Appendix 1 or 3 respectively;
exhaust back pressure shall not exceed that specified for the
approved engine in Schedule II, Appendix 1 or 3 respectively.
5. SPECIFICATION OF CONFORMITY OF PRODUCTION
ASSESSMENTS
With regard to the verification of the existence of satisfactory
arrangements and procedures for ensuring effective control of
production conformity before granting type-approval, the
approval authority must also accept the manufacturer's
registration to harmonized standard EN 29002 (whose scope
covers the engines concerned) or an equivalent accreditation
standard as satisfying the requirements. The manufacturer must
provide details of the registration and undertake to inform the
approval authority of any revisions to its validity or scope. In
order to verify that the requirements of section 4.2 are
continuously met, suitable controls of the production shall be
carried out.
The holder of the approval shall in particular
ensure existence of procedures for the effective control of the
quality of the product;
have access to the control equipment necessary for checking
the conformity to each approved type;
ensure that data of test results are recorded and that annexed
documents shall remain available for a period to be determined
in accordance with the approval authority;
analyse the results of each type of test, in order to verify and
ensure the stability of the engine characteristics, making
allowance for variations in the industrial production process;
ensure that any sampling of engines or components giving
evidence of non-conformity with the type of test considered
shall give rise to another sampling and another test. All the
necessary steps shall be taken to re-establish the conformity of
the corresponding production.
The competent authority which has granted approval may at
any time verify the conformity control methods applicable to
each production unit.
In every inspection, the test books and production survey
record shall be presented to the visiting inspector.
When the quality level appears unsatisfactory or when it seems
necessary to verify the validity of the data presented in
application of section 4.2, the following procedure is adopted
an engine is taken from the series and subjected to the test
described in Schedule III. The emissio ns of the carbon
monoxide, the emissions of the hydrocarbons, the emissions of
the oxides of nitrogen and the emissions of particulates
obtained shall not exceed the amounts shown in the table in
section 4.2.1, subject to the requirements of section 4.2.2, or
those shown in the table in section 4.2.3 respectively;
if t he engine taken from the series does not satisfy the
requirements of section 5.3.2.1 the manufacturer may ask for
measurements to be performed on a sample of engines of the
same specification taken from the series and including the
engine originally taken. The manufacturer shall determine the
size n of the sample in agreement with the technical service.
Engines other than the engine originally taken shall be
subjected to a test. The arithmetical mean (x Ä ) of the results
obtained with the sample shall then be determined for each
pollutant. The production of the series shall then be deemed to
confirm if the following condition is met
x þ k · S t ≤ L ( 11 )
where
L is the limit value laid down in section 4.2.1/4.2.3 for each
pollutant considered,
k is a statistical factor depending on n and given in the
following table
The approval authority or the technical service responsible for
verifying the conformity of production shall carry out tests on
engines which have been run-in partially or completely,
according to the manufacturer's specifications.
T he normal freq uency of inspections authorized by the
competent authority shall be one per year. If the requirements
of section 5.3.2 are not met, the competent authority shall
ensure that all necessary steps are taken to re-establish the
conformity of production as rapidly as possible.
where x is any one of the individual results obtained with the
sample n.
PARAMETERS DEFINING THE ENGINE FAMILY
The engine family may be defined by basic design parameters
which must be common to engines within the family. In some
cases there may be interaction of parameters. These effects
must also be taken into consideration to ensure that only
engines with similar exhaust emission characteristics are
included within an engine family.
In order that engines may be considered to belong to the same
engine family, the following list of basic parameters must be
common
Combustion cycle
- 2 cycle
- 4 cycle
Cooling medium
- air
- water
- oil
Individual cylinder displacement, within 85 % and 100 % of
the largest displacement within the engine family
Method of air aspiration
Fuel type
Diesel
Petrol.
Combustion chamber type/design
Valve and porting — configurations, size and number
Fuel system
For diesel
- pump-line injector
- in-line pump
- distributor pump
- single element
- unit injector.
For petrol
- carburettor
- port fuel injection
- direct injection.
Miscellaneous features
- Exhaust gas recirculation
- Water injection/emulsion
- Air injection
- Charge cooling system
- Ignition type (compression, spark).
Exhaust after-treatment
- Oxidation catalyst
- Reduction catalyst
- Three way catalyst
- Thermal reactor
- Particulate trap.
CHOICE OF THE PARENT ENGINE
The parent engine of the family shall be selected using the
primary criteria of the highest fuel delivery per stroke at the
declared maximum torque speed. In the event that two or more
engines share this primary criteria, the parent engine shall be
selected using the secondary criteria of highest fuel delivery
per stroke at rated speed. Under certain circumstances, the
approval authority may conclude that the worst case emission
rate of the family can best be characterized by testing a second
engine. Thus, the approval authority may select an additional
engine for test based upon features which indicate that it may
have the highest emission levels of the engines within that
family.
If engines within the family incorporate other variable features
which could be considered to affect exhaust emissions, these
features must also be identified and taken into account in the
selection of the parent engine.
TYPE APPROVAL REQUIREMENTS FOR STAGES IIIB
AND IV
This section shall apply to the type-approval of electronically
controlled engines, which uses electronic control to determine
both the quantity and timing of injecting fuel (hereafter
‘engine’). This section shall apply irrespective of the
techn olog y appl ied t o such en gines to com ply with the
emission limit values set out in sections 4.1.2.5 and 4.1.2.6 of
this Schedule.
Definitions
For the purpose of this section, the following definitions shall
apply
‘emission c ontro l strate gy ’ me ans a comb in at io n of an
emission control system with one base emission control
strategy and with one set of auxiliary emission control
strategies, incorporated into the overall design of an engine or
non-road mobile machinery into which the engine is installed.
‘reagent’ means any consumable or non-recoverable medium
required and used for the effective operation of the exhaust
after-treatment system.
General requirements
Requirements for base emission control strategy
The base emission control strategy, activated throughout the
speed and torque operating range of the engine, shall be
designed as to enable the engine to comply with the provisions
of these regulations.
Any base emission control strategy that can distinguish engine
operation between a standardised type approval test and other
operating conditions and subsequently reduce the level of
emission control when not operating under conditions
substantially included in the type approval procedure is
prohibited.
Requirements for auxiliary emission control strategy
An auxiliary emission control strategy may be used by an
engine or a non-road mobile machine, provided that the
auxiliary emission control strategy, when activated, modifies
the base emission control strategy in response to a specific set
of ambient and/or operating conditions but does not
permanently reduce the effectiveness of the emission control
system
where the auxiliary emission control strategy is activated
during the type approval test, sections 8.3.2.2 and 8.3.2.3 shall
not apply;
where the auxiliary emission control strategy is not activated
during the type approval test, it must be demonstrated that the
auxiliary emission control strategy is active only for as long as
required for the purposes identified in section 8.3.2.3.
The control conditions applicable to this section are all of the
following
a n a l t i t ud e no t e x c e e di n g 1 0 0 0 m e t r e s ( or e q ui v a l e n t
atmospheric pressure of 90 kPa);
an ambient temperature within the range 275 K to 303 K (2 °C
to 30 °C);
the engine coolant temperature above 343 K (70 °C).
Where the auxiliary emission control strategy is activated
when the engine is operating within the control conditions set
out in points (a), (b) and (c), the strategy shall only be
activated exceptionally.
An auxiliary emission control strategy may be activated in
particular for the following purposes
(a) by onboard signals, for protecting the engine (including
air-handling device protection) and/or non-road mobile
machine into which the engine is installed from damage;
(b)
for operational safety and strategies;
(c) for prevention of excessive emissions, during cold start or
warming-up, during shut-down;
(d) if used to trade-off the control of one regulated pollutant
under specific ambient or operating conditions, for maintaining
control of all other regulated pollutants, within the emission
limit values that are appropriate for the engine concerned. The
purpose is to compensate for naturally occurring phenomena in
a manner that provides acceptable control of all emission
constituents.
The manufacturer shall demonstrate to the technical service at
the time of the type-approval test that the operation of any
auxiliary emission strategy complies with the provisions of
section 8.3.2. The demonstration shall consist of an evaluation
of the documentation referred to in section 8.3.3.
Any operation of an auxiliary emission control strategy not
compliant with section 8.3.2 is prohibited.
Documentation requirements
The manufacturer shall provide an information folder
accompanying the application for type-approval at the time of
submission to the technical service, which ensures access to
any element of design and emission control strategy and the
means by which the auxiliary strategy directly or indirectly
controls the output variables. The information folder shall be
made available in two parts
(a) the documentation package, annexed to the application
for type-approval, shall include a full overview of the emission
control strategy. Evidence shall be provided that all outputs
permitted by a matrix, obtained from the range of control of the
individual unit inputs, have been identified. This evidence
shall be attached to the information folder as referred to in
Schedule II;
(b) the additional material, presented to the technical service
but not annexed to the application for type-approval, shall
include all the modified parameters by any auxiliary emission
control strategy and the boundary conditions under which this
strategy operates and in particular
(i) a description of the control logic and of timing
strategies and switch points, during all modes of operation
for the fuel and other essential systems, resulting in
effective emissions control (such as exhaust gas
recirculation system (EGR) or reagent dosing);
(ii) a justification for the use of any auxiliary
emission control strategy applied to the engine,
accompanied by material and test data, demonstrating the
effect on exhaust emissions. This justification may be
based on test data, sound engineering analysis, or a
combination of both;
(iii) a detailed description of algorithms or sensors
(where applicable) used for identifying, analysing, or
diagnosing incorrect operation of the NO x control system;
(vi) the tolerance used to satisfy the requirements in
section 8.4.7.2, regardless of the used means.
The additional material referred to in point (b) of section
8.3.3.1 shall be treated as strictly confidential. It shall be made
available to the type-approval authority on request. The type-
approval authority shall treat this material as confidential.
Requirements to ensure correct operation of NO x control
measures
The manufacturer shall provide information that fully
describes the functional operational characteristics of the NO x
control measures using the documents set out in section 2 of
Appendix 1 to Schedule II and in section 2 of Appendix 3 to
Schedule II.
If the emission control system requires a reagent, the
characteristics of that reagent, including the type of reagent,
information on concentration when the reagent is in solution,
operational temperature conditions and reference to
international standards for composition and quality must be
specified by the manufacturer, in section 2.2.1.13 of Appendix
1 and in section 2.2.1.13 of Appendix 3 to Schedule II.
The engine emission control strategy shall be operational under
all environmental conditions regularly pertaining in the
t e r r i t o r y o f t h e C o m m u n i t y, e s p e c i a l l y a t l o w a m b i e n t
temperatures.
The manufacturer shall demonstrate that the emission of
ammonia during the applicable emission test cycle of the type
approval procedure, when a reagent is used, does not exceed a
mean value of 25 ppm.
If separate reagent containers are installed on or connected to a
non-road mobile machine, means for taking a sample of the
reagent inside the containers must be included. The sampling
point must be easily accessible without requiring the use of any
specialised tool or device.
Use and maintenance requirements
The type approval shall be made conditional, in accordance
with regulation 5(3), upon providing to each operator of non-
road mobile machinery written instructions comprising the
following
(a) detailed warnings, explaining possible malfunctions
generated by incorrect operation, use or maintenance of the
installed engine, accompanied by respective rectification
measures;
(b) detailed warnings on the incorrect use of the machine
resulting in possible malfunctions of the engine, accompanied
by respective rectification measures;
(c) information on the correct use of the reagent,
accompanied by an instruction on refilling the reagent between
normal maintenance intervals;
(d) a clear warning, that the type-approval certificate, issued
for the type of engine concerned, is valid only when all of the
following conditions are met
(i) the engine is operated, used and maintained in
accordance with the instructions provided;
(ii) prompt action has been taken for rectifying
incorrect operation, use or maintenance in accordance
with the rectification measures indicated by the warnings
referred to in point (a) and (b);
(iii) no deliberate misuse of the engine has taken
place, in particular deactivating or not maintaining an
EGR or reagent dosing system.
The instructions shall be written in a clear and non-technical
manner using the same language as is used in the operator’s
manual on non-road mobile machinery or engine.
Reagent control (where applicable)
The type approval shall be made conditional, in accordance
with the provisions of section 3 of regulation 5, upon providing
indicators or other appropriate means, according to the
configuration of the non-road mobile machinery, informing the
operator on
(a) the amount of reagent remaining in the reagent storage
container and by an additional specific signal, when the
remaining reagent is less than 10 % of the full container ’s
capacity;
(b) when the reagent container becomes empty, or almost
empty;
(c) when the reagent in the storage tank does not comply with
the characteristics declared and recorded in section 2.2.1.13 of
Appendix 1 and section 2.2.1.13 of Appendix 3 to Schedule II,
according to the installed means of assessment.
(d)
when the dosing activity of the reagent is interrupted, in
cases other than those executed by the engine ECU or the
dosing controller, reacting to engine operating conditions
where the dosing is not required, provided that these operating
conditions are made available to the type approval authority.
By the choice of the manufacturer the requirements of reagent
compliance with the declared characteristics and the associated
NO x emission tolerance shall be satisfied by one of the
following means
(a)
direct means, such as the use of a reagent quality sensor.
(b)
indirect means, such as the use of a NO x sensor in the
exhaust to evaluate reagent effectiveness.
(c)
any other means, provided that its efficacy is at least
equal to the one resulting by the use of the means of points (a)
or (b) and the main requirements of this section are maintained.
Schedule II
INFORMATION DOCUMENT No. …
relating to type-approval and referring to measures against the emission of gaseous and
particulate pollutants from internal combustion engines to be installed in non-road mobile
machinery
(Directive 97/68/EC as last amended by Directive ../…/EC)
Schedule III
TEST PROCEDURE FOR C.I. ENGINES
1. INTRODUCTION
This Schedule describes the method of determining emissions of gaseous and
particulate pollutants from the engine to be tested.
The following test cycles shall apply
the NRSC (non-road steady cycle) appropriate for the equipment
specification which shall be used for the measurement of the
emissions of carbon monoxide, hydrocarbons, oxides of nitrogen and
particulates for stages I, II, IIIA, IIIB and IV of engines described in
points (i) and (ii) of section 1.A of Schedule I, and
the NRTC (non-road transient cycle) which shall be used for the
measurement of the emissions of carbon monoxide, hydrocarbons,
oxides of nitrogen and particulates for stages IIIB and IV of engines
described in point (i) of section 1.A of Schedule I,
for engines intended to be used in inland waterway vessels the ISO
test procedure as specified by ISO 8178-4:2002 and IMO ( 2 )
MARPOL ( 3 ) 73/78, Schedule VI (NO x Code) shall be used,
for engines intended for propulsion of railcars an NRSC shall be used
for the measurement of gaseous and particulate pollutants for stage
IIIA and for stage IIIB,
for engines intended for propulsion of locomotives an NRSC shall be
used for the measurement of gaseous and particulate pollutants for
stage IIIA and for stage IIIB.
The test shall be carried out with the engine mounted on a test bench and
connected to a dynamometer.
Measurement principle
The engine exhaust emissions to be measured include the gaseous components
(carbon monoxide, total hydrocarbons and oxides of nitrogen), and the
particulates. Additionally, carbon dioxide is often used as a tracer gas for
determining the dilution ratio of partial and full flow dilution systems. Good
engineering practice recommends the general measurement of carbon dioxide
as an excellent tool for the detection of measurement problems during the test
run.
IMO: International Maritime Organisation.
3 MARPOL: International Convention for the Prevention of Pollution from Ships.
NRSC test
During a prescribed sequence of operating conditions, with the engines
warmed up, the amounts of the above exhaust emissions shall be examined
continuously by taking a sample from the raw exhaust gas. The test cycle
consists of a number of speed and torque (load) modes, which cover the typical
operating range of diesel engines. During each mode, the concentration of each
gaseous pollutant, exhaust flow and power output shall be determined, and the
measured values weighted. The particulate sample shall be diluted with
conditioned ambient air. One sample over the complete test procedure shall be
taken and collected on suitable filters.
Alternatively, a sample shall be taken on separate filters, one for each mode,
and cycle-weighted results computed.
The grams of each pollutant emitted per kilowatt-hour shall be calculated as
described in Appendix 3 to this Schedule.
NRTC test
The prescribed transient test cycle, based closely on the operating conditions
of diesel engines installed in non-road machinery, is run twice
the first time (cold start) after the engine has soaked to room
temperature and the engine coolant and oil temperatures, after
treatment systems and all auxiliary engine control devices are
stabilised between 20 and 30 °C,
the second time (hot start) after a twenty-minute hot soak that
commences immediately after the completion of the cold start cycle.
During this test sequence the above pollutants shall be examined. The test
sequence consists of a cold start cycle following natural or forced cool-down
of the engine, a hot soak period and a hot start cycle, resulting in a composite
emissions calculation. Using the engine torque and speed feedback signals of
the engine dynamometer, the power shall be integrated with respect to the time
of the cycle, resulting in the work produced by the engine over the cycle. The
concentrations of the gaseous components shall be determined over the cycle,
either in the raw exhaust gas by integration of the analyser signal in
accordance with Appendix 3 to this Schedule, or in the diluted exhaust gas of a
CVS full-flow dilution system by integration or by bag sampling in accordance
with Appendix 3 to this Schedule. For particulates, a proportional sample shall
be collected from the diluted exhaust gas on a specified filter by either partial
flow dilution or full-flow dilution. Depending on the method used, the diluted
or undiluted exhaust gas flow rate shall be determined over the cycle to
calculate the mass emission values of the pollutants. The mass emission values
shall be related to the engine work to give the grams of each pollutant emitted
per kilowatt-hour.
Emissions (g/kWh) shall be measured during both the cold and hot start cycles.
Composite weighted emissions shall be computed by weighting the cold start
results 10 % and the hot start results 90 %. Weighted composite results shall
meet the limits.
2. TEST CONDITIONS
General requirements
All volumes and volumetric flow rates shall be related to 273 K (0 o C) and
101,3 kPa.
Engine test conditions
The absolute temperature T a of the engine intake air expressed in Kelvin, and
the dry atmospheric pressure p s , expressed in kPa, shall be measured, and the
parameter f a shall be determined according to the following provisions
Naturally aspirated and mechanically supercharged engines
Turbocharged engine with or without cooling of the intake air
Test validity
For a test to be recognized as valid, the parameter f a shall be such that
0; 96 ≤ f a ≤ 1; 06
Engines with charge air cooling
The charge air temperature shall be recorded and, at the declared rated speed
and full load, shall be within ± 5 K of the maximum charge air temperature
specified by the manufacturer. The temperature of the cooling medium shall be
at least 293 K (20 °C).
If a test shop system or external blower is used, the charge air temperature
shall be set to within ± 5 K of the maximum charge air temperature specified
by the manufacturer at the speed of the declared maximum power and full
load. Coolant temperature and coolant flow rate of the charge air cooler at the
above set point shall not be changed for the whole test cycle. The charge air
cooler volume shall be based upon good engineering practice and typical
vehicle/machinery applications.
Optionally, the setting of the charge air cooler may be done in accordance with
SAE J 1937 as published in January 1995.
Engine air inlet system
The test engine shall be equipped with an air inlet system presenting an air
inlet restriction within ± 300 Pa of the value specified by the manufacturer for
a clean air cleaner at the engine operating conditions as specified by the
manufacturer, which result in maximum air flow. The restrictions are to be set
at rated speed and full load. A test shop system may be used, provided it
duplicates actual engine operating conditions.
Engine exhaust system
The test engine shall be equipped with an exhaust system with exhaust back
pressure within ± 650 Pa of the value specified by the manufacturer at the
engine operating conditions resulting in maximum declared power.
If the engine is equipped with an exhaust after-treatment device, the exhaust
pipe shall have the same diameter as found in-use for at least four pipe
diameters upstream to the inlet of the beginning of the expansion section
containing the after-treatment device. The distance from the exhaust manifold
flange or turbocharger outlet to the exhaust after- treatment device shall be the
same as in the machine configuration or within the distance specifications of
the manufacturer. The exhaust backpressure or restriction shall follow the
same criteria as above, and may be set with a valve. The after-treatment
container may be removed during dummy tests and during engine mapping,
and replaced with an equivalent container having an inactive catalyst support.
Cooling system
An engine cooling system with sufficient capacity to maintain the engine at
normal operating temperatures prescribed by the manufacturer.
Lubricating oil
Specifications of the lubricating oil used for the test shall be recorded and
presented with the results of the test.
Test fuel
The fuel shall be the reference fuel specified in Schedule V.
The cetane number and the sulphur content of the reference fuel used for test
shall be recorded at sections 1.1.1 and 1.1.2 respectively of Schedule VII,
Appendix 1.
The fuel temperature at the injection pump inlet shall be 306- 316 K (33-43
o
C).
3. TEST RUN (NRSC TEST)
Determination of dynamometer settings
The basis of specific emissions measurement is uncorrected brake power
according to ISO 14396: 2002.
Certain auxiliaries, which are necessary only for the operation of the machine
and may be mounted on the engine, should be removed for the test. The
following incomplete list is given as an example
air compressor for brakes
power steering compressor
air conditioning compressor
pumps for hydraulic actuators.
Where auxiliaries have not been removed, the power absorbed by them at the
test speeds shall be determined in order to calculate the dynamometer settings,
except for engines where such auxiliaries form an integral part of the engine
(e.g. cooling fans for air cool engines).
The settings of inlet restriction and exhaust pipe backpressure shall be adjusted
to the manufacturer's upper limits, in accordance with sections 2.3. and 2.4.
The maximum torque values at the specified test speeds shall be determined by
experimentation in order to calculate the torque values for the specified test
modes. For engines which are not designed to operate over a range on a full
load torque curve, the maximum torque at the test speeds shall be declared by
the manufacturer.
The engine setting for each test mode shall be calculated using the formula
If the ratio,
The value of P AE may be verified by the technical authority granting type
approval.
Preparation of the sampling filters
At least one hour before the test, each filter (pair) shall be placed in a closed,
but unsealed, petri dish and placed in a weighing chamber for stabilization. At
the end of the stabilization period, each filter (pair) shall be weighed and the
tare weight shall be recorded. The filter (pair) shall then be stored in a closed
petri dish or filter holder until needed for testing. If the filter (pair) is not used
within eight hours of its removal from the weighing chamber, it must be
reweighed before use.
Installation of the measuring equipment
The instrumentation and sample probes shall be installed as required. When
using a full flow dilution system for exhaust gas dilution, the tailpipe shall be
connected to the system.
Starting the dilution system and engine
The dilution system and the engine shall be started and warmed up until all
temperatures and pressures have stabilized at full load and rated speed (section
3.6.2).
Adjustment of the dilution ratio
The particulate sampling system shall be started and running on bypass for the
single filter method (optional for the multiple filter method). The particulate
background level of the dilution air may be determined by passing dilution air
through the particulate filters. If filtered dilution air is used, one measurement
may be done at any time prior to, during, or after the test. If the dilution air is
not filtered, the measurement must be done on one sample taken for the
duration of the test.
The dilution air shall be set to obtain a filter face temperature between 315 K
(42 °C) and 325 K (52 °C) at each mode. The total dilution ratio shall not be
less than four.
NOTE: For steady-state procedure, the filter temperature may be kept at or
below the maximum temperature of 325 K (52 °C) instead of respecting the
temperature range of 42 °C to 52 °C.
For the single and multiple filter methods, the sample mass flow rate through
the filter shall be maintained at a constant proportion of the dilute exhaust
mass flow rate for full flow systems for all modes. This mass ratio shall be
within ± 5 % with respect to the averaged value of the mode, except for the
first 10 seconds of each mode for systems without bypass capability. For
partial flow dilution systems with single filter method, the mass flow rate
through the filter shall be constant within ± 5 % with respect to the averaged
value of the mode, except for the first 10 seconds of each mode for systems
without bypass capability.
For CO 2 or NO x concentration controlled systems, the CO 2 or NO x content of
the dilution air must be measured at the beginning and at the end of each test.
The pre and post test background CO 2 or NO x concentration measurements of
the dilution air must be within 100 ppm or 5 ppm of each other, respectively.
When using a dilute exhaust gas analysis system, the relevant background
concentrations shall be determined by sampling dilution air into a sampling
bag over the complete test sequence.
Continuous (non-bag) background concentration may be taken at the minimum
of three points, at the beginning, at the end, and a point near the middle of the
cycle and averaged. At the manufacturer's request background measurements
may be omitted.
Checking the analysers
The emission analysers shall be set at zero and spanned.
Test cycle
Equipment specification according to section 1.A of Schedule I
S p e c i f i c a t i o n A
For engines covered by points (i) and (iv) of section 1.A of Schedule I, the
following 8-mode cycle ( 4 ) shall be followed in dynamometer operation on the
test engine
Identical with D2 cycle as described in paragraph 8.4.1 of the ISO 8178-4: 2002(E) standard.
S p e c i f i c a t i o n B
For engines covered by point (ii) of section 1.A of Schedule I, the following 5-
mode cycle ( 5 ) shall be followed in dynamometer operation on the test engine
Identical with D2 cycle as described in paragraph 8.4.1 of the ISO 8178-4: 2002(E) standard.
The load figures are percentage values of the torque corresponding to the
prime power rating defined as the maximum power available during a variable
power sequence, which may be run for an unlimited number of hours per year,
between stated maintenance intervals and under the stated ambient conditions,
the maintenance being carried out as prescribed by the manufacturer.
S p e c i f i c a t i o n C
For propulsion engines ( 6 ) intended to be used in inland waterway vessels the
ISO test procedure as specified by ISO 8178-4:2002 and IMO MARPOL 73/
78, Schedule VI (NO x Code) shall be used.
Propulsion engines that operate on a fixed-pitch propeller curve shall be tested
on a dynamometer using the following 4-mode steady-state cycle ( 7 )
developed to represent in-use operation of commercial marine diesel engines.
Fixed speed inland waterway propulsion engines with variable pitch or
electrically coupled propellers shall be tested on a dynamometer using the
following 4-mode steady-state cycle ( 8 ) characterised by the same load and
weighting factors as the above cycle, but with engine operated in each mode at
rated speed
Constant-speed auxiliary engines must be certified to the ISO D2 duty cycle, i.e. the 5- mode steady-state cycle
specified in section 3.7.1.2, while variable-speed auxiliary engines must be certified to the ISO C1 duty cycle,
i.e. the 8-mode steady-state cycle specified in section 3.7.1.1.
7 Identical with E3 cycle as described in Sections 8.5.1, 8.5.2 and 8.5.3 of the ISO 8178-4: 2002(E) standard. The
four modes lie on an average propeller curve based on in-use measurements.
Identical with E2 cycle as described in Sections 8.5.1, 8.5.2 and 8.5.3 of the ISO 8178-4: 2002(E) standard.
S p e c i f i c a t i o n D
For engines covered by point (v) of section 1.A of Schedule I, the following 3-
mode cycle ( 9 ) shall be followed in dynamometer operation on the test engine
Conditioning of the engine
Warming up of the engine and the system shall be at maximum speed and
torque in order to stabilize the engine parameters according to the
recommendations of the manufacturer.
Note: The conditioning period should also prevent the influence of deposits
from a former test in the exhaust system. There is also a required period of
stabilization between test points which has been included to minimise point to
point influences.
Test sequence
The test sequence shall be started. The test shall be performed in the order of
the mode numbers as set out above for the test cycles.
9 Identical with F cycle of ISO 8178-4: 2002(E) standard.
During each mode of the given test cycle after the initial transition period, the
specified speed shall be held to within ± 1 % of rated speed or ± 3 min-1,
whichever is greater, except for low idle which shall be within the tolerances
declared by the manufacturer. The specified torque shall be held so that the
average over the period during which the measurements are being taken is
within ± 2 % of the maximum torque at the test speed.
For each measuring point a minimum time of 10 minutes is necessary. If for
the testing of an engine, longer sampling times are required for reasons of
obtaining sufficient particulate mass on the measuring filter the test mode
period can be extended as necessary.
The mode length shall be recorded and reported.
The gaseous exhaust emission concentration values shall be measured and
recorded during the last three minutes of the mode.
The particulate sampling and the gaseous emission measurement should not
commence before engine stabilisation, as defined by the manufacturer, has
been achieved and their completion must be coincident.
The fuel temperature shall be measured at the inlet to the fuel injection pump
or as specified by the manufacturer, and the location of measurement recorded.
Analyser response
The output of the analysers shall be recorded on a strip chart recorder or
measured with an equivalent data acquisition system with the exhaust gas
flowing through the analysers at least during the last three minutes of each
mode. If bag sampling is applied for the diluted CO and CO 2 measurement
(see Appendix 1, section 1.4.4), a sample shall be bagged during the last three
minutes of each mode, and the bag sample analysed and recorded.
Particulate sampling
The particulate sampling can be done either with the single filter method or
with the multiple filter method (Appendix 1, section 1.5). Since the results of
the methods may differ slightly, the method used must be declared with the
results.
For the single filter method the modal weighting factors specified in the test
cycle procedure shall be taken into account during sampling by adjusting
sample flow rate and/or sampling time, accordingly.
Sampling must be conducted as late as possible within each mode. The
sampling time per mode must be at least 20 seconds for the single filter method
and at least 60 seconds for the multi-filter method. For systems without bypass
capability, the sampling time per mode must be a least 60 seconds for single
and multiple filter methods.
Engine conditions
The engine speed and load, intake air temperature, fuel flow and air or exhaust
gas flow shall be measured for each mode once the engine has been stabilized.
If the measurement of the exhaust gas flow or the measurement of combustion
air and fuel consumption is not possible, it can be calculated using the carbon
and oxygen balance method (see Appendix 1, section 1.2.3).
Any additional data required for calculation shall be recorded (see Appendix 3,
sections 1.1 and 1.2).
Re-checking the analysers
After the emission test a zero gas and the same span gas will be used for re-
checking. The test will be considered acceptable if the difference between the
two measuring results is less than 2 %.
