PDF Actual Sample: GB 17691-2018 (PDF-excerpt released/modified date: 2019-08-17/2019-08-17. Translated/reviewed by: Wayne Zheng et al.)
| Standard ID | GB 17691-2018 (GB17691-2018) |
| Description (Translated English) | Limits and measurement methods for emissions from diesel fuelled heavy-duty vehicles (CHINA VI) |
| Sector / Industry | National Standard |
| Classification of Chinese Standard | Z64 |
| Date of Issue | 2018-06-22 |
| Date of Implementation | 2019-07-01 |
| Older Standard (superseded by this standard) | GB 11340-2005(Partial); GB 17691-2005 |
| Regulation (derived from) | Ministry of Ecology and Environment Announcement No. 14 of 2018 |
ENGLISH: GB 17691-2018 (Translated) GB 17691-2018
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
Replacing GB 17691-2005
Limits and measurement methods for emissions from
diesel fueled heavy-duty vehicles (CHINA VI)
重型柴油车污染物排放限值及测量方法
(中国第六阶段)
ISSUED ON: JUNE 22, 2018
IMPLEMENTED ON: JULY 01, 2019
Issued by: Ministry of Ecology and Environment;
State Market Regulatory Administration.
Table of Contents
State Market Regulatory Administration... 1
Foreword ... 4
1 Scope ... 7
2 Normative references ... 7
3 Terms and definitions ... 9
4 Pollution control requirements ... 20
5 Signage of engine (vehicle) ... 23
6 Technical requirements and tests ... 24
7 Installation on vehicles ... 31
8 Family and parent engine ... 32
9 Up-to-standard requirements and inspection of new produced vehicles ... 34
10 Requirements and inspection of in-use compliance ... 36
11 Implementation of standard ... 38
Appendix A (Normative) Materials for type test ... 40
Appendix B (Informative) Format of type test report ... 64
Appendix C (Normative) Test procedure of standard cycle of engine ... 68
Appendix D (Normative) Technical requirements for reference fuels ... 242
Appendix E (Normative) Test requirements of non-standard cycle of engine
... 245
Appendix F (Normative) On-board diagnostic system (OBD) ... 256
Appendix G (Normative) Requirements for proper operation of the NOx control
system ... 347
Appendix H (Normative) Durability of engine system ... 379
Appendix I (Normative) Requirements and inspection of production consistency
assurance ... 387
Appendix J (Normative) Technical requirements of in-use compliance ... 392
Appendix K (Normative) Portable emission measurement system (PEMS) along
actual road ... 407
Appendix L (Normative) Measurement method for pollutant emission of vehicle
chassis dynamometer ... 437
Appendix M (Normative) Special requirements for type test of liquefied
petroleum gas and natural gas engines and vehicles ... 442
Appendix N (Normative) Technical requirements for diesel-gas dual-fuel
engines and vehicles ... 448
Appendix O (Normative) Type test of alternative emission aftertreatment device
as an independent assembly ... 485
Appendix P (Normative) Acquisition of vehicle OBD and vehicle maintenance
information ... 499
Appendix Q (Normative) Technical requirements and communication data
format for remote emission management on-board terminal ... 501
Limits and measurement methods for emissions from
diesel fueled heavy-duty vehicles (CHINA VI)
1 Scope
This standard specifies the emission limits and test methods for gaseous and
particulate pollutants as emitted by the vehicles equipped with compression
ignition engine and its engines, as well as the emission limits and test methods
for gaseous pollutants emitted from the ignition engine vehicles and its engine
which use natural gas (NG) or liquefied petroleum gas (LPG) as fuel.
This standard is applicable to the type test, production consistency inspection,
supervisory inspection of emission from new produced vehicle, compliance
inspection of in-use vehicle of the category M2, M3, N1, N2, N3 which is equipped
with compression ignition and gas-fueled ignition engines as well as the
category M1 vehicles which have a total mass of more than 3500 kg.
The type test of whole vehicle according to this standard may be extended to
variants and modified vehicles which have a reference mass exceeding 2380
kg.
If the category M1, M2, N1, N2 vehicles which are equipped with compression
ignition and gas-fueled ignition engines have been type-tested according to GB
18352.6-2016, they may be exempted from the type test of this standard.
2 Normative references
This standard refers to the following documents or their terms. For undated
references, the latest edition applies to this standard.
GB/T 2624 Measurement of fluid flow by means of pressure differential
devices inserted in circular cross-section conduits running full (IDT ISO 5176)
GB/T 3730.2 Road vehicle - Masses - Vocabulary and codes
GB/T 8190.1 Reciprocating internal combustion engines - Exhaust emission
measurement - Part 1: Test-bed measurement of gaseous and particulate
exhaust emissions
GB/T 15089 Classification of power-driven vehicles and trailers
GB/T 17692 Measurement methods of net power for automotive engines
GB 18047 Compressed natural gas as vehicle fuel
GB 18352.6-2016 Limits and measurement methods for emissions from
light-duty vehicles (CHINA 6)
GB/T 19001 Quality management systems - Requirements
GB/T 27840 Fuel consumption test methods for heavy-duty commercial
vehicles
GB 30510 Fuel consumption limits for heavy-duty commercial vehicles
ISO 5725 Measurement method and result accuracy
ISO 7000 Equipment graphic symbol - Index and list
ISO 13400 Road vehicles - Internet protocol (DoIP)-based diagnostic
communication
ISO 15031 Road vehicles - Vehicles and emission diagnostics related
equipment communication
ISO 15031-3 Road vehicles - Communication between vehicle and external
equipment for emissions-related diagnostics - Part 3: Diagnostic connector
and related electrical circuits: Specification and use
ISO 15031-7 Road vehicles - Communication between vehicle and external
equipment for emissions-related diagnostics - Part 7: Data link security
ISO 15765-4 Road vehicles - Diagnostic communication over Controller
Area Network (DoCAN) - Part 4: Requirements for emissions-related
systems
ISO 27145 Road vehicles - Implementation of World-Wide Harmonized On-
Board Diagnostics (WWH-OBD) communication requirements
SAE J1708 Serial data communications between microcomputer systems in
heavy-duty vehicle applications
SAE J1939 Communication protocol of local area network (CAN bus) for
commercial vehicle's control system
SAE J1939-13 External diagnostic connector
SAE J1939-73 Application layer - diagnosing
SAE J2186 Electrical/electronic (E/E) data link security
ASTM E 29-06B Standard practice for using significant digits in test data to
additional type test of engine. Except for engine test, all vehicles undergoing
type test are required to be subject to the test by the portable emission
measurement system (PEMS) as specified in 6.2.2.
4.1.1.4 Requirements for fuels of type test
4.1.1.4.1 When the parent engine is subjected to type test, it shall use the
reference fuel complying with the provisions of Appendix D of this standard.
4.1.1.4.2 For natural gas and liquefied petroleum gas engines (vehicles), it shall
use the fuel types as specified in Appendix M to carry out type test.
