A new method to determine exhaust emission factors for heavy duty vehicles

In contrast to the evaluation of exhaust gas and fuel consumption factors for passenger cars, heavy duty trucks and buses have not been tested on a chassis dynamometer. For reasons of practicability and costs, exhaust gas emissions and fuel consumption of 34 different diesel engines have been measured on dynamic engine test benches. Using these engines, the fleet of heavy duty trucks and buses in the Federal Rebublic of Germany for the reference years 1986 and 1990 can be represented. From the enginesʹ emission data sets, and data concerning the drive train and the driving resistance of representative vehicles, the exhaust emission behaviour of more than 300 different types of trucks and buses could be simulated on the basis of a newly developed method. It is therefore possible to calculate exhaust emission and fuel consumption factors for all categories of the entire fleet of heavy duty vehicles taking into account the road category, gradient, load factor and traffic flow conditions. This new method allows the determination of exhaust emission and fuel consumption factors for a broad range of different scales, from the emission simulation for a single vehicle up to global emission assessments.