4. TEST RUN (NRTC TEST)
Introduction
The non-road transient cycle (NRTC) is listed in Schedule III, Appendix 4 as a
second-by-second sequence of normalised speed and torque values applicable
to all diesel engines covered by these regulations. In order to perform the test
on an engine test cell, the normalised values shall be converted to the actual
values for the individual engine under test, based on the engine mapping curve.
This conversion is referred to as denormalisation, and the test cycle developed
is referred to as the reference cycle of the engine to be tested. With these
reference speed and torque values, the cycle shall be run on the test cell, and
the feedback speed and torque values recorded. In order to validate the test run,
a regression analysis between reference and feedback speed and torque values
shall be conducted upon completion of the test.
The use of defeat devices or irrational control or irrational emission control
strategies shall be prohibited
Engine mapping procedure
When generating the NRTC on the test cell, the engine shall be mapped before
running the test cycle to determine the speed vs torque curve.
Determination of the mapping speed range
The minimum and maximum mapping speeds are defined as follows
Minimum mapping speed = idle speed
Maximum mapping speed = n hi x 1,02 or speed where full load torque drops
off to zero, whichever is lower (where n hi is the high speed, defined as the
highest engine speed where 70 % of the rated power is delivered).
Engine mapping curve
The engine shall be warmed up at maximum power in order to stabilise the
engine parameters according to the recommendation of the manufacturer and
good engineering practice. When the engine is stabilised, the engine mapping
shall be performed according to the following procedures.
T r a n s i e n t m a p
(a) The engine shall be unloaded and operated at idle speed.
(b) The engine shall be operated at full load setting of the injection pump at
minimum mapping speed.
(c) The engine speed shall be increased at an average rate of 8 ± 1 min-1/s
from minimum to maximum mapping speed. Engine speed and torque points
shall be recorded at a sample rate of at least one point per second.
S t e p m a p
(a) The engine shall be unloaded and operated at idle speed.
(b) The engine shall be operated at full load setting of the injection pump at
minimum mapping speed.
(c) While maintaining full load, the minimum mapping speed shall be
maintained for at least 15 s, and the average torque during the last 5 s shall be
recorded. The maximum torque curve from minimum to maximum mapping
speed shall be determined in no greater than 100 ± 20/min speed increments.
Each test point shall be held for at least 15 s, and the average torque during
the last 5 s shall be recorded.
Mapping curve generation
All data points recorded under section 4.2.2 shall be connected using linear
interpolation between points. The resulting torque curve is the mapping curve
and shall be used to convert the normalised torque values of the engine
dynamometer schedule of Schedule IV into actual torque values for the test
cycle, as described in section 4.3.3.
Alternate mapping
If a manufacturer believes that the above mapping techniques are unsafe or
unrepresentative for any given engine, alternate mapping techniques may be
used. These alternate techniques must satisfy the intent of the specified
mapping procedures to determine the maximum available torque at all engine
speeds achieved during the test cycles. Deviations from the mapping
techniques specified in this section for reasons of safety or representativeness
shall be approved by the parties involved along with the justification for their
use. In no case, however, shall the torque curve be run by descending engine
speeds for governed or turbocharged engines.
Replicate tests
An engine need not be mapped before each and every test cycle. An engine
must be remapped prior to a test cycle if
-
an unreasonable amount of time has transpired since the last map, as
determined by engineering judgement, or,
-
-
physical changes or recalibrations have been made to the engine,
which may potentially affect engine performance.
-
Generation of the reference test cycle
Reference speed
The reference speed (n ref ) corresponds to the 100% normalised speed values
specified in the engine dynamometer schedule of Appendix 4 of Schedule III.
The actual engine cycle resulting from denormalisation to the reference speed
depends largely on selection of the proper reference speed. The reference
speed shall be determined by the following formula
n ref = low speed + 0,95 x (high speed – low speed)
(the high speed is the highest engine speed where 70 % of the rated power is
delivered, while the low speed is the lowest engine speed where 50 % of the
rated power is delivered).
If the measured reference speed is within +/– 3 % of the reference speed as
declared by the manufacturer, the declared reference speed may be used for the
emissions test. If the tolerance is exceeded, the measured reference speed shall
be used for the emissions test ( 10 ).
Denormalisation of engine speed
The speed shall be denormalised using the following equation
Denormalisation of engine torque
The torque values in the engine dynamometer schedule of Schedule III,
Appendix 4 are normalised to the maximum torque at the respective speed.
The torque values of the reference cycle shall be denormalised, using the
mapping curve determined according to Section 4.2.2, as follows
for the respective actual speed as determined in Section 4.3.2.
Example of denormalisation procedure
As an example, the following test point shall be denormalised
% speed = 43 %
% torque = 82 %
Given the following values
reference speed = 2 200/min
idle speed = 600/min
results in
With the maximum torque of 700 Nm observed from the mapping curve at 1
288/min
This is consistent with the ISO 8178-11:2006 standard.
Dynamometer
When using a load cell, the torque signal shall be transferred to the engine axis
and the inertia of the dyno shall be considered. The actual engine torque is the
torque read on the load cell plus the moment of inertia of the brake multiplied
by the angular acceleration. The control system has to perform this calculation
in real time.
If the engine is tested with an eddy-current dynamometer, it is recommended
that the number of points, where the difference is smaller than – 5 % of the
peak torque, does not exceed 30 (where T sp is the demanded torque, is the
derivative of the engine speed, is the rotational inertia of the eddycurrent
dynamometer).
Emissions test run
The following flow chart outlines the test sequence
One or more practice cycles may be run as necessary to check engine, test cell
and emissions systems before the measurement cycle.
Preparation of the sampling filters
At least one hour before the test, each filter shall be placed in a petri dish,
which is protected against dust contamination and allows air exchange, and
placed in a weighing chamber for stabilisation. At the end of the stabilisation
period, each filter shall be weighed and the weight shall be recorded. The filter
shall then be stored in a closed petri dish or sealed filter holder until needed for
testing. The filter shall be used within eight hours of its removal from the
weighing chamber. The tare weight shall be recorded.
Installation of the measuring equipment
The instrumentation and sample probes shall be installed as required. The
tailpipe shall be connected to the full-flow dilution system, if used.
Starting the dilution system
The dilution system shall be started. The total diluted exhaust gas flow of a
full-flow dilution system or the diluted exhaust gas flow through a partial flow
dilution system shall be set to eliminate water condensation in the system, and
to obtain a filter face temperature between 315 K (42 °C) and 325 K (52 °C).
The particulate sampling system shall be started and run on by-pass. The
particulate background level of the dilution air may be determined by sampling
the dilution air prior to entrance of the exhaust into the dilution tunnel. It is
preferred that background particulate sample be collected during the transient
cycle if another PM sampling system is available. Otherwise, the PM sampling
system used to collect transient cycle PM can be used. If filtered dilution air is
used, one measurement may be done prior to or after the test. If the dilution air
is not filtered, measurements should be carried out prior to the beginning and
after the end of the cycle and the values averaged.
Checking the analysers
The emission analysers shall be set at zero and spanned. If sample bags are
used, they shall be evacuated.
Cool-down requirements
A natural or forced cool-down procedure may be applied. For forced cool-
down, good engineering judgement shall be used to set up systems to send
cooling air across the engine, to send cool oil through the engine lubrication
system, to remove heat from the coolant through the engine cooling system,
and to remove heat from an exhaust after-treatment system. In the case of a
forced after-treatment cool down, cooling air shall not be applied until the
after-treatment system has cooled below its catalytic activation temperature.
Any cooling procedure that results in unrepresentative emissions is not
permitted.
The cold start cycle exhaust emission test may begin after a cool-down only
when the engine oil, coolant and after- treatment temperatures are stabilised
between 20 °C and 30 °C for a minimum of 15 minutes.
Cycle run
C o l d s t a r t c y c l e
The test sequence shall commence with the cold start cycle at the completion
of the cool-down when all the requirements specified in section 4.5.6 are met.
The engine shall be started according to the starting procedure recommended
by the manufacturer in the owner's manual, using either a production starter
motor or the dynamometer.
As soon as it is determined that the engine is started, start a ‘free idle’ timer.
Allow the engine to idle freely with no-load for 23 ± 1 s. Begin the transient
engine cycle such that the first non-idle record of the cycle occurs at 23 ± 1 s.
The free idle time is included in the 23 ± 1 s.
The test shall be performed according to the reference cycle as set out in
Schedule III, Appendix 4. Engine speed and torque command set points shall
be issued at 5 Hz (10 Hz recommended) or greater. The set points shall be
calculated by linear interpolation between the 1 Hz set points of the reference
cycle. Feedback engine speed and torque shall be recorded at least once every
second during the test cycle, and the signals may be electronically filtered.
A n a l y s e r r e s p o n s e
At the start of the engine the measuring equipment shall be started,
simultaneously
-
start collecting or analysing dilution air, if a full flow dilution system
is used,
-
-
start collecting or analysing raw or diluted exhaust gas, depending on
the method used,
-
-
start measuring the amount of diluted exhaust gas and the required
temperatures and pressures,
-
-
start recording the exhaust gas mass flow rate, if raw exhaust gas
analysis is used,
-
-
start recording the feedback data of speed and torque of the
dynamometer.
-
If raw exhaust measurement is used, the emission concentrations (HC, CO and
NO x ) and the exhaust gas mass flow rate shall be measured continuously and
stored with at least 2 Hz on a computer system. All other data may be recorded
with a sample rate of at least 1 Hz. For analogue analysers the response shall
be recorded, and the calibration data may be applied online or offline during
the data evaluation.
If a full flow dilution system is used, HC and NO x shall be measured
continuously in the dilution tunnel with a frequency of at least 2 Hz. The
average concentrations shall be determined by integrating the analyser signals
over the test cycle. The system response time shall be no greater than 20 s, and
shall be coordinated with CVS flow fluctuations and sampling time/test cycle
offsets, if necessary. CO and CO 2 shall be determined by integration or by
analysing the concentrations in the sample bag collected over the cycle. The
concentrations of the gaseous pollutants in the dilution air shall be determined
by integration or by collection in the background bag. All other parameters that
need to be measured shall be recorded with a minimum of one measurement
per second (1 Hz).
P a r t i c u l a t e s a m p l i n g
At the start of the engine the particulate sampling system shall be switched
from by-pass to collecting particulates.
If a partial flow dilution system is used, the sample pump(s) shall be adjusted
so that the flow rate through the particulate sample probe or transfer tube is
maintained proportional to the exhaust mass flow rate.
If a full flow dilution system is used, the sample pump(s) shall be adjusted so
that the flow rate through the particulate sample probe or transfer tube is
maintained at a value within ± 5 % of the set flow rate. If flow compensation
(i.e. proportional control of sample flow) is used, it must be demonstrated that
the ratio of main tunnel flow to particulate sample flow does not change by
more than ± 5 % of its set value (except for the first 10 seconds of sampling).
NOTE: For double dilution operation, sample flow is the net difference
between the flow rate through the sample filters and the secondary dilution
airflow rate.
The average temperature and pressure at the gas meter(s) or flow
instrumentation inlet shall be recorded. If the set flow rate cannot be
maintained over the complete cycle (within ± 5 %) because of high particulate
loading on the filter, the test shall be voided. The test shall be rerun using a
lower flow rate and/or a larger diameter filter.
E n g i n e s t a l l i n g d u r i n g t h e c o l d s t a r t t e s t c y c l e
If the engine stalls anywhere during the cold start test cycle, the engine shall be
preconditioned, then the cool-down procedure repeated; finally the engine
shall be restarted, and the test repeated. If a malfunction occurs in any of the
required test equipment during the test cycle, the test shall be voided.
O p e r a t i o n s a f t e r c o l d s t a r t c y c l e
At the completion of the cold start cycle of the test, the measurement of the
exhaust gas mass flow rate, the diluted exhaust gas volume, the gas flow into
the collecting bags and the particulate sample pump shall be stopped. For an
integrating analyser system, sampling shall continue until system response
times have elapsed.
The concentrations of the collecting bags, if used, shall be analysed as soon as
possible and in any case not later than 20 minutes after the end of the test
cycle.
After the emission test, a zero gas and the same span gas shall be used for re-
checking the analysers. The test will be considered acceptable if the difference
between the pre-test and post-test results is less than 2 % of the span gas value.
The particulate filters shall be returned to the weighing chamber no later than
one hour after completion of the test. They shall be conditioned in a petri dish,
which is protected against dust contamination and allows air exchange, for at
least one hour, and then weighed. The gross weight of the filters shall be
recorded.
H o t s o a k
Immediately after the engine is turned off, the engine cooling fan(s) shall be
turned off if used, as well as the CVS blower (or disconnect the exhaust system
from the CVS), if used.
Allow the engine to soak for 20 ± 1 minutes. Prepare the engine and
dynamometer for the hot start test. Connect evacuated sample collection bags
to the dilute exhaust and dilution air sample collection systems. Start the CVS
(if used or not already on) or connect the exhaust system to the CVS (if
disconnected). Start the sample pumps (except the particulate sample pump(s),
the engine cooling fan(s) and the data collection system.
The heat exchanger of the constant volume sampler (if used) and the heated
components of any continuous sampling system(s) (if applicable) shall be
preheated to their designated operating temperatures before the test begins.
Adjust the sample flow rates to the desired flow rate and set the CVS gas flow
measuring devices to zero. Carefully install a clean particulate filter in each of
the filter holders and install assembled filter holders in the sample flow line.
H o t s t a r t c y c l e
As soon as it is determined that the engine is started, start a ‘free idle’ timer.
Allow the engine to idle freely with no-load for 23 ± 1 s. Begin the transient
engine cycle such that the first non-idle record of the cycle occurs at 23 ± 1 s.
The free idle time is included in the 23 ± 1 s.
The test shall be performed according to the reference cycle as set out in
Appendix 4 to Schedule III. Engine speed and torque command set points shall
be issued at 5 Hz (10 Hz recommended) or greater. The set points shall be
calculated by linear interpolation between the 1 Hz set points of the reference
cycle. Feedback engine speed and torque shall be recorded at least once every
second during the test cycle, and the signals may be electronically filtered.
The procedure described in previous sections 4.5.7.2 and 4.5.7.3 shall then be
repeated.
E n g i n e s t a l l i n g d u r i n g t h e h o t s t a r t c y c l e
If the engine stalls anywhere during the hot start cycle, the engine may be shut
off and re-soaked for 20 minutes. The hot start cycle may then be rerun. Only
one hot re-soak and hot start cycle restart is permitted.
O p e r a t i o n s a f t e r h o t s t a r t c y c l e
At the completion of the hot start cycle, the measurement of the exhaust gas
mass flow rate, the diluted exhaust gas volume, the gas flow into the collecting
bags and the particulate sample pump shall be stopped. For an integrating
analyser system, sampling shall continue until system response times have
elapsed.
The concentrations of the collecting bags, if used, shall be analysed as soon as
possible and in any case not later than 20 minutes after the end of the test
cycle.
After the emission test, a zero gas and the same span gas shall be used for re-
checking the analysers. The test will be considered acceptable if the difference
between the pre-test and post-test results is less than 2 % of the span gas value.
The particulate filters shall be returned to the weighing chamber no later than
one hour after completion of the test. They shall be conditioned in a petri dish,
which is protected against dust contamination and allows air exchange, for at
least one hour, and then weighed. The gross weight of the filters shall be
recorded.
Verification of the test run
Data shift
To minimise the biasing effect of the time lag between the feedback and
reference cycle values, the entire engine speed and torque feedback signal
sequence may be advanced or delayed in time with respect to the reference
speed and torque sequence. If the feedback signals are shifted, both speed and
torque must be shifted by the same amount in the same direction.
Calculation of the cycle work
The actual cycle work Wact (kWh) shall be calculated using each pair of
engine feedback speed and torque values recorded. The actual cycle work
Wact is used for comparison to the reference cycle work Wref and for
calculating the brake specific emissions. The same methodology shall be used
for integrating both reference and actual engine power. If values are to be
determined between adjacent reference or adjacent measured values, linear
interpolation shall be used.
In integrating the reference and actual cycle work, all negative torque values
shall be set equal to zero and included. If integration is performed at a
frequency of less than 5 Hertz, and if, during a given time segment, the torque
value changes from positive to negative or negative to positive, the negative
portion shall be computed and set equal to zero. The positive portion shall be
included in the integrated value.
Wact shall be between – 15 % and + 5 % of Wref.
Validation statistics of the test cycle
Linear regressions of the feedback values on the reference values shall be
performed for speed, torque and power. This shall be done after any feedback
data shift has occurred, if this option is selected. The method of least squares
shall be used, with the best fit equation having the form
y = mx + b
where
y = feedback (actual) value of speed (min -1 ), torque (N·m), or power (kW)
m = slope of the regression line
x = reference value of speed (min -1 ), torque (N·m), or power (kW)
b = y intercept of the regression line
The standard error of estimate (SE) of y on x and the coefficient of
determination (r 2 ) shall be calculated for each regression line.
It is recommended that this analysis be performed at 1 Hertz. For a test to be
considered valid, the criteria of Table 1 must be met.
For regression purposes only, point deletions are permitted where noted in
Table 2 before doing the regression calculation. However, those points must
not be deleted for the calculation of cycle work and emissions. An idle point is
defined as a point having a normalised reference torque of 0 % and a
normalised reference speed of 0 %. Point deletion may be applied to the whole
or to any part of the cycle.
Appendix I
MEASUREMENT AND SAMPLING PROCEDURES
1. MEASUREMENT AND SAMPLING PROCEDURES (NRSC TEST)
Gaseous and particulate components emitted by the engine submitted for testing
shall be measured by the methods described in Schedule VI. The methods of
Schedule VI describe the recommended analytical systems for the gaseous
emissions (Section 1.1) and the recommended particulate dilution and sampling
systems (Section 1.2).
Dynamometer specification
An engine dynamometer with adequate characteristics to perform the test cycle
described in Schedule III, Section 3.7.1 shall be used. The instrumentation for
torque and speed measurement shall allow the measurement of the power within
the given limits. Additional calculations may be necessary. The accuracy of the
measuring equipment must be such that the maximum tolerances of the figures
given in point 1.3 are not exceeded.
Exhaust gas flow
The exhaust gas flow shall be determined by one of the methods mentioned in
sections 1.2.1 to 1.2.4.
Direct measurement method
Direct measurement of the exhaust flow by flow nozzle or equivalent metering
system (for detail see ISO 5167:2000).
Note: Direct gaseous flow measurement is a difficult task. Precautions must be
taken to avoid measurement errors that will impact emission value errors.
Air and fuel measurement method
Measurement of the airflow and the fuel flow.
Air flow-meters and fuel flow-meters with the accuracy defined in Section 1.3
shall be used.
The calculation of the exhaust gas flow is as follows
G EXHW = G AIRW + G FUEL (for wet exhaust mass)
Carbon balance method
Exhaust mass calculation from fuel consumption and exhaust gas concentrations
using the carbon balance method (Schedule III, Appendix 3).
Tracer measurement method
This method involves measurement of the concentration of a tracer gas in the
exhaust. A known amount of an inert gas (e.g. pure helium) shall be injected into
the exhaust gas flow as a tracer. The gas is mixed and diluted by the exhaust gas,
but must not react in the exhaust pipe. The concentration of the gas shall then be
measured in the exhaust gas sample.
In order to ensure complete mixing of the tracer gas, the exhaust gas sampling
probe shall be located at least 1 m or 30 times the diameter of the exhaust pipe,
whichever is larger, downstream of the tracer gas injection point. The sampling
probe may be located closer to the injection point if complete mixing is verified
by comparing the tracer gas concentration with the reference concentration when
the tracer gas is injected upstream of the engine.
The tracer gas flow rate shall be set so that the tracer gas concentration at engine
idle speed after mixing becomes lower than the full scale of the trace gas
analyser.
The calculation of the exhaust gas flow is as follows
where
G EXHW = instantaneous exhaust mass flow (kg/s)
G T = tracer gas flow (cm 3 /min)
conc mix = instantaneous concentration of the tracer gas after mixing, (ppm)
ρ EXH = density of the exhaust gas (kg/m 3 )
conc a = background concentration of the tracer gas in the intake air (ppm)
The background concentration of the tracer gas (conc a ) may be determined by
averaging the background concentration measured immediately before and after
the test run.
When the background concentration is less than 1 % of the concentration of the
tracer gas after mixing (conc mix .) at maximum exhaust flow, the background
concentration may be neglected.
The total system shall meet the accuracy specifications for the exhaust gas flow
and shall be calibrated according to Appendix 2, Section 1.11.2.
Air flow and air to fuel ratio measurement method
This method involves exhaust mass calculation from the air flow and the air to
fuel ratio. The calculation of the instantaneous exhaust gas mass flow is as
follows
The air flowmeter shall meet the accuracy specifications in Table 3, the CO 2
analyser used shall meet the specifications of clause 1.4.1, and the total system
shall meet the accuracy specifications for the exhaust gas flow.
Optionally, air to fuel ratio measurement equipment, such as a zirconia type
sensor, may be used for the measurement of the relative air to fuel ratio in
accordance with the specifications of clause 1.4.4.
Total dilute exhaust gas flow
When using a full flow dilution system, the total flow of the dilute exhaust (G
TOTW ) shall be measured with a PDP or CFV or SSV (Schedule VI, Section
1.2.1.2) The accuracy shall conform to the provisions of Schedule III, Appendix
2, Section 2.2.
Accuracy
The calibration of all measurement instruments shall be traceable to national or
international standards and comply with the requirements listed in Table 3.
Determination of the gaseous components
General analyser specifications
The analysers shall have a measuring range appropriate for the accuracy required
to measure the concentrations of the exhaust gas components (section1.4.1.1). It
is recommended that the analysers be operated in such a way that the measured
concentration falls between 15 % and 100 % of full scale.
If the full scale value is 155 ppm (or ppm C) or less or if read-out systems
(computers, data loggers) that provide sufficient accuracy and resolution below
15 % of full scale are used, concentrations below 15 % of full scale are also
acceptable. In this case, additional calibrations are to be made to ensure the
accuracy of the calibration curves – Schedule III, Appendix 2, section 1.5.5.2.
The electromagnetic compatibility (EMC) of the equipment shall be on a level as
to minimise additional errors.
M e a s u r e m e n t e r r o r
The analyser shall not deviate from the nominal calibration point by more than ±
2 % of the reading or ± 0,3 % of full scale, whichever is larger.
NOTE: For the purpose of this standard, accuracy is defined as the deviation of
the analyser reading from the nominal calibration values using a calibration gas
(≡ true value)
R e p e a t a b i l i t y
The repeatability, defined as 2,5 times the standard deviation of 10 repetitive
responses to a given calibration or span gas, must be no greater than ± 1 % of full
scale concentration for each range used above 155 ppm (or ppm C) or ± 2 % of
each range used below 155 ppm (or ppm C).
N o i s e
The analyser peak-to-peak response to zero and calibration or span gases over
any 10-second period shall not exceed 2 % of full scale on all ranges used.
Z e r o d r i f t
The zero drift during a one-hour period shall be less than 2 % of full scale on the
lowest range used. The zero response is defined as the mean response, including
noise, to a zero gas during a 30-second time interval.
S p a n d r i f t
The span drift during a one-hour period shall be less than 2 % of full scale on the
lowest range used. Span is defined as the difference between the span response
and the zero response. The span response is defined as the mean response,
including noise, to a span gas during a 30-second time interval.
Gas drying
The optional gas drying device must have a minimal effect on the concentration
of the measured gases. Chemical dryers are not an acceptable method of
removing water from the sample.
Analysers
Sections 1.4.3.1 to 1.4.3.5 of this Appendix describe the measurement principles
to be used. A detailed description of the measurement systems is given in
Schedule VI.
The gases to be measured shall be analysed with the following instruments. For
non-linear analysers, the use of linearising circuits is permitted.
C a r b o n m o n o x i d e ( C O ) a n a l y s i s
The carbon monoxide analyser shall be of the non-dispersive infra-red (NDIR)
absorption type.
C a r b o n d i o x i d e ( C O 2 ) a n a l y s i s
The carbon dioxide analyser shall be of the non-dispersive infra-red (NDIR)
absorption type.
H y d r o c a r b o n ( H C ) a n a l y s i s
The hydrocarbon analyser shall be of the heated flame ionization detector
(HFID) type with detector, valves, pipework, etc, heated so as to maintain a gas
temperature of 463 K (190 °C) ± 10 K.
O x i d e s o f n i t r o g e n ( N O x ) a n a l y s i s
The oxides of nitrogen analyser shall be of the chemiluminescent detector (CLD)
or heated chemiluminescent detector (HCLD) type with a NO 2 /NO converter, if
measured on a dry basis. If measured on a wet basis, a HCLD with converter
maintained above 328 K (55 °C) shall be used, provided the water quench check
(Schedule III, Appendix 2, section 1.9.2.2) is satisfied.
For both CLD and HCLD, the sampling path shall be maintained at a wall
temperature of 328 K to 473 K (55 to 200 °C) up to the converter for dry
measurement, and up to the analyser for wet measurement.
Air to fuel measurement
The air to fuel measurement equipment used to determine the exhaust gas flow
as specified in section 1.2.5 shall be a wide range air to fuel ratio sensor or
lambda sensor of Zirconia type.
The sensor shall be mounted directly on the exhaust pipe where the exhaust gas
temperature is high enough to eliminate water condensation.
The accuracy of the sensor with incorporated electronics shall be within
± 3 % of reading λ < 2
± 5 % of reading 2 ≤ λ < 5
± 10 % of reading 5 ≤ λ
To fulfil the accuracy specified above, the sensor shall be calibrated as specified
by the instrument manufacturer.
Sampling for gaseous emissions
The gaseous emissions sampling probes must be fitted at least 0,5 m or three
times the diameter of the exhaust pipe — whichever is the larger — upstream of
the exit of the exhaust gas system as far as applicable and sufficiently close to
the engine as to ensure an exhaust gas temperature of at least 343 K (70 °C) at
the probe.
In the case of a multi-cylinder engine with a branched exhaust manifold, the inlet
of the probe shall be located sufficiently far downstream so as to ensure that the
sample is representative of the average exhaust emissions from all cylinders. In
multi-cylinder engines having distinct groups of manifolds, such as in a ‘V’-
engine configuration, it is permissible to acquire a sample from each group
individually and calculate an average exhaust emission. Other methods which
have been shown to correlate with the above methods may be used. For exhaust
emissions calculation the total exhaust mass flow of the engine must be used.
If the composition of the exhaust gas is influenced by any exhaust after-
treatment system, the exhaust sample must be taken upstream of this device in
the tests of stage I and downstream of this device in the tests of stage II. When a
full flow dilution system is used for the determination of the particulates, the
gaseous emissions may also be determined in the diluted exhaust gas. The
sampling probes shall be close to the particulate sampling probe in the dilution
tunnel (Schedule VI, section 1.2.1.2, DT and Section 1.2.2, PSP). CO and CO 2
may optionally be determined by sampling into a bag and subsequent
measurement of the concentration in the sampling bag.
Determination of the particulates
The determination of the particulates requires a dilution system. Dilution may be
accomplished by a partial flow dilution system or a full flow dilution system.
The flow capacity of the dilution system shall be large enough to completely
eliminate water condensation in the dilution and sampling systems, and maintain
the temperature of the diluted exhaust gas between 315 K (42 °C) and 325 K (52
°C) immediately upstream of the filter holders. De-humidifying the dilution air
before entering the dilution system is permitted, if the air humidity is high.
Dilution air pre-heating above the temperature limit of 303 K (30 °C) is
recommended, if the ambient temperature is below 293 K (20 °C). However, the
diluted air temperature must not exceed 325 K (52 °C) prior to the introduction
of the exhaust in the dilution tunnel.
Note: For steady-state procedure, the filter temperature may be kept at or below
the maximum temperature of 325 K (52 °C) instead of respecting the
temperature range of 42 to 52 °C.
For a partial flow dilution system, the particulate sampling probe must be fitted
close to and upstream of the gaseous probe as defined in Section 4.4 and in
accordance with Schedule VI, section 1.2.1.1, figure 4-12 EP and SP.
The partial flow dilution system has to be designed to split the exhaust stream
into two fractions, the smaller one being diluted with air and subsequently used
for particulate measurement. From that it is essential that the dilution ratio be
determined very accurately. Different splitting methods can be applied, whereby
the type of splitting used dictates to a significant degree the sampling hardware
and procedures to be used (Schedule VI, section 1.2.1.1).
To determine the mass of the particulates, a particulate sampling system,
particulate sampling filters, a microgram balance and a temperature and
humidity controlled weighing chamber are required.
For particulate sampling, two methods may be applied
-
the single filter method uses one pair of filters (1.5.1.3 of this
Appendix) for all modes of the test cycle. Considerable attention must
be paid to sampling times and flows during the sampling phase of the
test. However, only one pair of filters will be required for the test cycle,
-
-
the multiple filter method dictates that one pair of filters (section 1.5.1.3
of this Appendix) is used for each of the individual modes of the test
cycle. This method allows more lenient sample procedures but uses
more filters.
-
Particulate sampling filters
F i l t e r s p e c i f i c a t i o n
Fluorocarbon coated glass fibre filters or fluorocarbon based membrane filters
are required for certification tests. For special applications different filter
materials may be used. All filter types shall have a 0,3 μm DOP (di-
octylphthalate) collection efficiency of at least 99 % at a gas face velocity
between 35 and 100 cm/s. When performing correlation tests between
laboratories or between a manufacturer and an approval authority, filters of
identical quality must be used.
F i l t e r s i z e
Particulate filters must have a minimum diameter of 47 mm (37 mm stain
diameter). Larger diameter filters are acceptable (section 1.5.1.5).