4.1.1.4.3 Type test of natural gas engines and LPG engines shall meet the
requirements of Tables M.1 and M.2 of Appendix M.
4.1.1.4.4 The type test of the dual-fuel engine shall meet the requirements of
Table N.2 of clause N.6.1.2.
4.1.1.4.5 If the fuel to be used in the design of the engine family is not included
in the reference fuel range specified in Appendix D, the manufacturer shall:
a) A clear description of the types of commercially available fuel that the
engine family can use.
b) Prove that the parent engine can meet the requirements of this standard
when burning commercially available fuel.
c) Prove that the engine can meet the in-use compliance requirements when
using the specified fuel in combination with any of the commercially
available fuels of any component.
4.1.2 Type test of engine family (parent engine)
4.1.2.1 When the engine is subject to type test, select a parent engine that can
represent the engine model or family. If the selected engine does not fully
represent the model or family as described in Appendix A, it shall select another
representative engine for testing.
4.1.2.2 When the whole vehicle is subject to type test, select a vehicle that can
represent the vehicle model (family) for type test. If the selected vehicle does
not fully represent the vehicle model (family) as described in clause 8.4, it shall
select another representative vehicle for testing.
4.1.2.3 The parent engine (or the base model) represents the emission level of
all engine models (vehicle models) in the family, the type test of the parent
engine (or the parent vehicle) may be extended to all members of the family.
Other members in the family do not need to be tested.
be disclosed after technical processing.
5 Signage of engine (vehicle)
5.1 General requirements
The engine's signage may be in the form of text and numbers, or in the form of
a two-dimensional code.
The signage must be concise and clear, its text, numbers or graphics shall be
clear, obvious, readable, not erased. The fixing method of the signage must be
firm throughout the life of the engine and must not be removed.
5.2 Location of engine signage
The installation position of the signage on the engine shall not hinder the normal
operation of the engine. In the service life of engine, it generally requires no
position change. In addition, when all the accessories required for engine
operation are installed, the signage shall be located where it is easy for normal
people to see.
The signage shall be close to or incorporated on the nameplate of the
manufacturer.
5.3 Contents of engine signage
The engine's signage shall contain at least the following:
a) Engine model;
b) Date of manufacture: Year, month, day ("day" is optional. If the date of
manufacture has been marked in other parts, it may not be indicated in
the signage repeatedly);
c) The words “CHINA VI”;
d) The trademark or full name of the manufacturer;
e) Emission control key components (e.g., EGR, DOC, SCR, DPF, etc.).
5.4 Special requirements for natural gas and LPG engine (vehicle)'s
signages with a defined fuel range
5.4.1 For natural gas and liquefied petroleum gas engines with a defined fuel
range during type test, in addition to meeting the requirements of 5.3, it shall
also include the following information:
a) Limited to the use of natural gas of high (low) calorific value;
6.9.1 The manufacturer shall demonstrate that under all normal conditions,
especially at low temperatures, the NOx system can maintain its emission
control function.
6.9.2 The manufacturer shall report the information on the control strategy of
the exhaust gas recirculation system (EGR) and the selective catalytic
reduction system (SCR) in a low temperature environment to the competent
department of ecological environment under the State Council. The information
shall also include a description of the impact of this system running at low
temperature system onto the emission.
6.9.3 Ensure the normal operation of the NOx control measures, meet the
requirements of Appendix G. Follow the requirements of Appendix G to conduct
test and verification.
6.10 Requirements for duel fuel engine
Dual-fuel engines or vehicles that meet the requirements of this standard and
are tested according to Appendix N.
6.11 Requirements for replacement pollution control devices
The design, manufacture and installation of the replacement pollution control
device shall achieve the performance of the original emission control device, so
that the pollutant emissions of the engine and the vehicle comply with the
provisions of this standard, thereby effectively control the pollutant emission
under normal conditions of use and throughout the full life of the vehicle.
The replacement pollution control device shall be type-tested according to the
provisions of Appendix O.
6.12 Technical requirements for whole vehicle
6.12.1 The vehicle manufacturer shall install the engine on the whole vehicle
and shall strictly follow the installation requirements specified in Chapter 7, to
ensure that the vehicle meets the non-standard cycle emission requirements
as specified in Table 4.
6.12.2 The vehicle manufacturer shall ensure that after assembling the engine
into the whole vehicle, the OBD system and the NOx control system are not
changed; meanwhile when verified according to Annex KE along actual road, it
can still meet the technical requirements as specified in clause 6.8 and clause
6.9.
6.12.2.1 The vehicle shall have an OBD diagnostic interface that meets the
requirements of ISO 15031. The diagnostic interface shall be in the vicinity of
the driver in the vehicle, in a location that is easy to find and access, marked
shall not exceed the power absorbed by the accessories as specified in
Appendix A for engines that have been type-tested.
7.1.4 The characteristics of the exhaust aftertreatment system shall be
consistent with the declarations in the engine type test in Appendix A.
7.2 Installation of type-tested engine on vehicle
An engine that is type-tested as an independent technical assembly shall meet
the following requirements when installed on a vehicle:
a) The OBD systems shall, when installed according to the requirements of
Annex FA, meet the installation requirements of the engine manufacturer
as specified in Appendix A.
b) The NOx control system shall, when installed according to the provisions
of Annex GD, meet the installation requirements of the engine
manufacturer as specified in Appendix A.
c) The dual-fuel engines that are type-tested as independent technical
assemblies shall, when installed on vehicle, also meet the requirements
of N.6.3 and N.8.2, as well as the installation requirements of engine
manufacturer as specified in Annex AA.
8 Family and parent engine
8.1 Engine family
8.1.1 Determine the parameters of engine family
The same engine family must have the basic parameters as specified in C.4.2.
For dual-fuel engines, the engine family shall also comply with the additional
requirements of N.3.1 of Appendix N.
8.1.2 Selection of parent engine
The parent engine of the family shall be selected according to the requirements
specified in C.4.3.
For dual-fuel engines, the selection of parent engine shall also meet the
additional requirements of N.3.2.
8.1.3 Expansion of engine family
8.1.3.1 If the requirements of 8.1.1 are met, it may incorporate the new engine
model into the engine family that has been type-tested.
that meets the requirements of paragraphs b) ~ d) of 8.4.1.
9 Up-to-standard requirements and inspection of new
produced vehicles
9.1 General requirements
9.1.1 Vehicle and engine manufacturers shall take measures according to
Appendix I to ensure production consistency.
9.1.2 Engine manufacturers must take measures to ensure that the engine,
system, component or independent technology assembly is consistent with the
engine type that has been type-tested.
9.1.3 The production consistency inspection shall be based on the information
disclosure materials in Appendix A and Appendix B.
9.1.4 The vehicle and engine used for the test shall be randomly selected. The
manufacturer must not make any adjustments to the taken vehicle or engine
(including updates to the ECU software).
9.1.5 The vehicle shall not run-in in principle. If the manufacturer requests it, it
can be run-in according to the running-in specifications, but it must not exceed
500 km. Meanwhile it shall not make any adjustment of the vehicle.
