GB 18352.5-2013Limits and measurement methods for emissions from light-duty vehicles (CHINA 5) (Replaced by GB 18352.6-2016, Valid through July 2025) (English PDF)

1 Scope of application

This Standard specifies the limits and measurement methods for exhaust emissions at normal and low ambient temperature, exhaust emissions at two-speed idle condition, crankcase emissions, and evaporative emissions, and technical requirements and measurement methods for the durability of pollution control devices and onboard diagnostic (OBD) systems of light-duty vehicles equipped with positive-ignition engines.

This Standard specifies the limits and measurement methods for exhaust emissions at normal ambient temperature and free acceleration smoke, and technical requirements and measurement methods for the durability of pollution control devices and OBD systems of light-duty vehicles equipped with compression-ignition engines.

This Standard specifies the requirements for type-approval of light-duty vehicles, check and verification methods of conformity of production and in-service conformity.

This Standard also specifies the special requirements for light-duty vehicles fueled by LPG or NG.

This Standard also specifies the type-approval procedure for replacement pollution control devices as separate technical units intended to be fitted on light-duty vehicles with respect to pollutant emissions.

This Standard also stipulates the technical requirements for vehicles that use a reagent for the exhaust after-treatment system and the procedure for emission test of vehicles equipped with periodically regenerating systems.

This Standard applies to light-duty vehicles, including hybrid electric vehicles, powered by positive-ignition engines or compression-ignition engines, with the maximum design speed of being greater than or equal to 50 km/h.

At the manufacturer's request, type approval may be performed for Category

M 1 , M2 , and N 2 vehicles with the maximum mass exceeding 3500 kg and a reference mass not exceeding 2610 kg in accordance with this Standard; as for the vehicles type approval granted under this Standard may be extended from vehicles mentioned above to M 1 , M 2 , N 1 and N 2 vehicles with a reference mass not exceeding 2840 kg and which meet the conditions laid down in this

Standard.

Particulate matter (PM)

Components of the exhaust gas which are removed from the diluted exhaust gas at a maximum temperature of 325 K (52 °C) by means of the filters described in Attachment CE.

3.14

Particle numbers (PN)

The total number of particles of a diameter greater than 0.023 µm present in the diluted exhaust gas after it has been conditioned to remove volatile material, as described in Attachment CF.

3.15

Exhaust emissions

Gaseous pollutants and particulate matter emitted from vehicle exhaust pipes.

3.16

Evaporative emissions

The hydrocarbon vapors lost from the fuel (petrol) system of a motor vehicle other than those from exhaust emissions, including:

(1) "Hot soak losses" are hydrocarbon emissions arising from the fuel system of a stationary vehicle after a period of driving, expressed as

C 1 H 2.20 equivalent.

(2) "Tank breathing losses" are hydrocarbon emissions caused by temperature changes in the fuel tank, expressed as C 1 H 2.33 equivalent.

3.17

Crankcase

The spaces in or external to an engine which are connected to the oil sump by internal or external ducts through which gases and vapor can escape.

3.18

Cold start device

The device that temporarily enriches the air/fuel mixture of the engine thus assisting the engine to start.

3.19

Starting aid

Any element of design which measures or senses vehicle speed, engine rotational speed, transmission gear, temperature, air inlet manifold vacuum or any other parameter for the purpose of activating, to activate, modulate, delay, or deactivate the operation of any part or the function of the emission control system, so that the effectiveness of the emission control system is reduced under conditions which may reasonably be expected to be encountered in normal vehicle operation and use.

Such an element of design may not be considered as a defeat device:

(1) The device required for protecting the engine against damage or accident and for safe operation of the vehicle; or (2) The device that functions only when the engine is started;

(3) The device that does work in Type I or IV tests.

3.27

Properly maintained and used

"Properly maintained and used" means, for the purpose of a test vehicle, that such a vehicle satisfies the criteria for acceptance of a selected vehicle laid down in NA.2.

3.28

Reagent

Any product other than fuel that is stored on the vehicle and is provided to the exhaust after-treatment system upon request of the emission control system.

3.29

Periodically regenerating system

A pollution control device (e.g. catalytic converter, particulate trap) that requires a periodical regeneration process in less than 4000 km of normal vehicle operation.

During cycles where regeneration occurs, emission standards can be exceeded. If a regeneration of a pollution control device occurs at least once per Type I test and that has already regenerated at least once during vehicle preparation cycle, it will be considered as a continuously regenerating system and not suitable for the test procedures for periodically regenerating system specified in Annex P.

If the manufacturer provides data to the type-approval authority that, during cycles where regeneration occurs, emissions remain below the standards given in 5.1.3.4, at the request of the manufacturer, after agreement of the testing organization, the test procedure specific to periodically regenerating (3) A description of the malfunction indicator used by the OBD system.

(4) A declaration that the OBD system complies with the provisions of paragraph IA.7 related to in-use performance under all reasonably foreseeable driving conditions.

(5) A plan describing the detailed technical criteria and justification for incrementing the numerator and denominator of each monitor that shall fulfill the requirements of paragraphs IA.7.2 and IA.7.3, as well as for disabling numerators, denominators and the general denominator under the conditions outlined in paragraph IA.7.7.

