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Council Directive 70/220/EEC of 20 March 1970 on the approximation of the laws of the Member States relating to measures to be taken against air pollution by gases from positive-ignition engines of motor vehicles · European Union

METHOD OF MEASUREMENT OF THE VOLUME Qn NOT RECYCLED BY THE DEVICE 4.1. Steps to be taken before the test Before the test, all apertures other than that required for the recovery of the gases shall be stopped up. 4.2. Principle of the method 4.2.1. A suitable take-off not introducing any additional loss of pressure shall be installed on the recycling circuit of the device directly at the engine-connection aperture. 4.2.2. A flexible bag made of a material not absorbing hydrocarbons shall be so connected to the outlet from the take-off so as to collect the gases which are not recycled by the engine (see Appendix). The bag shall be emptied at each measurement. 4.3. Method of measurement The bag shall be stopped up before each measurement. It shall be brought into communication with the take-off for a known period of time and then emptied through a suitable volumetric meter. During emptying as aforesaid the pressure H, expressed in mm (mercury gauge), and the temperature N, expressed in degrees Celsius, shall be measured for the purpose of volume correction as referred to in item 3.2. 4.4. Measurement of hydrocarbon content 4.4.1. During emptying as aforesaid the hydrocarbon content shall, if appropriate, be measured by means of a non-dispersive n-hexane-sensitised infra-red analyser. The reading shall be multiplied by the coefficient 1 7 24 to allow for the absolute hydrocarbons concentration in the crankcase gases. 4.4.2. The analysers and the reference gases shall meet the conditions laid down in Annex III, items 3.5.7 and 3.5.8. 4.5. Measurement of fuel consumption The weight of fuel consumed in each of the conditions of operation defined in item 2.2 shall be determined. This weight shall be referred to the unit time. 4.6. Expression of results of measurements The values Q'n, in which n relates to each of the conditions referred to in item 2.2, and the consumptions Cn shall be referred to the same unit time for the purpose of applying the weighting coefficients and the calculations for determining the weighted weight of hydrocarbons and the weighted consumption of fuel. 4.7. Accuracy of measurements 4.7.1. The pressure in the bag during measurement of the volumes shall be measured to within ± 1 mm (mercury gauge). 4.7.2. The vacuum at intake shall be measured to within ± 8 mm (mercury gauge). 4.7.3. The vehicle speed shall be taken at the rollers and measured to within ± 2 km/h. 4.7.4. The quantity of gas discharged shall be measured to within ± 5 %. 4.7.5. The temperature of the gases during measurement of the volume shall be measured to within ± 2º C. 4.7.6. The hydrocarbon content shall be measured, if appropriate, to within ± 5 %, irrespective of the degree of accuracy of the reference gases. 4.7.7. The fuel consumption shall be measured to within ± 4 %. APPENDIX >PIC FILE= "T0002134">

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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.