P r i m a r y a n d b a c k - u p f i l t e r s
The diluted exhaust shall be sampled by a pair of filters placed in series (one
primary and one back-up filter) during the test sequence. The back-up filter shall
be located no more than 100 mm downstream of, and shall not be in contact
with, the primary filter. The filters may be weighed separately or as a pair with
the filters placed stain side to stain side.
F i l t e r f a c e v e l o c i t y
A gas face velocity through the filter of 35 to 100 cm/s shall be achieved. The
pressure drop increase between the beginning and the end of the test shall be no
more than 25 kPa.
F i l t e r l o a d i n g
The recommended minimum filter loadings for the most common filter sizes are
shown in the following table. For larger filter sizes, the minimum filter loading
shall be 0,065 mg/1000 mm 2 filter area.
For the multiple filter method, the recommended minimum filter loading for the
sum of all filters shall be the product of the appropriate value above and the
square root of the total number of modes.
Weighing chamber and analytical balance specifications
W e i g h i n g c h a m b e r c o n d i t i o n s
The temperature of the chamber (or room) in which the particulate filters are
conditioned and weighed shall be maintained to within 295 K (22 °C) ± 3 K
during all filter conditioning and weighing. The humidity shall be maintained to
a dew point of 282,5 (9,5 °C) ± 3 K and a relative humidity of 45 ± 8 %.
R e f e r e n c e f i l t e r w e i g h i n g
The chamber (or room) environment shall be free of any ambient contaminants
(such as dust) that would settle on the particulate filters during their stabilisation.
Disturbances to weighing room specifications as outlined in section 1.5.2.1 will
be allowed if the duration of the disturbances does not exceed 30 minutes. The
weighing room should meet the required specifications prior to personnel
entrance into the weighing room. At least two unused reference filters or
reference filter pairs shall be weighed within four hours of, but preferably at the
same time as the sample filter (pair) weighing. They shall be the same size and
material as the sample filters.
If the average weight of the reference filters (reference filter pairs) changes
between sample filter weighing by more than 10μg, then all sample filters shall
be discarded and the emissions test repeated.
If the weighing room stability criteria outlined in section 1.5.2.1 is not met, but
the reference filter (pair) weighing meet the above criteria, the engine
manufacturer has the option of accepting the sample filter weights or voiding the
tests, fixing the weighing room control system and re-running the test.
A n a l y t i c a l b a l a n c e
The analytical balance used to determine the weights of all filters shall have a
precision (standard deviation) of 2 μg and a resolution of 1 μg (1 digit = 1 μg)
specified by the balance manufacturer.
E l i m i n a t i o n o f s t a t i c e l e c t r i c i t y e f f e c t s
To eliminate the effects of static electricity, the filters shall be neutralised prior
to weighing, for example, by a Polonium neutraliser or a device of similar effect.
Additional specifications for particulate measurement
All parts of the dilution system and the sampling system from the exhaust pipe
up to the filter holder, which are in contact with raw and diluted exhaust gas,
must be designed to minimise deposition or alteration of the particulates. All
parts must be made of electrically conductive materials that do not react with
exhaust gas components, and must be electrically grounded to prevent
electrostatic effects.
2. MEASUREMENT AND SAMPLING PROCEDURES (NRTC TEST)
Introduction
Gaseous and particulate components emitted by the engine submitted for testing
shall be measured by the methods of Schedule VI. The methods of Schedule VI
describe the recommended analytical systems for the gaseous emissions (Section
1.1) and the recommended particulate dilution and sampling systems (Section
1.2).
Dynamometer and test cell equipment
The following equipment shall be used for emission tests of engines on engine
dynamometers
Engine dynamometer
An engine dynamometer shall be used with adequate characteristics to perform
the test cycle described in Appendix 4 to this Schedule. The instrumentation for
torque and speed measurement shall allow the measurement of the power within
the given limits. Additional calculations may be necessary. The accuracy of the
measuring equipment must be such that the maximum tolerances of the figures
given in Table 3 are not exceeded.
Other instruments
Measuring instruments for fuel consumption, air consumption, temperature of
coolant and lubricant, exhaust gas pressure and intake manifold depression,
exhaust gas temperature, air intake temperature, atmospheric pressure, humidity
and fuel temperature shall be used, as required. These instruments shall satisfy
the requirements given in Table 3
Raw exhaust gas flow
For calculating the emissions in the raw exhaust gas and for controlling a partial
flow dilution system, it is necessary to know the exhaust gas mass flow rate. For
determining the exhaust mass flow rate, either of the methods described below
may be used.
For the purpose of emissions calculation, the response time of either method
described below shall be equal to or less than the requirement for the analyser
response time, as defined in Appendix 2, Section 1.11.1.
For the purpose of controlling a partial flow dilution system, a faster response is
required. For partial flow dilution systems with online control, a response time
of ≤ 0,3 s is required. For partial flow dilution systems with look ahead control
based on a pre-recorded test run, a response time of the exhaust flow
measurement system of ≤ 5 s with a rise time of ≤ 1 s is required. The system
response time shall be specified by the instrument manufacturer. The combined
response time requirements for exhaust gas flow and partial flow dilution system
are indicated in Section 2.4.
Direct measurement method
Direct measurement of the instantaneous exhaust flow may be done by systems,
such as
- pressure differential devices, like flow nozzle, (for details see ISO
5167: 2000)
- ultrasonic flowmeter
-
vortex flowmeter.
Precautions shall be taken to avoid measurement errors, which will impact
emission value errors. Such precautions include the careful installation of the
device in the engine exhaust system according to the instrument manufacturers'
recommendations and to good engineering practice. Especially, engine
performance and emissions must not be affected by the installation of the device.
The flowmeters shall meet the accuracy specifications of Table 3.
Air and fuel measurement method
This involves measurement of the airflow and the fuel flow with suitable
flowmeters. The calculation of the instantaneous exhaust gas flow is as follows
G EXHW = G AIRW + G FUEL (for wet exhaust mass)
The flowmeters shall meet the accuracy specifications of Table 3, but shall also
be accurate enough to also meet the accuracy specifications for the exhaust gas
flow.
Tracer measurement method
This involves measurement of the concentration of a tracer gas in the exhaust.
A known amount of an inert gas (e.g. pure helium) shall be injected into the
exhaust gas flow as a tracer. The gas is mixed and diluted by the exhaust gas, but
must not react in the exhaust pipe. The concentration of the gas shall then be
measured in the exhaust gas sample.
In order to ensure complete mixing of the tracer gas, the exhaust gas sampling
probe shall be located at least 1 m or 30 times the diameter of the exhaust pipe,
whichever is larger, downstream of the tracer gas injection point. The sampling
probe may be located closer to the injection point if complete mixing is verified
by comparing the tracer gas concentration with the reference concentration when
the tracer gas is injected upstream of the engine.
The tracer gas flow rate shall be set so that the tracer gas concentration at engine
idle speed after mixing becomes lower than the full scale of the trace gas
analyser.
The calculation of the exhaust gas flow is as follows
where
G EXHW = instantaneous exhaust mass flow (kg/s)
G T = tracer gas flow (cm 3 /min)
conc mix = instantaneous concentration of the tracer gas after mixing (ppm)
ρ EXH = density of the exhaust gas (kg/m 3 )
conc a = background concentration of the tracer gas in the intake air (ppm)
The background concentration of the tracer gas (conc a ) may be determined by
averaging the background concentration measured immediately before the test
run and after the test run.
When the background concentration is less than 1 % of the concentration of the
tracer gas after mixing (conc mix .) at maximum exhaust flow, the background
concentration may be neglected.
The total system shall meet the accuracy specifications for the exhaust gas flow,
and shall be calibrated according to Appendix 2, paragraph 1.11.2.
Air flow and air to fuel ratio measurement method
This involves exhaust mass calculation from the airflow and the air to fuel ratio.
The calculation of the instantaneous exhaust gas mass flow is as follows
The air flowmeter shall meet the accuracy specifications in Table 3, the CO 2
analyser used shall meet the specifications of section 2.3.1, and the total system
shall meet the accuracy specifications for the exhaust gas flow.
Optionally, air to fuel ratio measurement equipment, such as a zirconia type
sensor, may be used for the measurement of the excess air ratio in accordance
with the specifications of section 2.3.4.
Diluted exhaust gas flow
For calculation of the emissions in the diluted exhaust gas, it is necessary to
know the diluted exhaust gas mass flow rate. The total diluted exhaust gas flow
over the cycle (kg/test) shall be calculated from the measurement values over the
cycle and the corresponding calibration data of the flow measurement device (V
0 for PDP, K V for CFV, C d for SSV): the corresponding methods described in
Appendix 3, section 2.2.1 shall be used. If the total sample mass of particulates
and gaseous pollutants exceeds 0,5 % of the total CVS flow, the CVS flow shall
be corrected or the particulate sample flow shall be returned to the CVS prior to
the flow measuring device.
Determination of the gaseous components
General analyser specifications
The analysers shall have a measuring range appropriate for the accuracy required
to measure the concentrations of the exhaust gas components (section 1.4.1.1). It
is recommended that the analysers be operated in such a way that the measured
concentration falls between 15 and 100 % of full scale.
If the full scale value is 155 ppm (or ppm C) or less, or if read-out systems
(computers, data loggers) that provide sufficient accuracy and resolution below
15 % of full scale are used, concentrations below 15 % of full scale are also
acceptable. In this case, additional calibrations are to be made to ensure the
accuracy of the calibration curves – Schedule III, Appendix 2, section 1.5.5.2.
The electromagnetic compatibility (EMC) of the equipment shall be of a level
such as to minimise additional errors.
M e a s u r e m e n t e r r o r
The analyser shall not deviate from the nominal calibration point by more than ±
2 % of the reading or ± 0,3 % of full scale, whichever is larger.
Note: For the purpose of this standard, accuracy is defined as the deviation of the
analyser reading from the nominal calibration values using a calibration gas (≡
true value).
R e p e a t a b i l i t y
The repeatability, defined as 2,5 times the standard deviation of 10 repetitive
responses to a given calibration or span gas, must be no greater than ± 1 % of full
scale concentration for each range used above 155 ppm (or ppm C) or ± 2 % for
each range used below 155 ppm (or ppm C).
N o i s e
The analyser peak-to-peak response to zero and calibration or span gases over
any 10-second period shall not exceed 2 % of full scale on all ranges used.
Z e r o d r i f t
The zero drift during a one-hour period shall be less than 2 % of full scale on the
lowest range used. The zero response is defined as the mean response, including
noise, to a zero gas during a 30-second time interval.
S p a n d r i f t
The span drift during a one-hour period shall be less than 2 % of full scale on the
lowest range used. Span is defined as the difference between the span response
and the zero response. The span response is defined as the mean response,
including noise, to a span gas during a 30-second time interval.
R i s e t i m e
For raw exhaust gas analysis, the rise time of the analyser installed in the
measurement system shall not exceed 2,5 s.
NOTE: Only evaluating the response time of the analyser alone will not clearly
define the suitability of the total system for transient testing. Volumes, and
especially dead volumes, through out the system will not only affect the
transportation time from the probe to the analyser, but also affect the rise time.
Also transport times inside of an analyser would be defined as analyser response
time, like the converter or water traps inside of a NO x analysers. The
determination of the total system response time is described in Appendix 2,
Section 1.11.1.
Gas drying
Same specifications as for NRSC test cycle apply (Section 1.4.2) as described
here below.
The optional gas drying device must have a minimal effect on the concentration
of the measured gases. Chemical dryers are not an acceptable method of
removing water from the sample.
Analysers
Same specifications as for NRSC test cycle apply (Section 1.4.3) as described
here below.
The gases to be measured shall be analysed with the following instruments. For
non-linear analysers, the use of linearising circuits is permitted.
C a r b o n m o n o x i d e ( C O ) a n a l y s i s
The carbon monoxide analyser shall be of the non-dispersive infra-red (NDIR)
absorption type.
C a r b o n d i o x i d e ( C O 2 ) a n a l y s i s
The carbon dioxide analyser shall be of the non-dispersive infra-red (NDIR)
absorption type.
H y d r o c a r b o n ( H C ) a n a l y s i s
The hydrocarbon analyser shall be of the heated flame ionization detector
(HFID) type with detector, valves, pipework, etc, heated so as to maintain a gas
temperature of 463K (190 °C) ± 10 K.
O x i d e s o f n i t r o g e n ( N O x ) a n a l y s i s
The oxides of nitrogen analyser shall be of the chemiluminescent detector (CLD)
or heated chemiluminescent detector (HCLD) type with a NO 2 /NO converter, if
measured on a dry basis. If measured on a wet basis, a HCLD with converter
maintained above 328 K (55 °C shall be used, provided the water quench check
(Schedule III, Appendix 2, section 1.9.2.2) is satisfied.
For both CLD and HCLD, the sampling path shall be maintained at a wall
temperature of 328K to 473 K (55 to 200 °C) up to the converter for dry
measurement, and up to the analyser for wet measurement.
Air to fuel measurement
The air to fuel measurement equipment used to determine the exhaust gas flow
as specified in section 2.2.3 shall be a wide range air to fuel ratio sensor or
lambda sensor of Zirconia type.
The sensor shall be mounted directly on the exhaust pipe where the exhaust gas
temperature is high enough to eliminate water condensation.
The accuracy of the sensor with incorporated electronics shall be within
± 3 % of reading λ < 2
± 5 % of reading 2 ≤ λ < 5
± 10 % of reading 5 ≤ λ
To fulfil the accuracy specified above, the sensor shall be calibrated as specified
by the instrument manufacturer.
Sampling of gaseous emissions
R a w e x h a u s t g a s f l o w
For calculation of the emissions in the raw exhaust gas the same specifications as
for NRSC test cycle apply (Section 1.4.4), as described here below.
The gaseous emissions sampling probes must be fitted at least 0,5 m or three
times the diameter of the exhaust pipe — whichever is the larger — upstream of
the exit of the exhaust gas system as far as applicable and sufficiently close to
the engine as to ensure an exhaust gas temperature of at least 343 K (70 °C) at
the probe.
In the case of a multicylinder engine with a branched exhaust manifold, the inlet
of the probe shall be located sufficiently far downstream so as to ensure that the
sample is representative of the average exhaust emissions from all cylinders. In
multicylinder engines having distinct groups of manifolds, such as in a ‘V’-
engine configuration, it is permissible to acquire a sample from each group
individually and calculate an average exhaust emission. Other methods which
have been shown to correlate with the above methods may be used. For exhaust
emissions calculation the total exhaust mass flow of the engine must be used.
If the composition of the exhaust gas is influenced by any exhaust after-
treatment system, the exhaust sample must be taken upstream of this device in
the tests of stage I and downstream of this device in the tests of stage II.
D i l u t e d e x h a u s t g a s f l o w
If a full flow dilution system is used, the following specifications apply.
The exhaust pipe between the engine and the full flow dilution system shall
conform to the requirements of Schedule VI.
The gaseous emissions sample probe(s) shall be installed in the dilution tunnel at
a point where the dilution air and exhaust gas are well mixed, and in close
proximity to the particulates sampling probe.
Sampling can generally be done in two ways
- the pollutants are sampled into a sampling bag over the cycle and
measured after completion of the test,
- the pollutants are sampled continuously and integrated over the cycle;
this method is mandatory for HC and NO x .
The background concentrations shall be sampled upstream of the dilution tunnel
into a sampling bag, and shall be subtracted from the emissions concentration
according to Appendix 3, Section 2.2.3.
Determination of the particulates
Determination of the particulates requires a dilution system. Dilution may be
accomplished by a partial flow dilution system or a full flow dilution system.
The flow capacity of the dilution system shall be large enough to completely
eliminate water condensation in the dilution and sampling systems, and maintain
the temperature of the diluted exhaust gas between 315 K (42 °C) and 325 K (52
°C) immediately upstream of the filter holders. De-humidifying the dilution air
before entering the dilution system is permitted, if the air humidity is high.
Dilution air pre-heating above the temperature limit of 303 K (30 °C) is
recommended if the ambient temperature is below 293 K (20 °C). However, the
diluted air temperature must not exceed 325 K (52 °C) prior to the introduction
of the exhaust in the dilution tunnel.
The particulate sampling probe shall be installed in close proximity to the
gaseous emissions sampling probe, and the installation shall comply with the
provisions of Section 2.3.5.
To determine the mass of the particulates, a particulate sampling system,
particulate sampling filters, microgram balance, and a temperature and humidity
controlled weighing chamber, are required.
Partial flow dilution system specifications
The partial flow dilution system has to be designed to split the exhaust stream
into two fractions, the smaller one being diluted with air and subsequently used
for particulate measurement. For this it is essential that the dilution ratio be
determined very accurately. Different splitting methods can be applied, whereby
the type of splitting used dictates to a significant degree the sampling hardware
and procedures to be used (Schedule VI, section 1.2.1.1).
For the control of a partial flow dilution system, a fast system response is
required. The transformation time for the system shall be determined by the
procedure described in Appendix 2, Section 1.11.1.
If the combined transformation time of the exhaust flow measurement (see
previous section) and the partial flow system is less than 0,3 s, online control
may be used. If the transformation time exceeds 0,3 s, look ahead control based
on a pre-recorded test run must be used. In this case, the rise time shall be ≤ 1 s
and the delay time of the combination ≤ 10 s.
The total system response shall be designed as to ensure a representative sample
of the particulates, G SE , proportional to the exhaust mass flow. To determine the
proportionality, a regression analysis of G SE versus G EXHW shall be conducted
on a minimum 5 Hz data acquisition rate, and the following criteria shall be met
-
the correlation coefficient r of the linear regression between G SE and G
EXHW shall be not less than 0,95,
-
the standard error of estimate of G SE on G EXHW shall not exceed 5 %
of G SE maximum.
-
G SE intercept of the regression line shall not exceed ± 2 % of G SE
maximum.
-
Optionally, a pre-test may be run, and the exhaust mass flow signal of the pre-
test be used for controlling the sample flow into the particulate system (look-
ahead control). Such a procedure is required if the transformation time of the
particulate system, t 50 ,P or/and the transformation time of the exhaust mass
flow signal, t 50 ,F are > 0,3 s. A correct control of the partial dilution system is
obtained, if the time trace of G EXHW ,pre of the pre-test, which controls G SE , is
shifted by a ‘look-ahead’ time of t 50 ,P + t 50 ,F .
For establishing the correlation between G SE and G EXHW the data taken during
the actual test shall be used, with G EXHW time aligned by t 50 ,F relative to G SE
(no contribution from t 50 , P to the time alignment). That is, the time shift
between G EXHW and G SE is the difference in their transformation times that
were determined in Appendix 2, Section 2.6.
For partial flow dilution systems, the accuracy of the sample flow G SE is of
special concern, if not measured directly, but determined by differential flow
measurement
G SE = G TOTW — G DILW
In this case an accuracy of ± 2 % for G TOTW and G DILW is not sufficient to
guarantee acceptable accuracies of G SE . If the gas flow is determined by
differential flow measurement, the maximum error of the difference shall be
such that the accuracy of G SE is within ± 5 % when the dilution ratio is less than
It can be calculated by taking root-mean-square of the errors of each
instrument.
Acceptable accuracies of G SE can be obtained by either of the following
methods
(a) The absolute accuracies of G TOTW and G DILW are ± 0,2 % which
guarantees an accuracy of G SE of ≤ 5 % at a dilution ratio of 15. However,
greater errors will occur at higher dilution ratios.
(b) Calibration of G DILW relative to G TOTW is carried out such that the same
accuracies for G SE as in (a) are obtained. For the details of such a calibration
see Appendix 2, Section 2.6.
(c) The accuracy of G SE is determined indirectly from the accuracy of the
dilution ratio as determined by a tracer gas, e.g. CO 2 . Again, accuracies
equivalent to method (a) for G SE are required.
(d) The absolute accuracy of G TOTW and G DILW is within ± 2 % of full
scale, the maximum error of the difference between G TOTW and G DILW is
within 0,2 %, and the linearity error is within ± 0,2 % of the highest G TOTW
observed during the test.
Particulate sampling filters
F i l t e r s p e c i f i c a t i o n
Fluorocarbon coated glass fibre filters or fluorocarbon based membrane filters
are required for certification tests. For special applications different filter
materials may be used. All filter types shall have a 0,3 μm DOP (di-
octylphthalate) collection efficiency of at least 99 % at a gas face velocity
between 35 and 100 cm/s. When performing correlation tests between
laboratories or between a manufacturer and an approval authority, filters of
identical quality must be used.
F i l t e r s i z e
Particulate filters must have a minimum diameter of 47 mm (37 mm stain
diameter). Larger diameter filters are acceptable (section 2.4.1.5).
P r i m a r y a n d b a c k - u p f i l t e r s
The diluted exhaust shall be sampled by a pair of filters placed in series (one
primary and one back-up filter) during the test sequence. The back-up filter shall
be located no more than 100mm downstream of, and shall not be in contact with,
the primary filter. The filters may be weighed separately or as a pair with the
filters placed stain side to stain side.
F i l t e r f a c e v e l o c i t y
A gas face velocity through the filter of 35 to 100 cm/s shall be achieved. The
pressure drop increase between the beginning and the end of the test shall be no
more than 25 kPa.
F i l t e r l o a d i n g
The recommended minimum filter loadings for the most common filter sizes are
shown in the following table. For larger filter sizes, the minimum filter loading
shall be 0,065 mg/1 000 mm 2 filter area.
Weighing chamber and analytical balance specifications
W e i g h i n g c h a m b e r c o n d i t i o n s
The temperature of the chamber (or room) in which the particulate filters are
conditioned and weighed shall be maintained to within 295 K (22 °C) ± 3 K
during all filter conditioning and weighing. The humidity shall be maintained to
a dewpoint of 282,5 (9,5 °C) ± 3 K and a relative humidity of 45 ± 8 %.
R e f e r e n c e f i l t e r w e i g h i n g
The chamber (or room) environment shall be free of any ambient contaminants
(such as dust) that would settle on the particulate filters during their stabilisation.
Disturbances to weighing room specifications as outlined in section 2.4.2.1 will
be allowed if the duration of the disturbances does not exceed 30 minutes. The
weighing room should meet the required specifications prior to personnel
entrance into the weighing room. At least two unused reference filters or
reference filter pairs shall be weighed within four hours of, but preferably at the
same time as the sample filter (pair) weighing. They shall be the same size and
material as the sample filters.
If the average weight of the reference filters (reference filter pairs) changes
between sample filter weighing by more than 10 μg, then all sample filters shall
be discarded and the emissions test repeated.
If the weighing room stability criteria outlined in section 2.4.2.1 are not met, but
the reference filter (pair) weighing meet the above criteria, the engine
manufacturer has the option of accepting the sample filter weights or voiding the
tests, fixing the weighing room control system and re-running the test.
A n a l y t i c a l b a l a n c e
The analytical balance used to determine the weights of all filters shall have a
precision (standard deviation) of 2 μg and a resolution of 1 μg (1 digit = 1 μg)
specified by the balance manufacturer.
E l i m i n a t i o n o f s t a t i c e l e c t r i c i t y e f f e c t s
To eliminate the effects of static electricity, the filters shall be neutralised prior
to weighing, for example, by a Polonium neutraliser or a device having similar
effect.
Additional specifications for particulate measurement
All parts of the dilution system and the sampling system from the exhaust pipe
up to the filter holder, which are in contact with raw and diluted exhaust gas,
must be designed to minimise deposition or alteration of the particulates. All
parts must be made of electrically conductive materials that do not react with
exhaust gas components, and must be electrically grounded to prevent
electrostatic effects.
Appendix 2
CALIBRATION PROCEDURE (NRSC, NRTC ( 11 ))
1. CALIBRATION OF THE ANALYTICAL INSTRUMENTS
Introduction
Each analyzer shall be calibrated as often as necessary to fulfil the accuracy
requirements of this standard. The calibration method that shall be used is
described in this paragraph for the analysers indicated in Appendix 1, section
1.4.3.
Calibration gases
The shelf life of all calibration gases must be respected.
The expiry date of the calibration gases stated by the manufacturer shall be
recorded.
Pure gases
The required purity of the gases is defined by the contamination limits given
below. The following gases must be available for operation
- purified nitrogen
(contamination ≤ 1 ppm C, ≤ 1 ppm CO, ≤ 400 ppm CO 2 , ≤ 0,1 ppm NO)
- purified oxygen
(purity > 99,5 % vol O 2 )
- hydrogen-helium mixture
(40 ± 2 % hydrogen, balance helium)
(contamination ≤ 1 ppm C, ≤ 400 ppm CO 2 )
- purified synthetic air
(contamination ≤ 1 ppm C, ≤ 1 ppm CO, ≤ 400 ppm CO 2 , ≤ 0,1 ppm NO)
(oxygen content between 18 – 21 % vol)
Calibration and span gases
Mixture of gases having the following chemical compositions shall be available
- C 3 H 8 and purified synthetic air (see section 1.2.1)
- CO and purified nitrogen
- NO and purified nitrogen (the amount of NO 2 contained in this calibration
gas must not exceed 5 % of the NO content)
- O 2 and purified nitrogen
- CO 2 and purified nitrogen
- CH 4 and purified synthetic air
- C 2 H 6 and purified synthetic air
Note: other gas combinations are allowed provided the gases do not react with
one another.
The true concentration of a calibration and span gas must be within ± 2 % of the
nominal value. All concentrations of calibration gas shall be given on a volume
basis (volume percent or volume ppm).
The calibration procedure is common for both NRSC and NRTC tests, with the exception of the requirements
specified in Sections 1.11 and 2.6.
The gases used for calibration and span may also be obtained by means of a gas
divider, diluting with purified N 2 or with purified synthetic air. The accuracy of
the mixing device must be such that the concentration of the diluted calibration
gases may be determined to within ± 2 %.
This accuracy implies that primary gases used for blending shall be known to
have an accuracy of at least ± 1 %, traceable to national or international gas
standards. The verification shall be performed at between 15 and 50 % of full
scale for each calibration incorporating a blending device. An additional
verification may be performed using another calibration gas, if the first
verification has failed.
Optionally, the blending device may be checked with an instrument which by
nature is linear, e.g. using NO gas with a CLD. The span value of the instrument
shall be adjusted with the span gas directly connected to the instrument. The
blending device shall be checked at the used settings and the nominal value shall
be compared to the measured concentration of the instrument. This difference
shall in each point be within ± 1 % of the nominal value.
Other methods may be used based on good engineering practice and with the
prior agreement of the parties involved.
Note: A precision gas divider of accuracy is within ± 1 %, is recommended for
establishing the accurate analyser calibration curve. The gas divider shall be
calibrated by the instrument manufacturer.
Operating procedure for analysers and sampling system
The operating procedure for analysers shall follow the start-up and operating
instructions of the instrument manufacturer. The minimum requirements given
in sections 1.4 to 1.9 shall be included.
Leakage test
A system leakage test shall be performed. The probe shall be disconnected from
the exhaust system and the end plugged. The analyser pump shall be switched
on. After an initial stabilization period all flow meters should read zero. If not,
the sampling lines shall be checked and the fault corrected. The maximum
allowable leakage rate on the vacuum side shall be 0,5 % of the in-use flow rate
for the portion of the system being checked. The analyser flows and bypass
flows may be used to estimate the in-use flow rates.
Another method is the introduction of a concentration step change at the
beginning of the sampling line by switching from zero to span gas.
If after an adequate period of time the reading shows a lower concentration
compared to the introduced concentration, this points to calibration or leakage
problems.
Calibration procedure
Instrument assembly
The instrument assembly shall be calibrated and calibration curves checked
against standard gases. The same gas flow rates shall be used as when sampling
exhaust.
Warming-up time
The warming-up time should be according to the recommendations of the
manufacturer. If not specified, a minimum of two Hours is recommended for
warming-up the analysers.
NDIR and HFID analyser
The NDIR analyser shall be tuned, as necessary, and the combustion flame of
the HFID analyser shall be optimized (section 1.8.1).
Calibration
Each normally used operating range shall be calibrated.
Using purified synthetic air (or nitrogen), the CO, CO 2 , No x , HC and O 2
analysers shall be set at zero.
The appropriate calibration gases shall be introduced to the analysers, the values
recorded, and the calibration curve established according to section 1.5.6.
The zero setting shall be re-checked and the calibration procedure repeated, if
necessary.
Establishment of the calibration curve
G e n e r a l g u i d e l i n e s
The analyser calibration curve is established by at least six calibration points
(excluding zero) spaced as uniformly as possible. The highest nominal
concentration must be equal to or higher than 90 % of full scale.
The calibration curve is calculated by the method of least squares. If the
resulting polynomial degree is greater than three, the number of calibration
points (zero included) must be at least equal to this polynomial degree plus two.
The calibration curve must not differ by more than ± 2 % from the nominal
value of each calibration point and by more than ± 0,3 % of full scale at zero.
From the calibration curve and the calibration points, it is possible to verify that
the calibration has been carried out correctly. The different characteristic
parameters of the analyser must be indicated, particularly
the measuring range,
the sensitivity,
the date of carrying out the calibration.
C a l i b r a t i o n b e l o w 1 5 % o f f u l l s c a l e
The analyser calibration curve is established by at least ten calibration points
(excluding zero) spaced so that 50 % of the calibration points is below 10 % of
full scale.
The calibration curve is calculated by the method of least squares.
The calibration curve must not differ by more than ± 4 % from the nominal
value of each calibration point and by more than ± 0,3 % of full scale at zero.
A l t e r n a t i v e m e t h o d s
If it can be shown that alternative technology (e.g. computer, electronically
controlled range switch, etc.) can give equivalent accuracy, then these
alternatives may be used.
Verification of the calibration
Each normally used operating range shall be checked prior to each analysis in
accordance with the following procedure.
The calibration is checked by using a zero gas and a span gas whose nominal
value is more than 80 % of full scale of the measuring range.
