Commission Delegated Regulation (EU) 2017/654Show full title

7. Test procedures U.K.

7.1. Introduction U.K.

This chapter describes the determination of brake specific emissions of gaseous and particulate pollutants on engines to be tested. The test engine shall be the parent engine configuration for the engine family as specified Annex IX to Implementing Regulation (EU) 2017/656.

A laboratory emission test consists of measuring emissions and other parameters for the test cycles specified in Annex XVII. The following aspects are treated:

(a)

The laboratory configurations for measuring the emissions (point 7.2);

(b)

The pre-test and post-test verification procedures (point 7.3);

(c)

The test cycles (point 7.4);

(d)

The general test sequence (point 7.5);

(e)

The engine mapping (point 7.6);

(f)

The test cycle generation (point 7.7);

(g)

The specific test cycle running procedure (point 7.8).

7.2. Principle of emission measurement U.K.

To measure the brake-specific emissions, the engine shall be operated over the test cycles defined in point 7.4, as applicable. The measurement of brake-specific emissions requires the determination of the mass of pollutants in the exhaust emissions (i.e. HC, CO, NO_x and PM), the number of particulates in the exhaust emissions (i.e. PN), the mass of CO₂ in the exhaust emissions, and the corresponding engine work.

7.2.1. Mass of constituent U.K.

The total mass of each constituent shall be determined over the applicable test cycle by using the following methods:

7.2.1.1. Continuous sampling U.K.

In continuous sampling, the constituent's concentration is measured continuously from raw or diluted exhaust gas. This concentration is multiplied by the continuous (raw or diluted) exhaust gas flow rate at the emission sampling location to determine the constituent's flow rate. The constituent's emission is continuously summed over the test interval. This sum is the total mass of the emitted constituent.

7.2.1.2. Batch sampling U.K.

In batch sampling, a sample of raw or diluted exhaust gas is continuously extracted and stored for later measurement. The extracted sample shall be proportional to the raw or diluted exhaust gas flow rate. Examples of batch sampling are collecting diluted gaseous emissions in a bag and collecting PM on a filter. In principal the method of emission calculation is done as follows: the batch sampled concentrations are multiplied by the total mass or mass flow (raw or dilute) from which it was extracted during the test cycle. This product is the total mass or mass flow of the emitted constituent. To calculate the PM concentration, the PM deposited onto a filter from proportionally extracted exhaust gas shall be divided by the amount of filtered exhaust gas.

7.2.1.3. Combined sampling U.K.

Any combination of continuous and batch sampling is permitted (e.g. PM with batch sampling and gaseous emissions with continuous sampling).

Figure 6.2 illustrates the two aspects of the test procedures for measuring emissions: the equipment with the sampling lines in raw and diluted exhaust gas and the operations requested to calculate the pollutant emissions in steady-state and transient test cycles.

Figure 6.2 Test procedures for emission measurement U.K.

7.2.2. Work determination U.K.

The work shall be determined over the test cycle by synchronously multiplying speed and brake torque to calculate instantaneous values for engine brake power. Engine brake power shall be integrated over the test cycle to determine total work.

7.3. Verification and calibration U.K.

7.3.1. Pre-test procedures U.K.

[F1 7.3.1.1. General requirements for preconditioning the sampling system and the engine] U.K.

To achieve stable conditions, the sampling system and the engine shall be preconditioned before starting a test sequence as specified in this point.

The intent of engine preconditioning is to achieve the representativeness of emissions and emission controls over the duty cycle and to reduce bias in order to meet stable conditions for the following emission test.

Emissions may be measured during preconditioning cycles, as long as a predefined number of preconditioning cycles are performed and the measurement system has been started according to the requirements of point 7.3.1.4. The amount of preconditioning shall be identified by the engine manufacturer before starting to precondition. Preconditioning shall be performed as follows, noting that the specific cycles for preconditioning are the same ones that apply for emission testing.

[F2 Engines fitted with an after-treatment system may be operated prior to cycle-specific preconditioning set out in points 7.3.1.1.1 to 7.3.1.1.4, so that the after-treatment system is regenerated and, where applicable, the soot load in the particulate after-treatment system is re-established.]

Textual Amendments

F2 Inserted by Commission Delegated Regulation (EU) 2018/989 of 18 May 2018 amending and correcting Delegated Regulation (EU) 2017/654 supplementing Regulation (EU) 2016/1628 of the European Parliament and of the Council with regard to technical and general requirements relating to emission limits and type-approval for internal combustion engines for non-road mobile machinery (Text with EEA relevance).

7.3.1.1.1. Preconditioning for cold-start run of NRTC U.K.

The engine shall be preconditioned by running at least one hot-start NRTC. Immediately after completing each preconditioning cycle, the engine shall be shut down and the engine-off hot-soak period shall be completed. Immediately after completing the last preconditioning cycle, the engine shall be shut down and the engine cool down described in point 7.3.1.2 shall be started.

7.3.1.1.2. Preconditioning for hot-start run of NRTC or for LSI-NRTC U.K.

This point describes the pre-conditioning that shall be applied when it is intended to sample emissions from the hot-start NRTC without running the cold-start run of the NRTC (‘cold-start NRTC’), or for the LSI-NRTC. The engine shall be preconditioned by running at least one hot-start NRTC or LSI-NRTC as applicable. Immediately after completing each preconditioning cycle, the engine shall be shut down, and then the next cycle shall be started as soon as practical. It is recommended that the next preconditioning cycle shall be started within 60 seconds after completing the last preconditioning cycle. Where applicable, following the last pre-conditioning cycle the appropriate hot-soak (hot-start NRTC) or cool-down (LSI-NRTC) period shall apply before the engine is started for the emissions test. Where no hot-soak or cool down period applies it is recommended that the emissions test shall be started within 60 seconds after completing the last pre-conditioning cycle.

7.3.1.1.3. Preconditioning for discrete-mode NRSC U.K.

For engine categories other than NRS and NRSh the engine shall be warmed-up and run until engine temperatures (cooling water and lube oil) have been stabilized on 50 % speed and 50 % torque for any discrete-mode NRSC test cycle other than type D2, E2, or G, or nominal engine speed and 50 % torque for any discrete-mode NRSC test cycle D2, E2 or G. The 50 % speed shall be calculated in accordance with point 5.2.5.1 in the case of an engine where MTS is used for the generation of test speeds, and calculated in accordance with point 7.7.1.3 in all other cases. 50 % torque is defined as 50 % of the maximum available torque at this speed. The emissions test shall be started without stopping the engine.