(6) A description of the provisions taken to prevent tampering with and modification of the emission control electronic control unit.

(7) If applicable, the particulars of the vehicle family as referred to in

Attachment IB.

(8) Where appropriate, copies of other type approvals accompanied by the relevant data to enable extension of approvals.

5 Specifications and tests

8 In-service conformity

8.1 For vehicles that have passed the pollutant emission type approval, necessary measures shall be taken by the manufacturer to ensure in-service conformity. The requirements for checking in-service conformity of exhaust emissions, OBD system and evaporative emissions are as described in Annex

N.

8.2 The procedure for checking in-service conformity shall confirm the functionality of the pollution control devices during the normal useful life of the

Vehicles equipped with semi-automatic-shift gearboxes shall be tested by using the gears normally employed for driving. The gear shift is used in accordance with the manufacturer's instructions.

C.5.1.1.2 Vehicles equipped with automatic-shift gearboxes shall be tested with the highest gear ("Drive") engaged. The accelerator shall be used in such a way as to obtain the steadiest acceleration possible, enabling the various gears to be engaged in the normal order. Furthermore, the gear-change points shown in Attachment CA shall not apply; acceleration shall continue throughout the period represented by the straight line connecting the end of each period of idling with the beginning of the next following period of steady speed. The tolerances given in paragraph C.5.1.2 shall apply.

C.5.1.1.3 Vehicles equipped with an overdrive that the driver can actuate shall be tested with the overdrive out of action for the urban cycle (Part 1) and with the overdrive in action for the extra-urban cycle (Part 2).

C.5.1.1.4 At the request of the manufacturer, for a vehicle type where the idle speed of the engine is higher than the engine speed that would occur during operations 5, 12 and 24 of the elementary urban cycle (Part 1), the clutch may be disengaged during the previous operation.

C.5.1.2 Tolerances

C.5.1.2.1 A tolerance of ±2 km/h shall be allowed between the indicated speed and the theoretical speed during acceleration, during steady speed, and during deceleration when the vehicle's brakes are used. If the vehicle decelerates more rapidly without the use of the brakes, only the provisions of paragraph

C.5.4.4.3 below shall apply. Speed tolerances greater than those prescribed shall be accepted during phase changes provided that the tolerances are never exceeded for more than 0.5 s on any one occasion.

C.5.1.2.2 The time tolerances shall be ±1 s. The above tolerances shall apply equally at the beginning and at the end of each gear-changing period for the urban cycle (Part 1) and for the operations Nos. 3, 5 and 7 of the extra-urban cycle (Part 2). It should be noted that the time of 2 seconds allowed includes the time for changing gear and, if necessary, a certain amount of latitude to catch up with the theoretical cycle.

C.5.2 Test preparation

C.5.2.1 Load and inertia setting

C.5.2.1.1 Load determined with vehicle road test

The dynamometer shall be adjusted so that the total inertia of the rotating masses will simulate the inertia and other road load forces acting on the vehicle when driving on the road. The means by which this load is determined is described in C.4.

Dynamometer with fixed load curve: The load simulator shall be adjusted to filtered dilution air through the particulate filter. This shall be drawn from the same point as the particulate sample. One measurement may be performed prior to or after the test. Particulate matter mass measurements may be corrected by subtracting the background contribution from the dilution system.

The permissible background contribution shall be <= 1 mg/km (or equivalent mass of particulate matter on the filter). If the background mass exceeds this level, the default figure of 1 mg/km (or equivalent mass of particulate matter on the filter) shall be employed. Where subtraction of the background contribution gives a negative result, the particulate matter mass result shall be considered to be zero.

C.5.2.5 Background particle number measurements

The background particle numbers may be determined by sampling dilution air drawn from a point downstream of the particle and hydrocarbon filters into the particle number measurement system. Background correction of particle number measurements shall not be allowed for type approval test; but may be used at the manufacturer's request for conformity of production and in-service conformity where there are indications that tunnel contribution is significant.

C.5.2.6 Selection of filter required for particulate matter mass measurement

A single particulate filter without back-up shall be employed for both urban and extra-urban phases of the cycle combined.

Twin particulate filters, one for the urban, one for the extra-urban phase, may be used without back-up filters, only where the pressure-drop increase across the sample filter between the beginning and the end of the emissions test is otherwise expected to exceed 25 kPa.

C.5.2.7 Preparation of filter required for particulate matter mass measurement

C.5.2.7.1 Particulate mass sampling filters shall be conditioned (as regards temperature and humidity) in an open dish that has been protected against dust ingress for at least 2 and for not more than 80 hours before the test in a weighing chamber. After this conditioning, the uncontaminated filters will be weighed and stored until they are used. If the filters are not used within 1 hour of their removal from the weighing chamber they shall be re-weighed.

C.5.2.7.2 The 1 hour limit may be replaced by an 8-hour limit if one or both of the following conditions are met:

- A stabilized filter is placed and kept in a sealed filter holder assembly with the ends plugged; or

- A stabilized filter is placed in a sealed filter holder assembly which is then immediately placed in a sample line through which there is no flow.

C.5.2.7.3 The particulate sampling system shall be started and prepared for the second reference fuel by driving a preconditioning cycle consisting of one

Part 1 and two times Part 2 of the test cycle described in Attachment CA. On the manufacturer's request and with the agreement of the testing organization this preconditioning may be extended. The dynamometer setting shall be the one indicated in paragraph C.5.2.1.