If, for the two points considered, the value found does not differ by more than ±
4 % of full scale from the declared reference value, the adjustment parameters
may be modified. Should this not be the case, a new calibration curve shall be
established in accordance with section 1.5.4.
Efficiency test of the NO x converter
The efficiency of the converter used for the conversion of NO 2 into NO is tested
as given in sections 1.7.1 to 1.7.8 (Figure 1).
Test set-up
Using the test set-up as shown in Figure 1 (see also Appendix 1, section 1.4.3.5)
and the procedure below, the efficiency of converters can be tested by means of
an ozonator.
Calibration
The CLD and the HCLD shall be calibrated in the most common operating
range following the manufacturer's specifications using zero and span gas (the
NO content of which must amount to about 80 % of the operating range and the
NO 2 concentration of the gas mixture to less than 5 % of the NO concentration).
The NO x analyser must be in the NO mode so that the span gas does not pass
through the converter. The indicated concentration has to be recorded.
Calculation
The efficiency of the NO x converter is calculated as follows
(a)
NO x concentration according to section 1.7.6;
(b)
NO x concentration according to section 1.7.7;
(c)
NO concentration according to section 1.7.4;
(d)
NO concentration according to section 1.7.5.
Adding of oxygen
Via a T-fitting, oxygen or zero air is added continuously to the gas flow until the
concentration indicated is about 20 % less than the indicated calibration
concentration given in section 1.7.2 (The analyser is in the NO mode.)
The indicated concentration (c) shall be recorded. The ozonator is kept de-
activated throughout the process.
Activation of the ozonator
The ozonator is now activated to generate enough ozone to bring the NO
concentration down to about 20 % (minimum 10 %) of the calibration
concentration given in section 1.7.2. The indicated concentration (d) shall be
recorded. (The analyser is in the NO mode.)
NO x mode
The NO analyser is then switched to the NO x mode so that the gas mixture
(consisting of NO, NO 2 , O 2 and N 2 ) now passes through the converter. The
indicated concentration (a) shall be recorded. (The analyser is in the NO x
mode.)
De-activation of the ozonator
The ozonator is now de-activated. The mixture of gases described in section
1.7.6 passes through the converter into the detector. The indicated concentration
(b) shall be recorded. (The analyser is in the NO x mode.)
NO mode
Switched to NO mode with the ozonator de-activated, the flow of oxygen or
synthetic air is also shut off. The NO x reading of the analyser shall not deviate
by more than ± 5 % from the value measured according to section 1.7.2 (The
analyser is in the NO mode.)
Test interval
The efficiency of the converter must be tested prior to each calibration of the
NO x analyser.
Efficiency requirement
The efficiency of the converter shall not be less than 90 %, but a higher
efficiency of 95 % is strongly recommended.
Note: If, with the analyser in the most common range, the ozonator cannot give
a reduction from 80 % to 20 % according to section 1.7.5, then the highest range
which will give the reduction shall be used.
Adjustment of the FID
Optimization of the detector response
The HFID must be adjusted as specified by the instrument manufacturer. A
propane in air span gas should be used to optimize the response on the most
common operating range.
With the fuel and air flow rates set at the manufacturer's recommendations, a
350 ± 75 ppm C span gas shall be introduced to the analyser. The response at a
given fuel flow shall be determined from the difference between the span gas
response and the zero gas response. The fuel flow shall be incrementally
adjusted above and below the manufacturer's specification. The span and zero
response at these fuel flows shall be recorded. The difference between the span
and zero response shall be plotted and the fuel flow adjusted to the rich side of
the curve.
Hydrocarbon response factors
The analyser shall be calibrated using propane in air and purified synthetic air,
according to section 1.5.
Response factors shall be determined when introducing an analyser into service
and after major service intervals. The response factor (R f ) for a particular
hydrocarbon species is the ratio of the FID C1 reading to the gas concentration
in the cylinder expressed by ppm C1.
The concentration of the test gas must be at a level to give a response of
approximately 80 % of full scale. The concentration must be known to an
accuracy of ± 2 % in reference to a gravimetric standard expressed in volume. In
addition, the gas cylinder must be pre-conditioned for 24 hours at a temperature
of 298 K (25 o C) ± 5 K.
The test gases to be used and the recommended relative response factor ranges
are as follows
methane and purified synthetic air: 1,00 ≤ R f ≤ 1,15
propylene and purified synthetic air: 0,90 ≤ R f ≤ 1,1
toluene and purified synthetic air: 0,90 ≤ R f ≤ 1,10
These values are relative to the response factor (R f ) of 1,00 for propane and
purified synthetic air.
Oxygen interference check
The oxygen interference check shall be determined when introducing an
analyser into service and after major service intervals.
A range shall be chosen where the oxygen interference check gases will fall
within the upper 50 %. The test shall be conducted with the oven temperature
set as required.
O x y g e n i n t e r f e r e n c e g a s e s
Oxygen interference check gases shall contain propane with 350 ppmC ÷ 75
ppmC hydrocarbon. The concentration value shall be determined to calibration
gas tolerances by chromatographic analysis of total hydrocarbons plus
impurities or by dynamic blending. Nitrogen shall be the predominant diluent
with the balance oxygen. Blends required for Diesel engine testing are
P r o c e d u r e
(a) The analyser shall be zeroed.
(b) The analyser shall be spanned with the 21 % oxygen blend.
(c) The zero response shall be rechecked. If it has changed more than 0,5 % of
full scale clauses (a) and (b) shall be repeated.
(d) The 5 % and 10 % oxygen interference check gases shall be introduced.
(e) The zero response shall be rechecked. If it has changed more than ± 1 % of
full scale, the test shall be repeated.
(f) The oxygen interference (%O 2 I) shall be calculated for each mixture in (d)
as follows
A = hydrocarbon concentration (ppmC) of the span gas used in (b)
B = hydrocarbon concentration (ppmC) of the oxygen interference check gases
used in (d)
C = analyser response
D = percent of full scale analyser response due to A.
(g) The % of oxygen interference (%O 2 I) shall be less than ± 3,0 % for all
required oxygen interference check gases prior to testing.
(h) If the oxygen interference is greater than ± 3,0 %, the air flow above and
below the manufacturer's specifications shall be incrementally adjusted,
repeating clause 1.8.1 for each flow.
(i) If the oxygen interference is greater than ± 3,0 % after adjusting the air
flow, the fuel flow and thereafter the sample flow shall be varied, repeating
clause 1.8.1 for each new setting.
(j) If the oxygen interference is still greater than ± 3,0 %, the analyser, FID
fuel, or burner air shall be repaired or replaced prior to testing. This clause shall
then be repeated with the repaired or replaced equipment or gases.
Interference effects with NDIR and CLD analysers
Gases present in the exhaust other than the one being analysed can interfere with
the reading in several ways. Positive interference occurs in NDIR instruments
where the interfering gas gives the same effect as the gas being measured, but to
a lesser degree. Negative interference occurs in NDIR instruments by the
interfering gas broadening the absorption band of the measured gas, and in CLD
instruments by the interfering gas quenching the radiation. The interference
checks in sections 1.9.1 and 1.9.2 shall be performed prior to an analyser's
initial use and after major service intervals.
CO analyser interference check
Water and CO 2 can interfere with the CO analyser performance. Therefore a
CO 2 span gas having a concentration of 80 to 100 % of full scale of the
maximum operating range used during testing shall be bubbled through water at
room temperature and the analyser response recorded. The analyser response
must not be more than 1 % of full scale for ranges equal to or above 300 ppm or
more than 3 ppm for ranges below 300 ppm.
NO x analyser quench checks
The two gases of concern for CLD (and HCLD) analysers are CO 2 and water
vapour. Quench responses of these gases are proportional to their
concentrations, and therefore require test techniques to determine the quench at
the highest expected concentrations experienced during testing.
C O 2 q u e n c h c h e c k
A CO 2 span gas having a concentration of 80 to 100 % of full scale of the
maximum operating range shall be passed through the NDIR analyser and the
CO 2 value recorded as A. It shall then be diluted approximately 50 % with NO
span gas and passed through the NDIR and (H)CLD with the CO 2 and NO
values recorded as B and C, respectively. The CO 2 shall be shut off and only the
NO span gas be passed through the (H)CLD and the NO value recorded as D.
The quench shall be calculated as follows
and must not be greater than 3 % of full scale.
where
A: undiluted CO 2 concentration measured with NDIR %
B: diluted CO 2 concentration measured with NDIR %
C: diluted NO concentration measured with CLD ppm
D: undiluted NO concentration measured with CLD ppm
W a t e r q u e n c h c h e c k
This check applies to wet gas concentration measurements only. Calculation of
water quench must consider dilution of the NO span gas with water vapour and
scaling of water vapour concentration of the mixture to that expected during
testing. A NO span gas having a concentration of 80 to 100 % of full scale to the
normal operating range shall be passed through the (H)CLD and the NO value
recorded as D. The NO gas shall be bubbled through water at room temperature
and passed through the (H)CLD and NO value recorded as C. The water
temperature shall be determined and recorded as F. The mixture's saturation
vapour pressure that corresponds to the bubbler water temperature (F) shall be
determined and recorded as G. The water vapour concentration (in %) of the
mixture shall be calculated as follows
and recorded as H. The expected diluted NO span gas (in water vapour)
concentration shall be calculated as follows
and recorded as De. For diesel exhaust, the maximum exhaust water vapour
concentration (in %) expected during testing shall be estimated, under the
assumption of a fuel atom H/C ratio of 1,8 to 1, from the maximum CO 2
concentration in the exhaust gas or from the undiluted CO 2 span gas
concentration (A, as measured in section 1.9.2.1) as follows
Hm ¼ 0; 9 Ü A
and recorded as Hm.
The water quench shall be calculated as follows
and must not be greater than 3 % of full scale.
De: expected diluted NO concentration (ppm)
C: diluted NO concentration (ppm)
Hm: maximum water vapour concentration (%)
H: actual water vapour concentration (%)
NB: It is important that the NO span gas contains minimal NO 2 concentration
for this check, since obsorption of NO 2 in water has not been accounted for in
the quench calculations.
Calibration intervals
The analysers shall be calibrated according to section 1.5 at least every three
months or whenever a system repair or change is made that could influence
calibration.
Additional calibration requirements for raw exhaust measurements over NRTC
test
Response time check of the analytical system
The system settings for the response time evaluation shall be exactly the same as
during measurement of the test run (i.e. pressure, flow rates, filter settings on the
analysers and all other response time influences). The response time
determination shall be done with gas switching directly at the inlet of the sample
probe. The gas switching shall be done in less than 0,1 second. The gases used
for the test shall cause a concentration change of at least 60 % FS.
The concentration trace of each single gas component shall be recorded. The
response time is defined as the difference in time between the gas switching and
the appropriate change of the recorded concentration. The system response time
(t 90 ) consists of the delay time to the measuring detector and the rise time of the
detector. The delay time is defined as the time from the change (t 0 ) until the
response is 10 % of the final reading (t 10 ). The rise time is defined as the time
between 10 and 90 % response of the final reading (t 90 — t 10 ).
For time alignment of the analyser and exhaust flow signals in the case of raw
measurement, the transformation time is defined as the time from the change (t
0 ) until the response is 50 % of the final reading (t 50 ).
The system response time shall be ≤ 10 seconds with a rise time ≤ 2,5 seconds
for all limited components (CO, NO x , HC) and all ranges used.
Calibration of tracer gas analyser for exhaust flow measurement
The analyser for measurement of the tracer gas concentration, if used, shall be
calibrated using the standard gas.
The calibration curve shall be established by at least 10 calibration points
(excluding zero) spaced so that a half of the calibration points are placed
between 4 to 20 % of analyser's full scale and the rest are in between 20 to 100
% of the full scale. The calibration curve is calculated by the method of least
squares.
The calibration curve shall not differ by more than ± 1 % of the full scale from
the nominal value of each calibration point, in the range from 20 to 100 % of the
full scale. It shall also not differ by more than ± 2 % from the nominal value in
the range from 4 to 20 % of the full scale.
The analyser shall be set at zero and spanned prior to the test run using a zero
gas and a span gas whose nominal value is more than 80 % of the analyser full
scale.
2. CALIBRATION OF THE PARTICULATE MEASURING SYSTEM
Introduction
Each component shall be calibrated as often as necessary to fulfil the accuracy
requirements of this standard. The calibration method to be used is described in
this section for the components indicated in Schedule III, Appendix 1, section
1.5 and Schedule V.
Flow measurement
The calibration of gas flow-meters or flow measurement instrumentation shall
be traceable to national and/or international standards.
The maximum error of the measured value shall be within ± 2 % of reading.
For partial flow dilution systems, the accuracy of the sample flow G SE is of
special concern, if not measured directly, but determined by differential flow
measurement
G SE = G TOTW — G DILW
In this case an accuracy of ± 2 % for G TOTW and G DILW is not sufficient to
guarantee acceptable accuracies of G SE . If the gas flow is determined by
differential flow measurement, the maximum error of the difference shall be
such that the accuracy of G SE is within ± 5 % when the dilution ratio is less than
15. It can be calculated by taking root-mean-square of the errors of each
instrument.
Checking the dilution ratio
When using particulate sampling systems without EGA (Schedule V, section
1.2.1.1), the dilution ratio shall be checked for each new engine installation with
the engine running and the use of either the CO 2 or NO x concentration
measurements in the raw and dilute exhaust.
The measured dilution ratio shall be within ± 10 % of the calculated dilution
ratio from CO 2 or NO x concentration measurement.
Checking the partial flow conditions
The range of the exhaust gas velocity and the pressure oscillations shall be
checked and adjusted according to the requirements of Schedule V, section
1.2.1.1, EP, if applicable.
Calibration intervals
The flow measurement instrumentation shall be calibrated at least every three
months, or whenever a system change is made that could influence calibration.
Additional calibration requirements for partial flow dilution systems
Periodical calibration
If the sample gas flow is determined by differential flow measurement the flow
meter or the flow measurement instrumentation shall be calibrated by one of the
following procedures, such that the probe flow G SE into the tunnel fulfils the
accuracy requirements of Appendix I section 2.4
The flow meter for G DILW is connected in series to the flow meter for G TOTW ,
the difference between the two flow meters is calibrated for at least five set
points with flow values equally spaced between the lowest G DILW value used
during the test and the value of G TOTW used during the test The dilution tunnel
may be bypassed.
A calibrated mass flow device is connected in series to the flowmeter for G
TOTW and the accuracy is checked for the value used for the test. Then the
calibrated mass flow device is connected in series to the flow meter for G DILW
, and the accuracy is checked for at least five settings corresponding to the
dilution ratio between 3 and 50, relative to G TOTW used during the test.
The transfer tube TT is disconnected from the exhaust, and a calibrated flow
measuring device with a suitable range to measure G SE is connected to the
transfer tube. Then G TOTW is set to the value used during the test, and G DILW is
sequentially set to at least five values corresponding to dilution ratios q between
3 and 50. Alternatively, a special calibration flow path may be provided, in
which the tunnel is bypassed, but the total and dilution air flow through the
corresponding meters are maintained as in the actual test.
A tracer gas is fed into the transfer tube TT. This tracer gas may be a component
of the exhaust gas, like CO 2 or NO x . After dilution in the tunnel the tracer gas
component is measured. This shall be carried out for five dilution ratios between
3 and 50. The accuracy of the sample flow is determined from the dilution ration
q
G SE = G TOTW /q
The accuracies of the gas analysers shall be taken into account to guarantee the
accuracy of G SE .
Carbon flow check
A carbon flow check using actual exhaust is strongly recommended for
detecting measurement and control problems and verifying the proper operation
of the partial flow dilution system. The carbon flow check should be run at least
each time a new engine is installed, or something significant is changed in the
test cell configuration.
The engine shall be operated at peak torque load and speed or any other steady-
state mode that produces 5 % or more of CO 2 . The partial flow sampling system
shall be operated with a dilution factor of about 15 to 1.
Pre-test check
A pre-test check shall be performed within two hours before the test run in the
following way
The accuracy of the flow meters shall be checked by the same method as used
for calibration for at least two points, including flow values of G DILW that
correspond to dilution ratios between five and 15 for the G TOTW value used
during the test.
If it can be demonstrated by records of the calibration procedure described
above that the flow meter calibration is stable over a longer period of time, the
pre-test check may be omitted.
Determination of the transformation time
The system settings for the transformation time evaluation shall be exactly the
same as during measurement of the test run. The transformation time shall be
determined by the following method
An independent reference flowmeter with a measurement range appropriate for
the probe flow shall be put in series with and closely coupled to the probe. This
flow meter shall have a transformation time of less than 100 ms for the flow step
size used in the response time measurement, with flow restriction sufficiently
low not to affect the dynamic performance of the partial flow dilution system,
and consistent with good engineering practice.
A step change shall be introduced to the exhaust flow (or air flow if exhaust
flow is calculated) input of the partial flow dilution system, from a low flow to
at least 90 % of full scale. The trigger for the step change should be the same
one as that used to start the look-ahead control in actual testing. The exhaust
flow step stimulus and the flowmeter response shall be recorded at a sample rate
of at least 10 Hz.
From this data, the transformation time shall be determined for the partial flow
dilution system, which is the time from the initiation of the step stimulus to the
50 % point of the flowmeter response. In a similar manner, the transformation
times of the G SE signal of the partial flow dilution system and of the G EXHW
signal of the exhaust flow meter shall be determined. These signals are used in
the regression checks performed after each test (Appendix I section 2.4).
The calculation shall be repeated for at least five rise-and-fall stimuli, and the
results shall be averaged. The internal transformation time (< 100 ms) of the
reference flowmeter shall be subtracted from this value. This is the ‘look-ahead’
value of the partial flow dilution system, which shall be applied in accordance
with Appendix I section 2.4.
3. CALIBRATION OF THE CVS SYSTEM
General
The CVS system shall be calibrated by using an accurate flowmeter and means
to change operating conditions.
The flow through the system shall be measured at different flow operating
settings, and the control parameters of the system shall be measured and related
to the flow.
Various type of flowmeters may be used, e.g. calibrated venturi, calibrated
laminar flowmeter, calibrated turbine meter.
Calibration of the positive displacement pump (PDP)
All the parameters related to the pump shall be simultaneously measured along
with the parameters related to a calibration venturi which is connected in series
with the pump. The calculated flow rate (in m 3 /min at pump inlet, absolute
pressure and temperature) shall be plotted against a correlation function which
is the value of a specific combination of pump parameters. The linear equation
which relates the pump flow and the correlation function shall be determined. If
a CVS has a multiple speed drive, the calibration shall be performed for each
range used.
Temperature stability shall be maintained during calibration.
Leaks in all the connections and ducting between the calibration venturi and the
CVS pump shall be maintained lower than 0,3 % of the lowest flow point
(highest restriction and lowest PDP speed point).
Data analysis
The air flowrate (Q s ) at each restriction setting (minimum 6 settings) shall be
calculated in standard m 3 /min from the flowmeter data using the
manufacturer's prescribed method. The air flow rate shall then be converted to
pump flow (V 0 ) in m 3 /rev at absolute pump inlet temperature and pressure as
follows
where,
Q s = air flow rate at standard conditions (101,3 kPa, 273 K) (m 3 /s)
T = temperature at pump inlet (K)
p A = absolute pressure at pump inlet (p B - p 1) (kPa)
n = pump speed (rev/s)
To account for the interaction of pressure variations at the pump and the pump
slip rate, the correlation function (X 0 ) between pump speed, pressure
differential from pump inlet to pump outlet and absolute pump outlet pressure
shall be calculated as follows
where,
= absolute outlet pressure at pump outlet (kPa)
A linear least-square fit shall be performed to generate the calibration equation
as follows
D 0 and m are the intercept and slope constants, respectively, describing the
regression lines.
For a CVS system with multiple speeds, the calibration curves generated for the
different pump flow ranges shall be approximately parallel, and the intercept
values (D 0 ) shall increase as the pump flow range decreases.
The values calculated by the equation shall be within ± 0,5 % of the measured
value of V0 . Values of m will vary from one pump to another. Particulate influx
over time will cause the pump slip to decrease, as reflected by lower values for
m. Therefore, calibration shall be performed at pump start-up, after major
maintenance, and if the total system verification (section 3.5) indicates a change
in the slip rate.
Calibration of the critical flow venturi (CFV)
Calibration of the CFV is based upon the flow equation for a critical venturi.
Gas flow is a function of inlet pressure and temperature, as shown below
where,
K v = calibration coefficient
p A = absolute pressure at venturi inlet (kPa)
T = temperature at venturi inlet (K)
Data analysis
The air flow rate (Q s ) at each restriction setting (minimum 8 settings) shall be
calculated in standard m 3 /min from the flowmeter data using the
manufacturer's prescribed method. The calibration coefficient shall be
calculated from the calibration data for each setting as follows
where,
Q s = air flow rate at standard conditions (101,3 kPa, 273 K) (m 3 /s)
T = temperature at the venturi inlet (K)
p A = absolute pressure at venturi inlet (kPa)
To determine the range of critical flow, K v shall be plotted as a function of
venturi inlet pressure. For critical (choked) flow, K v will have a relatively
constant value. As pressure decreases (vacuum increases), the venturi becomes
unchoked and K v decreases, which indicates that the CFV is operated outside
the permissible range.
For a minimum of eight points in the region of critical flow, the average K V
and the standard deviation shall be calculated. The standard deviation shall not
exceed ± 0,3 % of the average K V
Calibration of the subsonic venturi (SSV)
Calibration of the SSV is based upon the flow equation for a subsonic venturi.
Gas flow is a function of inlet pressure and temperature, pressure drop between
the SSV inlet and throat, as shown below
Data analysis
The air flow rate (Q SSV ) at each flow setting (minimum 16 settings) shall be
calculated in standard m 3 /min from the flowmeter data using the manufacturer's
prescribed method. The discharge coefficient shall be calculated from the
calibration data for each setting as follows
To determine the range of subsonic flow, C d shall be plotted as a function of
Reynolds number, at the SSV throat. The Re at the SSV throat is calculated with
the following formula
Because Q SSV is an input to the Re formula, the calculations must be started
with an initial guess for Q SSV or C d of the calibration venturi, and repeated until
Q SSV converges. The convergence method must be accurate to 0,1 % or better.
For a minimum of sixteen points in the subsonic flow region, the calculated
values of C d from the resulting calibration curve fit equation must be within ±
0,5 % of the measured C d for each calibration point.
Total system verification
The total accuracy of the CVS sampling system and analytical system shall be
determined by introducing a known mass of a pollutant gas into the system
while it is being operated in the normal manner. The pollutant is analysed, and
the mass calculated according to Schedule III, Appendix 3, section 2.4.1 except
in the case of propane where a factor of 0,000472 is used in place of 0,000479
for HC. Either of the following two techniques shall be used.
Metering with a critical flow orifice
A known quantity of pure gas (propane) shall be fed into the CVS system
through a calibrated critical orifice. If the inlet pressure is high enough, the flow
rate, which is adjusted by means of the critical flow orifice, is independent of
the orifice outlet pressure (critical flow). The CVS system shall be operated as
in a normal exhaust emission test for about five to 10 minutes. A gas sample
shall be analysed with the usual equipment (sampling bag or integrating
method), and the mass of the gas calculated. The mass so determined shall be
within ± 3 % of the known mass of the gas injected.
Metering by means of a gravimetric technique
The weight of a small cylinder filled with propane shall be determined with a
precision of ± 0,01 g. For about five to 10 minutes, the CVS system shall be
operated as in a normal exhaust emission test, while carbon monoxide or
propane is injected into the system. The quantity of pure gas discharged shall be
determined by means of differential weighing. A gas sample shall be analysed
with the usual equipment (sampling bag or integrating method), and the mass of
the gas calculated. The mass so determined shall be within ± 3 % of the known
mass of the gas injected.
Appendix 3
DATA EVALUATION AND CALCULATIONS
1. DATA EVALUATION AND CALCULATIONS
Gaseous emissions data evaluation
For the evaluation of the gaseous emissions, the chart reading of the last 60
seconds of each mode shall be averaged, and the average concentrations (conc)
of HC, CO, NO x and CO 2 if the carbon balance method is used, during each
mode shall be determined from the average chart readings and the
corresponding calibration data. A different type of recording can be used if it
ensures an equivalent data acquisition.
The average background concentrations (conc d ) may be determined from the
bag readings of the dilution air or from the continous (non- bag) background
reading and the corresponding calibration data.
Particulate emissions
For the evaluation of the particulates, the total sample masses (MSAM, i)
through the filters shall be recorded for each mode. The filters shall be returned
to the weighing chamber and conditioned for at least one hour, but not more
than 80 hours, and then weighed. The gross weight of the filters shall be
recorded and the tare weight (see section 3.1, Schedule III) subtracted. The
particulate mass (Mf for single filter method; Mf, i for the multiple filter
method) is the sum of the particulate masses collected on the primary and back-
up filters. If background correction is to be applied, the dilution air mass
(MDIL) through the filters and the particulate mass (Md) shall be recorded. If
more than one measurement was made, the quotient Md/MDIL must be
calculated for each single measurement and the values averaged.
Calculation of the gaseous emissions
The finally reported test results shall be derived through the following steps
Determination of the exhaust gas flow
The exhaust gas flow rate (G EXHW ,) shall be determined for each mode
according to Schedule III, Appendix 1, sections 1.2.1. to 1.2.3.
When using a full flow dilution system, the total dilute exhaust gas flow rate (G
TOTW ,) shall be determined for each mode according to Schedule III, Appendix
1, section 1.2.4.
Dry/wet correction
Dry/wet correction (G EXHW ,) shall be determined for each mode according to
Schedule III, Appendix 1, sections 1.2.1. to 1.2.3.
When applying G EXHW the measured concentration shall be converted to a wet
basis according to the following formulae, if not already measured on a wet
basis
conc (wet) = k w × conc (dry)
Humidity correction for NO x
As the NO x emission depends on ambient air conditions, the NO x concentration
shall be corrected for ambient air temperature and humidity by the factors K H
given in the following formula
1.3.4
Calculation of emission mass flow rates
The emission mass flow rates for each mode shall be calculated as follows
For the raw exhaust gas ( 13 )
Gas mass = u × conc × G EXHW
(b) For the dilute exhaust gas ( 13 )
Gas mass = u × conc c × G TOTW
In the case of NO x , the NO x concentration (NO x conc or NO x conc c ) has to be multiplied by K HNO x (humidity correction factor for
NO x quoted in section 1.3.3) as follows: K HNO x x conc or K HNO x x conc c
Calculation of the specific emissions
The specific emission (g/kWh) shall be calculated for all individual components
in the following way
The weighting factors and the number of modes (n) used in the above
calculation are according to Schedule III, section 3.7.1.
Calculation of the particulate emission
The particulate emission shall be calculated in the following way
Humidity correction factor for particulates
As the particulate emission of diesel engines depends on ambient air conditions,
the particulate mass flow rate shall be corrected for ambient air humidity with
the factor K p given in the following formula
where
R a : relative humidity of the intake air (%)
p a : saturation vapour pressure of the intake air (kPa)
p B : total barometric pressure (kPa)
Note: H a may be derived from relative humidity measurement, as described
above, or from dewpoint measurement, vapour pressure measurement or dry/
wet bulb measurement using the generally accepted formulae
Partial flow dilution system
The final reported test results of the particulate emission shall be derived
through the following steps. Since various types of dilution rate control may be
used, different calculation methods for equivalent diluted exhaust gas mass flow
rate G EDF apply. All calculations shall be based upon the average values of the
individual modes (i) during the sampling period.
I s o k i n e t i c s y s t e m s
S y s t e m s w i t h m e a s u r e m e n t o f C O 2 o r N O x c o n c e n t r a t i o n
S y s t e m s w i t h C O 2 m e a s u r e m e n t a n d c a r b o n b a l a n c e m e t h
o d
where
CO 2D = CO 2 concentration of the diluted exhaust
CO 2A = CO 2 concentration of the dilution air
(concentrations in volume % on wet basis)
This equation is based upon the carbon balance assumption (carbon atoms
supplied to the engine are emitted as CO 2 ) and derived through the following
steps
G EDFW, i = G EXHW, i × q i
and
S y s t e m s w i t h f l o w m e a s u r e m e n t
Full flow dilution system
The final reported test results of the particulate emission shall be derived
through the following steps.
All calculations shall be based upon the average values of the individual modes
(i) during the sampling period.
G EDFW, i = G TOTW, i
Calculation of the particulate mass flow rate
The particulate mass flow rate shall be calculated as follows
For the single filter method
where
(G EDFW ) aver over the test cycle shall be determined by summation of the
average values of the individual modes during the sampling period
The particulate mass flow rate may be background corrected as follows
For single filter method
If more than one measurement is made, (M d /M DIL ) shall be replaced with (M d
/M DIL ) aver
or
DF=13,4/concCO 2
For multiple filter method
If more than one measurement is made, (M d /M DIL ) shall be replaced with (M d
/M DIL ) aver
or
DF= 13,4/concCO 2
Calculation of the specific emissions
The specific emission of particulates PT (g/kWh) shall be calculated in the
following way ( 14 )
For the single filter method
For the multiple filter method
Effective weighting factor
For the single filter method, the effective weighting factor WF E, i for each
mode shall be calculated in the following way
where i = l, . . . n.
The value of the effective weighting factors shall be within ± 0,005 (absolute
value) of the weighting factors listed in Schedule III, section 3.7.1.
2. DATA EVALUATION AND CALCULATIONS (NRTC TEST)
The two following measurement principles that can be used for the evaluation of
pollutant emissions over the NRTC cycle are described in this section
the gaseous components are measured in the raw exhaust gas on a real-time
basis, and the particulates are determined using a partial flow dilution system,
the gaseous components and the particulates are determined using a full flow
dilution system (CVS system).