9.2 Up-to-standard self-inspection of new produced vehicle
9.2.1 In order to ensure that the mass-produced vehicles meet the technical
requirements as specified in clause 6.12, the vehicle manufacturer shall
formulate an off-line inspection plan for each vehicle type (family), including
inspection items, inspection methods, sampling methods, sampling ratios, etc.
9.2.2 The self-inspection of the pollutant emission of vehicle shall be tested
according to the PEMS test method of whole vehicle as specified in Appendix
K of this standard. If the vehicle is subject to the production consistency
inspection of the fuel consumption of whole vehicle according to GB 30510, it
shall carry out pollutant emission inspection according to Appendix L at the
same time.
9.2.3 The sampling method shall be statistically representative, which can
represent the emission control level of the same batch of vehicles within a
certain production cycle.
9.2.4 The vehicle manufacturer shall record and archive the vehicle inspection
test in detail. The record document shall be kept for at least 5 years. The
competent department of ecological environment may check the test records
competent department of ecological environment shall conduct sampling
inspection according to the requirements of 10.2.2.
10.2.1 Self-inspection of manufacturer
10.2.1.1 When the engine family is type-tested, the engine manufacturer shall
also formulate a self-inspection plan for in-use compliance. The self-inspection
of the engine manufacturer's in-use compliance shall be based on the engine
family.
10.2.1.2 When the vehicle model (family) is type-tested, the vehicle
manufacturer shall also establish a self-inspection plan for in-use compliance.
The vehicle manufacturer’s self-inspection for in-use compliance shall be based
on the vehicle model or vehicle family, which may cover the extended vehicle
models produced by refitted vehicle manufacturer.
10.2.1.3 The self-inspection plan for in-use compliance includes the test
schedule and sampling plan, which shall be reported to the competent
department of ecological environment under the State Council.
10.2.1.4 The engine manufacturer shall carry out the self-inspection of in-use
compliance according to the self-inspection plan, try to select the vehicles from
different vehicle manufacturers to conduct tests. The self-inspection report of
the in-use compliance of the engine family shall disclose the information,
meanwhile be used as a part of the self-inspection report of the in-use
compliance of the vehicle family of the vehicle manufacturer.
10.2.1.5 The vehicle manufacturer shall carry out the self-inspection of in-use
compliance according to the self-inspection plan, try to select different vehicle
models from the vehicle family to conduct test. The self-inspection report of in-
use compliance of the vehicle model (family) shall disclose the information.
10.2.2 Sampling inspection by competent department of ecological
environment
10.2.2.1 The competent department of ecological environment may follow the
test procedures of the in-use compliance as specified in Appendix J, to conduct
sampling inspection of the in-use compliance of the vehicle model (family).
10.2.2.2 If the competent department of ecological environment under the State
Council confirms that a certain vehicle model (family) does not meet the
requirements of this standard, the manufacturer shall take corrective measures
according to clauses 10.3 and J.5 of this standard.
10.3 Corrective measures
10.3.1 The manufacturer shall submit a plan for rectification measures to the
a) Official documents: It shall be disclosed to the competent department of
ecological environment under the State Council and may be provided to
relevant parties as needed.
b) Extended documents: It shall be kept confidential. The extension
documents shall be disclosed to the competent department of ecological
environment under the State Council or may be kept by the manufacturer.
However, it shall be ensured that these documents can be checked at any
time when the validity of the type test is being confirmed.
A.3.5.2 If all output signals are clearly represented by the matrix obtained from
the control range of the individual unit's input signals, the file shall describe the
functional operation of the drivability limit system as required by Appendix G,
including the parameters required to retrieve system-related information. The
material shall be disclosed to the competent department of ecological
environment under the State Council.
A.3.5.3 The extension document package shall include the operation
information of all auxiliary emission control strategy (AES) and basic emission
control strategy (BES), including description of AES revision parameters, AES
working boundary conditions, descriptions on possible startup of AES and BES
under the test conditions as specified in Appendix E. The extension document
shall also contain the descriptions on the control logic of the fuel system, timing
strategy, switching points during all operating conditions. It shall also include a
complete description of the drivability limitation system as required in Appendix
G, including related monitoring strategies.
A.3.6 For engine models or families that are type-tested as independent
technical assemblies, it shall also submit the following materials:
a) For ignition engines, as described in Appendix C, if misfire occurs from the
beginning of the emission and causes the engine's emissions to exceed
the limits as specified in Appendix F, or causes the exhaust catalyst to
overheat and eventually causes irreparable damage, the manufacturer
shall declare the minimum misfire rate in all above misfire events;
b) Instructions for preventing tampering and modification of the emission
control electronics unit, including preventing the renewal of equipment
approved or calibrated by the manufacturer;
c) The OBD document which complies with the requirements of F.8;
d) The OBD-related information provided for access of OBD shall comply
with the requirements of Appendix P of this standard;
e) Declare compliance with non-standard cyclic emissions according to the
requirements of 6.4.3 and the template of Appendix E;
requirements of CB.2. The technical indicators of the measurement system
shall comply with the requirements of clause CB.3 (measurement of gaseous
pollutants), clause CB.4 (measurement of particulate pollutants), Annex CE.
If other systems or analyzers are able to obtain the equivalent results as
described in C.3.2, the testing agency may approve them.
C.3.2 Equivalent system
To determine the equivalence between an equivalent system and a system of
this Appendix, it shall be confirmed on the basis of a correlation study of at least
seven pairs of samples.
The result is the specific emission value of the cycle. The comparison test shall
be carried out in the same laboratory, on the same test bench, on the same
engine, preferably at the same time. Under the test bench and engine
conditions of the laboratory as described above, the equivalency of the
sample's mean values is obtained from the F-test and t-test statistics as
described in clause CF.3. Outlier data is determined according to ISO 5725 and
removed from the database. The system used for the comparison test shall be
reported to the competent department of ecological environment under the
State Council.
C.4 Engine family
C.4.1 Overview
The design parameters are characteristics of a certain engine family. All
engines of the family members have these parameters. Engine manufacturers
may determine which engines belong to a family according to the criteria of the
family members in clause C.4.2.
The manufacturer shall submit to the State Council's competent department of
ecological environment the reasonable information on the emission level of the
engine family members.
C.4.2 Parameters of engine family
When determining the engine family, certain design parameters may interact
with each other under certain conditions. It shall ensure that only engines with
similar emissions characteristics can be included in the same engine family.
The manufacturer shall confirm this situation and report to the competent
department of ecological environment under the State Council. This can be
used as a standard for building a new engine family.
If the devices and characteristics as not listed in this clause seriously affect
emissions, the manufacturer shall identify the device based on good
it is a parent engine or a family member engine, if the same aftertreatment
system as the parent engine is installed, the engine must not be assigned to
the same engine family without the aftertreatment system.