For engine categories NRS and NRSh the engine shall be warmed up according to the recommendation of the manufacturer and good engineering judgment. Before emission sampling can start, the engine shall be running on mode 1 of the appropriate test cycle until engine temperatures have been stabilized. The emissions test shall be started without stopping the engine.

7.3.1.1.4. Preconditioning for RMC U.K.

The engine manufacturer shall select one of the following pre-conditioning sequences (a) or (b). The engine shall be pre-conditioned according to the chosen sequence.

(a)

The engine shall be preconditioned by running at least the second half of the RMC, based on the number of test modes. The engine shall not be shut down between cycles. Immediately after completing each preconditioning cycle, the next cycle (including the emission test) shall be started as soon as practical. Where possible, it is recommended that the next cycle be started within 60 seconds after completing the last preconditioning cycle.

(b)

The engine shall be warmed-up and run until engine temperatures (cooling water and lube oil) have been stabilized on 50 % speed and 50 % torque for any RMC test cycle other than type D2, E2, or G, or nominal engine speed and 50 % torque for any RMC test cycle D2, E2 or G. The 50 % speed shall be calculated in accordance with point 5.2.5.1 in the case of an engine where MTS is used for the generation of test speeds, and be calculated in accordance with point 7.7.1.3 in all other cases. 50 % torque is defined as 50 % of the maximum available torque at this speed.

F3 7.3.1.1.5. Engine cool-down (NRTC) U.K.

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Textual Amendments

F3 Deleted by Commission Delegated Regulation (EU) 2018/989 of 18 May 2018 amending and correcting Delegated Regulation (EU) 2017/654 supplementing Regulation (EU) 2016/1628 of the European Parliament and of the Council with regard to technical and general requirements relating to emission limits and type-approval for internal combustion engines for non-road mobile machinery (Text with EEA relevance).

Textual Amendments

F1 Substituted by Commission Delegated Regulation (EU) 2018/989 of 18 May 2018 amending and correcting Delegated Regulation (EU) 2017/654 supplementing Regulation (EU) 2016/1628 of the European Parliament and of the Council with regard to technical and general requirements relating to emission limits and type-approval for internal combustion engines for non-road mobile machinery (Text with EEA relevance).

[F1 7.3.1.2. Engine cool-down (NRTC) U.K.

A natural or forced cool-down procedure may be applied. For forced cool-down, good engineering judgment shall be used to set up systems to send cooling air across the engine, to send cool oil through the engine lubrication system, to remove heat from the coolant through the engine cooling system, and to remove heat from an exhaust after-treatment system. In the case of a forced after-treatment cool down, cooling air shall not be applied until the exhaust after-treatment system has cooled below its catalytic activation temperature. Any cooling procedure that results in unrepresentative emissions is not permitted.

7.3.1.3. Verification of HC contamination U.K.

If there is any presumption of an essential HC contamination of the exhaust gas measuring system, the contamination with HC may be checked with zero gas and the hang-up may then be corrected. If the amount of contamination of the measuring system and the background HC system has to be checked, it shall be conducted within 8 hours of starting each test-cycle. The values shall be recorded for later correction. Before this check, the leak check has to be performed and the FID analyzer has to be calibrated.

7.3.1.4. Preparation of measurement equipment for sampling U.K.

The following steps shall be taken before emission sampling begins:

(a)

Leak checks shall be performed within 8 hours prior to emission sampling in accordance with point 8.1.8.7;

(b)

For batch sampling, clean storage media shall be connected, such as evacuated bags or tare-weighed filters;

(c)

All measurement instruments shall be started in accordance with the instrument manufacturer's instructions and good engineering judgment;

(d)

Dilution systems, sample pumps, cooling fans, and the data-collection system shall be started;

(e)

The sample flow rates shall be adjusted to desired levels, using bypass flow, if desired;

(f)

Heat exchangers in the sampling system shall be pre-heated or pre-cooled to within their operating temperature ranges for a test;

(g)

Heated or cooled components such as sample lines, filters, chillers, and pumps shall be allowed to stabilize at their operating temperatures;

(h)

Exhaust gas dilution system flow shall be switched on at least 10 minutes before a test sequence;

(i)

Calibration of gas analyzers and zeroing of continuous analyzers shall be carried out in accordance with the procedure of point 7.3.1.5;

(j)

Any electronic integrating devices shall be zeroed or re-zeroed, before the start of any test interval.

7.3.1.5. Calibration of gas analyzers U.K.

Appropriate gas analyzer ranges shall be selected. Emission analyzers with automatic or manual range switching are allowed. During a test using transient (NRTC or LSI-NRTC) test cycles or RMC and during a sampling period of a gaseous emission at the end of each mode for discrete-mode NRSC testing, the range of the emission analyzers shall not be switched. Also the gains of an analyzer's analogue operational amplifier(s) shall not be switched during a test cycle.

All continuous analyzers shall be zeroed and spanned using internationally-traceable gases that meet the specifications of point 9.5.1. FID analyzers shall be spanned on a carbon number basis of one (C ₁ ).]

[F2 7.3.1.6. PM filter preconditioning and tare weighing U.K.

The procedures for PM filter preconditioning and tare weighing shall be performed in accordance with point 8.2.3.]

7.3.2. Post-test procedures U.K.

The following steps shall be taken after emission sampling is complete:

7.3.2.1. Verification of proportional sampling U.K.

For any proportional batch sample, such as a bag sample or PM sample, it shall be verified that proportional sampling was maintained according to point 8.2.1. For the single filter method and the discrete steady-state test cycle, effective PM weighting factor shall be calculated. Any sample that does not fulfil the requirements of point 8.2.1 shall be voided.

7.3.2.2. Post-test PM conditioning and weighing U.K.

Used PM sample filters shall be placed into covered or sealed containers or the filter holders shall be closed, in order to protect the sample filters against ambient contamination. Thus protected, the loaded filters have to be returned to the PM-filter conditioning chamber or room. Then the PM sample filters shall be conditioned and weighted accordingly to point 8.2.4 (PM filter post-conditioning and total weighing procedures).

