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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

If the sample gas flow is determined by differential flow measurement the flow meter or the flow measurement instrumentation shall be calibrated in one of the following procedures, such that the probe flow q mp into the tunnel shall fulfil the accuracy requirements of section 4.2.5.2 of Appendix 4 to this Annex: The flow meter for q mdw shall be connected in series to the flow meter for q mdew, the difference between the two flow meters shall be calibrated for at least 5 set points with flow values equally spaced between the lowest q mdw value used during the test and the value of q mdew used during the test. The dilution tunnel may be bypassed. A calibrated mass flow device shall be connected in series to the flowmeter for q mdew and the accuracy shall be checked for the value used for the test. Then the calibrated mass flow device shall be connected in series to the flow meter for q mdw, and the accuracy shall be checked for at least 5 settings corresponding to dilution ratio between 3 and 50, relative to q mdew used during the test. The transfer tube TT shall be disconnected from the exhaust, and a calibrated flow measuring device with a suitable range to measure q mp shall be connected to the transfer tube. Then q mdew shall be set to the value used during the test, and q mdw shall be sequentially set to at least 5 values corresponding to dilution ratios q between 3 and 50. Alternatively, a special calibration flow path, may be provided, in which the tunnel is bypassed, but the total and dilution air flow through the corresponding meters as in the actual test. A tracer gas, shall be fed into the exhaust transfer tube TT. This tracer gas may be a component of the exhaust gas, like CO2 or NOx. After dilution in the tunnel the tracer gas component shall be measured. This shall be carried out for 5 dilution ratios between 3 and 50. The accuracy of the sample flow shall be determined from the dilution ration r d: Text of image qmp = qmdew rd

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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.