(iii)

Commission Directive 2005/78/EC of 14 November 2005 implementing Directive 2005/55/EC of the European Parliament and of the Council 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 and amending Annexes I, II, III, IV and VI thereto (Text with EEA relevance) · European Union

The following new section 4 is inserted: ‘4. CALCULATION OF THE EXHAUST GAS FLOW 4.1. Determination of Raw Exhaust Gas Mass Flow For calculation of the emissions in the raw exhaust, it is necessary to know the exhaust gas flow. The exhaust gas mass flow rate shall be determined in accordance with section 4.1.1 or 4.1.2. The accuracy of exhaust flow determination shall be ± 2,5 % of reading or ± 1,5 % of the engine's maximum value whichever is the greater. Equivalent methods (e.g. those described in section 4.2 of Appendix 2 to this Annex) may be used. 4.1.1. Direct measurement method Direct measurement of the exhaust flow may be done by systems such as: Precautions shall be taken to avoid measurement errors which will impact emission value errors. Such precautions include the careful installation of the device in the engine exhaust system according to the instrument manufacturers’ recommendations and to good engineering practice. Especially, engine performance and emissions shall not be affected by the installation of the device. 4.1.2. Air and fuel measurement method This involves measurement of the air flow and the fuel flow. Air flowmeters and fuel flowmeters shall be used that meet the total accuracy requirement of section 4.1. The calculation of the exhaust gas flow is as follows: q mew = q maw + q mf 4.2. Determination of Diluted Exhaust Gas Mass Flow For calculation of the emissions in the diluted exhaust using a full flow dilution system it is necessary to know the diluted exhaust gas flow. The flow rate of the diluted exhaust (qmdew ) shall be measured over each mode with a PDP-CVS, CFV-CVS or SSV-CVS in line with the general formulae given in section 4.1 of Appendix 2 to this Annex. The accuracy shall be ± 2 % of reading or better, and shall be determined according to the provisions of section 2.4 of Appendix 5 to this Annex.’ pressure differential devices, like flow nozzle, ultrasonic flowmeter, vortex flowmeter.

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Source: EUR-Lex (Cellar) · retrieved 2026-11-10 · Text as adopted (Official Journal); later amendments are not incorporated in this text.