Comparison of on-road emissions with emissions measured on chassis dynamometer test cycles

In the context of the DECADE project, carried out under the 5th Framework Programme of the European Commission, a software package has been developed to predict vehicle fuel consumption and emissions for a given distance–speed profile. In order to give input to the model, specific light duty vehicles have been subjected to intensive measurements on engine dynamometers, on chassis dynamometers, on proving ground and in real traffic. This paper gives an overview of the emissions measured on the road for two vehicles in Belgium and in Spain (in urban, rural and motorway traffic), and compares these with the results obtained on chassis dynamometers. The tests on chassis dynamometers focused mainly on the European Drive Cycle, but a number of tests were performed using a cycle derived from real world speed profiles. When comparing emissions on a grams per kilometer basis, it was established that some of the emissions measured in the certification cycle differed dramatically from the real traffic emissions.