C.5.4 Test procedure

C.5.4.1 Starting-up of engine

C.5.4.1.1 The engine shall be started up by means of the devices provided for this purpose according to the manufacturer's instructions.

C.5.4.1.2 The Part 1 cycle starts on the initiation of the engine start-up procedure.

C.5.4.1.3 In cases where LPG or NG is used as a fuel it is permissible that the engine is started on petrol and switched to LPG or NG after a predetermined period of time which cannot be changed by the driver.

C.5.4.2 Idling

C.5.4.2.1 Manual-shift or semi-automatic gearbox

C.5.4.2.1.1 Idling, clutch engaged, transmission in neutral.

C.5.4.2.1.2 To enable the accelerations to be performed according to the normal cycle the vehicle shall be put in first gear, with the clutch disengaged, 5 seconds before the acceleration following the latter part of the idling period of the urban cycle (Part 1).

C.5.4.2.1.3 The first idling period at the beginning of the urban cycle (Part 1) shall consist of 6 seconds of idling in neutral with the clutch engaged and 5 seconds in first gear with the clutch disengaged.

The aforementioned two periods of idling shall be continuous. The idling at the start of the extra-urban cycle (Part 2) shall consist of 20 seconds of idling in first gear with the clutch disengaged.

C.5.4.2.1.4 For the idling periods during each urban cycle (Part 1) the corresponding times shall be 16 seconds in neutral with the clutch engaged and 5 seconds in first gear with the clutch disengaged.

C.5.4.2.1.5 For the urban cycle (Part 1), the idling time between two cycles shall consist of 13 seconds of idling in neutral with the clutch engaged and 5 seconds of idling in first gear with the clutch disengaged.

C.5.4.2.1.6 The idling period at the end of the deceleration period of the extra-urban cycle (Part 2) (with the vehicle already stopped on the rollers) shall consist of 20 seconds of idling in neutral with the clutch engaged.

C.5.4.6 Sampling

Sampling shall begin (BS) before or at the initiation of the engine start up procedure and end on conclusion of the final idling period in the extra-urban cycle (Part 2, end of sampling (ES)) or, in the case of test Type VI, on conclusion of the final idling period of the last elementary urban cycle (Part 1).

C.5.4.7 During the test the speed is recorded against time or collected by the data acquisition system so that the correctness of the cycles performed can be assessed.

C.5.4.8 Particle emissions shall be measured continuously in the particle sampling system. The average concentrations shall be determined by integrating the analyser signals over the test cycle.

C.5.5 Post-test procedures

C.5.5.1 Gas analyser check

Zero and span gas reading of the analysers used for continuous measurement shall be checked using standard gas. The test shall be considered acceptable if the difference between the pre-test and post-test results is less than 2 percent of the span gas value.

C.5.5.2 Filter weighing

Reference filters shall be weighed within 8 hours after the weighing of test filter.

The particulate matter test filter shall be taken to the weighing chamber within

1 hour following the analyses of the exhaust gases. The test filter shall be conditioned for at least 2 hours and not more than 80 hours and then weighed.

C.5.5.3 Sampling bag analysis

C.5.5.3.1 The exhaust gases contained in the bag shall be analysed as soon as possible and in any event not later than 20 minutes after the end of the test cycle.

C.5.5.3.2 Prior to each sample gas analysis, the analyser range to be used for each pollutant shall be set to zero with the appropriate zero gas.

C.5.5.3.3 The analysers shall then be set to the calibration curves by means of span gases of nominal concentrations of 70 to 100 percent of the range.

C.5.5.3.4 The analysers' zero settings shall then be rechecked: If any reading differs by more than 2 percent of the range from that set in paragraph C.5.5.3.2 above, the procedure shall be repeated for that analyser.

C.5.5.3.5 The samples shall then be analysed.

C.5.5.3.6 After the analysis, zero and span points shall be rechecked using the same gases. If these rechecks are within ±2 percent of those in paragraph

Attachment CC (Normative)

Exhaust dilution system

CC.1 System specification

CC.1.1 System overview

A full-flow exhaust dilution system shall be used. This requires that the vehicle exhaust be continuously diluted with ambient air under controlled conditions.

The total volume of the mixture of exhaust and dilution air shall be measured and a continuously proportional sample of the volume shall be collected for analysis. The quantities of exhaust emissions are determined from the sample concentrations. The sample concentrations are corrected according to the pollutant content of the ambient air and the totalised flow over the test period.

The exhaust dilution system shall consist of a transfer tube, a mixing chamber and dilution tunnel, a dilution air conditioning, a suction device and a flow measurement device. Sampling probes shall be fitted in the dilution tunnel as specified in Attachments CD, CE and CF.

The mixing chamber described above will be a vessel, such as those illustrated in Figures CC.1 and CC.2, in which vehicle exhaust gases and the dilution air are combined so as to produce a homogeneous mixture at the chamber outlet.

CC.1.2 General requirements

CC.1.2.1 The vehicle exhaust gases shall be diluted with a sufficient amount of ambient air to prevent any water condensation in the sampling and measuring system at all conditions which may occur during a test.