Calculation of gaseous emissions in the raw exhaust gas and of the particulate
emissions with a partial flow dilution system
The particulate mass flow rate PT mass has to be multiplied by Kp (humidity correction factor for particulates quoted in section 1.4.1).
Introduction
The instantaneous concentration signals of the gaseous components are used for
the calculation of the mass emissions by multiplication with the instantaneous
exhaust mass flow rate. The exhaust mass flow rate may be measured directly,
or calculated using the methods described in Schedule III, Appendix 1, section
2.2.3 (intake air and fuel flow measurement, tracer method, intake air and air/
fuel ratio measurement). Special attention shall be paid to the response times of
the different instruments. These differences shall be accounted for by time
aligning the signals.
For particulates, the exhaust mass flow rate signals are used for controlling the
partial flow dilution system to take a sample proportional to the exhaust mass
flow rate. The quality of proportionality is checked by applying a regression
analysis between sample and exhaust flow as described in Schedule III,
Appendix 1, section 2.4.
Determination of the gaseous components
C a l c u l a t i o n o f m a s s e m i s s i o n
The mass of the pollutants M gas (g/test) shall be determined by calculating the
instantaneous mass emissions from the raw concentrations of the pollutants, the
u values from Table 4 (see also Section 1.3.4) and the exhaust mass flow,
aligned for the transformation time and integrating the instantaneous values
over the cycle. Preferably, the concentrations should be measured on a wet
basis. If measured on a dry basis, the dry/wet correction as described here below
shall be applied to the instantaneous concentration values before any further
calculation is done.
The following formula shall be applied
where
u = ratio between density of exhaust component and density of
exhaust gas
conc i = instantaneous concentration of the respective component
in the raw exhaust gas (ppm)
G EXHW, i = instantaneous exhaust mass flow (kg/s)
f = data sampling rate (Hz)
n = number of measurements
For the calculation of NO x , the humidity correction factor k H , as
described here below, shall be used.
The instantaneously measured concentration shall be converted to
a wet basis as described here below, if not already measured on a
wet basis
D r y / w e t c o r r e c t i o n
If the instantaneously measured concentration is measured on a
dry basis, it shall be converted to a wet basis according to the
following formulae
Note: H a may be derived from relative humidity measurement, as
described above, or from dewpoint measurement, vapour pressure
measurement or dry/wet bulb measurement using the generally
accepted formulae.
N O x c o r r e c t i o n f o r h u m i d i t y a n d t e m p e r a t u r e
As the NO x emission depends on ambient air conditions, the NO x
concentration shall be corrected for humidity and ambient air
temperature with the factors given in the following formula
Note: H a may be derived from relative humidity measurement, as
described above, or from dewpoint measurement, vapour pressure
measurement or dry/wet bulb measurement using the generally
accepted formulae.
C a l c u l a t i o n o f t h e s p e c i f i c e m i s s i o n s
The specific emissions (g/kWh) shall be calculated for each
individual component in the following way
where
M gas,cold = total mass of gaseous pollutant over the cold start
cycle (g)
M gas,hot = total mass of gaseous pollutant over the hot start cycle
(g)
W act,cold = actual cycle work over the cold start cycle as
determined in Schedule III section 4.6.2 (kWh)
W act,hot = actual cycle work over the hot start cycle as determined
in Schedule III section 4.6.2 (kWh)
Particulate determination
C a l c u l a t i o n o f m a s s e m i s s i o n
The particulate masses M PT , cold and M PT , hot (g/test) shall be
calculated by either of the following methods
where
M PT = M PT,cold for the cold start cycle
M PT = M PT,hot for the hot start cycle
M f = particulate mass sampled over the cycle (mg)
M EDFW = mass of equivalent diluted exhaust gas over the cycle
(kg)
M SAM = mass of diluted exhaust gas passing the particulate
collection filters (kg)
The total mass of equivalent diluted exhaust gas mass over the
cycle shall be determined as follows
where
G EDFW,i = instantaneous equivalent diluted exhaust mass flow
rate (kg/s)
G EXHW,i = instantaneous exhaust mass flow rate (kg/s)
q i = instantaneous dilution ratio
G TOTW,i = instantaneous diluted exhaust mass flow rate through
dilution tunnel (kg/s)
G DILW,i = instantaneous dilution air mass flow rate (kg/s)
f = data sampling rate (Hz)
n = number of measurements
where
M PT = M PT,cold for the cold start cycle
M PT = M PT,hot for the hot start cycle
M f = particulate mass sampled over the cycle (mg)
r s = average sample ratio over the test cycle
where
M SE = sampled exhaust mass over the cycle (kg)
M EXHW = total exhaust mass flow over the cycle (kg)
M SAM = mass of diluted exhaust gas passing the particulate
collection filters (kg)
M TOTW = mass of diluted exhaust gas passing the dilution tunnel
(kg)
NOTE: In case of the total sampling type system, M SAM and M
TOTW are identical
P a r t i c u l a t e c o r r e c t i o n f a c t o r f o r h u m i d i t y
As the particulate emission of diesel engines depends on ambient
air conditions, the particulate concentration shall be corrected for
ambient air humidity with the factor Kp given in the following
formula.
where
H a = humidity of the intake air in g water per kg dry air
R a : relative humidity of the intake air (%)
p a : saturation vapour pressure of the intake air (kPa)
p B : total barometric pressure (kPa)
Note: H a may be derived from relative humidity measurement, as
described above, or from dewpoint measurement, vapour pressure
measurement or dry/wet bulb measurement using the generally
accepted formulae.
C a l c u l a t i o n o f t h e s p e c i f i c e m i s s i o n s
The specific emissions (g/kWh) shall be calculated for in the
following way
where
M PT,cold = particulate mass over the cold start cycle (g/test)
M PT,hot = particulate mass over the hot start cycle (g/test)
K p, cold = humidity correction factor for particulate over the cold
start cycle
K p, hot = humidity correction factor for particulate over the hot
start cycle
W act, cold = actual cycle work over the cold start cycle as
determined in section 4.6.2. of Schedule III, (kWh)
W act, hot = actual cycle work over the hot start cycle as determined
in section 4.6.2. of Schedule III, (kWh)
Determination of gaseous and particulate components with a
full flow dilution system
For calculation of the emissions in the diluted exhaust gas, it is
necessary to know the diluted exhaust gas mass flow rate. The
total diluted exhaust gas flow over the cycle M TOTW (kg/test) shall
be calculated from the measurement values over the cycle and the
corresponding calibration data of the flow measurement device (V
0 for PDP, K V for CFV, C d for SSV): the corresponding methods
described in section 2.2.1 may be used. If the total sample mass of
particulates (M SAM ) and gaseous pollutants exceeds 0,5 % of the
total CVS flow (M TOTW ), the CVS flow shall be corrected for M
SAM or the particulate sample flow shall be returned to the CVS
prior to the flow measuring device.
D e t e r m i n a t i o n o f t h e d i l u t e d e x h a u s t g a s f l o w
PDP-CVS system
The calculation of the mass flow over the cycle, if the temperature
of the diluted exhaust is kept within ± 6 K over the cycle by using
a heat exchanger, is as follows
M TOTW = 1,293 x V 0 x N P x (p B - p 1 ) x 273/(101,3 x T)
where
M TOTW = mass of the diluted exhaust gas on wet basis over the
cycle
V 0 = volume of gas pumped per revolution under test conditions
(m 3 /rev)
N P = total revolutions of pump per test
p B = atmospheric pressure in the test cell (kPa)
p 1 = pressure drop below atmospheric at the pump inlet (kPa)
T = average temperature of the diluted exhaust gas at pump inlet
over thecycle (K)
If a system with flow compensation is used (i.e. without heat
exchanger), the instantaneous mass emissions shall be calculated
and integrated over the cycle. In this case, the instantaneous mass
of the diluted exhaust gas shall be calculated as follows
M TOTW,i = 1,293 × V 0 × N P, i x (p B – p 1 ) × 273/(101,3 x T)
where
N P , i = total revolutions of pump per time interval
CFV-CVS system
The calculation of the mass flow over the cycle, if the temperature
of the diluted exhaust gas is kept within ± 11 K over the cycle by
using a heat exchanger, is as follows
M TOTW = 1,293 × t × K v × p A /T 0,5
where
M TOTW = mass of the diluted exhaust gas on wet basis over the
cycle
t = cycle time (s)
K V = calibration coefficient of the critical flow venturi for
standard conditions,
p A = absolute pressure at venturi inlet (kPa)
T = absolute temperature at venturi inlet (K)
If a system with flow compensation is used (i.e. without heat
exchanger), the instantaneous mass emissions shall be calculated
and integrated over the cycle. In this case, the instantaneous mass
of the diluted exhaust gas shall be calculated as follows
M TOTW,i = 1,293 × Δt i × K V × p A /T 0,5
where
Δt i = time interval(s)
SSV-CVS system
The calculation of the mass flow over the cycle is as follows if the
temperature of the diluted exhaust is kept within ± 11 K over the
cycle by using a heat exchanger
If a system with flow compensation is used (i.e. without heat
exchanger), the instantaneous mass emissions shall be calculated
and integrated over the cycle. In this case, the instantaneous mass
of the diluted exhaust gas shall be calculated as follows
The real time calculation shall be initialised with either a
reasonable value for C d , such as 0.98, or a reasonable value of Q
ssv . If the calculation is initialised with Q ssv , the initial value of Q
ssv shall be used to evaluate Re.
During all emissions tests, the Reynolds number at the SSV throat
must be in the range of Reynolds numbers used to derive the
calibration curve developed in Appendix 2 section 3.2.
NO x correction for humidity
As the NO x emission depends on ambient air conditions, the NO x
concentration shall be corrected for ambient air humidity with the
factors given in the following formulae.
R a = relative humidity of the intake air (%)
p a = saturation vapour pressure of the intake air (kPa)
p B = total barometric pressure (kPa)
Note: H a may be derived from relative humidity measurement, as
described above, or from dewpoint measurement, vapour pressure
measurement or dry/wet bulb measurement using the generally
accepted formulae.
Calculation of the emission mass flow
S y s t e m s w i t h c o n s t a n t m a s s f l o w
For systems with heat exchanger, the mass of the pollutants M GAS
(g/test) shall be determined from the following equation
M gaz = u × conc × M TOTW
where
u = ratio between density of the exhaust component and density of
diluted exhaust gas, as reported in Table 4, point 2.1.2.1
conc = average background corrected concentrations over the
cycle from integration (mandatory for NO x and HC) or bag
measurement (ppm)
M TOTW = total mass of diluted exhaust gas over the cycle as
determined in section 2.2.1 (kg)
As the NO x emission depends on ambient air conditions, the NO x
concentration shall be corrected for ambient air humidity with the
factor k H , as described in section 2.2.2.
Concentrations measured on a dry basis shall be converted to a wet
basis in accordance with section 1.3.2.
Determination of the background corrected concentrations
The average background concentration of the gaseous pollutants in
the dilution air shall be subtracted from measured concentrations
to get the net concentrations of the pollutants. The average values
of the background concentrations can be determined by the sample
bag method or by continuous measurement with integration. The
following formula shall be used.
conc = conc e – conc d × (1 – (1/DF))
where,
conc = concentration of the respective pollutant in the diluted
exhaust gas, corrected by the amount of the respective pollutant
contained in the dilution air (ppm)
conc e = concentration of the respective pollutant measured in the
diluted exhaust gas (ppm)
conc d = concentration of the respective pollutant measured in the
dilution air (ppm)
DF = dilution factor
The dilution factor shall be calculated as follows
Systems with flow compensation
For systems without heat exchanger, the mass of the pollutants M
GAS (g/test) shall be determined by calculating the instantaneous
mass emissions and integrating the instantaneous values over the
cycle. Also, the background correction shall be applied directly to
the instantaneous concentration value. The following formulae
shall be applied
where
conc e, i = instantaneous concentration of the respective pollutant
measured in the diluted exhaust gas (ppm)
conc d = concentration of the respective pollutant measured in the
dilution air (ppm)
u = ratio between density of the exhaust component and density of
diluted exhaust gas, as reported in Table 4, point 2.1.2.1
M TOTW, i = instantaneous mass of the diluted exhaust gas (section
2.2.1) (kg)
M TOTW = total mass of diluted exhaust gas over the cycle (section
2.2.1) (kg)
DF = dilution factor as determined in point 2.2.3.1.1.
As the NO x emission depends on ambient air conditions, the NO x
concentration shall be corrected for ambient air humidity with the
factor k H , as described in section 2.2.2.
Calculation of the specific emissions
The specific emissions (g/kWh) shall be calculated for each
individual component in the following way
where
M gas,cold = total mass of gaseous pollutant over the cold start
cycle (g)
M gas,hot = total mass of gaseous pollutant over the hot start cycle
(g)
W act,cold = actual cycle work over the cold start cycle as
determined in section 4.6.2. of Schedule III (kWh)
W act,hot = actual cycle work over the hot start cycle as determined
in section 4.6.2. of Schedule III. (kWh)
Calculation of the particulate emission
C a l c u l a t i o n o f t h e m a s s f l o w
The particulate masses M PT , cold and M PT,hot (g/test) shall be
calculated as follows
where
M PT = M PT,cold for the cold start cycle
M PT = M PT,hot for the hot start cycle
M f = particulate mass sampled over the cycle (mg)
M TOTW = total mass of diluted exhaust gas over the cycle as
determined in section 2.2.1. (kg)
M SAM = mass of diluted exhaust gas taken from the dilution
tunnel for collecting particulates (kg)
and,
M f = M f,p + M f,b , if weighed separately (mg)
M f,p = particulate mass collected on the primary filter (mg)
M f,b = particulate mass collected on the back-up filter (mg)
If a double dilution system is used, the mass of the secondary
dilution air shall be subtracted from the total mass of the double
diluted exhaust gas sampled through the particulate filters.
where,
M TOT = mass of double diluted exhaust gas through particulate
filter (kg)
M SEC = mass of secondary dilution air (kg)
If the particulate background level of the dilution air is determined
in accordance with section 4.4.4 of Schedule III, the particulate
mass may be background corrected. In this case, the particulate
masses M PT,cold and M PT,hot (g/test) shall be calculated as
follows
where
M PT = M PT,cold for the cold start cycle
M PT = M PT,hot for the hot start cycle
M f , M SAM , M TOTW = see above
M DIL = mass of primary dilution air sampled by background
particulate sampler (kg)
M d = mass of the collected background particulates of the primary
dilution air (mg)
DF = dilution factor as determined in section 2.2.3.1.1
P a r t i c u l a t e c o r r e c t i o n f a c t o r f o r h u m i d i t y
As the particulate emission of diesel engines depends on ambient
air conditions, the particulate concentration shall be corrected for
ambient air humidity with the factor Kp given in the following
formula.
where
H a = humidity of the intake air in g water per kg dry air
where
R a : relative humidity of the intake air ( %)
p a : saturation vapour pressure of the intake air (kPa)
p B : total barometric pressure (kPa)
Note: H a may be derived from relative humidity measurement, as
described above, or from dewpoint measurement, vapour pressure
measurement or dry/wet bulb measurement using the generally
accepted formulae.
C a l c u l a t i o n o f t h e s p e c i f i c e m i s s i o n s
The specific emissions (g/kWh) shall be calculated for in the
following way
where
M PT,cold = particulate mass over the cold start cycle of NRTC, (g/
test)
M PT,hot = particulate mass over the hot start cycle of NRTC, (g/
test)
K p, cold = humidity correction factor for particulate over the cold
start cycle
K p, hot = humidity correction factor for particulate over the hot
start cycle
W act, cold = actual cycle work over the cold start cycle as
determined in section 4.6.2. of Schedule III, (kWh)
W act, hot = actual cycle work over the hot start cycle as determined
in section 4.6.2 of Schedule III, (kWh)
Appendix 4
NRTC ENGINE DYNAMOMETER SCHEDULE
A graphical display of the NRTC dynamometer schedule is shown
below
.
.
Appendix 5
DURABILITY REQUIREMENTS
1. EMISSION DURABILITY PERIOD AND DETERIORATION FACTORS.
This appendix shall apply to CI engines Stage IIIA and IIIB and IV only.
Manufacturers shall determine a Deterioration Factor (DF) value for each
regulated pollutant for all Stage IIIA and IIIB engine families. Such DFs shall
be used for type approval and production line testing.
Test to establish DFs shall be conducted as follows
The manufacturer shall conduct durability tests to accumulate engine operating
hours according to a test schedule that is selected on the basis of good
engineering judgement to be representative of in-use engine operation in
respect to characterising emission performance deterioration. The durability test
period should typically represent the equivalent of at least one quarter of the
emission durability period (EDP).
Service accumulation operating hours may be acquired through running engines
on a dynamometer test bed or from actual in-field machine operation.
Accelerated durability tests can be applied whereby the service accumulation
test schedule is performed at a higher load factor than typically experienced in
the field. The acceleration factor relating the number of engine durability test
hours to the equivalent number of EDP hours shall be determined by the engine
manufacturer based on good engineering judgement.
During the period of the durability test, no emission sensitive components can
be serviced or replaced other than to the routine service schedule recommended
by the manufacturer.
The test engine, subsystems, or components to be used to determine exhaust
emission DFs for an engine family, or for engine families of equivalent
emission control system technology, shall be selected by the engine
manufacturer on the basis of good engineering judgement. The criterion is that
the test engine should represent the emission deterioration characteristic of the
engine families that will apply the resulting DF values for certification
approval. Engines of different bore and stroke, different configuration, different
air management systems, different fuel systems can be considered as equivalent
in respect to emissions deterioration characteristics if there is a reasonable
technical basis for such determination.
DF values from another manufacturer can be applied if there is a reasonable
basis for considering technology equivalence with respect to emissions
deterioration, and evidence that the tests have been carried according to the
specified requirements.
Emissions testing will be performed according to the procedures defined in
these regulations for the test engine after initial run-in but before any service
accumulation, and at the completion of the durability. Emission tests can also
be performed at intervals during the service accumulation test period, and
applied in determining the deterioration trend.
The service accumulation tests or the emissions tests performed to determine
deterioration must not be witnessed by the approval authority.
Determination of DF values from durability tests
An additive DF is defined as the value obtained by subtraction of the emission
value determine at the beginning of the EDP, from the emissions value
determined to represent the emission performance at the end of the EDP.
A multiplicative DF is defined as the emission level determined for the end of
the EDP divided by the emission value recorded at the beginning of the EDP.
Separate DF values shall be established for each of the pollutants covered by
the legislation. In the case of establishing a DF value relative to the NO x +HC
standard, for an additive DF, this is determined based on the sum of the
pollutants notwithstanding that a negative deterioration for one pollutant may
not offset deterioration for the other. For a multiplicative NO x +HC DF,
separate HC and NO x DFs shall be determined and applied separately when
calculating the deteriorated emission levels from an emissions test result before
combining the resultant deteriorated NO x and HC values to establish
compliance with the standard.
In cases where the testing is not conducted for the full EDP, the emission values
at the end of the EDP is determined by extrapolation of the emission
deterioration trend established for the test period, to the full EDP.
When emissions test results have been recorded periodically during the service
accumulation durability testing, standard statistical processing techniques based
on good practice shall be applied to determine the emission levels at the end of
the EDP; statistical significance testing can be applied in the determination of
the final emissions values.
If the calculation results in a value of less than 1,00 for a multiplicative DF, or
less than 0,00 for an additive DF, then the DF shall be 1,0 or 0,00, respectively.
A manufacturer may, with the approval of the type approval authority, use DF
values established from results of durability tests conducted to obtain DF values
for certification of on-road HD CI engines. This will be allowed if there is
technological equivalency between the test on- road engine and the non-road
engine families applying the DF values for certification. The DF values derived
from on-road engine emission durability test results, must be calculated on the
basis of EDP values defined in section 2.
In the case where an engine family uses established technology, an analysis
based on good engineering practices may be used in lieu of testing to determine
a deterioration factor for that engine family subject to approval of the type
approval authority.
DF information in approval applications
Additive DFs shall be specified for each pollutant in an engine family
certification application for CI engines not using any after-treatment device.
Multiplicative DFs shall be specified for each pollutant in an engine family
certification application for CI engines using an after-treatment device.
The manufacture shall furnish the type-approval agency on request with
information to support the DF values. This would typically include emission
test results, service accumulation test schedule, maintenance procedures
together with information to support engineering judgements of technological
equivalency, if applicable.
2. EMISSION DURABILITY PERIODS FOR STAGE IIIA, IIIB AND IV
ENGINES.
Manufacturers shall use the EDP in Table 1 of this section.
Schedule IV
TEST PROCEDURE FOR SPARK IGNITION ENGINES
1. INTRODUCTION
This Schedule describes the method of determining emissions of gaseous
pollutants from the engines to be tested.
The test shall be carried out with the engine mounted on a test bench and
connected to a dynamometer.
2. TEST CONDITIONS
Engine test conditions
The absolute temperature (T a ) of the engine air at the inlet to the engine,
expressed in Kelvin, and the dry atmospheric pressure (p s ), expressed in kPa,
shall be measured and the parameter f a shall be determined according to the
following provisions
Test validity
For a test to be recognised as valid, the parameter f a shall be such that
0; 93 ≤ f a ≤ 1; 07
Engines with charge air-cooling
The temperature of the cooling medium and the temperature of the charge air
have to be recorded.
Engine air inlet system
The test engine shall be equipped with an air inlet system presenting an air inlet
restriction within 10 % of the upper limit specified by the manufacturer for a
new air cleaner at the engine operating conditions, as specified by the
manufacturer, which result in maximum air flow in the respective engine
application.
For small spark ignition engines (< 1 000 cm 3 displacement) a system
representative of the installed engine shall be used.
Engine exhaust system
The test engine shall be equipped with an exhaust system presenting an exhaust
back pressure within 10 % of the upper limit specified by the manufacturer for
the engine operating conditions which result in the maximum declared power in
the respective engine application.
For small spark ignition engines (< 1 000 cm 3 displacement) a system
representative of the installed engine shall be used.
Cooling system
An engine cooling system with sufficient capacity to maintain the engine at
normal operating temperatures prescribed by the manufacturer shall be used.
This provision shall apply to units which have to be detached in order to
measure the power, such as with a blower where the blower (cooling) fan has to
be disassembled to get access to the crankshaft.
Lubricating oil
Lubricating oil that meets the engine manufacturer's specifications for a
particular engine and intended usage shall be used. Manufacturers must use
engine lubricants representative of commercially available engine lubricants.
The specifications of the lubricating oil used for the test shall be recorded at
section 1.2 of Schedule VII, Appendix 2, for SI engines and presented with the
results of the test.
Adjustable carburettors
Engines with limited adjustable carburettors shall be tested at both extremes of
the adjustment.
Test fuel
The fuel shall be the reference fuel specified in Schedule V.
The octane number and the density of the reference fuel used for test shall be
recorded at section 1.1.1 of Schedule VII, Appendix 2, for SI engines.
For two-stroke engines, the fuel/oil mixture ratio must be the ratio which shall
be recommended by the manufacturer. The percentage of oil in the fuel/
lubricant mixture feeding the two-stroke engines and the resulting density of the
fuel shall be recorded at section 1.1.4 of Schedule VII, Appendix 2, for SI
engines.
Determination of dynamometer settings
Emissions measurements shall be based on uncorrected brake power.
Auxiliaries necessary only for the operation of the machine and which may be
mounted on the engine shall be removed for the test. Where auxiliaries have not
been removed, the power absorbed by them shall be determined in order to
calculate the dynamometer settings except for engines where such auxiliaries
form an integral part of the engine (e.g. cooling fans for air cooled engines).
The settings of inlet restriction and exhaust pipe backpressure shall be adjusted,
for engines where it shall be possible to perform such an adjustment, to the
manufacturer's upper limits, in accordance with sections 2.2 and 2.3. The
maximum torque values at the specified test speeds shall be determined by
experimentation in order to calculate the torque values for the specified test
modes. For engines which are not designed to operate over a speed range on a
full load torque curve, the maximum torque at the test speeds shall be declared
by the manufacturer. The engine setting for each test mode shall be calculated
using the formula
where
S is the dynamometer setting [kW],
P M is the maximum observed or declared power at the test speed under the test
conditions (see Appendix 2 of Schedule VII) [kW],
P AE is the declared total power absorbed by any auxiliary fitted for the test
[kW] and not required by Appendix 3 of Schedule VII,
L is the percent torque specified for the test mode.
If the ratio
the value of P AE may be verified by the technical authority granting type-
approval.
3. TEST RUN
Installation of the measuring equipment
The instrumentation and sampling probes shall be installed as required. When
using a full flow dilution system for exhaust gas dilution, the tailpipe shall be
connected to the system.
Starting the dilution system and engine
The dilution system and the engine shall be started and warmed up until all
temperatures and pressures have stabilised at full load and rated speed (section
3.5.2).
Adjustment of the dilution ratio
The total dilution ratio shall not be less than four.
For CO 2 or NO x concentration controlled systems, the CO 2 or NO x content of
the dilution air must be measured at the beginning and at the end of each test.
The pre- and post-test background CO 2 or NO x concentration measurements of
the dilution air must be within 100 ppm or 5 ppm of each other, respectively.
When using a dilute exhaust gas analysis system, the relevant background
concentrations shall be determined by sampling dilution air into a sampling bag
over the complete test sequence.
Continuous (non-bag) background concentration may be taken at the minimum
of three points, at the beginning, at the end, and a point near the middle of the
cycle and averaged. At the manufacturer's request background measurements
may be omitted.
Checking the analysers
The emission analysers shall be set at zero and spanned.
Test cycle
Specification (c) of machinery according to section 1A(iii) of Schedule I.
The following test cycles shall be followed in dynamometer operation on the
test engine according to the given type of machinery
cycle D ( 1 ): engines with constant speed and intermittent load such as
generating sets;
cycle G1: non-hand-held intermediate speed applications;
cycle G2: non-hand-held rated speed applications;
cycle G3: hand-held applications.
1 Identical with D2 cycle of the ISO 8168-4: 1996(E) standard.
T e s t m o d e s a n d w e i g h t i n g f a c t o r s
C h o o s i n g a n a p p r o p r i a t e t e s t c y c l e
If the primary end use of an engine model is known then the test cycle may be
chosen based on the examples given in section 3.5.1.3. If the primary end use of
an engine is uncertain then the appropriate test cycle should be chosen based
upon the engine specification.
E x a m p l e s ( t h e l i s t i s n o t e x h a u s t i v e )
Typical examples are for
cycle D
generating sets with intermittent load including generating sets on board ships
and trains (not for propulsion), refrigerating units, welding sets;
gas compressors;
cycle G1
front or rear engines riding lawn mowers;
golf carts;
lawn sweepers;
pedestrian-controlled rotary or cylinder lawn mowers;
snow-removal equipment;
waste disposers;
cycle G2
portable generators, pumps, welders and air compressors;
may also include lawn and garden equipment, which operate at engine rated
speed;
cycle G3
blowers;
chain saws;
hedge trimmers;
portable saw mills;
rotary tillers;
sprayers;
string trimmers;
vacuum equipment.
Conditioning of the engine
Warming up of the engine and the system shall be at maximum speed and
torque in order to stabilise the engine parameters according to the
recommendations of the manufacturer.
Note: The conditioning period should also prevent the influence of deposits
from a former test in the exhaust system. There is also a required period of
stabilisation between test points which has been included to minimise point to
point influences.
Test sequence
Test cycles G1, G2 or G3 shall be performed in ascending order of mode
number of the cycle in question. Each mode sampling time shall be at least 180
s. The exhaust emission concentration values shall be measured and recorded
for the last 120 s of the respective sampling time. For each measuring point, the
mode length shall be of sufficient duration to achieve thermal stability of the
engine prior to the start of sampling. The mode length shall be recorded and
reported.
For engines tested with the dynamometer speed control test configuration
During each mode of the test cycle after the initial transition period, the
specified speed shall be held to within ± 1 % of rated speed or ± 3 min -1
whichever is greater except for low idle which shall be within the tolerances
declared by the manufacturer. The specified torque shall be held so that the
average over the period during which the measurements are being taken is
within ± 2 % of the maximum torque at the test speed.
For engines tested with the dynamometer load control test configuration
During each mode of the test cycle after the initial transition period, the
specified speed shall be within ± 2 % of rated speed or ± 3 min -1 whichever is
greater, but shall in any case be held within ± 5 %, except for low idle which
shall be within the tolerances declared by the manufacturer.
During each mode of the test cycle where the prescribed torque is 50 % or
greater of the maximum torque at the test speed the specified average torque
over the data acquisition period shall be held within ± 5 % of the prescribed
torque. During modes of the test cycle where the prescribed torque is less than
50 % of the maximum torque at the test speed the specified average torque over
the data acquisition period shall be held within ± 10 % of the prescribed torque
or ± 0,5 Nm whichever is greater.
Analyser response
The output of the analysers shall be recorded on a strip chart recorder or
measured with an equivalent data acquisition system with the exhaust gas
flowing through the analysers at least during the last 180 s of each mode. If bag
sampling is applied for the diluted CO and CO 2 measurement (see Appendix 1,
section 1.4.4), a sample shall be bagged during the last 180 s of each mode, and
the bag sample analysed and recorded.
Engine conditions
The engine speed and load, intake air temperature and fuel flow shall be
measured for each mode once the engine has been stabilised. Any additional
data required for calculation shall be recorded (see Appendix 3, sections 1.1 and
1.2).
Rechecking the analysers
After the emission test a zero gas and the same span gas shall be used for re-
checking. The test shall be considered acceptable if the difference between the
two measuring results is less than 2 %.
