Commission Delegated Regulation (EU) No 134/2014Show full title

Appendix 2.3 Determination of the maximum torque and maximum net power of L-category vehicles equipped with a compression ignition engine

1. Accuracy of the measurement of full load torque and power

1.1. Torque: ± 1 % of measured torque

1.2. Engine speed

The measurement shall be accurate to within ± 1 % of the full-scale reading. Engine speed shall be measured preferably with an automatically synchronised revolution counter and chronometer (or counter-timer).

1.3. Fuel consumption: ± 1 % of measured consumption.

1.4. Fuel temperature: ± 2 K.

1.5. Engine inlet air temperature: ± 2 K.

1.6. Barometric pressure: ± 100 Pa.

1.7. Pressure in inlet manifold(1): ± 50 Pa.

1.8. Pressure in vehicle exhaust pipe: 200 Pa.

2. Tests to measure the maximum torque and maximum net engine power

2.1. Accessories

2.1.1. Accessories to be fitted

During the test it is possible to locate the accessories needed for operation of the engine in the application in question (as referred to in Table Ap2.3-1 on the test bench as far as possible in the positions that they would occupy for that application.

2.1.2.

Table Ap2.3-1

Accessories to be fitted during the propulsion unit performance test in order to determine torque and net engine power

a The complete air intake system shall be fitted as provided for the intended application: where there is a risk of an appreciable effect on the engine power, in the case of two-stroke engines, when the manufacturer requests that this should be done. In other cases, an equivalent system may be used and a check should be made to ascertain that the intake pressure does not differ by more than 100 Pa from the limit specified by the manufacturer for a clean air filter.
b The complete exhaust system shall be fitted as provided for the intended application: where there is a risk of an appreciable effect on the engine power, in the case of two-stroke engines, when the manufacturer requests that this should be done. In other cases an equivalent system may be installed provided the pressure measured at the exit of the engine exhaust system does not differ by more than 1 000 Pa from that specified by the manufacturer. The exit of the engine exhaust system is defined as a point 150 mm downstream from the termination of the part of the exhaust system mounted on the engine.
c If an exhaust brake is incorporated in the engine, the throttle valve shall be held in the fully open position.
d The fuel-feed pressure may be adjusted, if necessary, to reproduce the pressures existing in the particular engine application (particularly when a ‘fuel-return’ system is used).
e The air-intake valve is the control valve for the pneumatic governor of the injection pump. The governor or the fuel-injection equipment may contain devices which can affect the amount of injected fuel.
f The radiator, fan, fan nozzle, water pump and thermostat shall, on the test bench, occupy as far as possible the same position relative to each other as if they were on the vehicle. If any of them have a position on the test bench which is different from that on the vehicle, this shall be described and noted in the test report. The cooling-liquid circulation shall be operated by the engine water pump only. Cooling of the liquid may be produced either by the engine radiator or by an external circuit, provided that the pressure loss of this circuit and the pressure at the pump inlet remain substantially the same as those of the engine cooling system. The radiator shutter, if incorporated, shall be in the open position. Where the fan, radiator and cowl system cannot conveniently be fitted to the engine, the power absorbed by the fan when separately mounted in its correct position in relation to the radiator and cowl (if used) shall be determined at the speeds corresponding to the engine speeds used for measurement of the engine power either by calculation from standard characteristics or by practical tests. This power, corrected to the standard atmospheric conditions defined in point 4.2, shall be deducted from the corrected power.
g Where a disconnectable or progressive fan or blower is incorporated, the test shall be carried out with the disconnectable fan (or blower) disconnected or with the progressive fan or blower running at maximum slip.
h Minimum power of the generator: the power of the generator shall be no more than that required to operate accessories which are indispensable for the operation of the engine. If the connection of a battery is necessary, a fully-charged battery in good order shall be used.
No	Accessories	Fitted for the torque and net power test
1	Air intake system Induction manifold Air filtera Induction silencer Crankcase emission-control system Electrical control device, where fitted	If series-mounted: yes
2	Induction manifold heater	If series-mounted: yes (if possible, it shall be set in the most favourable position)
3	Exhaust system Exhaust purifier Exhaust manifold Pipe workb Silencerb Exhaust pipeb Exhaust brakec Electrical control device, where fitted	If series-mounted: yes
5	Fuel injection system Upstream filter Filter Fuel supply pumpd and high pressure pump if applicable High-pressure lines Injector Air intake valvee, where fitted Fuel pressure / flow regulator, where fitted	If series-mounted: yes
6	Maximum rotational speed-or power governorsa	If series-mounted: yes
7	Liquid-cooling equipment Engine bonnet Bonnet air outlet Radiator Fanc Fan cowl Water pump Thermostatd	If series-mounted: yese
8	Air cooling Cowl Blowerf g Cooling temperature-regulating device(s) Auxiliary bench blower	If series-mounted: yes
9	Electrical equipment	If series-mounted: yesh
10	Super-charger or turbocharger, where fitted Compressor driven directly by the engine or by the exhaust gases Charge air coolerb Coolant pump or fan (engine driven) Coolant flow control device, where fitted.	If series-mounted: yes
11	Pollution-control devicesg	If series-mounted: yes
12	Lubrication system Oil feeder Oil cooler, where fitted.	If series-mounted: yes

2.1.3. Accessories to be removed

Certain vehicle accessories necessary only for the operation of the vehicle and which may be mounted on the engine shall be removed for the test.