C.4.3 Selection of parent engine
C.4.3.1 Compression ignition engine
The parent engine of the engine family shall be selected based on the preferred
principle of maximum fuel supply per stroke at the maximum torque speed. If
there are two or more engines complying with the preferred standard, it shall
use the maximum fuel supply per stroke at the rated speed as the secondary
principle for selecting parent engine.
C.4.3.2 Spark ignition engine
The parent engine in the family shall be selected according to the preferred
principle of maximum displacement. If two or more engines are according to the
preferred principle, the parent engine shall be selected according to the
following order of secondary selection:
a) Maximum fuel supply per stroke at rated power speed
b) Maximum ignition timing
c) Minimum EGR rate
C.4.3.3 Supplementary provisions for parent engine selection
In some cases, the inspection agency may add a second engine to conduct
emission test according to the technical data as provided by the engine
manufacturer, to facilitate determining the worst emission level of the engine in
the family.
If the engine in the family has other variable characteristics that can affect the
exhaust pollutants, these characteristics shall also be taken into account when
selecting the parent engine.
C.5 Test conditions
C.5.1 Laboratory test conditions
It shall measure the absolute temperature of the air at the engine inlet (Ta,
expressed in Kelvin) and dry air pressure (Ps, expressed in kPa). For multi-
cylinder engines with multiple sets of intake manifolds, such as “V-type” engines,
it shall measure the average temperature of each group of intake manifolds. It
shall follow the requirements below to determine the laboratory atmospheric
factors fα, which shall be recorded together with the test result. When fα meets
The engine shall be tested by installing accessories and equipment required by
the Annex CG.
If the engine accessories cannot be installed as required, the power of the
accessories shall be calculated according to the provisions of C.5.3.2 to C.5.3.5.
C.5.3.2 Accessories/equipment to be installed for testing
If the accessories to be installed according to the requirements of Annex CG
are not installed during the test, the power (reference and actual power) as
absorbed by these accessories shall be subtracted from the test.
C.5.3.3 Accessories/equipment that do not need to be installed for testing
If the accessories that shall not be installed according to the requirements of
Annex CG cannot be removed during the test, the power (reference and actual
power) as absorbed by these accessories shall be added during the test. If the
total power as absorbed by these accessories is more than 3% of the maximum
net power, the manufacturer shall provide a written description.
C.5.3.4 Determination of accessory power
In case:
a) As required by the Annex CG, the accessories/equipment that shall be
installed on the engine are not installed, and/or
b) As required by the Annex CG, the accessories/equipment that shall not be
installed on the engine cannot be removed.
It needs to determine the power absorbed by the accessory/equipment.
Meanwhile the testing agency shall confirm the test/calculation method for the
accessory power throughout the test cycle as submitted by the engine
manufacturer.
C.5.3.5 Engine cycle power
According to clause C.5.3.1, it shall be based on the engine power to calculate
the reference and actual cycle power (see clause C.6.4.8 and clause C.6.8.6).
In this case, the Pf and Pr Where are equal to 0, whilst P is equal to Pm.
If the corresponding accessories/equipment are installed according to C.5.3.2
and/or C.5.3.3, the transient cycle power Pm,i shall be corrected as follows:
Where:
type of reagent required for testing and the amount of reagent consumed.
Engines equipped with a continuous regenerative aftertreatment system do not
require special tests, but requires verification of the regeneration process
specified in C.5.6.2.
Engines equipped with a cyclic regenerative aftertreatment system shall be
tested according to the requirements of C.5.6.3 and the results of the emission
shall be corrected in consideration of the regeneration. In this case, in the test
portion where regeneration occurs, the average emissions depend on the
frequency at which regeneration occurs.
C.5.6.2 Continuous regeneration
For continuously regenerated exhaust aftertreatment systems, it shall, after the
aftertreatment system stabilizes, measure the pollutant emissions. At least one
regenerative test shall be carried out in the WHTC hot state test cycle. The
manufacturer shall state the conditions at which regeneration occurs (particle
load, temperature, exhaust back pressure, etc.).
To verify the continuous regeneration process, it shall carry out at least 3 WHTC
hot state cycles. When the engine is subject to the WHTC hot state test cycle,
it shall be warmed up according to the requirements of C.6.4.1 and hot-dipped
according to the requirements of C.6.6.3, then perform the first WHTC hot state
test, the other two WHTC tests shall also be carried out after hot dip according
to C.6.6.3. During the test, it shall record the exhaust temperature and pressure
(temperature before and after aftertreatment, exhaust back pressure, etc.).
If the test proves the regenerative conditions as specified by the manufacturer
and that the deviation of the specific emission results of the particulate matter
masses of the three WHTC hot state tests is less than ±25% or 0.005 g/kwh
(whichever is larger), the exhaust aftertreatment system is considered to be
continuously regenerative. It is tested according to the testing rules of clause
C.6.6 (WHTC) and clause C.6.7 (WHSC).
If the exhaust aftertreatment system has a safe mode that can be converted to
a cyclic regeneration mode, it shall be inspected according to C.5.6.3. In this
particular case, emissions may exceed emission limits and emissions are not
weighted.
C.5.6.3 Cyclic regeneration
For cyclic regenerative exhaust aftertreatment systems, emissions shall be
measured in at least 3 WHTC hot state cycles, wherein one is during the
regeneration process, two outside the regeneration process, meanwhile it shall
be the WHTC cycle after the exhaust aftertreatment system is stabilized. Finally
make the measurement results weighted according to the formula of C.5.6.3.
commercially available fuel according to national standards.
The fuel temperature and measuring point shall be as specified by the
manufacturer.
C.5.10 Crankcase emissions
It is not allowed to emit any gas in the crankcase to the atmosphere.
For engines equipped with an air intake booster such as a turbocharger, pump,
fan, or mechanical supercharger, which may discharge the emission from the
crankcase into the environment, it shall, when the engine is subject to emission
test, add the emission from crankcase to the exhaust emission.
If, under all operating conditions, crankcase emissions are introduced into the
upstream exhaust of the exhaust aftertreatment, the crankcase emissions are
deemed to meet the requirements.
Pollutants in open crankcases shall be introduced into the exhaust gas for
measurement as follows:
a) The inner wall of the connecting pipe shall be smooth, conductive, not
reacting with the crankcase pollutants, have a length as short as possible;
b) The number of elbows in the crankcase's piping shall be as small as
possible, the radius of the elbows that must be installed shall be as large
as possible;
c) The crankcase's exhaust pipe shall be heated, thin-walled or insulated.
The back pressure of the crankcase shall meet the requirements of the
engine manufacturer;
d) The crankcase's exhaust shall be routed downstream of the aftertreatment
or emission control device, but shall be upstream of the sampling probe
and fully mixed with the engine exhaust before sampling. In order to
accelerate mixing to avoid boundary layer effects, the exhaust pipe of the
crankcase shall extend into the exhaust flow, the direction of the
crankcase's exhaust pipe outlet is fixed relative to the direction of the
exhaust.
