Document ID: chunk:federal_register_of_legislation:F2023C00229:reg:4:p22
Version: federal_register_of_legislation:F2023C00229
Segment Type: reg
Provision Reference: reg 4 (pt 22/42)
Character Range: 62165–65280

maximum power occurs;

2.19.                          'high speed (nhi)' means the highest engine speed where 70 % of the declared maximum power occurs;

2.20.                          'engine speeds A, B and C' means the test speeds within the engine operating speed range to be used for the ESC test and the ELR test, as set out in Annex III, Appendix 1 to this Directive;

2.21.                          'control area' means the area between the engine speeds A and C and between 25 to 100 per cent load;

2.22.                          'reference speed (nref)' means the 100 per cent speed value to be used for denormalising the relative speed values of the ETC test, as set out in Annex III, Appendix 2 to this Directive;

2.23.                          'opacimeter' means an instrument designed to measure the opacity of smoke particles by means of the light extinction principle;

2.24.                          'NG gas range' means one of the H or L range as defined in European Standard EN 437, dated November 1993;

2.25.                          'self adaptability' means any engine device allowing the air/fuel ratio to be kept constant;

2.26.                          'recalibration' means a fine tuning of an NG engine in order to provide the same performance (power, fuel consumption) in a different range of natural gas;

2.27.                          'Wobbe Index (lower Wl; or upper Wu)' means the ratio of the corresponding calorific value of a gas per unit volume and the square root of its relative density under the same reference conditions:

2.28.                          'λ-shift factor (Sλ)' means an expression that describes the required flexibility of the engine management system regarding a change of the excess-air ratio λ if the engine is fuelled with a gas composition different from pure methane (see Annex VII for the calculation of Sλ);

2.29.                          'defeat device' means a device which measures, senses or responds to operating variables (e.g. vehicle speed, engine speed, gear used, temperature, intake pressure or any other  parameter)  for  the  purpose  of  activating, modulating, delaying or deactivating the operation of any component or  function  of  the  emission control system such that the effectiveness of the emission control system is reduced under  conditions encountered during normal vehicle use unless the use of such a device is substantially included    in the applied emission certification test procedures.

        Figure 1

        Specific definitions of the test cycles

2.30.                          'auxiliary control device' means a system, function or control strategy installed to an engine or on a vehicle, that is used to protect the engine and/or its ancillary equipment against operating conditions that could result in damage or failure, or is used to facilitate engine starting. An auxiliary control device may also be   a strategy or measure that has been satisfactorily demonstrated not to be a defeat device;

2.31.                          'irrational emission control strategy' means any strategy