7.3.2.3. Analysis of gaseous batch sampling U.K.

As soon as practical, the following shall be performed:

(a)

All batch gas analyzers shall be zeroed and spanned no later than 30 minutes after the test cycle is complete or during the soak period if practical to check if gaseous analyzers are still stable;

(b)

Any conventional gaseous batch samples shall be analyzed no later than 30 minutes after the hot-start NRTC is complete or during the soak period;

(c)

The background samples shall be analyzed no later than 60 minutes after the hot-start NRTC is complete.

7.3.2.4. Drift verification U.K.

After quantifying exhaust gas, drift shall be verified as follows:

(a)

For batch and continuous gas analyzers, the mean analyzer value shall be recorded after stabilizing a zero gas to the analyzer. Stabilization may include time to purge the analyzer of any sample gas, plus any additional time to account for analyzer response;

(b)

The mean analyzer value shall be recorded after stabilizing the span gas to the analyzer. Stabilization may include time to purge the analyzer of any sample gas, plus any additional time to account for analyzer response;

(c)

These data shall be used to validate and correct for drift as described in point 8.2.2.

[F1 7.4. Test cycles U.K.

The EU type-approval test shall be conducted using the appropriate NRSC and, where applicable, NRTC or LSI-NRTC, specified in Article 18 of Regulation (EU) 2016/1628 and Annex IV thereto. The technical specifications and characteristics of the NRSC, NRTC and LSI-NRTC are laid down in Annex XVII of this Regulation and the method for determination of the torque, power and speed settings for these test cycles set out in section 5.2.]

7.4.1. Steady-state test cycles U.K.

Non-road steady-state test cycles (NRSC) are specified in Appendices 1 and 2 of Annex XVII as a list of discrete-modes NRSC (operating points), where each operating point has one value of speed and one value of torque. A NRSC shall be measured with a warmed up and running engine according to manufacturer's specification. At the choice of the manufacturer, a NRSC may be run as a discrete-mode NRSC or a RMC, as explained in points 7.4.1.1 and 7.4.1.2. It shall not be required to conduct an emission test according to both points 7.4.1.1 and 7.4.1.2.

7.4.1.1. Discrete-mode NRSC U.K.

The discrete-mode NRSC are hot running cycles where emissions shall be started to be measured after the engine is started, warmed up and running as specified in point 7.8.1.2. Each cycle consists of a number of speed and load modes (with the respective weighing factor for each mode) which cover the typical operating range of the specified engine category.

7.4.1.2. Ramped modal NRSC U.K.

The RMC are hot running cycles where emissions shall be started to be measured after the engine is started, warmed up and running as specified in point 7.8.2.1. The engine shall be continuously controlled by the test bed control unit during the RMC. The gaseous and particulate emissions shall be measured and sampled continuously during the RMC in the same way as in a transient (NRTC or LSI-NRTC) test cycles.

An RMC is intended to provide a method for performing a steady-state test in a pseudo-transient manner. Each RMC consists of a series of steady state modes with a linear transition between them. The relative total time at each mode and its preceding transition match the weighting of the discrete-mode NRSC. The change in engine speed and load from one mode to the next one has to be linearly controlled in a time of 20 ± 1 seconds. The mode change time is part of the new mode (including the first mode). In some cases modes are not run in the same order as the discrete-mode NRSC or are split to prevent extreme changes in temperature.

7.4.2. Transient (NRTC and LSI-NRTC) test cycles U.K.

The non-road transient cycle for engines of category NRE (NRTC) and the non-road transient cycle for large spark ignition engines of category NRS (LSI-NRTC) are each specified in Appendix 3 of Annex XVII as a second-by-second sequence of normalized speed and torque values. In order to perform the test in an engine test cell, the normalized values shall be converted to their equivalent reference values for the individual engine to be tested, based on specific speed and torque values identified in the engine-mapping curve. The conversion is referred to as denormalization, and the resulting test cycle is the reference NRTC or LSI-NRTC test cycle of the engine to be tested (see point 7.7.2).

7.4.2.1. Test sequence for NRTC U.K.

A graphical display of the normalized NRTC dynamometer schedule is shown in Figure 6.3.

Figure 6.3 NRTC normalized dynamometer schedule U.K.

The NRTC shall be run twice after completion of pre-conditioning (see point 7.3.1.1.1) in accordance with the following procedure:

(a)

[F1 the cold start run shall commence after either the engine and exhaust after-treatment systems have cooled down to room temperature after natural engine cool down, or after forced cool down, and the engine, coolant and oil temperatures, exhaust after-treatment systems and all engine control devices are stabilized between 293 K and 303 K (20 °C and 30 °C). The measurement of the emissions for this run shall be started with the start of the cold engine;]

(b)

the hot soak period shall commence immediately upon completion of the cold start phase. The engine shall be shut-down and conditioned for the hot-start run by soaking it for 20 minutes ± 1 minute;

(c)

[F1 the hot-start run shall commence immediately after the soak period with the cranking of the engine. The gaseous analyzers shall be switched on at least 10 seconds before the end of the soak period to avoid switching signal peaks. The measurement of emissions for this run shall be started in parallel with the cranking of the engine.

Brake specific emissions expressed in (g/kWh), or number per kilowatt-hour (#/kWh) for PN, shall be determined by using the procedures set out in this section for both the cold start run and hot-start run of the test cycle. Composite weighted emissions shall be computed by weighting the cold-start run results by 10 % and the hot-start run results by 90 % as detailed in Annex VII.]

7.4.2.2. Test sequence for LSI-NRTC U.K.

The LSI-NRTC shall be run once as a hot-start run after completion of pre-conditioning (see point 7.3.1.1.2) in accordance with the following procedure:

(a)

the engine shall be started and operated for the first 180 seconds of the duty cycle, then operated at idle without load for 30 seconds. Emissions shall not be measured during this warm-up sequence.

(b)

At the end of the 30-second idling period, emissions measurement shall be started and the engine be operated over the entire duty cycle from the beginning (time 0 sec).

Brake specific emissions expressed in (g/kWh) shall be determined by using the procedures of Annex VII.

If the engine was already operating before the test, use good engineering judgment to let the engine cool down enough so measured emissions will accurately represent those from an engine starting at room temperature. For example, if an engine starting at room temperature warms up enough in three minutes to start closed-loop operation and achieve full catalyst activity, then minimal engine cooling is necessary before starting the next test.