If the emission test results meet the limit requirements, it is determined that
the crankcase emissions meet the standard requirements.
C.5.11 Requirements for emission measurement of crankcases for
ignition engines
C.5.11.1 The crankcase pressure shall be measured at the appropriate position
throughout the test cycle. The pressure measurement accuracy of the
crankcase pressure shall be within ±1 kPa.
C.5.11.2 If the crankcase pressure is not more than atmospheric pressure
under any of the measurement conditions of C.5.11.1, the crankcase emissions
are considered to comply with the provisions of C.5.10.
C.6 Test procedure
C.6.1 Principles of emission measurement
Run the test cycle according to the requirements of C.6.2.1. and C.6.2.2.
Perform the measurement of pollutant according to the sampling methods
described in C.6.1.1 and C.6.1.2. Use the mass of various pollutants exhausted
and the corresponding engine cycle work to calculate the specific emission.
C.6.1.1 Continuous sampling
Pollutant concentration, exhaust mass flow (raw or diluted) are continuously
tested in raw or diluted emissions, to calculate pollutant mass flow and cycle
emissions.
C.6.1.2 Air bag sampling
The diluted sample gas is continuously extracted and stored in proportion. Use
air bag to collect the gaseous pollutants. Use filter paper to collect the
particulate matter. Calculate the specific emission of gaseous pollutants and
the specific emission of particulate matter.
C.6.1.3 Measurement procedures
In this standard, it describes two measurement systems with the same function:
a) The gas component is measured directly from the original exhaust gas,
the particulate matter is measured by a partial-flow dilution system;
b) Gas components and particulate matter are measured by a full-flow
dilution system (CVS system).
Both measurement systems can be used in the emission measurement cycle
and allow any combination of the two systems (e.g., direct gas measurement
and full-flow particle measurement, etc.).
C.6.2 Test cycle
C.6.2.1 World harmonized transient cycle (WHTC)
The world harmonized transient cycle (WHTC) in Annex CJ includes a set of
nominal percentages of speed and torque that vary from second to second. The
WHTC test cycle is as shown in Figure C.3. In order to perform tests on an
experience. At the end of the warm-up of engine, it shall ensure that the
temperature of engine coolant and lubricant remain within ±2% of the average
for at least 2 min, or the engine coolant's temperature is regulated by the
thermostat.
C.6.4.2 Determination of transient performance speed
Use the formula below to determine the minimum and maximum transient
performance speeds.
Minimum transient performance speed = Idle speed;
Maximum transient performance speed = nhi × 1.02 or the speed at which the
torque drops to 0 (whichever is smaller).
C.6.4.3 Transient performance curve of engine
According to the requirements of C.6.4.1, when the engine has been running
stably, it shall follow the steps below to test the engine's transient performance.
a) The engine shall be unloaded and operated at idle speed;
b) The engine shall be operated with the full load setting of the fuel injection
pump and the minimum transient performance speed;
c) The average increase rate of the engine from the minimum transient
performance speed to the maximum transient performance speed is 8 ± 1
(r/min) / s. Or use a constant rate to increase the minimum transient
performance speed to the maximum transient performance speed in 4 ~
6 minutes. It shall use the sampling rate at least one point per second to
record the speed and torque of the engine. When selecting the item b) in
C.6.4.7, to determine the negative torque, it can be set directly to the
minimum throttle after the transient performance test, reducing from the
maximum transient performance speed to the minimum transient
performance speed.
C.6.4.4 Determination of alternative performance
If the manufacturer believes that the measurement technique of the engine's
transient performance curve as described above is unsafe or does not
represent the engine, it may use a measurement technique for alternative
engine transient performance curve. The alternative measurement technique
for engine transient performance curve must achieve the purpose of the
specified determination procedure for engine transient performance curve, that
is, to determine the maximum effective torque that can be produced over the
entire allowable speed range of the engine. For safety or representative
reasons, if the measurement technique for engine transient performance curve
The choice of analyzer's range. An emission analyzer capable of automatically
or manually switching the range can be used, but during the test cycle, the
range of the emission analysis shall not be switched. At the same time, the gain
of the analyzer's analog amplifier shall not be switched during the test cycle.
It shall use the traceable standard gas which meets the technical requirements
as described in CB.3.3 to determine the zero gas and span gas response of the
analyzer. The FID analysis unit shall be based on a single carbon element (C1)
for analysis.
C.6.5.4 Preparation of particle sampling filter paper
At least one hour before the test, it shall place the filter paper in a dust-proof
and vented petri dish and place it in a weighing chamber for stabilization. After
the stabilization is completed, it shall weigh the filter paper and record the dead-
weight. Then store the filter paper in a petri dish or in a sealed filter holder, until
it is required for the test. If the filter paper is removed from the weighing
chamber, it must be used within 8 hours.
C.6.5.5 Adjustment of dilution system
The total diluted exhaust flow rate of the dilution system or the diluted exhaust
flow that passes through the particle flow system shall be set to prevent
condensation of water in the system, meanwhile, to ensure that the diluted
exhaust's temperature immediately before the particulate matter's primary filter
paper is between 315 K (42 °C) and 325 K (52 °C).
C.6.5.6 Startup of particle sampling system
The particle sampling system shall initially work in bypass mode. The test can
be performed against the background of the particles. Background
measurements may be made prior to or after the test. If the measurements are
taken before and after the test, it shall take the average value. If there is another
sampling system is available for background measurements, it may perform
sampling test for the background whilst sampling the exhaust particles.
C.6.6 WHTC cycle
C.6.6.1 Engine cooling
It may use natural cooling or forced cooling. For forced cooling, use a mature
engineering experience to set the system to pass cold air through the engine.
The cold oil passes through the engine lubrication system. Use the engine
cooling system to take away the heat from the coolant, to reduce the
temperature of the exhaust aftertreatment system. When the aftertreatment
device is forced to cool down, unless otherwise the aftertreatment system has
been cooled to a temperature lower than its catalytic activation temperature, it
a) At the beginning of the test cycle, the test equipment shall start
synchronously:
b) If it is a full-flow dilution system, start collecting and analyzing the dilution
air;
c) According to the method used, start collecting and analyzing the original
exhaust or diluted exhaust;
d) Start measuring the amount of diluted exhaust gas and the necessary
temperature and pressure;
e) If analyzing the original exhaust gas, start recording the exhaust mass
flow;
f) Start recording the feedback value of the dynamometer's speed and torque.
If the original exhaust measurement method is used, the concentration of
gaseous pollutants ((NM) HC, CO, NOx) and the mass flow of exhaust gas shall
be continuously measured and recorded in the computer system. The data
recording frequency is at least 2 Hz, the other data recording frequencies are
at least 1 Hz. For the analog recorder, it shall record its responsiveness. The
calibration shall be performed online or offline during data evaluation.
