Emissions of Passenger Cars in Special Driving Situations

Testing of real driving emissions (RDE), as an element of a type approval of passenger cars (since September 2017), offers the opportunity to collect the data about the emissions in special driving, or non-driving situations. These situations are: cold start, warm-up of the engine, stop & go and idling.
In the present work of the Laboratory for Exhaust Emissions Control (AFHB) of the Berne University of Applied Sciences (BFH), the definitions of the special driving situations were proposed and the emissions of 7 passenger cars (gasoline & Diesel) were extracted from the present RDE data.
Furthermore, some special driving situations, particularly the stop & go operation with varying share of idling were reproduced on chassis dynamometer.
As expected, the emissions of CO, NOx and PN are in the cold start and in the first part of the warm-up phase (c.a. 25s) considerably higher than in the rest of the investigated urban phase.
The singular emitting situations like “stop & go” or idling occur frequently in the warm-up phase, i.e. in the city operation when the engine and the exhaust system are still not warm enough.
The emissions in the investigated particular driving situations scatter considerably for the different vehicles due to varying efficiencies and warm-up of the exhaust aftertreatment systems.