With the prior agreement of the technical service, the engine warm-up procedure may include up to 15 minutes of operation over the duty cycle.

7.5. General test sequence U.K.

To measure engine emissions the following steps have to be performed:

(a)

The engine test speeds and test loads have to be defined for the engine to be tested by measuring the max torque (for constant-speed engines) or max torque curve (for variable-speed engines) as function of the engine speed;

(b)

Normalized test cycles have to be denormalized with the torque (for constant-speed engines) or speeds and torques (for variable-speed engines) found in the previous point 7.5(a);

(c)

The engine, equipment, and measurement instruments shall be prepared for the following emission test or test series (cold-start run and hot-start run) in advance;

(d)

Pre-test procedures shall be performed to verify proper operation of certain equipment and analyzers. All analysers have to be calibrated. All pre-test data shall be recorded;

(e)

The engine shall be started (NRTC) or kept running (steady-state cycles and LSI-NRTC) at the beginning of the test cycle and the sampling systems shall be started at the same time;

(f)

Emissions and other required parameters shall be measured or recorded during sampling time (for NRTC, LSI-NRTC and RMC throughout the whole test cycle);

(g)

Post-test procedures shall be performed to verify proper operation of certain equipment and analyzers;

(h)

[F1 PM filter(s) shall be pre-conditioned, weighed (empty weight), loaded, re-conditioned, again weighed (loaded weight) and then samples shall be evaluated in accordance with the pre-test (point 7.3.1.6) and post-test (point 7.3.2.2) procedures;]

(i)

Emission test results shall be evaluated.

Figure 6.4 gives an overview about the procedures needed to conduct NRMM test cycles with measuring exhaust engine emissions.

[F1 Figure 6.4 Test sequence] U.K.

7.5.1. Engine starting, and restarting U.K.

7.5.1.1. Engine start U.K.

The engine shall be started:

(a)

As recommended in the end-users' instructions using a production starter motor or air-start system and either an adequately charged battery, a suitable power supply or a suitable compressed air source; or

(b)

By using the dynamometer to crank the engine until it starts. Typically operate the engine within ± 25 % of its typical in-use cranking speed or start the engine by linearly increasing the dynamometer speed from zero to 100 min^– 1 below low idle speed but only until the engine starts.

Cranking shall be stopped within 1 s of starting the engine. If the engine does not start after 15 s of cranking, cranking shall be stopped and the reason for the failure to start determined, unless the end-users' instructions or the service-repair manual describes a longer cranking time as normal.

7.5.1.2. Engine stalling U.K.

(a)

[F1 If the engine stalls anywhere during the cold start run of the NRTC, the entire test shall be voided;

(b)

If the engine stalls anywhere during the hot-start run of the NRTC, only this run shall be voided. The engine shall be soaked in accordance with point 7.8.3, and the hot-start run repeated. In this case, the cold-start run does not need to be repeated;]

(c)

If the engine stalls anywhere during the LSI-NRTC, the test shall be voided.

(d)

If the engine stalls anywhere during the NRSC (discrete or ramped), the test shall be voided and be repeated beginning with the engine warm-up procedure. In the case of PM measurement utilizing the multi-filter method (one sampling filter for each operating mode), the test shall be continued by stabilizing the engine at the previous mode for engine temperature conditioning and then initiating measurement with the mode where the engine stalled.

7.5.1.3 Engine operation U.K.

The ‘operator’ may be a person (i.e., manual), or a governor (i.e., automatic) that mechanically or electronically signals an input that demands engine output. Input may be from an accelerator pedal or signal, a throttle-control lever or signal, a fuel lever or signal, a speed lever or signal, or a governor set point or signal.

7.6. Engine mapping U.K.

Before starting the engine mapping, the engine shall be warmed up and towards the end of the warm up it shall be operated for at least 10 minutes at maximum power or according to the recommendation of the manufacturer and good engineering judgement in order to stabilize the engine coolant and lube oil temperatures. When the engine is stabilized, the engine mapping shall be performed.

Where the manufacturer intends to use the torque signal broadcast by the electronic control unit, of engines so equipped, during the conduct of in-service monitoring tests according to Delegated Regulation (EU) 2017/655 on monitoring of emissions of in-service engines, the verification set out in Appendix 3 shall additionally be performed during the engine mapping.

Except constant-speed engines, engine mapping shall be performed with fully open fuel lever or governor using discrete speeds in ascending order. The minimum and maximum mapping speeds are defined as follows:

Minimum mapping speed

=

warm idle speed

Maximum mapping speed

=

n _hi × 1,02 or speed where max torque drops off to zero, whichever is smaller.

Where:

n _hi

is the high speed, [F1 as defined in Article 1(12)].

If the highest speed is unsafe or unrepresentative (e.g., for ungoverned engines), good engineering judgement shall be used to map up to the maximum safe speed or the maximum representative speed.

7.6.1. Engine mapping for variable-speed NRSC U.K.

In the case of engine mapping for a variable-speed NRSC (only for engines which have not to run the NRTC or LSI-NRTC cycle), good engineering judgment shall be used to select a sufficient number of evenly spaced set-points. At each set-point, speed shall be stabilized and torque allowed to stabilize at least for 15 seconds. The mean speed and torque shall be recorded at each set-point. It is recommended that the mean speed and torque are calculated using the recorded data from the last 4 to 6 seconds. Linear interpolation shall be used to determine the NRSC test speeds and torques if needed. When engines are additionally required to run an NRTC or LSI-NRTC, the NRTC engine mapping curve shall be used to determine steady-state test speeds and torques.

At the choice of the manufacturer the engine mapping may alternatively be conducted according to the procedure in point 7.6.2.