If a full-flow dilution system is used, HC and NOx shall be continuously
measured in the dilution tunnel, which has a minimum measurement frequency
of 2 Hz. The average concentration is calculated by integrating the measured
values of the analyzer in the entire test cycle. The system's response time does
not exceed 20 s. If necessary, it shall be aligned with CVS flow fluctuations,
sampling time, test cycle. The CO, CO2, NMHC are integration of continuously
measured values or the analyzed bag-sampling results of the entire cycle. Prior
to continuous sampling and analysis of the bag-sampling concentration,
determine the concentration of pollutants in the background air. All other data
that needs to be measured is recorded at a frequency of at least 1 Hz.
C.6.6.7 Sampling of particulate matter
At the beginning of the test cycle, the particle sampling system shall be switched
back from the bypass state.
If a partial-flow sampling system is used, it shall control the sampling pump, so
that the flow through the particle sampling probe or delivery tube is proportional
to the mass flow of the exhaust gas as determined according to CA.5.1.
If a full-flow sampling system is used, it shall control the sampling pump, so that
the flow through the particle sampling probe or delivery tube is within ±2.5% of
the set flow. If flow compensation is used (i.e., proportional flow control of
C.6.7.4 Record of emission-related data
a) At the beginning of the test cycle, the test equipment shall start
synchronously:
b) If it is a full-flow dilution system, start collecting and analyzing the dilution
air;
c) According to the method used, start collecting and analyzing the original
exhaust or diluted exhaust;
d) Start measuring the amount of diluted exhaust gas and the necessary
temperature and pressure;
e) If analyzing the original exhaust gas, start recording the exhaust mass
flow;
f) Start recording the feedback value of the dynamometer's speed and torque.
If the original exhaust measurement method is used, the concentration of
gaseous pollutants ((NM) HC, CO, NOx) and the mass flow of exhaust gas shall
be continuously measured and recorded in the computer system. The data
recording frequency is at least 2 Hz, the other data recording frequencies are
at least 1 Hz. For the analog recorder, it shall record its responsiveness. The
calibration shall be performed online or offline during data evaluation.
If a full-flow dilution system is used, HC and NOx shall be continuously
measured in the dilution tunnel, which has a minimum measurement frequency
of 2 Hz. The average concentration is calculated by integrating the measured
values of the analyzer in the entire test cycle. The system's response time does
not exceed 20 s. If necessary, it shall be aligned with CVS flow fluctuations,
sampling time, test cycle. The CO, CO2, NMHC are integration of continuously
measured values or the analyzed bag-sampling results of the entire cycle.
Before the exhaust enters the dilution tunnel, carry out continuous sampling or
use the background air-bag sampling method to determine the concentration of
pollutants in the background air. All other data that needs to be measured is
recorded at a frequency of at least 1 Hz.
C.6.7.5 Sampling of particulate matter
At the beginning of the test cycle, the particle sampling system shall be switched
back from the bypass state. If a partial-flow sampling system is used, it shall
control the sampling pump, so that the flow through the particle sampling probe
or delivery tube is proportional to the mass flow of the exhaust gas as
determined according to CB.4.6.1.
If a full-flow sampling system is used, it shall control the sampling pump, so that
purposes of this clause, the test cycle is defined as follows;
a) WHTC: Cold start - hot-dip - hot start;
b) Hot WHTC: Hot-dip - hot start;
c) Hot start WHTC for multiple regenerations - All hot start tests;
d) WHSC - Test cycle.
The deviation of the analyzer shall meet:
a) Before determining the drift, substitute the measured values of the zero
point and the span gas before and after the test into the formula in CA.7.1
for calculation;
b) If the deviation before and after the test is within ±1% F.S, the measured
concentration does not need to be corrected or corrected according to the
requirements of CA.7.1;
c) If the deviation before and after the test exceeds ±1% F.S, the test is invalid,
or it is corrected as required by CA.7.1.
C.6.8.5 Sampling analysis by gas bag
Specific requirements are as follows:
a) Gas bag analysis shall be carried out within 30 minutes after the
completion of the hot start test, or cold start sampling bag analysis during
hot-dip period;
b) Background sampling bag analysis shall be performed within 60 minutes
after the hot start test.
C.6.8.6 Calculation of cycle work
Before calculating the cycle work, it shall delete any records during engine start.
The actual cycle power Wact (kWh) of the entire test cycle shall be determined
based on the speed and torque values as feedback by the engine, to calculate
the transient power. The transient power of the entire test cycle is integrated to
obtain the actual cycle work Wact (kWh). If the engine is not equipped with
accessories/equipment as described in C.5.3.1, use the formula of C.5.3.5 to
correct the power.
Calculate the actual cycle work in the same way through integration as in
C.6.4.8.
Compare the actual cycle work Wact with the reference cycle work Wref, wherein
Wact shall be between 85% Wref and 105% Wref.
Where:
cref,z - The reference concentration of zero gas (usually 0), ppm;
cref,s - The reference concentration of the span gas, ppm;
cpre,z - The concentration of zero gas in the analyzer before the test, ppm;
cpre,s - The concentration of the span gas in the analyzer before the test, ppm;
cpost,z - The concentration of zero gas in the analyzer after the test, ppm;
cpost,s - The concentration of the span gas in the analyzer after the test, ppm;
cgas - The concentration of the sample gas, ppm.
After all corrections have been completed, follow the requirements of clause
CA.7.3 to calculate the specific emissions of each pollutant component of the
two groups. One set of calculations use the uncorrected concentration. The
other set uses the concentration after drift correction according to the formula
in clause CA.7.1.
Depending on the measurement system and calculation method used, calculate
the uncorrected emissions using the formulas in CA.5.2.3, CA.5.2.4, CA.6.2.3.1
or the formula in CA.6.2.3.3. Correspondingly, when calculating the corrected
emissions, use the formulas in clause CA.5.2.3, CA.5.2.4, CA.6.2.3.1 or the
formula in clause CA.6.2.3.3, wherein the Cgas is replaced by Ccor in the formula
of CA.7.1, respectively. If the transient concentration value cgas,i is used in the
corresponding formula, the corrected value is also the transient concentration
value ccor,i. In the formulas in CA.6.2.3.1, both the measured value and the
background concentration need to be corrected.
The final specific emission results of the corrected concentration calculation are
compared with the uncorrected specific emissions. The difference between the
two shall be within ±4% of the uncorrected result or ±4% of the limit, whichever
is larger. If it exceeds ±4%, the test is invalid.
If drift correction is performed, the results as shown in the report shall be the
corrected results.
CA.7.2 Calculation of NMHC and CH4
The calculation method of NMHC and CH4 is determined by the calibration
method. FID test equipment without non-methane cut-off NMC (the lower part
of Figure CE.3 in Annex CE) shall be calibrated by propane. For FID test
equipment with non-methane cut-off NMC (upper part of Figure CE.3 in Annex)
may be calibrated as follows:
d) The linearization inspection shall confirm at least 10 points (including the
zero point) from the zero point to the maximum value of the emission test.
For gas analyzers, the gas of known concentration which complies with
CB.3.3.2 shall be directly led into the analyzer interface;
e) Measure the reference value at a frequency of not less than 1 Hz.