CC.1.2.2 The mixture of air and exhaust gases shall be homogeneous at the point where the sampling probe is located (see CC.1.3.3). The sampling probe shall extract a representative sample of the diluted exhaust gas.

CC.1.2.3 The system shall enable the total volume of the diluted exhaust gases to be measured.

CC.1.2.4 The sampling system shall be gas-tight. The design of the variable-dilution sampling system and the materials that go to make it up shall be such that they do not affect the pollutant concentration in the diluted exhaust gases. Should any component in the system (heat exchanger, cyclone separator, blower, etc.) change the concentration of any of the pollutants in the diluted exhaust gases and the fault cannot be corrected, then sampling for that pollutant shall be carried out upstream from that component.

CC.1.2.5 All parts of the dilution system that are in contact with raw and diluted

At the vehicle manufacturer's request, the dilution air may be sampled according to good engineering practice to determine the tunnel contribution to background particulate mass levels, which can then be subtracted from the values measured in the diluted exhaust.

CC.1.3.3 Dilution tunnel

Provision shall be made for the vehicle exhaust gases and the dilution air to be mixed. A mixing orifice may be used.

In order to minimize the effects on the conditions at the exhaust outlet and to limit the drop in pressure inside the dilution-air conditioning device, if any, the pressure at the mixing point shall not differ by more than ±0.25 kPa from atmospheric pressure.

The homogeneity of the mixture in any cross-section at the location of the sampling probe shall not vary by more than 2 percent from the average of the values obtained for at least 5 points located at equal intervals on the diameter of the gas stream.

For particulate and particle emissions sampling, a dilution tunnel shall be used which:

- Shall consist of a straight tube of electrically-conductive material, which shall be earthed;

- Shall be small enough in diameter to cause turbulent flow (Reynolds number >= 4000) and of sufficient length to cause complete mixing of the exhaust and dilution air;

- Shall be at least 200 mm in diameter;

- May be insulated.

CC.1.3.4 Suction device

This device may have a range of fixed speeds to ensure sufficient flow to prevent any water condensation. This result is generally obtained if the flow is either:

- Twice as high as the maximum flow of exhaust gas produced by accelerations of the driving cycle; or

- Sufficient to ensure that the CO2 concentration in the dilute exhaust sample bag is less than 3 percent by volume for petrol and diesel, less than 2.2 percent by volume for LPG and less than 1.5 percent by volume for NG.

CC.1.3.5 Volume measurement in the primary dilution system

The method of measuring total dilute exhaust volume incorporated in the

The positive displacement pump (PDP) full flow dilution system satisfies the requirements of this attachment by metering the flow of gas through the pump at constant temperature and pressure.

The total volume is measured by counting the revolutions made by the calibrated positive displacement pump. The proportional sample is achieved by sampling with pump, flowmeter and flow control valve at a constant flow rate. The collecting equipment consists of:

CC.1.4.1.1 A filter (DAF) for the dilution air, which can be preheated if necessary. This filter shall consist of the following filters in sequence: an optional activated charcoal filter (inlet side), a high efficiency particulate air (HEPA) filter (outlet side). It is recommended that an additional coarse particle filter is situated before the HEPA filter and after the charcoal filter, if used. The purpose of the charcoal filter is to reduce and stabilize the hydrocarbon concentrations of ambient emissions in the dilution air;

CC.1.4.1.2 A transfer tube (TT) by which vehicle exhaust is admitted into a dilution tunnel (DT) in which the exhaust gas and dilution air are mixed homogeneously;

CC.1.4.1.3 The positive displacement pump (PDP), producing a constant-volume flow of the air/exhaust-gas mixture. The PDP revolutions, together with associated temperature and pressure measurement are used to determine the flowrate;

CC.1.4.1.4 A heat exchanger (HE) of a capacity sufficient to ensure that throughout the test the temperature of the air/exhaust-gas mixture measured at a point immediately upstream of the positive displacement pump is within ±6

K of the set operating temperature during the test. This device shall not affect the pollutant concentrations of diluted gases taken off after for analysis;

CC.1.4.1.5 A mixing chamber (MC) in which exhaust gas and air are mixed homogeneously, and which may be located close to the vehicle exhaust pipe so that the length of the transfer tube (TT) is minimized.

CC.1.4.2 Full flow dilution system with critical flow Venturi tube (Figure CC.2)

CC.1.4.2.5 A measuring critical-flow venturi tube (CFV), to measure the flow volume of the diluted exhaust gas;

CC.1.4.2.6 A blower (BL), of sufficient capacity to handle the total volume of diluted exhaust gas.

CC.2 CVS calibration procedure

CC.2.1 General requirements

The CVS system shall be calibrated by using an accurate flow-meter and a restricting device. At various pressure readings, the flow through the system and the control parameters related to the flows of the system measured shall be measured. The flow-metering device shall be dynamic and suitable for the high flow-rate encountered in constant volume sampler testing. The device shall be of certified accuracy traceable to an approved national or international standard.

CC.2.1.1 Various types of flow-meter may be used, e.g. calibrated venturi, laminar flow-meter, calibrated turbine-meter, provided that they are dynamic measurement systems and can meet the requirements of paragraph CC.1.3.5.