7.6.2. Engine mapping for NRTC and LSI-NRTC U.K.

The engine mapping shall be performed according to the following procedure:

(a)

The engine shall be unloaded and operated at idle speed;

(i)

For engines with a low-speed governor, the operator demand shall be set to the minimum, the dynamometer or another loading device shall be used to target a torque of zero on the engine's primary output shaft and the engine shall be allowed to govern the speed. This warm idle speed shall be measured;

(ii)

For engines without a low-speed governor, the dynamometer shall be set to target a torque of zero on the engine's primary output shaft, and the operator demand shall be set to control the speed to the manufacturer-declared lowest engine speed possible with minimum load (also known as manufacturer-declared warm idle speed);

(iii)

The manufacturer declared idle torque may be used for all variable-speed engines (with or without a low-speed governor), if a nonzero idle torque is representative of in-use operation;

(b)

Operator demand shall be set to maximum and engine speed shall be controlled to between warm idle and 95 % of its warm idle speed. For engines with reference duty cycles, which lowest speed is greater than warm idle speed, the mapping may be started at between the lowest reference speed and 95 % of the lowest reference speed;

(c)

The engine speed shall be increased at an average rate of 8 ± 1 min^{– 1}/s or the engine shall be mapped by using a continuous sweep of speed at a constant rate such that it takes 4 to 6 min to sweep from minimum to maximum mapping speed. The mapping speed range shall be started between warm idle and 95 % of warm idle and ended at the highest speed above maximum power at which less than 70 % of maximum power occurs. If this highest speed is unsafe or unrepresentative (e.g., for ungoverned engines), good engineering judgment shall be used to map up to the maximum safe speed or the maximum representative speed. Engine speed and torque points shall be recorded at a sample rate of at least 1 Hz;

(d)

If a manufacturer believes that the above mapping techniques are unsafe or unrepresentative for any given engine, alternate mapping techniques may be used. These alternate techniques shall satisfy the intent of the specified mapping procedures to determine the maximum available torque at all engine speeds achieved during the test cycles. Deviations from the mapping techniques specified in this section for reasons of safety or representativeness shall be approved by the approval authority along with the justification for their use. In no case, however, the torque curve shall be run by descending engine speeds for governed or turbocharged engines;

(e)

An engine need not be mapped before each and every test cycle. An engine shall be remapped if:

(i)

an unreasonable amount of time has transpired since the last map, as determined by good engineering judgment; or

(ii)

physical changes or recalibrations have been made to the engine which potentially affect engine performance; or

(iii)

the atmospheric pressure near the engine's air inlet is not within ± 5 kPa of the value recorded at the time of the last engine map.

7.6.3. Engine mapping for constant-speed NRSC U.K.

The engine may be operated with a production constant-speed governor or a constant-speed governor maybe simulated by controlling engine speed with an operator demand control system. Either isochronous or speed-droop governor operation shall be used, as appropriate.

7.6.3.1. Rated power check for engines to be tested on cycles D2 or E2 U.K.

The following check shall be conducted:

(a)

With the governor or simulated governor controlling speed using operator demand the engine shall be operated at the rated speed and the rated power for as long as required to achieve stable operation;

(b)

The torque shall be increased until the engine is unable to maintain the governed speed. The power at this point shall be recorded. Before this check is performed the method to safely determine when this point has been reached shall be agreed between the manufacturer and the technical service conducting the check, depending upon the characteristics of the governor. [F1 The power recorded shall not exceed the rated power as defined in Article 3(27) of Regulation (EU) 2016/1628 by more than 12,5 %. If this value is exceeded the manufacturer shall revise the declared rated power.]

If the specific engine being tested is unable to perform this check due to risk of damage to the engine or dynamometer the manufacturer shall present to the approval authority robust evidence that maximum power does not exceed the rated power by more than 12,5 %.

7.6.3.2. Mapping procedure for constant-speed NRSC U.K.

(a)

With the governor or simulated governor controlling speed using operator demand, the engine shall be operated at no-load governed speed (at high speed, not low idle) for at least 15 seconds, unless the specific engine is unable to perform this task;

(b)

The dynamometer shall be used to increase torque at a constant rate. The map shall be conducted such that it takes no less than 2 min to sweep from no-load governed speed to the torque corresponding to rated power for engines to be tested on cycle D2 or E2 or to maximum torque in the case of other constant-speed test cycles. During the engine mapping actual speed and torque shall be recorded with at least 1 Hz;

(c)

In case of a constant-speed engine with a governor that can be reset to alternative speeds, the engine shall be tested at each applicable constant-speed.

For constant-speed engines good engineering judgment shall be used in agreement with the approval authority to apply other methods to record torque and power at the defined operating speed(s).

For engines tested on cycles other than D2 or E2, when both measured and declared values are available for the maximum torque, the declared value may be used instead of the measured value if it is between 95 and 100 % of the measured value.

7.7. Test cycle generation U.K.

7.7.1. Generation of NRSC U.K.

This point shall be used to generate the engine speeds and loads over which the engine shall be operated during steady-state tests with discrete-mode NRSC or RMC.

7.7.1.1. Generation of NRSC test speeds for engines tested with both NRSC and either NRTC or LSI-NRTC. U.K.

For engines that are tested with either NRTC or LSI-NRTC in addition to a NRSC, the MTS specified in point 5.2.5.1 shall be used as the 100 % speed for both transient and steady state tests.

The MTS shall be used in place of rated speed when determining intermediate speed in accordance with point 5.2.5.4.

The idle speed shall be determined in accordance with point 5.2.5.5.

7.7.1.2. Generation of NRSC test speeds for engines only tested with NRSC U.K.

For engines that are not tested with a transient (NRTC or LSI-NRTC) test cycle, the rated speed specified in point 5.2.5.3 shall be used as the 100 % speed.

The rated speed shall be used to determine the intermediate speed in accordance with point 5.2.5.4. If the NRSC specifies additional speeds as a percentage they shall be calculated as a percentage of the rated speed.

The idle speed shall be determined in accordance with point 5.2.5.5.

With prior approval of the technical service, MTS may be used instead of rated speed for the generation of test speeds in this point.

7.7.1.3. Generation of NRSC load for each test mode U.K.

The per cent load for each test mode of the chosen test cycle shall be taken from the appropriate NRSC Table of Appendix 1 or 2 of Annex XVII. Depending upon the test cycle, the per cent load in these Tables is expressed as either power or torque in accordance with point 5.2.6 and in the footnotes for each Table.

The 100 % value at a given test speed shall be the measured or declared value taken from the mapping curve generated in accordance with point 7.6.1, point 7.6.2 or point 7.6.3 respectively, expressed as power (kW).