Continuously record it for 30 seconds;
f) Calculate the arithmetic mean of the 30 second period. Follow the formula
of C.6.8.7 and use the least squares method to calculate the linear
regression parameter;
g) Linear regression parameters shall meet the requirements of CB.1 in Table
CB.1;
h) If necessary, check the zero setting again and repeat the confirmation
procedure.
CB.3 Measurement and sampling system of gaseous pollutants
CB.3.1 Technical requirements for analyzer
CB.3.1.1 General requirements
The analyzer's range and response time shall be compatible with the accuracy
required to measure the exhaust component's concentration under transient
and steady-state conditions.
The electromagnetic compatibility level of the equipment shall minimize
additional errors.
CB.3.1.2 Accuracy
Accuracy is the deviation of the analyzer reading from the reference value,
which shall not exceed ±2% of the reading or ±0.3% of full range, whichever is
larger.
CB.3.1.3 Precision
Precision is 2.5 times the standard deviation of 10 repeated response values
for a given calibration gas or span gas. For calibration gas or span gas of more
than 155 ppm (or ppm C), the repeatability does not exceed 1% of the full range
concentration of the range; for the calibration gas or span gas which is less than
155 ppm (or ppm C), it shall not exceed 2% of the full range concentration of
the range.
CB.3.1.4 Noise
(190 ± 10 °C). For NG-fueled engines or ignition engines, hydrocarbon
analyzers may be of non-heated hydrogen flame ion analyzers (FID, see Annex
CE.2.1.1) depending on the method of measurement.
CB.3.2.5 Analysis of methane and non-methane hydrocarbons (NMHC)
The determination of components of methane and non-methane hydrocarbon
shall be carried out according to Annex CE.2.2 by the use of a heated non-
methane cut-off (NMC) and two FIDs. The concentration of the components
shall be determined according to CA.7.2.
CB.3.2.6 Nitrogen oxide (NOx) analyzer
There are two types of measuring instruments for NOx measurement. Any
instrument may be used as long as it meets the corresponding criteria of
CB.3.2.6.1 or CB.3.2.6.2. However, when following the requirements of C.3.2
to determine the equivalence of different test systems, only CLD is allowed as
the benchmark.
CB.3.2.6.1 CLD
For dry-base measurements, the NOx analyzer shall use a CLD or a heated
CLD equipped with a NO2/NO converter. For wet-base measurements, it shall
use the HCLD whose water-extinction inspection complies with requirements
(see CB.3.9.2.2) which has a converter that maintains a temperature above 328
K (55 °C). Regardless of CLD and HCLD, the inner wall temperature of the
sampling path shall be maintained at 328K ~ 473K (55 °C ~ 200 °C). For dry-
base measurement, the thermal insulated sampling line connects to the
converter. For wet-base measurement, the thermal insulated sampling line
connects to the analyzer.
CB.3.2.6.2 Non-dispersive UV detector (NDUV)
The measurement of NOx concentration may be performed by the use of a non-
dispersive ultraviolet detector (NDUV). If the NDUV only measures NO, it shall
install a NO2/NO converter upstream of the NDUV analyzer. The NDUV shall
be maintained at a temperature to prevent condensation of water vapor, unless
a sample dryer is installed upstream of the NO2/NO converter (if used) or
upstream of the analyzer.
CB.3.2.7 Measurement of air-fuel ratio
The air-fuel ratio measuring device of the exhaust flow according to CA.5.1.6
shall be a wide air-fuel ratio sensor or a zirconia type λ sensor. Sensor shall be
installed directly on the tailpipe. The exhaust temperature is high enough that
the water vapor cannot condense.
CB.3.6.7 Turn off the ozone generator
Turn off the ozone generator, to allow the mixed gas as described in CB.6.3.6
to flow through the converter into the detector. Record the indicated
concentration (b) (the analyzer is placed in NOx mode).
CB.3.6.8 NO mode
Switch the ozone generator, in the off state, to NO mode. Cut off the flow of
oxygen or synthetic air. At this time, the analyzer's NOx reading shall not deviate
by more than ±5% of the value as recorded in CB.3.6.2. (The analyzer is placed
in NO mode).
CB.3.6.9 Test interval
The efficiency of the converter is measured at least once a month.
CB.3.6.10 Efficiency requirements
The efficiency of the converter ENOx must not be less than 95%.
If in the most common range of the analyzer, the ozone generator cannot
reduce the NO concentration from 80% to 20% as required by CB.3.6.5, it shall
use the highest range of operation of the NOx converter.
CB.3.7 FID adjustment
CB.3.7.1 Optimization of detector response
The FID shall be adjusted according to the requirements of the instrument
manufacturer. It shall, in the most common working range, use propane span
gas which uses air as the equilibrium gas to optimize the response.
Set the gas and air flow to the value as recommended by the manufacturer.
Lead the span gas of 350 ± 75 ppm into the analyzer. The response of a given
gas flow is determined by the difference between the span gas response and
the zero gas response. Gas flow is adjusted incrementally above and below the
requirements of the manufacturer. Record the response of the span gas and
zero gas at these gas flows. Use the difference between the responses of the
span gas and the zero gas to draw a curve. Adjust the gas flow to the high
response region of the curve. The setting of initial flow rate may need to be
further optimized according to the hydrocarbon response and oxygen
interference inspection results as specified in CB.3.7.2 and CB.3.7.3. If the
hydrocarbon response and oxygen interference inspection results do not meet
the following requirements, the flow rate shall be gradually adjusted above and
below the conditions as specified by the manufacturer to repeat CB.3.7.2,
CB.3.7.3.
recommended to combine the various sets of manifolds upstream of the
sampling probe. If this is not possible, it is allowed to take the sample gas from
the set of manifolds with the highest CO2 emissions. The calculation of exhaust
emissions must use the total exhaust mass flow.
If the engine is equipped with an exhaust aftertreatment system, it shall take
the exhaust sample gas downstream of the exhaust aftertreatment system.
CB.3.11 Sampling from diluted exhaust
The tailpipe between the engine and the full-flow dilution system shall comply
with the requirements of Annex CE. The exhaust sampling probe shall be
installed in the dilution tunnel at a position near the particulate sampling probe,
where the dilution air and exhaust can be thoroughly mixed.
Sampling may be done in two ways:
a) Collect the pollutants from entire cycle into a sampling bag for
measurement after the test is completed. For HC, if the bag sampling
result is used, the sampling bag shall be heated to 464 ± 11K (191 ± 11 °C).
for NOx, the temperature of sampling bag shall be above the dew point
temperature;
b) Continuously sample and integrate the pollutants of entire cycle.
The concentration of background gas shall be determined upstream of the
dilution tunnel according to a) or b) and subtracted from the pollutant
concentration value as measured in CA.6.2.3.2.