The following non-exhaustive list is given as an example:

• air compressor for brakes,

• power-steering compressor,

• suspension compressor,

• air-conditioning system.

Where accessories cannot be removed, the power absorbed by them in the unloaded condition may be determined and added to the measured engine power.

2.1.4. Compression-ignition engine starting accessories

For the accessories used in starting compression-ignition engines, the two following cases shall be considered:

(a)

electrical starting: the generator is fitted and supplies, where necessary, the accessories indispensable to the operation of the engine;

(b)

starting other than electrical: if there are any electrically-operated accessories indispensable to the operation of the engine, the generator is fitted to supply these accessories. Otherwise it is removed.

In either case, the system for producing and accumulating the energy necessary for starting is fitted and operated in the unloaded condition.

2.2. Setting conditions

The conditions applying to settings during the tests to determine maximum torque and maximum net power are set out in Table Ap2.3-2.

Table Ap2.3-2

Setting conditions

1	Setting of injection pump delivery system	Setting carried out in accordance with the manufacturer’s specifications for series production applied, without any other change, to the use under consideration
2	Ignition or injection setting (timing curve)
3	(Electronic) Throttle control
4	Any other rotational speed governor setting
5	(Noise and tailpipe) emission abatement system settings and devices

2.3. Test conditions

2.3.1. The maximum-torque and net-power tests shall be conducted at full load fuel-injection pump setting, the engine being equipped as specified in Table Ap2.3-1.

2.3.2. The measurements shall be carried out under normal, stabilised operating conditions with an adequate fresh-air supply to the engine. The engine shall have been run in accordance with the manufacturer’s recommendations. Combustion chambers may contain deposits, but in limited quantities.

2.3.3. The test conditions selected, such as air inlet temperature, shall resemble reference conditions (see point 3.2.) as closely as possible in order to minimise the magnitude of the correction factor.

2.3.4. The temperature of the (ambient) inlet air to the engine shall be measured at no more than 0,15 m upstream from the point of entry into the air cleaner or, if no air cleaner is used, within 0,15 m of the air-inlet trumpet. The thermometer or thermocouple shall be shielded from radiant heat and be placed directly in the airstream. It shall also be shielded from fuel spray-back.

A sufficient number of locations shall be used to give a representative average inlet temperature.

2.3.7. No data shall be taken until torque, speed and temperature have remained substantially constant for at least 30 seconds.

2.3.8. The engine speed during a run or reading shall not deviate from the selected speed by more than ± 1 % or ± 10 min^–1, whichever is greater.

2.3.9. Observed brake-load and inlet-air temperature data shall be taken simultaneously and shall be the average of two stabilised consecutive values. In the case of the brake load, these values shall not vary more than 2 %.

2.3.10. The temperature of the coolant at the outlet from the engine shall be kept within ± 5 K of the upper thermostatically controlled temperature specified by the manufacturer. If no temperature is specified by the manufacturer, the temperature shall be 353,2 ± 5 K.

For air-cooled engines, the temperature at a point indicated by the manufacturer shall be kept between + 0 / – 20 K of the maximum temperature specified by the manufacturer under the reference conditions.

2.3.11. The fuel temperature shall be measured at the inlet of the injection system and maintained within the limits set by the manufacturer.

2.3.12. The temperature of the lubricating oil measured in the oil sump or at the outlet from the oil cooler, if fitted, shall be maintained within the limits established by the engine manufacturer.

2.3.13. The outlet temperature of the exhaust gases shall be measured at right angles to the exhaust flange(s), manifold(s) or orifices.

2.3.14. An auxiliary regulating system may be used if necessary to maintain the temperature within the limits specified in points 2.3.10., 2.3.11 and 2.3.12.

2.3.15. Where an automatically triggered device is used to measure engine speed and consumption, the measurement shall last at least ten seconds; if the measuring device is manually controlled, it shall measure for at least 20 seconds.

2.3.16. Test fuel

The test fuel to be used shall be the reference fuel referred to in Appendix 2 of Annex II.

2.3.17. If it is not possible to use the standard exhaust silencer for the test, a device shall be used that is compatible with the engine’s normal operating conditions, and specified by the manufacturer.

During the laboratory tests in particular, when the engine is running, the exhaust gas extractor shall not, at the point where the exhaust system is connected to the test bench, give rise in the exhaust-gas extraction duct to a pressure differing from the atmospheric pressure by more than ± 740 Pa (7,4 mbar) unless the manufacturer has deliberately specified the back pressure existing before the test; in this case, the lower of the two pressures shall be used.