CC.2.1.2 The following paragraphs give details of methods of calibrating PDP and CFV units, using a laminar flow-meter, which gives the required accuracy, together with a statistical check on the calibration validity.

CC.2.2 Calibration of the positive displacement pump (PDP)

CC.2.2.1 The following calibration procedure outlines the equipment, the test configuration and the various parameters that are measured to establish the flow-rate of the CVS pump. All the parameters related to the pump are simultaneously measured with the parameters related to the flowmeter which is connected in series with the pump. The calculated flowrate (given in m

/min at pump inlet, absolute pressure and temperature) can then be plotted versus a correlation function that is the value of a specific combination of pump parameters. The linear equation that relates the pump flow and the correlation function is then determined. In the event that a PDP has a multiple speed drive, a calibration for each range used shall be performed.

CC.2.2.2 This calibration procedure is based on the measurement of the absolute values of the pump and flow-meter parameters that relate the flow rate at each point. Three conditions shall be maintained to ensure the accuracy and integrity of the calibration curve:

CC.2.2.2.1 The pump pressures shall be measured at tapping on the pump rather than at the external piping on the pump inlet and outlet. Pressure taps that are mounted at the top centre and bottom centre of the pump drive headplate are exposed to the actual pump cavity pressures, and therefore reflect the absolute pressure differentials;

CC.2.2.2.2 Temperature stability shall be maintained during the calibration.

Plot K v as a function of venturi inlet pressure. For sonic flow, K v will have a relatively constant value. As pressure decreases (vacuum increases) the venturi becomes unchoked and K v decreases. The resultant K v changes are not permissible.

For a minimum of 8 points in the critical region, calculate an average Kv and the standard deviation.

If the ratio of the standard deviation to the average K v exceeds 0.3%, the cause shall be found and corrective action taken.

CC.3 Verification of total accuracy of system

CC.3.1 General requirements

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 whilst it is being operated as if during a normal test and then analysing and calculating the pollutant mass according to the formula in paragraph C.5.6 except that the density of propane shall be taken as 1.967 grams per litre at standard conditions. The following two techniques are known to give sufficient accuracy.

The maximum permissible deviation between the quantity of gas introduced and the quantity of gas measured is 5 percent.

CC.3.2 Critical flow orifice (CFO) flowmeter method

CC.3.2.1 Metering a constant flow of pure gas (CO or C 3 H 8 ) using a critical flow orifice device. This method is based on the operating characteristics of the

CFO, i.e. If the inlet pressure is high enough (critical flow), the flow-rate (q), which is adjusted by means of the critical flow orifice, is independent of orifice outlet pressure.

CC.3.2.2 The CVS system is operated as in an exhaust emission test for about

5 to 10 minutes. A known quantity of pure gas (CO or C3 H 8 ) is fed into the CVS system through the calibrated critical orifice. The gas collected in the sampling bag is analysed by the usual equipment and the results compared to the concentration of the gas samples which was known beforehand. If deviations exceeding 5 percent occur, the cause of the deviation shall be found and determined.

CC.3.3 Gravimetric method

CC.3.3.1 Metering a limited quantity of pure gas (CO or C 3 H 8 ) by means of a gravimetric technique.

CC.3.3.2 The following gravimetric procedure may be used to verify the CVS system. The weight of a small cylinder filled with either carbon monoxide (CO) or propane (C 3 H 8 ) is determined with a balance with a precision of ±0.01 g. For about 5 to 10 minutes, the CVS system is operated as in a normal exhaust

Attachment CD (Normative)

Gaseous emissions measurement equipment

CD.1 Specification

CD.1.1 System overview

A continuously proportional sample of the diluted exhaust gases and the dilution air shall be collected for analysis.

Mass of gaseous emissions shall be determined from the proportional sample concentrations and the total volume measured during the test. The sample concentrations shall be corrected to take account of the pollutant content of the ambient air.

CD.1.2 Sampling system requirements

CD.1.2.1 The sample of diluted exhaust gases shall be taken upstream from the suction device but downstream from the conditioning devices (if any).

CD.1.2.2 The flow rate shall not deviate from the average by more than ±2 percent.

CD.1.2.3 The sampling rate shall not fall below 5 litres per minute and shall not exceed 0.2 percent of the flow rate of the dilute exhaust gases. An equivalent limit shall apply to constant-mass sampling systems.

CD.1.2.4 A sample of the dilution air shall be taken at a constant flow rate near the ambient air-inlet (after the filter if one is fitted).

CD.1.2.5 The dilution air sample shall not be contaminated by exhaust gases from the mixing area.

CD.1.2.6 The sampling rate for the dilution air shall be comparable to that used in the case of the dilute exhaust gases.

CD.1.2.7 The materials used for the sampling operations shall be such as not to change the pollutant concentration.

CD.1.2.8 Filters may be used in order to extract the solid particles from the sample.

CD.1.2.9 The various valves used to direct the exhaust gases shall be of a quick adjustment, quick-acting type.