CB.4 Particulate measurement and sampling system
CB.4.1 General provisions
Particulate mass measurement requires a particulate dilution sampling system,
particulate sampling filter paper, microgram balance, weighing chamber of
controlled temperature and humidity. The particulate sampling system shall be
designed to ensure that the particulate sampling exhaust is proportional to the
total diluted exhaust flow. General requirements for dilution systems: particulate
measurement requires using dilution gas (filtered ambient air, synthetic air, or
nitrogen) to dilute the sample gas. The requirements for dilution system are as
follows:
a) Completely eliminate condensation of water in the dilution and sampling
system;
b) Maintain the diluted exhaust temperature within 20 cm upstream or
downstream of the filter holder at 315 K (42 °C) ~ 325 K (52 °C);
CB.4.3 Sampling filter paper of particulate matter
During the test, the diluted exhaust gas shall pass through a filter paper that
meets the requirements of CB.4.4.1 ~ CB.4.4.3.
CB.4.3.1 Requirements for sampling filter paper
All filter paper types have a collection efficiency of at least 99% for 0.3 μm DOP
(dioctyl dicarboxylate) or PAO (poly alpha olefin). Whether the filter paper meets
the requirements can be judged by the product grade as ranked by the sampling
filter paper manufacturer according to the test conditions. Filter paper material
shall be:
a) Glass fiber filter paper coated with fluorocarbon (PTFE);
b) Membrane filter paper based on fluorocarbon (PTFE).
CB.4.3.2 Size of filter paper
The nominal diameter of the filter paper shall be 47 mm (with a tolerance of
46.50 ± 0.6 mm). The filter paper's contamination diameter shall be at least 38
mm.
CB.4.3.3 Oncoming speed of filter paper
The oncoming speed of the gas passing through the filter paper shall be 0.90 ~
1.00 m/s, the recorded airflow value of up to 5% can exceed this range. If the
total mass of the particulate matter on the filter paper exceeds 400 μg, the
oncoming speed of the filter paper may be reduced to 0.50 m/s. The oncoming
speed shall be calculated by dividing the volumetric flow of the filter paper at
the upstream pressure of the filter paper and the surface temperature of the
filter paper by the contaminated area of the filter paper.
CB.4.4 Technical requirements for weighing chambers and analytical
balances
The weighing chamber (compartment) environment shall be free of any
environmental pollutants (such as dust, aerosols or semi-volatiles) that may
contaminate the particulate filter paper. The weighing chamber shall meet the
specified technical conditions for at least 60 minutes before the filter paper is
weighed.
CB.4.4.1 Conditions of weighing chamber
During the pretreatment and weighing of the filter paper, the temperature of the
weighing chamber for pretreatment and weighing of the particulate filter paper
shall be maintained at 295K ± 1K (22 ± 1 °C). The humidity shall be maintained
at a dew point of 282.5 ± 1K (9.5 ± 1 °C).
tweezers;
c) The tweezers shall be grounded through the grounding wire or grounded
by the operator through the grounding wire, so that the grounding wire and
the balance are grounded together. The grounding wire shall have an
appropriate resistance to prevent accidental electric shock.
CB.4.4.5 Additional technical requirements
All components of the dilution system and sampling system from the tailpipe to
the filter holder are designed to minimize the adhesion or variation of particulate
matter due to contact with the original and diluted exhaust. All components must
be made of a conductive material that does not react with the exhaust
components and must be grounded, to prevent electrostatic effects.
CB.4.4.6 Calibration of flow measuring instrument
Each flow meter used in the particulate matter sampling and partial-flow dilution
system shall be linearly confirmed according to CB.2.3, to confirm that the
frequency meets the accuracy requirements of this standard. For airflow
reference values, it shall be measured by accurate flowmeters that meet
international and/or national standards. The reference requirements for the
measurement of different airflows are as shown in CB.4.5.2.
CB.4.5 Special requirements for partial-flow dilution system
The partial-flow dilution system shall ensure that a certain proportion of the
original exhaust sample is extracted from the engine's exhaust flow. The dilution
ratio or sampling rate rd or rs is determined to ensure reaching the accuracy as
specified in CB.4.5.2.
CB.4.5.1 System response time
Partial-flow dilution systems require fast system response. The system's
switching time shall be determined according to the procedures as specified in
CB.4.5.6. If the exhaust flow measurement (see CA.5.1.2) and the partial-flow
system have a combined switching time ≤ 0.3 seconds, it shall use online
control. If the switching time exceeds 0.3 seconds, it shall carry out the pre-
judgment control based on the previously recorded test cycle. In this case, the
comprehensive rise time shall be ≤ 1 second and the comprehensive delay time
shall be ≤ 10 seconds.
The overall system response design shall ensure that the particulate sampling
gas (qmp,i) is proportional to the exhaust flow. In order to determine the
proportional relationship, it shall use the data collection frequency of at least 5
Hz to perform regression analysis for qmp,i and qmew,i, and meet the following
criteria:
d) The absolute accuracy of qmdew and qmdw shall be within ±0.2% of full range.
The maximum deviation of difference between qmdew and qmdw shall be
within 0.2%. In the test, the linearity deviation shall be within ±0.2% of the
maximum value of qmdew.
CB.4.5.3 Calibration of differential flow measurement
It shall use one of the following methods to calibrate the flowmeter or the flow
measuring instrument, to ensure that the flow qmp of the probe which extends
into the tunnel reaches the accuracy requirements of CB.4.5.2.
a) The qmdw flowmeter shall be connected in series with the qmdew flowmeter.
The deviation of two flowmeters shall be calibrated for at least 5 calibration
points. The gas flow at these 5 calibration points shall be evenly
distributed between the minimum value qmdw used in the test and the qmdew
used in the test. The dilution tunnel may be bypassed;
b) The calibrated flow device shall be connected in series with the qmdew
flowmeter and shall be checked for the numerical accuracy of the test. The
calibrated flow device is connected in series with the qmdw flowmeter.
Within the dilution ratio of 3 ~ 50, select at least 5 reference points, to
check the accuracy of the corresponding qmdew as used in the test;
c) Disconnect the transmission tube (TT) from the exhaust and connect the
calibrated flow measuring device to the transmission tube. The measured
range shall be suitable for measuring qmp. qmdew shall be set to the value
used in the test. The qmdw within the range of corresponding dilution ratio
3 ~ 50 shall be set sequentially to at least 5 values. Alternatively, it may
also provide a dedicated calibration airflow path to bypass the tunnel.
However, the total airflow passing through the corresponding flowmeter
and the dilution airflow shall be same as those in actual test;
d) Tracer gas shall be led into the exhaust transmission tube (TT). The tracer
gas can be an exhaust component, such as CO2 or NOx. After being
diluted in the tunnel, the tracer gas's component is measured. It shall be
performed at 5 dilution ratios between 3 and 50. The accuracy of the
sample gas flow shall be determined according to the dilution ratio formula
rd.
(Above excerpt released/modified date: 2019-08-17 / 2019-08-17. Translated/reviewed by: Wayne Zheng et al.)
https://www.chinesestandard.net/PDF.aspx/GB17691-2018