The engine setting for each test mode shall be calculated by means of equation (6-14):

(6-14)

Where:

S

is the dynamometer setting in kW

P _max

is the maximum observed or declared power at the test speed under the test conditions (specified by the manufacturer) in kW

P _AUX

is the declared total power absorbed by auxiliaries as defined in equation (6-8) (see point 6.3.5) at the specified test speed in kW

L

is per cent torque

A warm minimum torque that is representative of in-use operation may be declared and used for any load point that would otherwise fall below this value if the engine type will not normally operate below this minimum torque, for example because it will be connected to a non-road mobile machinery that does not operate below a certain minimum torque.

In the case of cycles E2 and D2 the manufacturer shall declare the rated power and these shall be used as 100 % power when generating the test cycle.

7.7.2. Generation of NRTC & LSI-NRTC speed and load for each test point (denormalization) U.K.

This point shall be used to generate the corresponding engine speeds and loads over which the engine shall be operated during NRTC or LSI-NRTC tests. Appendix 3 of Annex XVII defines applicable test cycles in a normalized format. A normalized test cycle consists of a sequence of paired values for speed and torque %.

Normalized values of speed and torque shall be transformed using the following conventions:

(a)

The normalized speed shall be transformed into a sequence of reference speeds, n _ref, in accordance with point 7.7.2.2;

(b)

The normalized torque is expressed as a percentage of the mapped torque from the curve generated according to point 7.6.2 at the corresponding reference speed. These normalized values shall be transformed into a sequence of reference torques, T _ref, according to point 7.7.2.3;

(c)

The reference speed and reference torque values expressed in coherent units are multiplied to calculate the reference power values.

7.7.2.1. Reserved U.K.

7.7.2.2. Denormalization of engine speed U.K.

The engine speed shall be denormalized using by means of equation (6-15):

(6-15)

Where:

n _ref

is the reference speed

MTS

is the maximum test speed

n _idle

is the idle speed

%speed

is the value of NRTC or LSI-NRTC normalized speed taken from Appendix 3 of Annex XVII.

7.7.2.3 Denormalization of engine torque U.K.

The torque values in the engine dynamometer schedule of Appendix 3 of Annex XVII. are normalized to the maximum torque at the respective speed. The torque values of the reference cycle shall be denormalized, using the mapping curve determined according to point 7.6.2, by means of equation (6-16):

(6-16)

for the respective reference speed as determined in point 7.7.2.2

Where:

T _ref

is the reference torque for the respective reference speed

[F1 max.torque

is the maximum torque for the respective test speed taken from the engine mapping performed in accordance with point 7.6.2 adjusted where necessary in accordance with point 7.7.2.3(b)]

%torque

is the value of NRTC or LSI-NRTC normalized torque taken from Appendix 3 of Annex XVII

(a) Declared minimum torque U.K.

A minimum torque that is representative of in-use operation may be declared. For example, if the engine is typically connected to a non-road mobile machinery that does not operate below a certain minimum torque, this torque may be declared and used for any load point that would otherwise fall below this value.

(b) Adjustment of engine torque due to auxiliaries fitted for the emissions test U.K.

Where auxiliaries are fitted in accordance with Appendix 2 there shall be no adjustment to the maximum torque for the respective test speed taken from the engine mapping performed according to point 7.6.2.

Where, according to points 6.3.2 or 6.3.3 necessary auxiliaries that should have been fitted for the test are not installed, or auxiliaries that should have been removed for the test are installed, the value of T _max shall be adjusted by means of equation (6-17).

T max = T map – T AUX

(6-17)

with:

TAUX = Tr – Tf

(6-18)

where:

T _map

is the unadjusted maximum torque for the respective test speed taken from the engine mapping performed in accordance with point 7.6.2

T _f

is the torque required to drive auxiliaries that should have been fitted but were not installed for the test

Tr

is the torque required to drive auxiliaries that should have been removed for the test but were installed for the test

7.7.2.4. Example of denormalization procedure U.K.

As an example, the following test point shall be denormalized:

• % speed = 43 %

• % torque = 82 %

Given the following values:

• MTS = 2 200 min^{– 1}

• n _idle = 600 min^{– 1}

results in

With the maximum torque of 700 Nm observed from the mapping curve at 1 288 min^–1

7.8. Specific test cycle running procedure U.K.

7.8.1. Emission test sequence for discrete-mode NRSC U.K.

7.8.1.1. Engine warming-up for steady state discrete-mode NRSC U.K.

Pre-test procedure according to point 7.3.1 shall be performed, including analyzer calibration. The engine shall be warmed-up using the pre-conditioning sequence in point 7.3.1.1.3. Immediately from this engine conditioning point, the test cycle measurement starts.

7.8.1.2. Performing discrete-mode NRSC U.K.

(a)

The test shall be performed in ascending order of mode numbers as set out for the test cycle (see Appendix 1 of Annex XVII);

(b)

[F1 Each mode has a mode length of at least 10 minutes. In each mode the engine shall be stabilised for at least 5 minutes. Gaseous emissions, and, where applicable, PN, shall be sampled for 1 to 3 minutes at the end of each mode and PM emissions shall be sampled in accordance with point (c);

Notwithstanding the previous paragraph, when either testing spark ignition engines using cycles G1, G2 or G3 or when conducting measurements in accordance with Annex V of this Regulation each mode has a mode length of at least 3 minutes. In this case gaseous emissions, and, where applicable, PN, shall be sampled for at least the last 2 minutes of each mode and PM emissions shall be sampled in accordance with point (c). The mode length and sampling time may be extended to improve accuracy;

The mode length shall be recorded and reported.]

(c)

[F1 For PM emissions, the PM sampling may be done either with the single filter method or with the multiple filter method. Since the results of the methods may differ slightly, the method used shall be declared with the results;]

For the single filter method the modal weighting factors specified in the test cycle procedure and the actual exhaust gas flow shall be taken into account during sampling by adjusting sample flow rate and/or sampling time, accordingly. It is required that the effective weighing factor of the PM sampling is within ± 0,005 of the weighing factor of the given mode;

Sampling shall be conducted as late as possible within each mode. For the single filter method, the completion of PM sampling shall be coincident within ± 5 s with the completion of the gaseous emission measurement. The sampling time per mode shall be at least 20 s for the single filter method and at least 60 s for the multi-filter method. For systems without bypass capability, the sampling time per mode shall be at least 60 s for single and multiple filter methods;

(d)

The engine speed and load, intake air temperature, fuel flow and where applicable air or exhaust gas flow shall be measured for each mode at the same time interval which is used for the measurement of the gaseous concentrations;

Any additional data required for calculation shall be recorded.