Appendix 1
1. MEASUREMENT AND SAMPLING PROCEDURES
Gaseous components emitted by the engine submitted for testing shall be
measured by the methods described in Schedule VI. The methods of Schedule
VI describe the recommended analytical systems for the gaseous emissions
(section 1.1).
Dynamometer specification
An engine dynamometer with adequate characteristics to perform the test cycles
described in Schedule IV, section 3.5.1 shall be used. The instrumentation for
torque and speed measurement shall allow the measurement of the shaft power
within the given limits. Additional calculations may be necessary.
The accuracy of the measuring equipment must be such that the maximum
tolerances of the figures given in section 1.3 are not exceeded.
Fuel flow and total diluted flow
Fuel flow meters with the accuracy defined in section 1.3 shall be used to
measure the fuel flow that will be used to calculate emissions (Appendix 3).
When using a full flow dilution system, the total flow of the dilute exhaust (G
TOTW ) shall be measured with a PDP or CFV — Schedule VI, section 1.2.1.2.
The accuracy shall conform to the provisions of Schedule III, Appendix 2,
section 2.2.
Accuracy
The calibration of all measuring instruments shall be traceable to national
(international) standards and comply with the requirements given in tables 2
and 3.
Determination of the gaseous components
General analyser specifications
The analysers shall have a measuring range appropriate for the accuracy
required for measuring the concentrations of the exhaust gas components
(section 1.4.1.1). It is recommended that the analysers be operated such that the
measured concentration falls between 15 % and 100 % of full scale.
If the full scale value is 155 ppm (or ppm C) or less or if read-out systems
(computers, data loggers) that provide sufficient accuracy and resolution below
15 % of full scale are used concentrations below 15 % of full scale are also
acceptable. In this case, additional calibrations are to be made to ensure the
accuracy of the calibration curves — Appendix 2, section 1.5.5.2, of this
Schedule.
The electromagnetic compatibility (EMC) of the equipment shall be on a level
as to minimise additional errors.
A c c u r a c y
The analyser shall not deviate from the nominal calibration point by more than
± 2 % of the reading over the whole measurement range except zero, and ± 0,3
% of full scale at zero. The accuracy shall be determined according to the
calibration requirements laid down in section 1.3.
R e p e a t a b i l i t y
The repeatability, shall be such that 2,5 times the standard deviation of 10
repetitive responses to a given calibration or span gas is not greater than ± 1 %
of full scale concentration for each range used above 100 ppm (or ppmC) or ± 2
% of each range used below 100 ppm (or ppmC).
N o i s e
The analyser peak-to-peak response to zero and calibration or span gases over
any 10-s period shall not exceed 2 % of full scale on all ranges used.
Z e r o d r i f t
Zero response is defined as the mean response, including noise, to a zero gas
during a 30-s time interval. The drift of the zero response during a one-hour
period shall be less than 2 % of full scale on the lowest range used.
S p a n d r i f t
Span response is defined as the mean response, including noise, to a span gas
during a 30-s time interval. The drift of the span response during a one-hour
period shall be less than 2 % of full scale on the lowest range used.
Gas drying
Exhaust gases may be measured wet or dry. Any gas-drying device, if used,
must have a minimal effect on the concentration of the measured gases.
Chemical dryers are not an acceptable method of removing water from the
sample.
Analysers
Sections 1.4.3.1 to 1.4.3.5 describe the measurement principles to be used. A
detailed description of the measurement systems is given in Schedule VI.
The gases to be measured shall be analysed with the following instruments. For
non-linear analysers, the use of linearising circuits is permitted.
C a r b o n m o n o x i d e ( C O) a n a l y s i s
The carbon monoxide analyser shall be of the non-dispersive infrared (NDIR)
absorption type.
C a r b o n d i o x i d e ( C O 2 ) a n a l y s i s
The carbon dioxide analyser shall be of the non-dispersive infrared (NDIR)
absorption type.
O x y g e n ( O 2 ) a n a l y s i s
Oxygen analysers shall be of the paramagnetic detector (PMD), zirconium
dioxide (ZRDO) or electrochemical sensor (ECS) types.
Note: Zirconium dioxide sensors are not recommended when HC and CO
concentrations are high such as for lean burn spark ignited engines.
Electrochemical sensors shall be compensated for CO 2 and NO X interference.
H y d r o c a r b o n ( H C ) a n a l y s i s
For direct gas sampling the hydrocarbon analyser shall be of the heated flame
ionisation detector (HFID) type with detector, valves, pipework, etc., heated so
as to maintain a gas temperature of 463 K ± 10 K (190 o C ± 10 o C).
For diluted gas sampling the hydrocarbon analyser shall be either the heated
flame ionisation detector (HFID) type or the flame ionisation detector (FID)
type.
O x i d e s o f n i t r o g e n ( N O x ) a n a l y s i s
The oxides of nitrogen analyser shall be of the chemiluminescent detector
(CLD) or heated chemiluminescent detector (HCLD) type with a NO 2 /NO
converter, if measured on a dry basis. If measured on a wet basis, a HCLD with
converter maintained above 328 K (55 o C) shall be used, provided the water
quench check (Schedule III, Appendix 2, section 1.9.2.2) is satisfied. For both
CLD and HCLD, the sampling path shall be maintained at a wall temperature of
328 K to 473 K (55 o C to 200 o C) up to the converter for dry measurement, and
up to the analyser for wet measurement.
Sampling for gaseous emissions
If the composition of the exhaust gas is influenced by any exhaust after-
treatment system, the exhaust sample shall be taken downstream of this device.
The exhaust sampling probe should be in a high pressure side of the muffler,
but as far from the exhaust port as possible. To ensure complete mixing of the
engine exhaust before sample extraction, a mixing chamber may be optionally
inserted between the muffler outlet and the sample probe. The internal volume
of the mixing chamber must be not less than 10 times the cylinder displacement
of the engine under test and should be roughly equal dimensions in height,
width and depth, being similar to a cube. The mixing chamber size should be
kept as small as practicable and should be coupled as close as possible to the
engine. The exhaust line leaving the mixing chamber of muffler should extend
at least 610 mm beyond the sample probe location and be of sufficient size to
minimise back pressure. The temperature of the inner surface of the mixing
chamber must be maintained above the dew point of the exhaust gases and a
minimum temperature of 338 o K (65 o C) is recommended.
All components may optionally be measured directly in the dilution tunnel, or
by sampling into a bag and subsequent measurement of the concentration in the
sampling bag.
Appendix 2
1. CALIBRATION OF THE ANALYTICAL INSTRUMENTS
Introduction
Each analyser shall be calibrated as often as necessary to fulfil the accuracy
requirements of this standard. The calibration method that shall be used is
described in this paragraph for the analysers indicated in Appendix 1, section
1.4.3.
Calibration gases
The shelf life of all calibration gases must be respected.
The expiry date of the calibration gases stated by the manufacturer shall be
recorded.
Pure gases
The required purity of the gases is defined by the contamination limits given
below. The following gases must be available for operation
- purified nitrogen (contamination ≤ 1 ppm C, ≤ 1 ppm CO, ≤ 400 ppm CO 2 , ≤
0,1 ppm NO),
- purified oxygen (purity > 99,5 Vol.-% O 2 ),
- hydrogen-helium mixture (40 ± 2 % hydrogen, balance helium);
contamination ≤ 1 ppm C, ≤ 400 ppm CO 2 ,
- purified synthetic air (contamination ≤ 1 ppm C, ≤ 1 ppm CO, ≤ 400 ppm
CO 2 , ≤ 0,1 ppm NO (oxygen content between 18 % and 21 % vol).
Calibration and span gases
Mixture of gases having the following chemical compositions shall be
available: C 3 H 8 and purified synthetic air (see section 1.2.1),
- CO and purified nitrogen,
- and purified nitrogen (the amount of NO 2 contained in this calibration gas
must not exceed 5 % of the NO content),
- CO 2 and purified nitrogen,
CH 4 and purified synthetic air,
- C 2 H 6 and purified synthetic air.
Note: Other gas combinations are allowed provided the gases do not react with
one another.
The true concentration of a calibration and span gas shall be within ± 2 % of the
nominal value. All concentrations of calibration gas shall be given on a volume
basis (volume percent or volume ppm).
The gases used for calibration and span may also be obtained by means of
precision blending devices (gas dividers), diluting with purified N 2 or with
purified synthetic air. The accuracy of the mixing device must be such that the
concentration of the diluted calibration gases is accurate to within ± 1,5 %. This
accuracy implies that primary gases used for blending must be known to an
accuracy of at least ± 1 %, traceable to national or international gas standards.
The verification shall be performed at between 15 % and 50 % of full scale for
each calibration incorporating a blending device.
Optionally, the blending device may be checked with an instrument, which by
nature is linear, e.g. using NO gas with a CLD. The span value of the instrument
shall be adjusted with the span gas directly connected to the instrument. The
blending device shall be checked at the used settings and the nominal value
shall be compared to the measured concentration of the instrument. This
difference shall in each point be within ± 0,5 % of the nominal value.
Oxygen interference check
Oxygen interference check gases shall contain propane with 350 ppm C ± 75
ppm C hydrocarbon. The concentration value shall be determined to calibration
gas tolerances by chromatographic analysis of total hydrocarbons plus
impurities or by dynamic blending. Nitrogen shall be the predominant diluent
with the balance oxygen. Blend required for gasoline-fuelled engine testing is
as follows
O 2 interference concentration
Balance
10 (9 to 11)
Nitrogen
5 (4 to 6)
Nitrogen
0 (0 to 1)
Nitrogen.
Operating procedure for analysers and sampling system
The operating procedure for analysers shall follow the start-up and operating
instructions of the instrument manufacturer. The minimum requirements given
in sections 1.4 to 1.9 shall be included. For laboratory instruments such as GC
and high performance liquid chromatography (HPLC) only section 1.5.4 shall
apply.
Leakage test
A system leakage test shall be performed. The probe shall be disconnected from
the exhaust system and the end plugged. The analyser pump shall be switched
on. After an initial stabilisation period all flow meters should read zero. If not,
the sampling lines shall be checked and the fault corrected.
The maximum allowable leakage rate on the vacuum side shall be 0,5 % of the
in-use flow rate for the portion of the system being checked. The analyser flows
and bypass flows may be used to estimate the in-use flow rates.
Alternatively, the system may be evacuated to a pressure of at least 20 kPa
vacuum (80 kPa absolute). After an initial stabilisation period the pressure
increase δp (kPa/min) in the system shall not exceed
δp ¼ p=V syst x 0; 005 x fr
Where
V syst = system volume [l]
fr = system flow rate [l/min]
Another method is the introduction of a concentration step change at the
beginning of the sampling line by switching from zero to span gas. If after an
adequate period of time the reading shows a lower concentration compared to
the introduced concentration, this points to calibration or leakage problems.
Calibration procedure
Instrument assembly
The instrument assembly shall be calibrated and calibration curves checked
against standard gases. The same gas flow rates shall be used as when sampling
exhaust gas.
Warming-up time
The warming-up time should be according to the recommendations of the
manufacturer. If not specified, a minimum of two hours is recommended for
warming-up the analysers.
NDIR and HFID analyser
The NDIR analyser shall be tuned, as necessary, and the combustion flame of
the HFID analyser shall be optimised (section 1.9.1).
GC and HPCL
Both instruments shall be calibrated according to good laboratory practice and
the recommendations of the manufacturer.
Establishment of the calibration curves
G e n e r a l g u i d e l i n e s
(a) Each normally used operating range shall be calibrated.
(b) Using purified synthetic air (or nitrogen), the CO, CO 2 , NO x and HC
analysers shall be set at zero.
(c) The appropriate calibration gases shall be introduced to the analysers, the
values recorded, and the calibration curves established.
(d) For all instrument ranges except for the lowest range, the calibration curve
shall be established by at least 10 calibration points (excluding zero) equally
spaced. For the lowest range of the instrument, the calibration curve shall be
established by at least 10 calibration points (excluding zero) spaced so that half
of the calibration points are placed below 15 % of the analyser's full scale and
the rest are placed above 15 % of full scale. For all ranges the highest nominal
concentration must be equal to or higher than 90 % of full scale.
(e) The calibration curve shall be calculated by the method of least squares. A
best-fit linear or non-linear equation may be used.
(f) The calibration points must not differ from the least-squares best- fit line
by more than ± 2 % of reading or ± 0,3 % of full scale whichever is larger.
(g) The zero setting shall be rechecked and the calibration procedure repeated,
if necessary.
A l t e r n a t i v e m e t h o d s
If it can be shown that alternative technology (e.g. computer, electronically
controlled range switch, etc.) can give equivalent accuracy, then these
alternatives may be used.
Verification of the calibration
Each normally used operating range shall be checked prior to each analysis in
accordance with the following procedure.
The calibration is checked by using a zero gas and a span gas whose nominal
value is more than 80 % of full scale of the measuring range.
If, for the two points considered, the value found does not differ by more than ±
4 % of full scale from the declared reference value, the adjustment parameters
may be modified. Should this not be the case, the span gas shall be verified or a
new calibration curve shall be established in accordance with section 1.5.5.1.
Calibration of tracer gas analyser for exhaust flow measurement
The analyser for measurement of the tracer gas concentration shall be calibrated
using the standard gas.
The calibration curve shall be established by at least 10 calibration points
(excluding zero) spaced so that half of the calibration points are placed between
4 % to 20 % of the analyser's full scale and the rest are in between 20 % and 100
% of the full scale. The calibration curve shall be calculated by the method of
least squares.
The calibration curve must not differ by more than ± 1 % of the full scale from
the nominal value of each calibration point, in the range from 20 % to 100 % of
the full scale. It also must not differ by more than ± 2 % of reading from the
nominal value in the range from 4 % to 20 % of the full scale. The analyser
shall be set at zero and spanned prior to the test run using a zero gas and a span
gas whose nominal value is more than 80 % of the analyser full scale.
Efficiency test of the NO x converter
The efficiency of the converter used for the conversion of NO 2 into NO is tested
as given in sections 1.8.1 to 1.8.8 (figure 1 of Schedule III, Appendix 2).
Test set-up
Using the test set-up as shown in figure 1 of Schedule III and the procedure
below, the efficiency of converters can be tested by means of an ozonator.
Calibration
The CLD and the HCLD shall be calibrated in the most common operating
range following the manufacturer's specifications using zero and span gas (the
NO content of which must amount to about 80 % of the operating range and the
NO 2 concentration of the gas mixture to less than 5 % of the NO concentration).
The NO x analyser must be in the NO mode so that the span gas does not pass
through the converter. The indicated concentration has to be recorded.
Calculation
The efficiency of the NO x , converter is calculated as follows
where
a = NO x concentration according to section 1.8.6
b = NO x concentration according to section 1.8.7
c = NO concentration according to section 1.8.4
d = NO concentration according to section 1.8.5.
Adding of oxygen
Via a T-fitting, oxygen or zero air is added continuously to the gas flow until
the concentration indicated is about 20 % less than the indicated calibration
concentration given in section 1.8.2. (The analyser is in the NO mode.)
The indicated concentration (c) shall be recorded. The ozonator is kept
deactivated throughout the process.
Activation of the ozonator
The ozonator is now activated to generate enough ozone to bring the NO
concentration down to about 20 % (minimum 10 %) of the calibration
concentration given in section 1.8.2. The indicated concentration (d) shall be
recorded. (The analyser is in the NO mode.)
NO x mode
The NO analyser is then switched to the NO x mode so that the gas mixture
(consisting of NO, NO 2 , O 2 and N 2 ) now passes through the converter. The
indicated concentration (a) shall be recorded. (The analyser is in the NO x
mode.)
Deactivation of the ozonator
The ozonator is now deactivated. The mixture of gases described in section
1.8.6 passes through the converter into the detector. The indicated concentration
(b) shall be recorded. (The analyser is in the NO x mode.)
NO mode
Switched to NO mode with the ozonator deactivated, the flow of oxygen or
synthetic air is also shut off. The NO x reading of the analyser shall not deviate
by more than ± 5 % from the value measured according to section 1.8.2. (The
analyser is in the NO mode.)
Test interval
The efficiency of the converter must be checked monthly.
Efficiency requirement
The efficiency of the converter shall not be less than 90 %, but a higher
efficiency of 95 % is strongly recommended.
Note: If, with the analyser in the most common range, the ozonator cannot give
a reduction from 80 % to 20 % according to section 1.8.5, then the highest
range which will give the reduction shall be used.
Adjustment of the FID
Optimisation of the detector response
The HFID must be adjusted as specified by the instrument manufacturer. A
propane in air span gas should be used to optimise the response on the most
common operating range.
With the fuel and airflow rates set at the manufacturer's recommendations, a
350 ± 75 ppm C span gas shall be introduced to the analyser. The response at a
given fuel flow shall be determined from the difference between the span gas
response and the zero gas response. The fuel flow shall be incrementally
adjusted above and below the manufacturer's specification. The span and zero
response at these fuel flows shall be recorded. The difference between the span
and zero response shall be plotted and the fuel flow adjusted to the rich side of
the curve. This is the initial flow rate setting, which may need further
optimisation depending on the results of the hydrocarbon response factor and
the oxygen interference check according to sections 1.9.2 and 1.9.3.
If the oxygen interference or the hydrocarbon response factors do not meet the
following specifications, the airflow shall be incrementally adjusted above and
below the manufacturer's specifications, sections 1.9.2 and 1.9.3 should be
repeated for each flow.
Hydrocarbon response factors
The analyser shall be calibrated using propane in air and purified synthetic air,
according to section 1.5.
Response factors shall be determined when introducing an analyser into service
and after major service intervals. The response factor (R f ) for a particular
hydrocarbon species is the ratio of the FID C1 reading to the gas concentration
in the cylinder expressed by ppm C1.
The concentration of the test gas must be at a level to give a response of
approximately 80 % of full scale. The concentration must be known to an
accuracy of ± 2 % in reference to a gravimetric standard expressed in volume.
In addition, the gas cylinder must be preconditioned for 24 hours at a
temperature of 298 K (25 o C) ± 5 K.
The test gases to be used and the recommended relative response factor ranges
are as follows
methane and purified synthetic air: 1,00 ≤ R f ≤ 1,15
propylene and purified synthetic air: 0,90 ≤ R f ≤ 1,1
toluene and purified synthetic air: 0,90 ≤ R f ≤ 1,10.
These values are relative to the response factor (R f ) of 1,00 for propane and
purified synthetic air.
Oxygen interference check
The oxygen interference check shall be determined when introducing an
analyser into service and after major service intervals. A range shall be chosen
where the oxygen interference check gases will fall in the upper 50 %. The test
shall be conducted with the oven temperature set as required. The oxygen
interference gases are specified in section 1.2.3.
(a) The analyser shall be zeroed.
(b) The analyser shall be spanned with the 0 % oxygen blend for gasoline
fuelled engines.
(c) The zero response shall be rechecked. If it has changed more than 0,5 % of
full scale subsections (a) and (b) of this section shall be repeated.
(d) The 5 % and 10 % oxygen interference check gases shall be introduced.
(e) The zero response shall be rechecked. If it has changed more than ± 1 % of
full scale, the test shall be repeated.
(f) The oxygen interference (% O 2 I) shall be calculated for each mixture in
step (d) as follows
where
A = hydrocarbon concentration (ppm C) of the span gas used in subsection (b)
B = hydrocarbon concentration (ppm C) of the oxygen interference check gases
used in subsection (d)
C = analyser response
D = percent of full scale analyser response due to A
(g) The % of oxygen interference (% O 2 I) shall be less than ± 3 % for all
required oxygen interference check gases prior to testing.
(h) If the oxygen interference is greater than ± 3 %, the air flow above and
below the manufacturer's specifications shall be incrementally adjusted,
repeating section 1.9.1 for each flow.
(i) If the oxygen interference is greater than ± 3 %, after adjusting the air
flow, the fuel flow and thereafter the sample flow shall be varied, repeating
section 1.9.1 for each new setting.
(j) If the oxygen interference is still greater than ± 3 %, the analyser, FID fuel,
or burner air shall be repaired or replaced prior to testing. This section shall
then be repeated with the repaired or replaced equipment or gases.
Interference effects with CO, CO 2 , NO X and O 2 analysers
Gases other than the one being analysed can interfere with the reading in several ways.
Positive interference occurs in NDIR and PMD instruments where the interfering gas gives
the same effect as the gas being measured, but to a lesser degree. Negative interference
occurs in NDIR instruments by the interfering gas broadening the absorption band of the
measured gas, and in CLD instruments by the interfering gas quenching the radiation. The
interference checks in sections 1.10.1 and 1.10.2 shall be performed prior to an analyser's
initial use and after major service intervals, but at least once per year.
CO analyser interference check
Water and CO 2 can interfere with the CO analyser performance. Therefore a
CO 2 span gas having a concentration of 80 % to 100 % of full scale of the
maximum operating range used during testing shall be bubbled through water at
room temperature and the analyser response recorded. The analyser response
must not be more than 1 % of full scale for ranges equal to or above 300 ppm or
more than 3 ppm for ranges below 300 ppm.
NO x analyser quench checks
The two gases of concern for CLD (and HCLD) analysers are CO 2 and water
vapour. Quench responses of these gases are proportional to their
concentrations, and therefore require test techniques to determine the quench at
the highest expected concentrations experienced during testing.
C O 2 q u e n c h c h e c k
A CO 2 span gas having a concentration of 80 % to 100 % of full scale of the
maximum operating range shall be passed through the NDIR analyser and the
CO 2 value recorded as A. It shall then be diluted approximately 50 % with NO
span gas and passed through the NDIR and (H)CLD with the CO 2 and NO
values recorded as B and C, respectively. The CO 2 shall be shut off and only the
NO span gas is passed through the (H)CLD and the NO value recorded as D.
The quench, which shall not be greater than 3 % full scale, shall be calculated as
follows
where
A: undiluted CO 2 concentration measured with NDIR %
B: diluted CO 2 concentration measured with NDIR %
C: diluted NO concentration measured with CLD ppm
D: undiluted NO concentration measured with CLD ppm
Alternative methods of diluting and quantifying CO 2 and NO span gas values,
such as dynamic/mixing/blending, can be used.
W a t e r q u e n c h c h e c k
This check applies to wet gas concentration measurements only. Calculation of
water quench must consider dilution of the NO span gas with water vapour and
scaling of water vapour concentration of the mixture to that expected during
testing.
A NO span gas having a concentration of 80 % to 100 % of full scale to the
normal operating range shall be passed through the (H)CLD and the NO value
recorded as D. The NO span gas shall then be bubbled through water at room
temperature and passed through the (H)CLD and the NO value recorded as C.
The water temperature shall be determined and recorded as F. The mixture's
saturation vapour pressure that corresponds to the bubbler water temperature
(F) shall be determined and recorded as G. The water vapour concentration (in
%) of the mixture shall be calculated as follows
and recorded as H. The expected diluted NO span gas (in water vapour)
concentration shall be calculated as follows
and recorded as D e .
The water quench shall not be greater than 3 % and shall be calculated as
follows
where
D e : expected diluted NO concentration (ppm)
C: diluted NO concentration (ppm)
H m : maximum water vapour concentration
H: actual water vapour concentration (%).
Note: It is important that the NO span gas contains minimal NO 2 concentration
for this check, since absorption of NO 2 in water has not been accounted for in
the quench calculations.
O 2 analyser interference
Instrument response of a PMD analyser caused by gases other than oxygen is
comparatively slight. The oxygen equivalents of the common exhaust gas
constituents are shown in table 1.
The observed oxygen concentration shall be corrected by the following formula
if high precision measurements are to be done
Calibration intervals
The analysers shall be calibrated according to section 1.5 at least every three
months or whenever a system repair or change is made that could influence
calibration.
Appendix 3
1. DATA EVALUATION AND CALCULATIONS
Gaseous emissions evaluation
For the evaluation of the gaseous emissions, the chart reading for a minimum of
the last 120 s of each mode shall be averaged, and the average concentrations
(conc) of HC, CO, NO x and CO 2 during each mode shall be determined from
the average chart readings and the corresponding calibration data. A different
type of recording can be used if it ensures an equivalent data acquisition.
The average background concentration (conc d ) may be determined from the
bag readings of the dilution air or from the continuous (non-bag) background
reading and the corresponding calibration data.
Calculation of the gaseous emissions
The finally reported test results shall be derived through the following steps.
Dry/wet correction
The measured concentration, if not already measured on a wet basis, shall be
converted to a wet basis
where α is the hydrogen to carbon ratio in the fuel.
The factor k w1 shall be calculated from the following equations
where
H d absolute humidity of the dilution air, g of water per kg of dry air
H a absolute humidity of the intake air, g of water per kg of dry air
For the dilution air
k w;d ¼ 1 Ä k w1
The factor k w1 shall be calculated from the following equations
where
H d absolute humidity of the dilution air, g of water per kg of dry air
H a absolute humidity of the intake air, g of water per kg of dry air
For the intake air (if different from the dilution air)
k w;a ¼ 1 Ä k w2
The factor k w2 shall be calculated from the following equations
with H a absolute humidity of the intake air, g of water per kg of dry air.
Humidity correction for NO x
As the NO x emission depends on ambient air conditions, the NO x concentration
shall be multiplied by the factor K H taking into account humidity
with H a absolute humidity of the intake air as g of water per kg of dry air.
Calculation of emission mass flow rate
The emission mass flow rates Gas mass [g/h] for each mode shall be calculated
as follows.
For the raw exhaust gas ( 1 )
where
G FUEL [kg/h] is the fuel mass flow rate;
MW Gas [kg/kmol] is the molecular weight of the individual gas shown in table
1;
MW FUEL = 12,011 + α × 1,00794 + β × 15,9994 [kg/kmole] is the fuel
molecular weight with α hydrogen to carbon ratio and β oxygen to carbon ratio
of the fuel ( 2 );
CO 2AIR is the CO 2 concentration in the intake air (that is assumed equal to 0,04
% if not measured).
(b) For the diluted exhaust gas ( 3 )
Gas mass ¼ u x conc c x G TOTW
where
- G TOTW [kg/h] is the diluted exhaust gas mass flow rate on wet basis that,
when using a full flow dilution system, shall be determined according to
Schedule III, Appendix 1, section 1.2.4,
- conc c is the background corrected concentration
The u coefficient is shown in table 2.
In the ISO 8178-1 a more complete formula of the fuel molecular weight is quoted (formula 50 of Chapter 13.5.1(b)). The
formula takes into account not only the hydrogen to carbon ratio and the oxygen to carbon ratio but also other possible fuel
components such as sulphur and nitrogen. However, as the SI. engines of the Directive are tested with a petrol (quoted as a reference
fuel in Annex V) containing usually only carbon and hydrogen, the simplified formula is considered.
Values of the u coefficient are based upon a molecular weight of the dilute
exhaust gases equal to 29 [kg/kmol]; the value of u for HC is based upon an
average carbon to hydrogen ratio of 1:1,85.
In the case of NO x the concentration has to be multiplied by the humidity correction factor K H (humidity correction factor for
Calculation of specific emissions
The specific emission (g/kWh) shall be calculated for all individual
components
When auxiliaries, such as cooling fan or blower, are fitted for the test, the
power absorbed shall be added to the results except for engines where such
auxiliaries are an integral part of the engine. The fan or blower power shall be
determined at the speeds used for the tests either by calculation from standard
characteristics or by practical tests (Appendix 3 of Schedule VII).
The weighting factors and the number of the n modes used in the above
calculation are shown in Schedule IV, section 3.5.1.1.
2. EXAMPLES
Raw exhaust gas data from a four-stroke SI engine
With reference to the experimental data (table 3), calculations are carried out
first for mode 1 and then are extended to other test modes using the same
procedure.
2.1.1
Dry/wet correction factor k w
The dry/wet correction factor kw shall be calculated for converting dry CO and
CO 2 measurements on a wet basis
2.1.2
HC emissions
2.1.3
NO x emissions
At first the humidity correction factor K H of NO x emissions shall be
calculated
2.1.4
CO emissions
2.1.5
CO 2 emissions
2.1.6
Specific emissions
The specific emission (g/kWh) shall be calculated for all individual
components
Raw exhaust gas data from a two-stroke SI engine
With reference to the experimental data (table 11), calculations shall be carried
out first for mode 1 and then extended to the other test mode using the same
procedure.
2.2.1
Dry/wet correction factor k w
The dry/wet correction factor k w shall be calculated for converting dry CO and
CO 2 measurements on a wet basis
2.2.2
HC emissions
2.2.3
NO x emissions
The factor K H for the correction of the NO x emissions is equal to 1 for two-
stroke engines
2.2.4
CO emissions
2.2.5
CO 2 emissions
2.2.6
Specific emissions
The specific emission (g/kWh) shall be calculated for all individual components
in the following way
Diluted exhaust gas data from a four-stroke SI engine
With reference to the experimental data (table 18), calculations shall be carried
out first for mode 1 and then extended to other test modes using the same
procedure.
2.3.1
Dry/wet correction factor k w
The dry/wet correction factor k w shall be calculated for converting dry CO and
CO 2 measurements on a wet basis.
For the diluted exhaust gas
2.3.2
HC emissions
HC mass ¼ u x conc c x G TOTW
Where
u = 0,000478 from table 2
conc c = conc – conc d × (1–1/DF)
conc c = 91 – 6 × (1–1/9,465) = 86 ppm
HC mass = 0,000478 × 86 × 625,722 = 25,666 g/h
2.3.3
NO x emissions
The factor K H for the correction of the NO x emissions shall be calculated from
2.3.4
CO emissions
2.3.5
CO 2 emissions
2.3.6
Specific emissions
The specific emission (g/kWh) shall be calculated for all individual
components
Appendix 4
1. COMPLIANCE WITH EMISSION STANDARDS
This Appendix shall apply to SI engines stage 2 only.
The exhaust emission standards for stage 2 engines in Schedule I (4.2) apply to
the emissions of the engines for their emission durability period EDP as
determined in accordance with this Appendix.