2.4. Test procedure

Measurements shall be taken at a sufficient number of engine speeds to define correctly the complete power curve between the lowest and the highest engine speeds recommended by the manufacturer. This range of speeds shall include the speeds of revolution at which the engine produces its maximum torque and at which it produces its maximum power. For each speed, the average of at least two stabilised measurements is to be determined.

2.5. Measurement of smoke index

In the case of compression-ignition engines, the exhaust gases shall be examined during the test for compliance with the requirements for test type II.

2.6. Data to be recorded

The data to be recorded are those set out in the template of the test report referred to in Article 32(1) of Regulation (EU) No 168/2013.

3. Power and torque correction factors

3.1. Definition of factors α_d and α₂

3.1.1. α_d and α₂ shall be factors by which the torque and power measured are to be multiplied in order to determine the torque and power of an engine, taking account of the efficiency of the transmission (factor α2) used during the tests and in order to bring them within the reference atmospheric conditions specified in point 3.2.1 (factor α_d). The power correction formula is as follows:

Equation Ap2.3-1:

where:

P₀

=

the corrected power (i.e. the power under the reference conditions at the end of the crankshaft);

α_d

=

the correction factor for reference atmospheric conditions;

α₂

=

the correction factor for the efficiency of the transmission (see point 3.4 of Appendix 2.2.);

P

=

the power measured (power observed).

3.2. Reference atmospheric conditions

3.2.1. Temperature: 298,2 K (25 °C)

3.2.2. Dry reference pressure (p_so): 99 kPa (990 mbar)

Note: the dry reference pressure is based on a total pressure of 100 kPa and a water vapour pressure of 1 kPa.

3.2.3. Atmospheric test conditions

3.2.3.1. During the test, the atmospheric conditions shall lie within the following range:

• 283,2 K < T < 318,2 K

• 80 kPa ≤ p_s ≤ 110 kPa

where:

T

=

test temperature (K);

p_s

=

the dry atmospheric pressure in kilopascals (kPa), i.e. the total barometric pressure minus the water vapour pressure.

3.3. Determination of the correction factor α_d (2)

Equation Ap2.3-2:

The power correction factor (α_d) for compression-ignition engines at constant fuel rate is obtained by applying the formula:

where:

f_a

=

the atmospheric factor

f_m

=

the characteristic parameter for each type of engine and adjustment.

3.3.1. Atmospheric factor f_a

This factor indicates the effects of environmental conditions (pressure, temperature and humidity) on the air drawn in by the engine. The atmospheric factor formula differs according to type of engine.

3.3.1.1. Naturally aspirated and mechanically supercharged engines

Equation Ap2.3-3:

where:

T

=

the absolute temperature of the ingested air (K)

p_s

=

the dry atmospheric pressure in kilopascals (kPa), i.e. the total barometric pressure minus the water vapour pressure.

3.3.1.2. Turbocharger engines or without cooling of inlet air

Equation Ap2.3-4:

3.3.2. Engine factor f_m

f_m is a function of q_c (fuel flow corrected) as follows:

Equation Ap2.3-5:

where:

Equation Ap2.3-6:

where:

q

=

the fuel flow in milligrams per cycle per litre of total swept volume (mg/(litre ·cycle))

r

=

the pressure ratio of compressor outlet and compressor inlet (r = 1 for naturally aspirated engines

3.3.2.1. This formula is valid for a value interval of q_c included between 40 mg/(litre · cycle) and 65 mg/(litre · cycle).

For q_c values lower than 40 mg/(litre · cycle), a constant value of f_m equal to 0.3 (f_m = 0.3) will be taken.

For q_c values higher than 65 mg/(litre · cycle), a constant value of fm equal to 1.2 = (f_m = 1.2) will be taken (see the figure).

3.3.2.2.

Figure Ap2.3-1

Characteristic parameter f_m for each type of engine and adjustment as function of corrected fuel flow

3.3.3. Conditions to be complied with in the laboratory

For a test to be valid, the correction factor αd shall be such that:

0,9 α_d ≤ 1.1

If these limits are exceeded, the corrected value obtained shall be given and the test conditions (temperature and pressure) stated precisely in the test report.

4. Measuring maximum torque and maximum net power tolerances

The tolerances set out in point 4 of Appendix 2.2 shall apply.

(1)

The complete air intake system shall be fitted as provided for the intended application:

• where there is a risk of an appreciable effect on the engine power,

• in the case of two-stroke engines,

• when the manufacturer requests that this should be done. In other cases, an equivalent system may be used and a check should be made to ascertain that the intake pressure does not differ by more than 100 Pa from the limit specified by the manufacturer for a clean air filter.

(2)

Minimum power of the generator: the power of the generator shall be no more than that required to operate accessories which are indispensable for the operation of the engine. If the connection of a battery is necessary, a fully-charged battery in good order shall be used.