ISO 6855-3:2012 pdf download – Mopeds —Measurement method forgaseous exhaust emissions and fuelconsumption — Part 3: Fuel consumption measurement at a constant speed.
6.5.5 If the mean value of average moped speeds. Vt.j. is within ± 1,0km/h of target test speed, , the tests are acceptable and the mean value of average specific fuel consumptions shall be adopted as the results of the fuel consumption measurement.
6.5.6 If the mean value of average moped speeds, Vj. exceeds ± 1,0 km/h from the target test speed, Virn. the extreme data set of the average moped speed. t.j. and the average specific fuel consumption. F,1, shall be neglected and an additional test shall be carried out.
The additional tests shall be performed until the mean value of average moped speeds, is within ± 1,0km/h of target test speed.
If the test moped cannot be stably controlled at the test target speed, the specific fuel consumption may be obtained by the determination method specified in Annex A.
6.5.7 The mean value of average specific fuel consumpuons, F.1. shall be rounded to one decimal place.
7 Chassis dynamometer measurement method
The chassis dynaniorneter shall be set in ac.ordance with ISO 28981.
7.1 Test method
7.1.1 The fuel consumption measurement by the carbon balance method
7.1.1.1 The speed of the test moped shall not differ by more than 1.0 km/h from the target test speed during the test. The sampling, analysing and measuring the gaseous exhaust emissions shall be performed In accordance with ISO 6855.1.
7.1.1.2 The specific fuel consumption shall be calculated in accordance with ISO 6855.1:2012, Clause 12.
7.1.1.3 At least three tests shall be performed and the mean value of specific fuel consumptions shall be calculated. The mean value of specific fuel consumption shall be rounded to one decimal place.
7.1.2 The fuel consumption measurement by the fuel flowmeter
7.1.2.1 The fuel consumption measuring distance shall be either long enough to consume the fuel more than 10 mL or be longer than 300 m.
7.1.2.2 The speed of the test moped shall not differ by more than ± 1.0 km/h from the target test speed
during the test. The specific fuel consumption shall be calculated from in accordance with ISO 6855. 1:—. Clause 12.
7.1.2.3 At least three tests shall be performed and the mean value of specific fuel consumptions shall be calculated. The mean value of specific fuel consumptions shall be rounded to one decimal place.
A.1 General
A.1,1 To determine the consumption at a steady target test speed (see Figure Al), four testsshall be made:
— two at an average speed less than the target test speed, and
— two at an average speed exceeding the target test speed.
Two tests shall not he made toward the same direction, i.e. the test shall be made one direction and he repeated in the opposite direction. During each test run, the speed shall be kept steady within ± 1 km/h The average speed for each test shall not differ from the reference speed by more than 2 km/h
The fuel consumption for each test run shall be calculated from theequations in ISO 68S5-1:2012,Clause 12.
A.1.2 The difference between the two lower calculated values shall not be greater than 5 % of their mean value and the same condition shall apply for two higher calculated values. The value of the fuel consumption at the appropriate target test speed shall be calculated by liner interpolation as shown in Figure A.1.
A.1.3 If the condition in A.l.2 is not achieved for either pair of calculated values, then the four test runs shall be repeated. If after 10 attempts the required consistency has still not been achieved, then another moped shall be selected to be tested in accordance with this procedure.