BS ISO 6855-1:2012 pdf download – Mopeds — Measurement method for gaseous exhaust emissions and fuel consumption Part 1: General test requirements

BS ISO 6855-1:2012 pdf download – Mopeds — Measurement method for gaseous exhaust emissions and fuel consumption Part 1: General test requirements 7.2.8 A probe, located near to but outside the gas-collecting device, to collect, through a pump, a filter and a flowmeter, samples of the dilution air stream, at constant flow rates, throughout the test. 7.2.9 A sample probe, pointed upstream into the diluted exhaust mixture flow, upstream of the positive displacement pump or the critical flow venturi to collect, through a pump, a filter and a flowmeter, samples of the diluted exhaust mixture, at constant flow rates, throughout the test. The minimum sample flow rate in the two sampling devices described in 7.2.8 and 7.2.9 shall be 150 L/h. 7.2.10 Three way valves, on the sampling system, described in 7.2.8 and 7.2.9, to direct the samples either to their respective bags or to the outside throughout the test. 7.2.11 Gas-tight collection bags, for dilution air and diluted exhaust mixture of sufficient capacity so as not to impede normal sample flow and which will not change the nature of the gaseous exhaust emissions concerned. The bags shall have an automatic self-locking device, and shall be easily and tightly fastened either to the sampling system or the analysing system at the end of the test. 7.2.12 A revolution counter, to count the revolutions of the positive displacement pump throughout the test. Good care shall be taken with the connecting method and the material or configuration of the connecting parts because there is a possibility that each section (e.g. the adapter and the coupler) of the sampling system will become very hot. If the measurement cannot be performed normally due to heat-damages of the sampling system, an auxiliary cooling device may be used as long as the exhaust gases are not affected. NOTE 1 With open type devices, there is a risk of incomplete gas collection and gas leakage into the test room, so it is important to make sure that there is no leakage throughout the sampling period. NOTE 2 If a constant CVS flow rate is used throughout the test cycle that includes low and high speeds all in one, it is advisable that special attention be paid because of higher risk of water condensation in high speed range. 7.3 Analytical equipment 7.3.1 The sample probe shall consist of a sampling tube leading into the collecting bags, or of...