Assessment of Gaseous and Particulate Emissions of a Euro 6d-Temp Diesel Vehicle Driven >1300 km Including Six Diesel Particulate Filter Regenerations

Abstract

Diesel fueled vehicles have classically had high particulate and NOx emissions. The introduction of diesel particulate filters (DPFs) and selective catalytic reduction for NOx (SCR) systems have decreased Particle Number (PN) and NOx emissions respectively to very low levels. However, there are concerns regarding the emissions released during the periodic DPF regenerations, which are necessary to clean the filters. The absolute emission levels and the frequency of the regenerations determine the contribution of regenerations, but where it happens (city or highway) is also of importance due to different levels of human exposure. In this study, we measured regulated and non-regulated emissions of a Euro 6d-temp vehicle both on in the laboratory and on the road. Particle number (PN) and NOx emissions were similar in the laboratory and on-the road ranging 1010 p/km and 50 mg/km, respectively. Six regeneration events took place during the 1300 km driven, with an average distance between regeneration events of only 200 km. During regeneration events, the laboratory limits for PN and NOx, although not applicable, were exceeded in one of the two measured events. However, on the road the emissions were below the applicable not-to-exceed limits when regenerations occurred. The weighted PN and NOx emissions over the regeneration distance were approximately two times below the applicable limits. The N2O emissions were <14 mg/km and NH3 at instrument background level (< 1 ppm), reaching 8 ppm only during regenerations. The results of this study indicate that due to the short interval between regenerations, studies of diesel vehicles should report the emissions during regeneration events.