The Influence of Testing Parameters on Exhaust Gas Emissions 780649
The ambient conditions in the test facilities, the dynamometer characteristics, and the test drivers influence the formation of the components in vehicular exhaust gas emissions. To quantify the specific effects a standard test vehicle which is equipped with a mechanized driver and a measuring system is used as a calibrating instrument.
Variations of the barometric pressure were found to influence the exhaust test results significantly. Systematic errors up to a factor of two may be caused by malfunctions of apparently well-adjusted dynos.
Furthermore, the drivers can create large deviations without violating the tolerances of the driving schedule.