CD.1.2.10 Quick-fastening gas-tight connections may be used between the the analyser may be used (three-way stopcocks, for instance);

CD.1.4.8 Bags (B), for collecting samples of the diluted exhaust gas/air mixture and of the dilution air during the test;

CD.1.4.9 A sampling critical-flow venturi (SV), to take proportional samples of the diluted exhaust gas at sampling probe S 2 (CFV-CVS only);

CD.1.4.10 A scrubber (PS), in the sampling line (CFV-CVS only);

CD.1.4.11 Components for hydrocarbon sampling using HFID:

Fh is a heated filter;

S 3 is a sampling point close to the mixing chamber;

V h is a heated multi-way valve;

Q is a quick connector to allow the ambient air sample B A to be analysed on the HFID;

HFID is a heated hydrogen flame ionisation analyser;

R and I are a means of recording and integrating the instantaneous hydrocarbon concentrations;

Lh is a heated sample line.

CD.2 Calibration procedures

CD.2.1 Analyser calibration procedure

CD.2.1.1 Each analyser shall be calibrated as often as necessary and once in any case in the month before type approval testing and at least once every six months for verifying conformity of production.

CD.2.1.2 Each normally used operating range shall be calibrated by the following procedure:

CD.2.1.2.1 The analyser calibration curve is established by at least 5 calibration points spaced as uniformly as possible. The nominal concentration of the calibration gas of the highest concentration shall be not less than 80 percent of the full scale.

CD.2.1.2.2 The calibration gas concentration required may be obtained by means of a gas divider, diluting with purified N 2 or with purified synthetic air.

The accuracy of the mixing device shall be such that the concentrations of the diluted calibration gases may be determined to within ±2 percent.

CD.2.1.2.3 The calibration curve is calculated by the least square method. If the resulting polynomial degree is greater than 3, the number of calibration points shall be at least equal to this polynomial degree plus 2.

Establish a calibration curve as described in CD.2.1.

CD.2.3.3 Response factors of different hydrocarbons and recommended limits

The response factor (R f), for a particular hydrocarbon species is the ratio of the

FID C 1 reading to the gas cylinder concentration, expressed as ppmC.

The concentration of the test gas shall be at a level to give a response of approximately 80 percent of full-scale deflection, for the operating range. The concentration shall be known, to an accuracy of ±2 percent in reference to a gravimetric standard expressed in volume. In addition, the gas cylinder shall be pre-conditioned for 24 hours at a temperature between 293 K and 303 K (20 and 30 °C).

Response factors shall be determined when introducing an analyser into service and thereafter at major service intervals. The test gases to be used and the recommended response factors are:

- Methane and purified air: 1.00<R f<1.15, or for NG fuelled vehicles: 1.00<R f<1.05;

- Propylene and purified air: 0.90<R f<1.00;

- Toluene and purified air: 0.90<R f<1.00;

These are relative to a response factor (R f) of 1.00 for propane and purified air.

CD.2.3.4 Oxygen interference check and recommended limits

The response factor shall be determined as described in paragraph CD.2.3.3 above. The test gas to be used and recommended response factor range is:

- Propane and nitrogen: 0.95<R f<1.05

CD.2.4 NOx converter efficiency test procedure

The efficiency of the converter used for the conversion of NO2 into NO is tested as follows:

USE the test set up as shown in Figure CD.2 and the procedure described below. The efficiency of converters can be tested by means of an ozonator.

Attachment CE (Normative)

Particulate matter mass emissions measurement equipment

CE.1 Specification

CE.1.1 System overview

CE.1.1.1 The particulate matter sampling unit shall consist of a sampling probe located in the dilution tunnel, a particle transfer tube, a filter holder, a partial-flow pump, and flow rate regulators and measuring units.

CE.1.1.2 It is recommended that a particle size pre-classifier (e.g. cyclone or impactor) be employed upstream of the filter holder. However, a sampling probe, acting as an appropriate size-classification device such as that shown in Figure CE.2, is acceptable.

CE.1.2 General requirements

CE.1.2.1 The sampling probe for the test gas flow for particulates shall be so arranged within the dilution tract that a representative sample gas flow can be taken from the homogeneous air/exhaust mixture.

CE.1.2.2 The particulate sample flow rate shall be proportional to the total flow of diluted exhaust gas in the dilution tunnel to within a tolerance of ±5 percent of the particulate sample flow rate.

CE.1.2.3 The sampled dilute exhaust gas shall be maintained at a temperature below 325 K (52 °C) within 20 cm upstream or downstream of the particulate filter face, except in the case of a regeneration test where the temperature shall be below 465 K (192 °C).

CE.1.2.4 The particulate sample shall be collected on a single filter mounted within a holder in the sampled dilute exhaust gas flow.

CE.1.2.5 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, shall be designed to minimize deposition or alteration of the particulates. All parts shall be made of electrically conductive materials that do not react with exhaust gas components. The system shall be electrically grounded to prevent electrostatic effects.

CE.1.2.6 If it is not possible to compensate for variations in the flow rate, provision shall be made for a heat exchanger and a temperature control device as specified in Attachment CC so as to ensure that the flow rate in the system is constant and the sampling rate accordingly proportional.

of flow shall be decreased.

CE.1.3.3 Filter and filter holder

CE.1.3.3.1 A valve shall be located downstream of the filter in the direction of flow. The valve shall be quick enough acting to open and close within 1 s of the start and end of test.

CE.1.3.3.2 It is recommended that the mass collected on the 47 mm diameter filter (Pe) is >= 20 µg and that the filter loading shall be maximized consistent with the requirements of paragraphs CE.1.2.3 and CE.1.3.3.

