Impact of varying ambient conditions during RDE on the measurement result of the AVL Gas PEMS iS
This paper discusses the qualification of the AVL 492 Gas PEMS iS for RDE measurements. The Gas PEMS iS is a mobile measurement device for gaseous components in the exhaust gas of combustion engines especially under real driving conditions. RDE boundary conditions are varying ambient temperature and humidity and also atmospheric pressure variations due to altitude changes.
Beside tests on the road mounted on the trailer coupling of passenger cars or mounted inside the trunk the device was tested during elevated ambient conditions in a climate chamber.
The tests were done with calibration gas to maintain stable concentrations and the gas was humidified with a bubbler to a dew point of 51 °C in order to simulate real exhaust gas.
The influence of sudden temperature changes between - 7 °C and + 40 °C and ambient humidity changes between 20 % rel. and 90 % rel. to the measurement signals of CO, CO2, NO and NO2 has been investigated.
Furthermore a pressure change up to a sea level of 3000 m (700 mbar abs.) was studied.
In summary the AVL 492 Gas PEMS iS performed very well under these elevated ambient conditions. The deviation of all measured concentrations remained within 2 % rel. of the measured value.
KeywordsClimate Chamber Humidity Change Heated Line Altitude Change Sudden Temperature Change
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