1.1. Determination of engine speeds A, B and C

Directive 2005/55/EC of the European Parliament and of the Council of 28 September 2005 on the approximation of the laws of the Member States relating to the measures to be taken against the emission of gaseous and particulate pollutants from compression-ignition engines for use in vehicles, and the emission of gaseous pollutants from positive-ignition engines fuelled with natural gas or liquefied petroleum gas for use in vehicles (Text with EEA relevance) · European Union

The engine speeds A, B and C shall be declared by the manufacturer in accordance with the following provisions: The high speed nhi shall be determined by calculating 70 % of the declared maximum net power P(n), as determined in Annex II, Appendix 1, Section 8.2. The highest engine speed where this power value occurs on the power curve is defined as nhi. The low speed nlo shall be determined by calculating 50 % of the declared maximum net power P(n), as determined in Annex II, Appendix 1, Section 8.2. The lowest engine speed where this power value occurs on the power curve is defined as nlo. The engine speeds A, B and C shall be calculated as follows: The engine speeds A, B and C may be verified by either of the following methods: additional test points shall be measured during engine power approval according to Directive 80/1269/EEC for an accurate determination of nhi and nlo. The maximum power, nhi and nlo shall be determined from the power curve, and engine speeds A, B and C shall be calculated according to the above provisions; the engine shall be mapped along the full load curve, from maximum no load speed to idle speed, using at least 5 measurement points per 1 000 rpm intervals and measurement points within ± 50 rpm of the speed at declared maximum power. The maximum power, nhi and nlo shall be determined from this mapping curve, and engine speeds A, B and C shall be calculated according to the above provisions. If the measured engine speeds A, B and C are within ± 3 % of the engine speeds as declared by the manufacturer, the declared engine speeds shall be used for the emissions test. If the tolerance is exceeded for any of the engine speeds, the measured engine speeds shall be used for the emissions test.

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Source: EUR-Lex (Cellar) · retrieved 2026-11-01 · Text as adopted (Official Journal); later amendments are not incorporated in this text.