For all stage 2 engines, if, when properly tested according to the procedures in
these regulations, all test engines representing an engine family have emissions
which, when adjusted by multiplication by the deterioration factor (DF) laid
down in this Appendix, are less than or equal to each stage 2 emission standard
(family emission limit (FEL), where applicable) for a given engine class, that
family shall be considered to comply with the emission standards for that
engine class. If any test engine representing an engine family has emissions
which, when adjusted by multiplication by the deterioration factor laid down in
this Appendix, are greater than any single emission standard (FEL, where
applicable) for a given engine class, that family shall be considered not to
comply with the emission standards for that engine class.
Small volume engine manufacturers may, optionally, take deterioration factors
for HC+NO x and CO from table 1 or 2 in this section, or they may calculate
deterioration factors for HC + NO x and CO according to the process described
in section 1.3.1. For technologies not covered by tables 1 and 2 in this section,
the manufacturer must use the process described in section 1.4 in this
Appendix.
Formula for calculating deterioration factors for engines with after treatment
where
DF = deterioration factor
NE = new engine emission levels prior to the catalyst (g/kWh)
EDF = deterioration factor for engines without catalyst as shown in table 1
CC = amount converted at 0 hours in g/kWh
F = 0,8 for HC and 0,0 for NO x for all classes of engines
F = 0,8 for CO for all classes of engines
Manufacturers shall obtain an assigned DF or calculate a DF, as appropriate, for
each regulated pollutant for all stage 2 engine families. Such DFs shall be used
for type approval and production line testing.
For engines not using assigned DFs from tables 1 or 2 of this section, DFs shall
be determined as follows
On at least one test engine representing the configuration chosen to be the most
likely to exceed HC + NO x emission standards, (FELs where applicable), and
constructed to be representative of production engines, conduct (full) test
procedure emission testing as described in these regulations after the number of
hours representing stabilised emissions.
If more than one engine is tested, average the results and round to the same
number of decimal places contained in the applicable standard, expressed to one
additional significant figure.
Conduct such emission testing again following ageing of the engine. The ageing
procedure should be designed to allow the manufacturer to appropriately
predict the in-use emission deterioration expected over the durability period of
the engine, taking into account the type of wear and other deterioration
mechanisms expected under typical consumer use which could affect emissions
performance. If more than one engine is tested, average the results and round to
the same number of decimal places contained in the applicable standard,
expressed to one additional significant figure.
Divide the emissions at the end of the durability period (average emissions, if
applicable) for each regulated pollutant by the stabilised emissions (average
emissions, if applicable) and round to two significant figures. The resulting
number shall be the DF, unless it is less than 1,00, in which case the DF shall be
1,0.
At the manufacturer's option additional emission test points can be scheduled
between the stabilised emission test point and the emission durability period. If
intermediate tests are scheduled, the test points must be evenly spaced over the
EDP (plus or minus two hours) and one such test point shall be at one half of
full EDP (plus or minus two hours).
For each pollutant HC + NO x and CO, a straight line must be fitted to the data
points treating the initial test as occurring at hour zero, and using the method of
least-squares. The deterioration factor is the calculated emissions at the end of
the durability period divided by the calculated emissions at zero hours.
Calculated deterioration factors may cover families in addition to the one on
which they were generated if the manufacturer submits a justification
acceptable to the national type approval authority in advance of type approval
that the affected engine families can be reasonably expected to have similar
emission deterioration characteristic based on the design and technology used.
A non-exclusive list of design and technology groupings is given below
- conventional two-stroke engines without after treatment system,
- conventional two-stroke engines with a ceramic catalyst of the same active
material and loading, and the same number of cells per cm 2 ,
- conventional two-stroke engines with a metallic catalyst of the same active
material and loading, same substrate and the same number of cells per cm 2 ,
- two-stroke engines provided with a stratified scavenging system,
- four-stroke engines with catalyst (defined as above) with same valve
technology and identical lubrication system,
- four-stroke engines without catalyst with the same valve technology and
identical lubrication system.
2. EMISSION DURABILITY PERIODS FOR STAGE 2 ENGINES
Manufacturers shall declare the applicable EDP category for each engine family
at the time of type approval. Such category shall be the category which most
closely approximates the expected useful lives of the equipment into which the
engines are expected to be installed as determined by the engine manufacturer.
Manufacturers shall retain data appropriate to support their choice of EDP
category for each engine family. Such data shall be supplied to the approval
authority upon request.
For hand-held engines: manufacturers shall select an EDP category from table
1. For non-hand-held engines: manufacturers shall select an EDP category from
table 2.
The manufacturer must satisfy the approval authority that the declared useful
life is appropriate. Data to support a manufacturer's choice of EDP category, for
a given engine family, may include but are not limited to
- surveys of the life spans of the equipment in which the subject engines are
installed,
- engineering evaluations of field aged engines to ascertain when engine
performance deteriorates to the point where usefulness and/or reliability is
impacted to a degree sufficient to necessitate overhaul or replacement,
- warranty statements and warranty periods,
- marketing materials regarding engine life,
- failure reports from engine customers, and
- engineering evaluations of the durability, in hours, of specific engine
technologies, engine materials or engine designs.
Schedule V
TECHNICAL CHARACTERISTICS OF REFERENCE FUEL PRESCRIBED
FOR APPROVAL TESTS AND TO VERIFY CONFORMITY OF
PRODUCTION
NON-ROAD MOBILE MACHINERY REFERENCE FUEL FOR CI
ENGINES TYPE APPROVED TO MEET STAGE I and II LIMIT VALUES
AND FOR ENGINES TO BE USED IN INLAND WATERWAY VESSELS
Note: Key properties for engine performance/exhaust emissions are
highlighted.
Note 1: If it is required to calculate thermal efficiency of an engine or vehicle,
the calorific value of the fuel can be calculated from
Specific energy (calorific value)(net) MJ/kg = (46,423 – 8.792·d 2 + 3,17·d) x (1
– (x + y + s)) + 9, 42·s – 2,499·x
where
d is the density at 288 K (15 o C)
x is the proportion by mass of water (% 100)
y is the proportion by mass of ash (% 100)
s is the proportion by mass of sulphur (% 100).
Note 2: The values quoted in the specification are ‘true values’. In
establishment of their limit values the terms of ASTM D 3244 ‘Defining a basis
for petroleum produce quality disputes’ have been applied and in fixing a
minimum value, a minimum difference of 2R above zero has been taken into
account; in fixing a maximum and minimum value, the minimum difference is
4R (R = reproducibility).
Notwithstanding this measure, which is necessary for statistical reasons, the
manufacturer of fuel should nevertheless aim at a zero value where the
stipulated maximum value is 2R and the mean value in the case of quotations of
maximum and minimum limits. Should it be necessary to clarify the question as
to whether a fuel meets the requirements of the specifications, the terms of
ASTM D 3244 should be applied.
Note 3: The figures quoted show the evaporated quantities (percentage
recovered + percentage loss).
Note 4: The range of cetane is not in accordance with the requirement of a
minimum range of 4R. However, in cases of dispute between fuel supplier and
fuel user, the terms in ASTM D 3244 can be used to resolve such disputes
provided replicate measurements, of sufficient number to achieve the necessary
precision, are made in preference to single determinations.
Note 5: Even though oxidation stability is controlled, it is likely that shelf life
will be limited. Advice should be sought from the supplier as to storage
conditions and life.
Note 6: This fuel should be based straight run and cracked hydrocarbon
distillate components only; desulphurization is allowed. It must not contain any
metallic additives or cetane improver additives.
Note 7: Lower values are permitted, in which case the cetane number of the
reference fuel used is to be reported.
Note 8: Higher values are permitted, in which case the sulphur content of the
reference fuel used is to be reported.
Note 9: To be kept under constant review in the light of trends in the markets.
For the purpose of the initial approval of an engine with no exhaust gas
after treatment on the request of the applicant a 0,05 % mass nominal
sulphur level (minimum 0,03 % mass) is permissible, in which case the
measured particulate level must be corrected upward to the average value
that is nominally specified for fuel sulphur content (0,15 % mass) per the
equation below
where
PT adj = adjusted PT value (g/kWh)
PT = measured weighted specific emission value for particulate emission (g/
kWh)
SFC = weighted specific fuel consumption (g/kWh) calculated according to the
formula as below
NSLF = average of the nominal specification of sulphur content mass fraction
(i.e. 0,15 %/100)
FSF = fuel sulphur content mass fraction (%/100)
Equation for the calculation of the weighted specific fuel consumption
where
P i = P m,i + P AE,i
For the purpose of conformity of production assessments in accordance with
section 5.3.2. of Schedule I, the requirements must be met using reference fuel
with a sulphur content which complies with the minimum/maximum level of
0,1/0,2 % mass.
Note 10: Higher values are permitted up to 855 kg/m 3 , in which case the
density of the reference fuel used is to be reported. For the purpose of
conformity of production assessments in accordance with section 5.3.2. of
Schedule I, the requirements must be met using reference fuel which
complies with the minimum/ maximum level of 835/845 kg/m 3 .
Note 11: All fuel characteristics and limit values are to be kept under review in
light of trends in the markets.
Note 12: To be replaced by EN/ISO 6245 with effect of the date of
implementation.
NON-ROAD MOBILE MACHINERY REFERENCE FUEL FOR CI
ENGINES TYPE APPROVED TO MEET STAGE IIIA LIMIT VALUES.
Schedule VI
ANALYTICAL AND SAMPLING SYSTEM
1. GASEOUS AND PARTICULATE SAMPLING SYSTEMS
Determination of the gaseous emissions
Section 1.1.1 and Figures 2 and 3 contain detailed descriptions of the
recommended sampling and analysing systems. Since various configurations
can produce equivalent results, exact conformance with these figures is not
required. Additional components such as instruments, valves, solenoids, pumps
and switches may be used to provide additional information and coordinate the
functions of the component systems. Other components which are not needed to
maintain the accuracy on some systems, may be excluded if their exclusion is
based upon good engineering judgement.
Gaseous exhaust components CO, CO 2 , HC, NO x
An analytical system for the determination of the gaseous emissions in the raw
or diluted exhaust gas is described based on the use of
HFID analyser for the measurement of hydrocarbons,
NDIR analysers for the measurement of carbon monoxide and carbon dioxide,
HCLD or equivalent analyser for the measurement of nitrogen oxide.
For the raw exhaust gas (Figure 2), the sample for all components may be taken
with one sampling probe or with two sampling probes located in close
proximity and internally split to the different analysers. Care must be taken that
no condensation of exhaust components (including water and sulphuric acid)
occurs at any point of the analytical system.
For the diluted exhaust gas (Figure 3), the sample for the hydrocarbons shall be
taken with another sampling probe than the sample for the other components.
Care must be taken that no condensation of exhaust components (including
water and sulphuric acid) occurs at any point of the analytical system.
Descriptions — Figures 2 and 3
General statement
All components in the sampling gas path must be maintained at the temperature
specified for the respective systems.
- SP1 raw exhaust gas sampling probe (Figure 2 only)
A stainless steel straight closed and multihole probe is recommended. The
inside diameter shall not be greater than the inside diameter of the sampling
line. The wall thickness of the probe shall not be greater than 1 mm. There shall
be a minimum of three holes in three different radial planes sized to sample
approximately the same flow. The probe must extend across at least 80 % of the
diameter of the exhaust pipe.
- SP2 dilute exhaust gas HC sampling probe (Figure 3 only)
The probe shall
- be defined as the first 254 mm to 762 mm of the hydrocarbon sampling line
(HSL3),
- have a 5 mm minimum inside diameter,
- be installed in the dilution tunnel DT (section 1.2.1.2) at a point where the
dilution air and exhaust gas are well mixed (i.e. approximately 10 tunnel
diameters downstream of the point where the exhaust enters the dilution
tunnel), - be sufficiently distant (radially) from other probes and the tunnel wall
so as to - be free from the influence of any wakes or eddies,
- be heated so as to increase the gas stream temperature to 463 K (190 °C) ± 10
K at the exit of the probe.
- SP3 dilute exhaust gas CO, CO 2 , NO x sampling probe (Figure 3 only)
The probe shall
- be in the same plane as SP2,
- be sufficiently distant (radially) from other probes and the tunnel wall so as to
- be free from the influence of any wakes or eddies,
- be heated and insulated over its entire length to a minimum temperature of
328 K (55 °C) to prevent water condensation.
- HSL1 heated sampling line
The sampling line provides gas sampling from a single probe to the split
point(s) and the HC analyser.
The sampling line shall
- have a 5 mm minimum and a 13,5 mm maximum inside diameter,
- be made of stainless steel or PTFE,
- maintain a wall temperature of 463 (190 °C) ± 10 K as measured at every
separately controlled heated section, if the temperature of the exhaust gas at the
sampling probe is equal or below 463 K (190 °C),
- maintain a wall temperature greater than 453 K (180 °C) if the temperature of
the exhaust gas at the sampling probe is above 463 K (190 °C),
- maintain a gas temperature of 463 K (190 °C) ± 10 K immediately before the
heated filter (F2) and the HFID.
- HSL2 heated NO x sampling line
The sampling line shall
- maintain a wall temperature of 328 to 473 K (55 to 200 °C) up to the
converter when using a cooling bath, and up to the analyser when a cooling bath
is not used,
- be made of stainless steel or PTFE.
Since the sampling line need only be heated to prevent condensation of water
and sulphuric acid, the sampling line temperature will depend on the sulphur
content of the fuel.
- SL sampling line for CO (CO 2 )
The line shall be made of PTFE or stainless steel. It may be heated or unheated.
- BK background bag (optional; Figure 3 only)
For the measurement of the background concentrations.
- BG sample bag (optional; Figure 3 CO and CO 2 only)
For the measurement of the sample concentrations.
- F1 heated pre-filter (optional)
The temperature shall be the same as HSL1.
- F2 heated filter
The filter shall extract any solid particles from the gas sample prior to the
analyser. The temperature shall be the same as HSL1. The filter shall be
changed as needed.
- P heated sampling pump
The pump shall be heated to the temperature of HSL1.
- HC
Heated flame ionization detector (HFID) for the determination of the
hydrocarbons. The temperature shall be kept at 453 to 473 K (180 to 200 °C).
- CO, CO 2
NDIR analysers for the determination of carbon monoxide and carbon dioxide.
- NO 2
(H)CLD analyser for the determination of the oxides of nitrogen. If a HCLD is
used it shall be kept at a temperature of 328 to 473 K (55 to 200 °C).
- C converter
A converter shall be used for the catalytic reduction of NO 2 to NO prior to
analysis in the CLD or HCLD.
- B cooling bath
To cool and condense water from the exhaust sample. The bath shall be
maintained at a temperature of 273 to 277 K (0 to 4 °C) by ice or refrigeration.
It is optional if the analyser is free from water vapour interference as
determined in Schedule III, Appendix 2, sections 1.9.1 and 1.9.2.
Chemical dryers are not allowed for removing water from the sample.
- T1, T2, T3 temperature sensor
To monitor the temperature of the gas stream.
- T4 temperature sensor
Temperature of the NO 2 -NO converter.
- T5 temperature sensor
To monitor the temperature of the cooling bath.
- G1, G2, G3 pressure gauge
To measure the pressure in the sampling lines.
- R1, R2 pressure regulator
To control the pressure of the air and the fuel, respectively, for the HFID.
- R3, R4, R5 pressure regulator
To control the pressure in the sampling lines and the flow to the analysers.
- FL1, FL2, FL3 flow meter
To monitor the sample bypass flow.
- FL4 to FL7 flow meter (optional)
To monitor the flow rate through the analysers.
- V1 to V6 selector valve
Suitable valving for selecting sample, span gas or zero gas flow to the analyser.
- V7, V8 solenoid valve
To bypass the NO 2 -NO converter.
- V9 needle valve
To balance the flow through the NO 2 -NO converter and the bypass.
- V10, V11 needle valve
To regulate the flows to the analysers.
- V12, V13 toggle valve
To drain the condensate from the bath B.
- V14 selector valve
Selecting the sample or background bag.
Determination of the particulates
Sections 1.2.1 and 1.2.2 and Figures 4 to 15 contain detailed descriptions of the
recommended dilution and sampling systems. Since various configurations can
produce equivalent results, exact conformance with these figures is not
required. Additional components such as instruments, valve, solenoids, pumps
and switches may be used to provide additional information and coordinate the
functions of the component systems. Other components which are not needed to
maintain the accuracy on some systems, may be excluded if their exclusion is
based on good engineering judgement.
Dilution system
P a r t i a l f l o w d i l u t i o n s y s t e m ( F i g u r e s 4 t o 1 2 ) ( 1 )
A dilution system is described based on the dilution of a part of the exhaust
stream. Splitting of the exhaust stream and the following dilution process may
be done by different dilution system types. For subsequent collection of the
particulates, the entire dilute exhaust gas or only a portion of the dilute exhaust
gas may be passed to the particulate sampling system (section 1.2.2, Figure 14).
The first method is referred to as total sampling type, the second method as
fractional sampling type.
The calculation of the dilution ratio depends on the type of system used.
The following types are recommended
- isokinetic systems (Figures 4 and 5)
With these systems, the flow into the transfer tube is matched to the bulk
exhaust flow in terms of gas velocity and/or pressure, thus requiring an
undisturbed and uniform exhaust flow at the sampling probe. This is usually
achieved by using a resonator and a straight approach tube upstream of the
sampling point. The split ratio is then calculated from easily measurable values
like tube diameters. It should be noted that isokinesis is only used for matching
the flow conditions and not for matching the size distribution. The latter is
typically not necessary, as the particles are sufficiently small as to follow the
fluid streamlines,
- flow controlled systems with concentration measurement (Figures 6 to 10)
With these systems, a sample is taken from the bulk exhaust stream by
adjusting the dilution air flow and the total dilution exhaust flow. The dilution
ratio is determined from the concentrations of tracer gases, such as CO 2 or NO x ,
naturally occurring in the engine exhaust. The concentrations in the dilution
exhaust gas and in the dilution air are measured, whereas the concentration in
the raw exhaust gas can be either measured directly or determined from fuel
flow and the carbon balance equation, if the fuel composition is known. The
systems may be controlled by the calculated dilution ratio (Figures 6 and 7) or
by the flow into the transfer tube (Figures 8, 9 and 10),
- flow controlled systems with flow measurement (Figures 11 and 12)
With these systems, a sample is taken from the bulk exhaust stream by setting
the dilution air flow and the total dilution exhaust flow. The dilution ratio is
determined from the difference of the two flow rates. Accurate calibration of
the flow meters relative to one another is required, since the relative magnitude
of the two flow rates can lead to significant errors at higher dilution ratios. Flow
control is very straightforward by keeping the dilute exhaust flow rate constant
and varying the dilution air flow rate, if needed.
In order to realise the advantages of the partial flow dilution systems, attention
must be paid to avoiding the potential problems of loss of particulates in the
transfer tube, ensuring that a representative sample is taken from the engine
exhaust, and determination of the split ratio.
1 Figures 4 to 12 show many types of partial flow dilution systems, which normally can be used for the steady-state test (NRSC). But,
because of very severe constraints of the transient tests, only those partial flow dilution systems (Figures 4 to 12) able to fulfill all the
requirements quoted in the section ‘Partial flow dilution system specifications’ of Annex III, Appendix 1, Section 2.4, are accepted for
the transient test (NRTC).
The systems described pay attention to these critical areas.
Raw exhaust gas is transferred from the exhaust pipe to EP to the dilution
tunnel DT through the transfer tube TT by the isokinetic sampling probe ISP.
The differential pressure of the exhaust gas between exhaust pipe and inlet to
the probe is measured with the pressure transducer DPT. This signal is
transmitted to the flow controller FC1 that controls the suction blower SB to
maintain a differential pressure of zero at the tip of the probe. Under these
conditions, exhaust gas velocities in EP and ISP are identical, and the flow
through ISP and TT is a constant fraction (split) of the exhaust gas flow. The
split ratio is determined from the cross sectional areas of EP and ISP. The
dilution air flow rate is measured with the flow measurement device FM1. The
dilution ratio is calculated from the dilution air flow rate and the split ratio.
Raw exhaust gas is transferred from the exhaust pipe EP to the dilution tunnel
DT through the transfer tube TT by the isokinetic sampling probe ISP. The
differential pressure of the exhaust gas between exhaust pipe and inlet to the
probe is measured with the pressure transducer DPT. This signal is transmitted
to the flow controller FC1 that controls the pressure blower PB to maintain a
differential pressure of zero at the tip of the probe. This is done by taking a
small fraction of the dilution air whose flow rate has already been measured
with the flow measurement device FM1, and feeding it to TT by means of a
pneumatic orifice. Under these conditions, exhaust gas velocities in EP and ISP
are identical, and the flow through ISP and TT is a constant fraction (split) of
the exhaust gas flow. The split ratio is determined from the cross sectional areas
of EP and ISP. The dilution air is sucked through DT by the suction blower SB,
and the flow rate is measured with FM1 at the inlet to DT. The dilution ratio is
calculated from the dilution air flow rate and the split ratio.
Raw exhaust gas is transferred from the exhaust pipe EP to the dilution tunnel
DT through the sampling probe SP and the transfer tube TT. The concentrations
of a tracer gas (CO 2 or NO x ) are measured in the raw and diluted exhaust gas as
well as in the dilution air with the exhaust gas analyser(s) EGA. These signals
are transmitted to the flow controller FC2 that controls either the pressure
blower PB or the suction blower SB to maintain the desired exhaust split and
dilution ratio in DT. The dilution ratio is calculated from the tracer gas
concentrations in the raw exhaust gas, the diluted exhaust gas, and the dilution
air.
Raw exhaust gas is transferred from the exhaust pipe EP to the dilution tunnel
DT through the sampling probe SP and the transfer tube TT. The CO 2
concentrations are measured in the diluted exhaust gas and in the dilution air
with the exhaust gas analyser(s) EGA. The CO 2 and fuel flow G FUEL signals
are transmitted either to the flow controller FC2, or to the flow controller FC3
of the particulate sampling system (Figure 14). FC2 controls the pressure
blower PB, while FC3 controls the particulate sampling system (Figure 14),
thereby adjusting the flows into and out of the system so as to maintain the
desired exhaust split and dilution ratio in DT. The dilution ratio is calculated
from the CO 2 concentrations and G FUEL using the carbon balance assumption.
Raw exhaust gas is transferred from the exhaust pipe EP to the dilution tunnel
DT through the sampling probe SP and the transfer tube TT due to the negative
pressure created by the venturi VN in DT. The gas flow rate through TT
depends on the momentum exchange at the venturi zone, and is therefore
affected by the absolute temperature of the gas at the exit of TT. Consequently,
the exhaust split for a given tunnel flow rate is not constant, and the dilution
ratio at low load is slightly lower than at high load. The tracer gas
concentrations (CO 2 or NO x ) are measured in the raw exhaust gas, the diluted
exhaust gas, and the dilution air with the exhaust gas analyser(s) EGA, and the
dilution ratio is calculated from the values so measured.
Raw exhaust gas is transferred from the exhaust pipe EP to the dilution tunnel
DT through the sampling probe SP and the transfer tube TT by a flow divider
that contains a set of orifices or venturis. The first one (FD1) is located in EP,
the second one (FD2) in TT. Additionally, two pressure control valves (PCV1
and PCV2) are necessary to maintain a constant exhaust split by controlling the
backpressure in EP and the pressure in DT. PCV1 is located downstream of SP
in EP, PCV2 between the pressure blower PB and DT. The tracer gas
concentrations (CO 2 or NO x ) are measured in the raw exhaust gas, the diluted
exhaust gas, and the dilution air with the exhaust gas analyser(s) EGA. They are
necessary for checking the exhaust split, and may be used to adjust PCV1 and
PCV2 for precise split control. The dilution ratio is calculated from the tracer
gas concentrations.
Raw exhaust gas is transferred from the exhaust pipe EP to the dilution tunnel
DT through the transfer tube TT by the flow divider FD3 that consists of a
number of tubes of the same dimensions (same diameter, length and bed radius)
installed in EP. The exhaust gas through one of these tubes is lead to DT, and
the exhaust gas through the rest of the tubes is passed through the damping
chamber DC. Thus, the exhaust split is determined by the total number of tubes.
A constant split control requires a differential pressure of zero between DC and
the outlet of TT, which is measured with the differential pressure transducer
DPT. A differential pressure of zero is achieved by injecting fresh air into DT at
the outlet of TT. The tracer gas concentrations (CO 2 or NO x ) are measured in
the raw exhaust gas, the diluted exhaust gas, and the dilution air with the
exhaust gas analyser(s) EGA. They are necessary for checking the exhaust split
and may be used to control the injection air flow rate for precise split control.
The dilution ratio is calculated from the tracer gas concentrations.
Raw exhaust gas is transferred from the exhaust pipe EP to the dilution tunnel
DT through the sampling probe SP and the transfer tube TT. The total flow
through the tunnel is adjusted with the flow controller FC3 and the sampling
pump P of the particulate sampling system (Figure 16).
The dilution air flow is controlled by the flow controller FC2, which may use G
EXH , G AIR or G FUEL as command signals, for the desired exhaust split. The
sample flow into DT is the difference of the total flow and the dilution air flow.
The dilution air flow rate is measured with flow measurement device FM1, the
total flow rate with the flow measurement device FM3 of the particulate
sampling system (Figure 14). The dilution ratio is calculated from these two
flow rates.
Raw exhaust gas is transferred from the exhaust pipe EP to the dilution tunnel
DT through the sampling probe SP and the transfer tube TT. The exhaust split
and the flow into DT is controlled by the flow controller FC2 that adjusts the
flows (or speeds) of the pressure blower PB and the suction blower SB,
accordingly. This is possible since the sample taken with the particulate
sampling system is returned into DT. GG EXH , G AIR or G FUEL may be used
as command signals for FC2. The dilution air flow rate is measured with the
flow measurement device FM1, the total flow with the flow measurement
device FM2. The dilution ratio is calculated from these two flow rates.
Description - Figures 4 to 12
EP exhaust pipe
The exhaust pipe may be insulated. To reduce the thermal inertia of the exhaust
pipe a thickness to diameter ratio of 0,015 or less is recommended. The use of
flexible sections shall be limited to a length to diameter ratio of 12 or less.
Bends will be minimised to reduce inertial deposition. If the system includes a
test bed silencer, the silencer may also be insulated.
For an isokinetic system, the exhaust pipe must be free of elbows, bends and
sudden diameter changes for at least six pipe diameters upstream and three pipe
diameters downstream of the tip of the probe. The gas velocity at the sampling
zone must be higher than 10 m/s except at idle mode. Pressure oscillations of
the exhaust gas must not exceed ± 500 Pa on the average. Any steps to reduce
pressure oscillations beyond using a chassis-type exhaust system (including
silencer and after-treatment device) must not alter engine performance nor
cause the deposition of particulates.
For systems without isokinetic probes, it is recommended to have a straight
pipe of six pipe diameters upstream and three pipe diameters downstream of the
tip of the probe.
- SP sampling probe (Figures 6 to 12)
The minimum inside diameter shall be 4 mm. The minimum diameter ratio
between exhaust pipe and probe shall be four. The probe shall be an open tube
facing upstream on the exhaust pipe centre-line, or a multiple hole probe as
described under SP1 in section 1.1.1.
- ISP isokinetic sampling probe (Figures 4 and 5)
The isokinetic sampling probe must be installed facing upstream on the exhaust
pipe centre-line where the flow conditions in section EP are met, and designed
to provide a proportional sample of the raw exhaust gas. The minimum inside
diameter shall be 12 mm.
A control system is necessary for isokinetic exhaust splitting by maintaining a
differential pressure of zero between EP and ISP. Under these conditions
exhaust gas velocities in EP and ISP are identical and the mass flow through
ISP is a constant fraction of the exhaust gas flow. The ISP has to be connected
to a differential pressure transducer. The control to provide a differential
pressure of zero between EP and ISP is done with blower speed or flow
controller.
- FD1, FD2 flow divider (Figure 9)
A set of venturis or orifices is installed in the exhaust pipe EP and in the transfer
tube TT, respectively, to provide a proportional sample of the raw exhaust gas.
A control system consisting of two pressure control valves PCV1 and PCV2 is
necessary for proportional splitting by controlling the pressures in EP and DT.
- FD3 flow divider (Figure 10)
A set of tubes (multiple tube unit) is installed in the exhaust pipe EP to provide
a proportional sample of the raw exhaust gas. One of the tubes feeds exhaust
gas to the dilution tunnel DT, whereas the other tubes exit exhaust gas to a
damping chamber DC. The tubes must have the same dimensions (same
diameter, length, bend radius), so that the exhaust split depends on the total
number of tubes. A control system is necessary for proportional splitting by
maintaining a differential pressure of zero between the exit of the multiple tube
unit into DC and the exit of TT. Under these conditions, exhaust gas velocities
in EP and FD3 are proportional, and the flow TT is a constant fraction of the
exhaust gas flow. The two points have to be connected to a differential pressure
transducer DPT. The control to provide a differential pressure of zero is done
with the flow controller FC1.
- EGA exhaust gas analyser (Figures 6 to 10)
CO 2 or NO x analysers may be used (with carbon balance method CO 2 only).
The analysers shall be calibrated like the analysers for the measurement of the
gaseous emissions. One or several analysers may be used to determine the
concentration differences.
The accuracy of the measuring systems has to be such that the accuracy of
G EDFW , i is within ± 4 %.
- TT transfer tube (Figures 4 to 12)
The particulate sample transfer tube shall be
- as short as possible, but not more than 5 m in length,
- equal to or greater than the probe diameter, but not more than 25 mm in
diameter,
- exiting on the centre-line of the dilution tunnel and pointing downstream.