(e)

If the engine stalls or the emission sampling is interrupted at any time after emission sampling begins for a discrete-mode NRSC and the single filter method, the test shall be voided and be repeated beginning with the engine warm-up procedure. In the case of PM measurement utilizing the multi-filter method (one sampling filter for each operating mode), the test shall be continued by stabilizing the engine at the previous mode for engine temperature conditioning and then initiating measurement with the mode where the engine stalled;

(f)

Post-test procedures according to point 7.3.2 shall be performed.

7.8.1.3. Validation criteria U.K.

During each mode of the given steady-state test cycle after the initial transition period, the measured speed shall not deviate from the reference speed for more than ± 1 % of rated speed or ± 3 min^{– 1}, whichever is greater except for idle which shall be within the tolerances declared by the manufacturer. The measured torque shall not deviate from the reference torque for more than ± 2 % of the maximum torque at the test speed.

7.8.2. Emission test sequence for RMC U.K.

7.8.2.1. Engine warming-up U.K.

Pre-test procedure according to point 7.3.1 shall be performed, including analyzer calibration. The engine shall be warmed-up using the pre-conditioning sequence in point 7.3.1.1.4. Immediately after this engine conditioning procedure, if the engine speed and torque are not already set for the first mode of the test they shall be changed in a linear ramp of 20 ± 1 s to the first mode of the test. In between 5 to 10 s after the end of the ramp, the test cycle measurement shall start.

7.8.2.2. Performing an RMC U.K.

The test shall be performed in the order of mode numbers as set out for the test cycle (see Appendix 2 of Annex XVII) Where there is no RMC available for the specified NRSC the discrete-mode NRSC procedure set out in point 7.8.1 shall be followed.

The engine shall be operated for the prescribed time in each mode. The transition from one mode to the next shall be done linearly in 20 s ± 1 s following the tolerances prescribed in point 7.8.2.4.

For RMC, reference speed and torque values shall be generated at a minimum frequency of 1 Hz and this sequence of points shall be used to run the cycle. During the transition between modes, the denormalized reference speed and torque values shall be linearly ramped between modes to generate reference points. The normalized reference torque values shall not be linearly ramped between modes and then denormalized. If the speed and torque ramp runs through a point above the engine's torque curve, it shall be continued to command the reference torques and it shall be allowed for the operator demand to go to maximum.

Over the whole RMC (during each mode and including the ramps between the modes), the concentration of each gaseous pollutant shall be measured and where there is an applicable limit the PM and PN be sampled. The gaseous pollutants may be measured raw or diluted and be recorded continuously; if diluted, they can also be sampled into a sampling bag. The particulate sample shall be diluted with conditioned and clean air. One sample over the complete test procedure shall be taken, and, in the case of PM collected on a single PM sampling filter.

For calculation of the brake specific emissions, the actual cycle work shall be calculated by integrating actual engine power over the complete cycle.

7.8.2.3. Emission test sequence U.K.

(a)

Execution of the RMC, sampling exhaust gas, recording data, and integrating measured values shall be started simultaneously;

(b)

Speed and torque shall be controlled to the first mode in the test cycle;

(c)

If the engine stalls anywhere during the RMC execution, the test shall be voided. The engine shall be pre-conditioned and the test repeated;

(d)

At the end of the RMC, sampling shall be continued, except for PM sampling, operating all systems to allow system response time to elapse. Then all sampling and recording shall be stopped, including the recording of background samples. Finally, any integrating devices shall be stopped and the end of the test cycle shall be indicated in the recorded data;

(e)

Post-test procedures according to point 7.3.2 shall be performed.

7.8.2.4. Validation criteria U.K.

RMC tests shall be validated using the regression analysis as described in points 7.8.3.3 and 7.8.3.5. The allowed RMC tolerances are given in the following Table 6.1. Note that the RMC tolerances are different from the NRTC tolerances of Table 6.2. [F1 When conducting testing of engines of reference power greater than 560 kW the regression line tolerances of Table 6.2 and the point deletion of Table 6.3 may be used.]

Table 6.1

RMC Regression line tolerances

	Speed	Torque	Power
Standard error of estimate (SEE) of y on x	maximum 1 % of rated speed	maximum 2 % of maximum engine torque	maximum 2 % of maximum engine power
Slope of the regression line, a 1	0,99 to 1,01	0,98 - 1,02	0,98 - 1,02
Coefficient of determination, r 2	minimum 0,990	minimum 0,950	minimum 0,950
y intercept of the regression line, a 0	± 1 % of rated speed	± 20 Nm or 2 % of maximum torque whichever is greater	± 4 kW or 2 % of maximum power whichever is greater

In case of running the RMC test not on a transient test bed, where the second by second speed and torque values are not available, the following validation criteria shall be used.

At each mode the requirements for the speed and torque tolerances are given in point 7.8.1.3. For the 20 s linear speed and linear torque transitions between the RMC steady-state test modes (point 7.4.1.2) the following tolerances for speed and load shall be applied for the ramp:

(a)

the speed shall be held linear within ± 2 % of rated speed,

(b)

the torque shall be held linear within ± 5 % of the maximum torque at rated speed.

7.8.3. Transient (NRTC and LSI-NRTC) test cycles U.K.

Reference speeds and torques commands shall be sequentially executed to perform the NRTC and LSI-NRTC. Speed and torque commands shall be issued at a frequency of at least 5 Hz. Because the reference test cycle is specified at 1 Hz, the in between speed and torque commands shall be linearly interpolated from the reference torque values generated from cycle generation.

Small denormalized speed values near warm idle speed may cause low-speed idle governors to activate and the engine torque to exceed the reference torque even though the operator demand is at a minimum. In such cases, it is recommended to control the dynamometer so it gives priority to follow the reference torque instead of the reference speed and let the engine govern the speed.

Under cold-start conditions engines may use an enhanced-idle device to quickly warm up the engine and the exhaust after-treatment system. Under these conditions, very low normalized speeds will generate reference speeds below this higher enhanced idle speed. In this case it is recommended controlling the dynamometer so it gives priority to follow the reference torque and let the engine govern the speed when the operator demand is at minimum.

