Real-world gaseous and particulate emissions from Euro IV to VI medium duty diesel trucks

Abstract

This study offers emission factors for earlier and late technology medium duty diesel particulate filter (DPF) -equipped trucks, operating on real-world conditions. The analysis includes levels of nitrous oxide (N2O) emissions as well as the impacts of DPF regenerations on emission levels. The real-driving gaseous and particulate emissions, as well as fuel consumption of 14 Euro IV, Euro V, and Euro VI medium duty diesel trucks were analysed and the efficiency of different emission control technologies were assessed. Measurements were conducted using portable emission measurement systems (PEMS) over a wide range of driving and operating conditions. Distance-based integration of emission rates over 500 m sections was considered for statistical analysis, providing a large dataset of emission factors to be used for network link-based traffic and emissions modelling. In terms of emissions performance, nitrogen oxides (NOx) levels were in general above the corresponding Euro standard limits, while carbon monoxide (CO), total hydrocarbons (THC) and particulate matter (PM) levels were within limits. Selective catalytic reduction (SCR) -equipped Euro V vehicles were seen to emit more than their non-SCR-equipped counterparts. NOx and fuel consumption were positively correlated with road gradient over the −6% to 6% gradient range. The emission levels of ammonia (NH3) were measured significantly lower than the respective Euro VI provisions for heavy duty engines, while the N2O levels were found to contribute approximately 1% to the respective total greenhouse gases levels. DPF regeneration events in real world seem to have a measurable impact mostly on THC and PM emissions, increasing baseline levels by 8.1% and 29%, respectively, for Euro VI vehicles.