CE.1.3.3.3 For a given test the gas filter face velocity shall be set to a single value within the range 20 cm/s to 80 cm/s unless the dilution system is being operated with sampling flow proportional to CVS flow rate.

CE.1.3.3.4 Fluorocarbon coated glass fibre filters or fluorocarbon membrane filters are required. All filter types shall have a 0.3 µm DOP (di-octylphthalate) collection efficiency of at least 99 percent at a gas filter face velocity of at least

35 cm/s.

CE.1.3.3.5 The filter holder assembly shall be of a design that provides an even flow distribution across the filter stain area. The filter stain area shall be at least 1075 mm

CE.1.3.4 Filter weighing chamber and balance

CE.1.3.4.1 The microgram balance used to determine the weight of a filter shall have a precision (standard deviation) of 2 µg and resolution of 1 µg.

It is recommended that the balance be checked at the start of each weighing session by weighing one reference weight of 50 mg. This weight shall be weighed at least 3 times and the average result recorded. If the average result of the weighings is ±5 µg from the result from the previous weighing session then the weighing session and balance are considered valid.

The weighing chamber (or room) shall meet the following conditions during all filter conditioning and weighing operations:

Temperature maintained at 295 ±3 K (22 ±3 °C);

Relative humidity maintained at 45 ±8 percent;

Dewpoint maintained at 9.5 °C ±3 °C.

It is recommended that temperature and humidity conditions are recorded along with sample and reference filter weights.

CE.1.3.4.2 Buoyancy correction

All filter weights shall be corrected for filter buoyancy in air.

Attachment CF (Normative)

Particle number emissions measurement equipment

CF.1 Specification

CF.1.1 System overview

CF.1.1.1 The particle sampling system shall consist of a dilution tunnel, a sampling probe and a volatile particle remover (VPR) upstream of a particle number counter (PNC) and suitable transfer tubing.

CF.1.1.2 It is recommended that a particle size pre-classifier (e.g. cyclone, impactor etc.) be located prior to the inlet of the VPR. However, a sample probe acting as an appropriate size-classification device, such as that shown in Figure CE.2, is an acceptable alternative to the use of a particle size pre-classifier.

CF.1.2 General requirements

CF.1.2.1 The particle sampling point shall be located within a dilution tunnel.

The sampling probe tip (PSP) and particle transfer tube (PTT) together comprise the particle transfer system (PTS). The PTS conducts the sample from the dilution tunnel to the entrance of the VPR. The PTS shall meet the following conditions:

It shall be installed near the tunnel centre line, 10 to 20 times the tunnel diameter from downstream of the gas inlet, facing upstream into the tunnel gas flow with its axis at the tip parallel to that of the dilution tunnel.

It shall have an internal diameter of >= 8 mm.

Sample gas drawn through the PTS shall meet the following conditions:

It shall have a flow Reynolds number (Re) of < 1700;

It shall have a residence time in the PTS of <= 3 seconds.

Any other sampling configuration for the PTS for which equivalent particle penetration at 30 nm can be demonstrated will be considered acceptable.

The outlet tube (OT) conducting the diluted sample from the VPR to the inlet of the PNC shall have the following properties:

It shall have an internal diameter of >= 4 mm;

Sample gas flow through the OT shall have a residence time of <= 0.8 seconds.

heating and reduction of partial pressures of the tetracontane.

CF.1.3.4 The PNC shall:

CF.1.3.4.1 Operate under full flow operating conditions;

CF.1.3.4.2 Have a counting accuracy of ±10 percent across the range 1 cm

-3 to the upper threshold of the single particle count mode of the PNC against a traceable standard. At concentrations below 100 cm

-3 measurements averaged over extended sampling periods may be required to demonstrate the accuracy of the PNC with a high degree of statistical confidence;

CF.1.3.4.3 Have a readability of at least 0.1 cm

-3 at particle concentrations below 100 cm

-3

CF.1.3.4.4 Have a linear response to particle concentrations over the full measurement range in single particle count mode;

CF.1.3.4.5 Have a data reporting frequency equal to or greater than 0.5 Hz;

CF.1.3.4.6 Have a T90 response time over the measured concentration range of less than 5 s;

CF.1.3.4.7 Incorporate a coincidence correction function up to a maximum 10 percent correction and may make use of an internal calibration factor as determined in CF.2.1.3, but shall not make use of any other algorithm to correct for or define the counting efficiency;

CF.1.3.4.8 Have counting efficiencies at particle sizes of 23 nm (±1 nm) and 41 nm (±1 nm) electrical mobility diameter of 50 percent (±12 percent) and > 90 percent respectively. These counting efficiencies may be achieved by internal (for example, control of instrument design) or external (for example, size pre-classification) means;

CF.1.3.4.9 If the PNC makes use of a working liquid, it shall be replaced at the frequency specified by the instrument manufacturer.

CF.1.3.5 Where they are not held at a known constant level at the point at which PNC flow rate is controlled, the pressure and/or temperature at inlet to the PNC shall be measured and reported for the purposes of correcting particle concentration measurements to standard conditions.

CF.1.3.6 The sum of the residence time of the PTS, VPR and OT plus the T 90 response time of the PNC shall be no greater than 20 s.