During an emission test, reference speeds and torques and the feedback speeds and torques shall be recorded with a minimum frequency of 1 Hz, but preferably of 5 Hz or even 10 Hz. This larger recording frequency is important as it helps to minimize the biasing effect of the time lag between the reference and the measured feedback speed and torque values.

The reference and feedback speeds and torques maybe recorded at lower frequencies (as low as 1 Hz), if the average values over the time interval between recorded values are recorded. The average values shall be calculated based on feedback values updated at a frequency of at least 5 Hz. These recorded values shall be used to calculate cycle-validation statistics and total work.

7.8.3.1. Performing an NRTC test U.K.

Pre-test procedures according to point 7.3.1 shall be performed, including pre-conditioning, cool-down and analyzer calibration.

Testing shall be started as follows:

• The test sequence shall commence immediately after the engine has started from cooled down condition specified in point 7.3.1.2 in case of the cold-start NRTC or from hot soak condition in case of the hot-start NRTC. The sequence in point 7.4.2.1 shall be followed.

• Data logging, sampling of exhaust gas and integrating measured values shall be initiated simultaneously at the start of the engine. The test cycle shall be initiated when the engine starts and shall be executed according to the schedule of Appendix 3 of Annex XVII.

• At the end of the cycle, sampling shall be continued, operating all systems to allow system response time to elapse. Then all sampling and recording shall be stopped, including the recording of background samples. Finally, any integrating devices shall be stopped and the end of the test cycle shall be indicated in the recorded data.

Post-test procedures according to point 7.3.2 shall be performed.

7.8.3.2. Performing an LSI-NRTC test U.K.

Pre-test procedures according to point 7.3.1 shall be performed, including pre-conditioning and analyzer calibration.

Testing shall be started as follows:

• The test shall commence according to the sequence given in point 7.4.2.2.

• Data logging, sampling of exhaust gas and integrating measured values shall be initiated simultaneously with the start of the LSI-NRTC at the end of the 30-second idle period specified in point 7.4.2.2(b). The test cycle shall be executed according to the schedule of Appendix 3 of Annex XVII.

• At the end of the cycle, sampling shall be continued, operating all systems to allow system response time to elapse. Then all sampling and recording shall be stopped, including the recording of background samples. Finally, any integrating devices shall be stopped and the end of the test cycle shall be indicated in the recorded data.

Post-test procedures according to point 7.3.2 shall be performed.

7.8.3.3. Cycle validation criteria for transient (NRTC and LSI-NRTC) test cycles U.K.

In order to check the validity of a test, the cycle-validation criteria in this point shall be applied to the reference and feedback values of speed, torque, power and overall work.

7.8.3.4. Calculation of cycle work U.K.

Before calculating the cycle work, any speed and torque values recorded during engine starting shall be omitted. Points with negative torque values have to be accounted for as zero work. The actual cycle work W _act (kWh) shall be calculated based on engine feedback speed and torque values. The reference cycle work W _ref (kWh) shall be calculated based on engine reference speed and torque values. The actual cycle work W _act is used for comparison to the reference cycle work W _ref and for calculating the brake specific emissions (see point 7.2).

W _act shall be between 85 % and 105 % of W _ref.

7.8.3.5. Validation statistics (see Appendix 2 of Annex VII) U.K.

Linear regression between the reference and the feedback values shall be calculated for speed, torque and power.

To minimize the biasing effect of the time lag between the reference and feedback cycle values, the entire engine speed and torque feedback signal sequence may be advanced or delayed in time with respect to the reference speed and torque sequence. If the feedback signals are shifted, both speed and torque shall be shifted by the same amount in the same direction.

The method of least squares shall be used, with the best-fit equation having the form set out in equation (6-19):

y = a 1 x + a 0

(6-19)

where:

y

is the feedback value of speed (min^{– 1}), torque (Nm), or power (kW)

a ₁

is the slope of the regression line

x

is the reference value of speed (min^{– 1}), torque (Nm), or power (kW)

a ₀

is the y intercept of the regression line.

The standard error of estimate (SEE) of y on x and the coefficient of determination (r ²) shall be calculated for each regression line in accordance with Appendix 3 of Annex VII.

It is recommended that this analysis be performed at 1 Hz. For a test to be considered valid, the criteria of Table 6.2 shall be met.

Table 6.2

Regression line tolerances

	Speed	Torque	Power
Standard error of estimate (SEE) of y on x	≤ 5,0 percent of maximum test speed	≤ 10,0 % of maximum mapped torque	≤ 10,0 % of maximum mapped power
Slope of the regression line, a 1	0,95 to 1,03	0,83 - 1,03	0,89 - 1,03
Coefficient of determination, r 2	minimum 0,970	minimum 0,850	minimum 0,910
y intercept of the regression line, a 0	≤ 10 % of idle	± 20 Nm or ± 2 % of maximum torque whichever is greater	± 4 kW or ± 2 % of maximum power whichever is greater

For regression purposes only, point deletions are permitted where noted in Table 6.3 before doing the regression calculation. However, those points shall not be deleted for the calculation of cycle work and emissions. An idle point is defined as a point having a normalized reference torque of 0 % and a normalized reference speed of 0 %. Point deletion may be applied to the whole or to any part of the cycle; points to which the point deletion is applied have to be specified.

[F1 Table 6.3

Permitted point deletions from regression analysis

Where: n ref is the reference speed (see section 7.7.2.), n idle is the idle speed, n act is the actual (measured) speed, T ref is the reference torque (see section 7.7.2.), T act is the actual (measured) torque, T maxmappedtorque is the highest value of torque on the full-load torque curve mapped in accordance with section 7.6.]
Event	Conditions ( n = engine speed, T = torque)	Permitted point deletions
Minimum operator demand (idle point)	n ref = n idle and T ref = 0 % and T act > ( T ref – 0,02 T maxmappedtorque ) and T act < ( T ref + 0,02 T maxmappedtorque )	speed and power
Minimum operator demand	n act ≤ 1,02 n ref and T act > T ref or n act > n ref and T act ≤ T ref' or n act > 1,02 n ref and T ref < T act ≤ ( T ref + 0,02 T maxmappedtorque )	power and either torque or speed
Maximum operator demand	n act < n ref and T act ≥ T ref or n act ≥ 0,98 n ref and T act < T ref or n act < 0,98 n ref and T ref > T act ≥ ( T ref – 0,02 T maxmappedtorque )	power and either torque or speed