In order to gain insight into trends in real-world emissions of light-duty diesel vehicles under conditions relevant for the Dutch and European situations, eighteen Euro 6 passenger cars and ten Euro 5 light commercial vehicles (LCV’s) were extensively tested in the laboratory and on the road. These measurements also form a basis for the annual update of Dutch emission factors. The majority of the vehicles comply in type approval emission tests but on the road real-world NOx emissions are on average 5 to 6 times higher than the type approval limit value. Euro 6 passenger cars emit in the range of 50-2000 mg/km. The average NOx emissions of the N1 class III Euro 5 commercial vehicles range from 1421 to 1670 mg/km. In general the difference between real-world emissions and type approval emissions has been growing over the years. Improvement of real world NOx emissions of future diesel vehicles is possible with Real Driving Emission legislation. Currently the relative expensive PEMS is foreseen as the type approval standard for on-road testing. TNO applies also a NOx-O2 sensor based system with data logger (SEMS) as a NOx screening tool. In the RDE legislation it is prescribed to normalize the measured data of RDE test trips. The current normalization tools (EMROAD and CLEAR) show a variation in the results.
Keywords: Real-world NOx emissions, light-duty vehicles, RDE, PEMS, SEMS.