Directive 2005/55/EC of the European Parliament and of the Council (repealed)Show full title

8. ENGINE FAMILY

8.1. Parameters defining the engine family

The engine family, as determined by the engine manufacturer, may be defined by basic characteristics which must be common to engines within the family. In some cases there may be interaction of parameters. These effects must also be taken into consideration to ensure that only engines with similar exhaust emission characteristics are included within an engine family.

In order that engines may be considered to belong to the same engine family, the following list of basic parameters must be common:

8.1.1. Combustion cycle:

• 2 cycle

• 4 cycle

8.1.2. Cooling medium:

• air

• water

• oil

8.1.3. For gas engines and engines with aftertreatment:

• number of cylinders

(other diesel engines with fewer cylinders than the parent engine may be considered to belong to the same engine family provided the fuelling system meters fuel for each individual cylinder)

8.1.4. Individual cylinder displacement:

• engines to be within a total spread of 15 %

8.1.5. Method of air aspiration:

• naturally aspirated

• pressure charged

• pressure charged with charge air cooler

8.1.6. Combustion chamber type/design:

• pre-chamber

• swirl chamber

• open chamber

8.1.7. Valve and porting — configuration, size and number:

• cylinder head

• cylinder wall

• crankcase

8.1.8. Fuel injection system (diesel engines):

• pump-line-injector

• in-line pump

• distributor pump

• single element

• unit injector

8.1.9. Fuelling system (gas engines):

• mixing unit

• gas induction/injection (single point, multi-point)

• liquid injection (single point, multi-point)

8.1.10. Ignition system (gas engines)

8.1.11. Miscellaneous features:

• exhaust gas recirculation

• water injection/emulsion

• secondary air injection

• charge cooling system

8.1.12. Exhaust aftertreatment:

• 3-way-catalyst

• oxidation catalyst

• reduction catalyst

• thermal reactor

• particulate trap

8.2. Choice of the parent engine

8.2.1. Diesel engines

The parent engine of the family shall be selected using the primary criteria of the highest fuel delivery per stroke at the declared maximum torque speed. In the event that two or more engines share this primary criteria, the parent engine shall be selected using the secondary criteria of highest fuel delivery per stroke at rated speed. Under certain circumstances, the approval authority may conclude that the worst case emission rate of the family can best be characterised by testing a second engine. Thus, the approval authority may select an additional engine for test based upon features which indicate that it may have the highest emission level of the engines within that family.

If engines within the family incorporate other variable features which could be considered to affect exhaust emissions, these features shall also be identified and taken into account in the selection of the parent engine.

8.2.2. Gas engines

The parent engine of the family shall be selected using the primary criteria of the largest displacement. In the event that two or more engines share this primary criteria, the parent engine shall be selected using the secondary criteria in the following order:

• the highest fuel delivery per stroke at the speed of declared rated power;

• the most advanced spark timing;

• the lowest EGR rate;

• no air pump or lowest actual air flow pump.

Under certain circumstances, the approval authority may conclude that the worst case emission rate of the family can best be characterised by testing a second engine. Thus, the approval authority may select an additional engine for test based upon features which indicate that it may have the highest emission level of the engines within that family.