CF.1.4 Descriptions of recommended system

The following Figure CF.1 is the recommended system for measurement of particle numbers. However, any system meeting the performance specifications in CF.1.2 and CF.1.3 is acceptable.

Any other sampling configuration for the PTS for which equivalent particle penetration for particles of 30 nm electrical mobility diameter can be demonstrated will be considered acceptable.

The outlet tube (OT) conducting the diluted sample from the VPR to the inlet of the PNC shall have the following properties:

It shall have an internal diameter of >= 4 mm;

Sample gas flow through the POT shall have a residence time of <= 0.8 seconds.

Any other sampling configuration for the OT for which equivalent particle penetration for particles of 30 nm electrical mobility diameter can be demonstrated will be considered acceptable.

CF.1.4.3 Particle pre-classifier (PCF)

The recommended particle pre-classifier shall be located upstream of the VPR.

The pre-classifier 50 percent cut point particle diameter shall be between 2.5

µm and 10 µm at the volumetric flow rate selected for sampling particle number emissions. The pre-classifier shall allow at least 99 percent of the mass concentration of 1 µm particles entering the pre-classifier to pass through the exit of the pre-classifier at the volumetric flow rate selected for sampling particle number emissions.

CF.1.4.4 Volatile particle remover (VPR)

The VPR shall comprise one particle number diluter (PND1), an evaporation tube (ET) and a second diluter (PND2) in series. This dilution function is to reduce the number concentration of the sample entering the particle concentration measurement unit to be less than the upper threshold of the single particle count mode of the PNC and to suppress nucleation within the sample. The VPR shall provide an indication of whether or not PND1 and the evaporation tube (ET) are at their correct operating temperatures.

The VPR shall achieve > 99 percent vaporisation of 0.03 µm tetracontane (CH3 (CH 2 ) 38 CH3 ) particles, with an inlet concentration of >= 10000 cm

-3 , by means of heating and reduction of partial pressures of the tetracontane. The particle concentration reduction factor (fr(di)) shall also be able to reach: For the volatile particle remover as a whole, the particles with an electromobility particle size of 30 nm and 50 nm do not exceed 30% and 20%, respectively;

the particles with an electromobility particle size of 100 nm are not less than

5%.

CF.1.4.4.1 First particle number dilution device (PND1 )

The first particle number dilution device shall be specifically designed to dilute particle number concentration and operate at a (wall) temperature of 150 °C -

400 °C. The wall temperature setpoint shall not exceed the temperature of the

ET (See CF.1.4.4.2). The diluter shall be supplied with HEPA filtered dilution

A calibration factor equal to the reciprocal of the gradient shall be applied to the PNC under calibration. Linearity of response is calculated as the square of the Pearson product moment correlation coefficient (R

) of the two data sets and shall be equal to or greater than 0.97. In calculating both the gradient and

2 the linear regression shall be forced through the origin (zero concentration on both instruments).

In the reference PNC case, calibration shall be undertaken using at least 6 standard concentrations across the PNC's measurement range. At least 3 points shall be at concentrations below 1000 cm

-3 , the remaining concentrations shall be linearly spaced between 1000 cm

-3 and the maximum of the PNC's range in single particle count mode. These points will include a nominal zero concentration point produced by attaching HEPA filters of at least class H13 of EN 1822 to the inlet of each instrument. With no calibration factor applied to the PNC under calibration, measured concentrations shall be within

±10 percent of the standard concentration for each concentration, with the exception of the zero point, otherwise the PNC under calibration shall be rejected. The gradient from a linear regression of the two data sets shall be calculated and recorded. A calibration factor equal to the reciprocal of the gradient shall be applied to the PNC under calibration. Linearity of response is calculated as the square of the Pearson product moment correlation coefficient (R

) of the two data sets and shall be equal to or greater than 0.97. In calculating both the gradient and R

2 the linear regression shall be forced through the origin (zero concentration on both instruments).

CF.2.1.4 Calibration shall also include a check, against the requirements in

CF.1.3.4.8, on the PNC's detection efficiency with particles of 23 nm electrical mobility diameter. A check of the counting efficiency with 41 nm particles is not required.

CF.2.2 Calibration/validation of the volatile particle remover

CF.2.2.1 Calibration of the VPR's particle concentration reduction factors across its full range of dilution settings, at the instrument's fixed nominal operating temperatures, shall be required when the unit is new and following any major maintenance. The periodic validation requirement for the VPR's particle concentration reduction factor is limited to a check at a single setting, typical of that used for measurement on diesel particulate filter equipped vehicles. The testing organization shall ensure the existence of a calibration or validation certificate for the volatile particle remover within a 6 month period. If the volatile particle remover incorporates temperature monitoring alarms a 12 month validation interval shall be permissible.

The VPR shall be characterised for particle concentration reduction factor with solid particles of 0.03µm, 0.05µm and 0.1µm electrical mobility diameter.

Particle concentration reduction factors for particles of 0.03µm and 0.05µm electrical mobility diameters shall be no more than 30 percent and 20 percent higher respectively, and no more than 5 percent lower than that for particles of

0.1µm electrical mobility diameter. For the purposes of validation, the mean particle concentration reduction factor shall be within ±10 percent of the mean