A Research on the Real Driving Emission Characteristics of Light-duty Diesel Vehicles

The real driving emissions from two diesel vehicles meeting Euro-IV and Euro-VI emission regulations respectively are measured using portable emission measurement system in accordance with real driving emissions (RDE) procedure newly formulated by EU. The results show that the NO_x emission factors of two vehicles with RDE procedure are 6.8~7.7 times as high as those with laboratory certification cycle NEDC, and the NO_x conformity factors (0.71~7.09) with NEDC, FTP75 and WLTC cycles and RDE procedure are all larger than those of CO (0.11~0.63). The instantaneous emission rate of NO_x rises with the increase of vehicle acceleration and under the suburban and motorway conditions, peaks in instantaneous emission rate of NO_x appear whenever vehicle acceleration exceeds the maximum acceleration in NEDC cycle. Accordingly particular attentions should be paid on the NO_x emission of light-duty diesel vehicles in formulating RDE regulation.