If the tube is 1 metre or less in length, it is to be insulated with material with a
maximum thermal conductivity of 0,05 W/(m · K) with a radial insulation
thickness corresponding to the diameter of the probe. If the tube is longer than 1
metre, it must be insulated and heated to a minimum wall temperature of 523 K
(250 °C).
Alternatively, the transfer tube wall temperatures required may be determined
through standard heat transfer calculations.
- DPT differential pressure transducer (Figures 4, 5 and 10)
The differential pressure transducer shall have a range of ± 500 Pa or less.
- FC1 flow controller (Figures 4, 5 and 10)
For the isokinetic systems (Figures 4 and 5) a flow controller is necessary to
maintain a differential pressure of zero between EP and ISP. The adjustment
can be done by
(a) controlling the speed or flow of the suction blower (SB) and keeping the
speed of the pressure blower (PB) constant during each mode (Figure 4); or
(b) adjusting the suction blower (SB) to a constant mass flow of the diluted
exhaust and controlling the flow of the pressure blower PB, and therefore the
exhaust sample flow in a region at the end of the transfer tube (TT) (Figure 5).
In the case of a pressure controlled system the remaining error in the control
loop must not exceed ± 3 Pa. The pressure oscillations in the dilution tunnel
must not exceed ± 250 Pa on average.
For a multi-tube system (Figure 10) a flow controller is necessary for
proportional exhaust splitting to maintain a differential pressure of zero
between the outlet of the multi-tube unit and the exit of TT. The adjustment can
be done by controlling the injection air flow rate into DT at the exit of TT.
PCV1, PCV2 pressure control valve (Figure 9)
Two pressure control valves are necessary for the twin venturi/twin orifice
system for proportional flow splitting by controlling the backpressure of EP and
the pressure in DT. The valves shall be located downstream of SP in EP and
between PB and DT.
DC damping chamber (Figure 10)
A damping chamber shall be installed at the exit of the multiple tube unit to
minimise the pressure oscillations in the exhaust pipe EP.
VN venturi (Figure 8)v
A venturi is installed in the dilution tunnel DT to create a negative pressure in
the region of the exit of the transfer tube TT. The gas flow rate through TT is
determined by the momentum exchange at the venturi zone, and is basically
proportional to the flow rate of the pressure blower PB leading to a constant
dilution ratio. Since the momentum exchange is affected by the temperature at
the exit of TT and the pressure difference between EP and DT, the actual
dilution ratio is slightly lower at low load than at high load.
FC2 flow controller (Figures 6, 7, 11 and 12; optional)
A flow controller may be used to control the flow of the pressure blower PB
and/or the suction blower SB. It may be connected to the exhaust flow or fuel
flow signal and/or to the CO 2 or NO x differential signal.
When using a pressurised air supply (Figure 11) FC2 directly controls the air
flow.
- FM1 flow measurement device (Figures 6, 7, 11 and 12)
Gas meter or other flow instrumentation to measure the dilution air flow. FM1
is optional if PB is calibrated to measure the flow.
- FM2 flow measurement device (Figure 12)
Gas meter or other flow instrumentation to measure the diluted exhaust gas
flow. FM2 is optional if the suction blower SB is calibrated to measure the
flow.
- PB pressure blower (Figures 4, 5, 6, 7, 8, 9 and 12)
To control the dilution air flow rate, PB may be connected to the flow
controllers FC1 or FC2. PB is not required when using a butterfly valve. PB
may be used to measure the dilution air flow, if calibrated.
- SB suction blower (Figures 4, 5, 6, 9, 10 and 12)
For fractional sampling systems only. SB may be used to measure the dilute
exhaust gas flow, if calibrated.
- DAF dilution air filter (Figures 4 to 12)
It is recommended that the dilution air be filtered and charcoal scrubbed to
eliminate background hydrocarbons. The dilution air shall have a temperature
of 298 K (25 °C) ± 5 K.
At the manufacturer's request the dilution air shall be sampled according to
good engineering practice to determine the background particulate levels,
which can then be subtracted from the values measured in the diluted exhaust.
- PSP particulate sampling probe (Figures 4, 5, 6, 8, 9, 10 and 12)
The probe is the leading section of PTT and
shall be installed facing upstream at a point where the dilution air and exhaust
gas are well mixed, i.e. on the dilution tunnel DT centre-line of the dilution
systems approximately 10 tunnel diameters downstream of the point where the
exhaust enters the dilution tunnel,
- shall be 12 mm in minimum inside diameter,
- may be heated to no greater than 325 K (52 °C) wall temperature by direct
heating or by dilution air pre-heating, provided the air temperature does not
exceed 325 K (52 °C) prior to the introduction of the exhaust in the dilution
tunnel,
- may be insulated.
DT dilution tunnel (Figures 4 to 12)
The dilution tunnel
- shall be of a sufficient length to cause complete mixing of the exhaust and
dilution air under turbulent flow conditions,
- shall be constructed of stainless steel with
- a thickness to diameter ratio of 0,025 or less for dilution tunnels of greater
than 75 mm inside diameter,
- a nominal wall thickness of not less than 1,5 mm for dilution tunnels of equal
to or less than 75 mm inside diameter,
- shall be at least 75 mm in diameter for the fractional sampling type,
- is recommended to be at least 25 mm in diameter for the total sampling type,
- may be heated to no greater than 325 K (52 °C) wall temperature by direct
heating or by dilution air pre-heating, provided the air temperature does not
exceed 325 K (52 °C) prior to the introduction of the exhaust in the dilution
tunnel,
- may be insulated.
The engine exhaust shall be thoroughly mixed with the dilution air. For
fractional sampling systems, the mixing quality shall be checked after
introduction into service by means of a CO 2 profile of the tunnel with the
engine running (at least four equally spaced measuring points). If necessary, a
mixing orifice may be used.
Note: If the ambient temperature in the vicinity of the dilution tunnel (DT) is
below 293 K (20 °C), precautions should be taken to avoid particle losses onto
the cool walls of the dilution tunnel. Therefore, heating and/or insulating the
tunnel within the limits given above is recommended.
At high engine loads, the tunnel may be cooled by a non- aggressive means
such as a circulating fan, as long as the temperature of the cooling medium is
not below 293 K (20 °C).
- HE heat exchanger (Figures 9 and 10)
The heat exchanger shall be of sufficient capacity to maintain the temperature at
the inlet to the suction blower SB within ± 11 K of the average operating
temperature observed during the test.
F u l l f l o w d i l u t i o n s y s t e m ( F i g u r e 1 3 )
A dilution system is described based upon the dilution of the total exhaust using
the constant volume sampling (CVS) concept. The total volume of the mixture
of exhaust and dilution air must be measured. Either a PDP or a CFV or a SSV
system may be used.
For subsequent collection of the particulates, a sample of the dilute exhaust gas
is passed to the particulate sampling system (section 1.2.2, Figures 14 and 15).
If this is done directly, it is referred to as single dilution. If the sample is diluted
once more in the secondary dilution tunnel, it is referred to as double dilution.
This is useful, if the filter face temperature requirement cannot be met with
single dilution. Although partly a dilution system, the double dilution system is
described as a modification of a particulate sampling system in section 1.2.2,
(Figure 15), since it shares most of the parts with a typical particulate sampling
system.
The gaseous emissions may also be determined in the dilution tunnel of a full
flow dilution system. Therefore, the sampling probes for the gaseous
components are shown in Figure 13 but do not appear in the description list.
The respective requirements are described in section 1.1.1.
Descriptions (Figure 13)
- EP exhaust pipe
The exhaust pipe length from the exit of the engine exhaust manifold,
turbocharger outlet or after-treatment device to the dilution tunnel is required to
be not more than 10 m. If the system exceeds 4 m in length, then all tubing in
excess of 4 m shall be insulated, except for an in-line smoke-meter, if used. The
radial thickness of the insulation must be at least 25 mm. The thermal
conductivity of the insulating material must have a value no greater than 0,1 W/
(m · K) measured at 673 K (400 °C). To reduce the thermal inertia of the
exhaust pipe a thickness to diameter ratio of 0,015 or less is recommended. The
use of flexible sections shall be limited to a length to diameter ratio of 12 or
less.
The total amount of raw exhaust gas is mixed in the dilution tunnel DT with the
dilution air. The diluted exhaust gas flow rate is measured either with a positive
displacement pump PDP or with a critical flow venturi CFV or with a sub-sonic
venturi SSV. A heat exchanger HE or electronic flow compensation EFC may
be used for proportional particulate sampling and for flow determination. Since
particulate mass determination is based on the total diluted exhaust gas flow,
the dilution ratio is not required to be calculated.
- PDP positive displacement pump
The PDP meters total diluted exhaust flow from the number of the pump
revolutions and the pump displacement. The exhaust system back pressure must
not be artificially lowered by the PDP or dilution air inlet system. Static exhaust
back pressure measured with the CVS system operating shall remain within ±
1,5 kPa of the static pressure measured without connection to the CVS at
identical engine speed and load.
The gas mixture temperature immediately ahead of the PDP shall be within ± 6
K of the average operating temperature observed during the test, when no flow
compensation is used.
Flow compensation can only be used if the temperature at the inlet of the PDP
does not exceed 50°C (323 K).
- CFV critical flow venture
- CFV measures total diluted exhaust flow by maintaining the flow at choked
conditions (critical flow). Static exhaust backpressure measured with the CFV
system operating shall remain within ± 1,5 kPa of the static pressure measured
without connection to the CFV at identical engine speed and load. The gas
mixture temperature immediately ahead of the CFV shall be within ± 11 K of
the average operating temperature observed during the test, when no flow
compensation is used.
- SSV subsonic venture
- SSV measures total diluted exhaust flow as a function of inlet pressure, inlet
temperature, pressure drop between the SSV inlet and throat. Static exhaust
backpressure measured with the SSV system operating shall remain within ±
1,5 kPa of the static pressure measured without connection to the SSV at
identical engine speed and load. The gas mixture temperature immediately
ahead of the SSV shall be within ± 11 K of the average operating temperature
observed during the test, when no flow compensation is used.
- HE heat exchanger (optional if EFC is used)
The heat exchanger shall be of sufficient capacity to maintain the temperature
within the limits required above.
- EFC electronic flow compensation (optional if HE is used)
If the temperature at the inlet to either the PDP or CFV or SSV is not kept
within the limits stated above, a flow compensation system is required for
continuous measurement of the flow rate and control of the proportional
sampling in the particulate system. To that purpose, the continuously measured
flow rate signals are used to correct the sample flow rate through the particulate
filters of the particulate sampling system (Figures 14 and 15), accordingly.
- DT dilution tunnel
The dilution tunnel
- shall be small enough in diameter to cause turbulent flow (Reynolds number
greater than 4 000) of sufficient length to cause complete mixing of the exhaust
and dilution air. A mixing orifice may be used,
- shall be at least 75 mm in diameter,
- may be insulated.
The engine exhaust shall be directed downstream at the point where it is
introduced into the dilution tunnel, and thoroughly mixed.
When using single dilution, a sample from the dilution tunnel is transferred to
the particulate sampling system (section 1.2.2, Figure 14). The flow capacity of
the PDP or CFV or SSV must be sufficient to maintain the diluted exhaust at a
temperature of less than or equal to 325 K (52 °C) immediately before the
primary particulate filter.
When using double dilution, a sample from the dilution tunnel is transferred to
the secondary dilution tunnel where it is further diluted, and then passed
through the sampling filters (section 1.2.2, Figure 15). The flow capacity of the
PDP or CFV or SSV must be sufficient to maintain the diluted exhaust stream
in the DT at a temperature of less than or equal to 464 K (191 °C) at the
sampling zone. The secondary dilution system must provide sufficient
secondary dilution air to maintain the doubly-diluted exhaust stream at a
temperature of less than or equal to 325 K (52 °C) immediately before the
primary particulate filter.
- DAF dilution air filter
It is recommended that the dilution air be filtered and charcoal scrubbed to
eliminate background hydrocarbons. The dilution air shall have a temperature
of 298 K (25 °C) ± 5 K. At the manufacturer's request the dilution air shall be
sampled according to good engineering practice to determine the background
particulate levels, which can then be subtracted from the values measured in the
diluted exhaust.
- PSP particulate sampling probe
The probe is the leading section of PTT and
- shall be installed facing upstream at a point where the dilution air and exhaust
gas are well mixed, i.e. on the dilution tunnel DT centre-line of the dilution
systems approximately 10 tunnel diameters downstream of the point where the
exhaust enters the dilution tunnel,
- shall be 12 mm in minimum inside diameter,
- may be heated to no greater than 325 K (52 °C) wall temperature by direct
heating or by dilution air pre- heating, provided the air temperature does not
exceed 325 K (52 °C) prior to the introduction of the exhaust in the dilution
tunnel,
- may be insulated.
Particulate sampling system (Figures 14 and 15)
The particulate sampling system is required for collecting the particulates on
the particulate filter. In the case of total sampling partial flow dilution, which
consists of passing the entire dilute exhaust sample through the filters, dilution
(section 1.2.1.1, Figures 7 and 11) and sampling system usually form an
integral unit. In the case of fractional sampling partial flow dilution or full flow
dilution, which consists of passing through the filters only a portion of the
diluted exhaust, the dilution (section 1.2.1.1, Figures 4, 5, 6, 8, 9, 10 and 12 and
section 1.2.1.2, Figure 13) and sampling systems usually form different units.
In these regulations, the double dilution system DDS (Figure 15) of a full flow
dilution system is considered as a specific modification of a typical particulate
sampling system as shown in Figure 14. The double dilution system includes all
important parts of the particulate sampling system, like filter holders and
sampling pump, and additionally some dilution features, like a dilution air
supply and a secondary dilution tunnel.
In order to avoid any impact on the control loops, it is recommended that the
sample pump be running throughout the complete test procedure. For the single
filter method, a bypass system shall be used for passing the sample through the
sampling filters at the desired times. Interference of the switching procedure on
the control loops must be minimised.
Descriptions - Figures 14 and 15
- PSP particulate sampling probe (Figures 14 and 15)
The particulate sampling probe shown in the figures is the leading section of the
particulate transfer tube PTT. The probe
- shall be installed facing upstream at a point where the dilution air and exhaust
gas are well mixed, i.e. on the dilution tunnel DT centre-line of the dilution
systems (section 1.2.1), approximately 10 tunnel diameters downstream of the
point where the exhaust enters the dilution tunnel),
- shall be 12 mm in minimum inside diameter,
- may be heated to no greater than 325 K (52 °C) wall temperature by direct
heating or by dilution air pre- heating, provided the air temperature does not
exceed 325 K (52 °C) prior to the introduction of the exhaust in the dilution
tunnel,
- may be insulated.
A sample of the diluted exhaust gas is taken from the dilution tunnel DT of a
partial flow or full flow dilution system through the particulate sampling probe
PSP and the particulate transfer tube PTT by means of the sampling pump P.
The sample is passed through the filter holders(s) FH that contain the
particulate sampling filters. The sample flow rate is controlled by the flow
controller FC3. If electronic flow compensation EFC (Figure 13) is used, the
diluted exhaust gas flow is used as command signal for FC3.
A sample of the diluted exhaust gas is transferred from the dilution tunnel DT
of a full flow dilution system through the particulate sampling probe PSP and
the particulate transfer tube PTT to the secondary dilution tunnel SDT, where it
is diluted once more. The sample is then passed through the filter holder(s) FH
that contain the particulate sampling filters. The dilution air flow rate is usually
constant whereas the sample flow rate is controlled by the flow controller FC3.
If electronic flow compensation EFC (Figure 13) is used, the total diluted
exhaust gas flow is used as command signal for FC3.
- PTT particulate transfer tube (Figures 14 and 15)
The particulate transfer tube must not exceed 1 020 mm in length, and must be
minimised in length whenever possible.
The dimensions are valid for
- the partial flow dilution fractional sampling type and the full flow single
dilution system from the probe tip to the filter holder,
- the partial flow dilution total sampling type from the end of the dilution
tunnel to the filter holder,
- the full flow double dilution system from the probe tip to the secondary
dilution tunnel.
The transfer tube
- may be heated to no greater than 325 K (52 °C) wall temperature by direct
heating or by dilution air pre-heating, provided the air temperature does not
exceed 325 K (52 °C) prior to the introduction of the exhaust in the dilution
tunnel,
- may be insulated.
- SDT secondary dilution tunnel (Figure 15)
The secondary dilution tunnel should have a minimum diameter of 75 mm and
should be sufficient length so as to provide a residence time of at least 0,25
seconds for the doubly-diluted sample. The primary filter holder, FH, shall be
located within 300 mm of the exit of the SDT.
The secondary dilution tunnel
- may be heated to no greater than 325 K (52 °C) wall temperature by direct
heating or by dilution air pre-heating, provided the air temperature does not
exceed 325 K (52 °C) prior to the introduction of the exhaust in the dilution
tunnel,
- may be insulated.
- FH filter holder(s) (Figures 14 and 15)
For primary and back-up filters one filter housing or separate filter housings
may be used. The requirements of Schedule III, Appendix 1, section 1.5.1.3
have to be met.
The filter holder(s)
- may be heated to no greater than 325 K (52 °C) wall temperature by direct
heating or by dilution air pre-heating, provided the air temperature does not
exceed 325 K (52 °C),
- may be insulated.
- P sampling pump (Figures 14 and 15)
The particulate sampling pump shall be located sufficiently distant from the
tunnel so that the inlet gas temperature is maintained constant (± 3 K), if flow
correction by FC3 is not used.
- DP dilution air pump (Figure 15) (full flow double dilution only)
The dilution air pump shall be located so that the secondary dilution air is
supplied at a temperature of 298 K (25 °C) ± 5 K.
- FC3 flow controller (Figures 14 and 15)
A flow controller shall be used to compensate the particulate sample flow rate
for temperature and backpressure variations in the sample path, if no other
means are available. The flow controller is required if electronic flow
compensation EFC (Figure 13) is used.
- FM3 flow measurement device (Figures 14 and 15) (particulate sample flow)
The gas meter or flow instrumentation shall be located sufficiently distant from
the sample pump so that the inlet gas temperature remains constant (± 3 K), if
flow correction by FC3 is not used.
- FM4 flow measurement device (Figure 15) (dilution air, full flow double
dilution only)
The gas meter or flow instrumentation shall be located so that the inlet gas
temperature remains at 298 K (25 °C) ± 5 K.
- BV ball valve (optional)
The ball valve shall have a diameter not less than the inside diameter of the
sampling tube and a switching time of less than 0,5 seconds.
Note: If the ambient temperature in the vicinity of PSP, PTT, SDT, and FH is
below 239 K (20 °C), precautions should be taken to avoid particle losses onto
the cool wall of these parts. Therefore, heating and/or insulating these parts
within the limits given in the respective descriptions is recommended. It is also
recommended that the filter face temperature during sampling be not below 293
K (20 °C).
At high engine loads, the above parts may be cooled by a non- aggressive
means such as a circulating fan, as long as the temperature of the cooling
medium is not below 293 K (20 °C).
Schedule VII
Appendix 1
TEST RESULTS FOR COMPRESSION IGNITION
1. INFORMATION CONCERNING THE CONDUCT OF THE NRSC TEST ( 5 )
Reference fuel used for test
Cetane number: .....................................................................................................
Sulphur content: ...................................................................................................
Density .................................................................................................................
Lubricant
Make(s)
Type(s)
(state percentage of oil in mixture if lubricant and fuel are mixed)
Engine driven equipment (if applicable)
Enumeration and identifying details: ....................................................................
Power absorbed at indicated engine speeds (as specified by the manufacturer)
Engine performance
Engine speeds
For the case of several parent engines to be indicated for each of them.
Engine power ( 1 )
1.5
Emission levels
1.5.1
Dynamometer setting (kW)
1.5.2
Emission results on the NRSC test
Sampling system used for the NRSC test
Gaseous emissions ( 7 )
Particulates
Method ( 3 ): single/multiple filter
2. INFORMATION CONCERNING THE CONDUCT OF THE NRTC TEST ( 8 )
Emission results on the NRTC test
Sampling system used for the NRTC test
Gaseous emissions: ..............................................................................................
Particulates: ..........................................................................................................
Method: single/multiple filter
7 Indicate figure numbers defined in Annex VI section 1.
Delete as appropriate.
Appendix 2
TEST RESULTS FOR SPARK IGNITION ENGINES
1. INFORMATION CONCERNING THE CONDUCT OF THE TEST(S) ( 9 )
Octane number
Octane number
State percentage of oil in mixture when lubricant and petrol are mixed as in the
case of two-stroke engines
Density of petrol for four-stroke engines and petrol/oil mixture for two- stroke
engines
Lubricant
Make(s)
Type(s)
Engine driven equipment (if applicable)
Enumeration and identifying details
Power absorbed at indicated engine speed (as specified by the manufacturer)
For the case of several parent engines, to be indicated for each of them.
1.4
Engine performance
1.4.1
Engine speeds
Idle: min -1
Intermediate: min -1
Rated: min -1
1.4.2
Engine power ( 6 )
Uncorrected power measured in accordance with section 2.4 of Annex I.
1.5
Emission levels
1.5.1
Dynamometer setting (kW)
1.5.2
Emission results on the test cycle
CO: g/kWh
HC: g/kWh
NO x : g/kWh
Appendix 3
EQUIPMENT AND AUXILIARIES TO BE INSTALLED
Schedule VIII
APPROVAL CERTIFICATE NUMBERING SYSTEM
(see Regulation 5 (2))
1. The number shall consist of five sections separated by the ‘*’ character.
Section 1: the lower case letter ‘e’ followed by the distinguishing letter(s) or
number of the Member State issuing the approval
1 for Germany
2 for France
3 for Italy
4 for the Netherlands
5 for Sweden
6 for Belgium
7 for Hungary
8 for the Czech Republic
9 for Spain
11 for the United Kingdom
12 for Austria
13 for Luxembourg
17 for Finland
18 for Denmark
19 for Romania
20 for Poland
21 for Portugal
23 for Greece
24 for Ireland
26 for Slovenia
27 for Slovakia
29 for Estonia
32 for Latvia
34 for Bulgaria
36 for Lithuania
CY for Cyprus
MT for Malta
Section 2: the number of these regulations. As it contains different
implementation dates and different technical standards, two alphabetical
characters are added. These characters refer to the different application dates for
the stages of severity and to the application of the engine for different
specification of mobile machinery, on the basis of which type-approval was
granted. The first character is defined in Regulation 11. The second character is
defined in Schedule I, section 1 with regard to the test mode defined in
Schedule III, section 3.6.
Section 3: the number of the latest amending Regulation applicable to the
approval. If applicable two further alphabetical characters are to be added
depending on the conditions described in section 2, even if as a result of the
new parameters only one of the characters was to be changed. If no change of
these characters apply they shall be omitted.
Section 4: a four-digit sequential number (with leading zeros as applicable) to
denote the base approval number. The sequence shall start from 0001.
Section 5: a two-digit sequential number (with a leading zero if applicable) to
denote the extension. The sequence shall start from 01 for each base approval
number.
2. Example for the third approval (with, as yet, no extension) corresponding to
application date A (stage I, upper powerband) and to the application of the
engine for specification A of mobile machinery, issued by the United Kingdom
e 11*98/…AA*00/000XX*0003*00
3. Example of the second extension to the fourth approval corresponding to
application date E (stage II, medium powerband) for the same specification of
machinery (A), issued by Germany
e 1*01/…EA*00/000XX*0004*02
Schedule IX
Schedule X
Schedule XI
Schedule XII
1. The following type-approvals and, where applicable, the pertaining approval
marks are recognised as being equivalent to an approval to these regulations for
engines of categories A, B and C as defined in Regulation 11(2)
Directive 2000/25/EC.
Type-approvals to Directive 88/77/EEC, complying with the requirements of
stage A or B regarding Regulation 3, and Schedule I, section 6.2.1 of Directive
88/77/EEC as amended by Directive 91/542/EEC, or UN-ECE Regulation
49.02 series of amendments corrigenda I/2.
Certificates of type approvals according to UN-ECE Regulation 96.
2. For engines categories D, E, F and G (stage II) as defined in Regulatio 11(3),
the following type-approvals and, where applicable, the pertaining approval
marks are recognised as being equivalent to an approval to these regulations
Directive 2000/25/EC, stage II approvals;
Type-approvals to Directive 88/77/EEC as amended by Directive 99/96/EC
which are in compliance with stages A, B1, B2 or C provided for in Regulation
3 and section 6.2.1 of Schedule I;
UN-ECE Regulation 49.03 series of amendments;
UN-ECE Regulation 96 stage B approvals according to paragraph 5.2.1 of the
01 series of amendments of Regulation 96.
3. For engines categories H, I, and J (stage IIIA) and engines category K, L and M
(stage IIIB) as defined in Regulatio 11, section 3, the following type-approvals
and, where applicable, the pertaining approval marks are recognised as being
equivalent to an approval to these regulations.
Type-approvals to Directive 88/77/EEC, as amended by Directive 99/96/EC,
which are in compliance with stages B1, B2 or C provided for in Regulation 3
and section 6.2.1. of Schedule I.
UN-ECE Regulation 49.03. series of amendments which are in compliance with
stages B1, B2 and C provided for in paragraph 5.2.
Schedule XIII
PROVISIONS FOR ENGINES PLACED ON THE MARKET UNDER A
‘FLEXIBLE SCHEME’
On the request of an equipment manufacturer (OEM), and permission being
granted by an approval authority, an engine manufacturer may during the period
between two successive stages of limit values place a limited number of engines
on the market that only comply with the previous stage of emission limit values
in accordance with the following provisions
1. ACTIONS BY THE OEM
Except during Stage III B, an OEM that wishes to make use of the flexibility
scheme, with the exception of engines for the propulsion of railcars and
locomotives, shall request permission from any approval authority for the
OEM’s engine manufacturers to place on the market engines intended for the
OEM’s exclusive use. The number of engines that do not comply with the
current emission limits, but are approved to the most recent previous stage of
emission limits, shall not exceed the ceilings set out in Sections 1.1.1 and 1.1.2.
The number of engines placed on the market under the flexibility scheme shall,
in each engine category, not exceed 20 % of the annual quantity of equipment
with engines in that category that is placed on the market by the OEM
(calculated as an average of the latest 5 years’ sales on the Union market).
Where an OEM has placed equipment on the Union market for less than 5
years, the average shall be calculated based on the period for which the OEM
has placed equipment on the Union market.
As an optional alternative to Section 1.1.1 and with the exception of engines for
the propulsion of railcars and locomotives, the OEM may seek permission for
the OEM’s engine manufacturers to place on the market a fixed number of
engines for the OEM’s exclusive use. The number of engines in each engine
category shall not exceed the following ceilings
During Stage III B, but for a period no longer than 3 years from the beginning
of that stage, with the exception of engines for use in the propulsion of railcars
and locomotives, an OEM that wishes to make use of the flexibility scheme
shall request permission from any approval authority for the OEM’s engine
manufacturers to place on the market engines intended for the OEM’s exclusive
use. The quantities of engines that do not comply with the current emission
limits, but are approved to the most recent previous stage of emission limits,
shall not exceed the ceilings set out in Sections 1.2.1 and 1.2.2.
The number of engines placed on the market under the flexibility scheme shall,
in each engine category, not exceed 37,5 % of the annual quantity of equipment
with engines in that category that is placed on the market by the OEM
(calculated as an average of the latest 5 years’ sales on the Union market).
Where an OEM has placed equipment on the Union market for less than 5
years, the average shall be calculated based on the period for which the OEM
has placed equipment on the Union market.
As an optional alternative to Section 1.2.1, the OEM may seek permission for
the OEM’s engine manufacturers to place on the market a fixed number of
engines for the OEM’s exclusive use. The number of engines in each engine
category shall not exceed the following ceilings
As regards engines for use in the propulsion of locomotives, during Stage III B,
but for a period no longer than 3 years from the beginning of that stage, an
OEM may seek permission for the OEM’s engine manufacturers to place on the
market a maximum of 16 engines for the OEM’s exclusive use. The OEM may
also seek permission for his engine manufacturers to place on the market a
maximum of 10 additional engines with rated powers greater than 1 800 kW to
be installed in locomotives designed exclusively for use on the United Kingdom
network. Locomotives will be considered to meet this requirement only if they
have, or are able to be issued with, a safety certificate for operation on the
United Kingdom network.
Such permission shall be granted only where there are technical grounds for not
being able to comply with the Stage III B emission limits.
The OEM shall include in the application to an approval authority the following
information
(a) a sample of the labels to be affixed to each piece of non-road mobile
machinery in which an engine placed on the market under the flexibility scheme
will be installed. The labels shall bear the following text: ‘MACHINE No …
(sequence of machines) OF … (total number of machines in respective power
band) WITH ENGINE No … WITH TYPE-APPROVAL (Dir. 97/68/EC) No
…’;
(b) a sample of the supplementary label to be affixed on the engine bearing
the text referred to in Section 2.2.
The OEM shall provide the approval authority with any necessary information
connected with the implementation of the flexibility scheme that the approval
authority may request in order to make a decision.
The OEM shall provide any requesting approval authority in the Member States
with any information that the approval authority requires in order to confirm
that engines claimed to be, or labelled as being, placed on the market under the
flexibility scheme are properly so claimed or labelled.
2. ACTIONS BY THE ENGINE MANUFACTURER
An engine manufacturer may place on the market engines under a flexible
scheme covered by an approval in accordance with Section 1 of this Schedule.
The engine manufacturer must put a label on those engines with the following
text: ‘Engine placed on the market under the flexibility scheme’.
3. ACTIONS BY THE APPROVAL AUTHORITY
The approval authority shall evaluate the content of the flexibility scheme
request and the enclosed documents. As a consequence it will inform the OEM
of its decision as to whether or not to allow use of the flexibility scheme.
Schedule XIV
Schedule XV
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