Abstract:

To investigate the effects of traffic scenarios on emissions and fuel consumption of heavy-duty diesel vehicles. A dump truck with a maximum design total mass of 24.5 t was selected, and the engine-in-the-loop (EIL) method was used to construct vehicle, road, and driver models. Examined the fuel consumption and emission characteristics under three typical scenarios: the re-starting after a long idle with selective catalytic reduction (SCR) temperature, the congestion-related stop duration, and the vehicle load. The results show that when the SCR temperature is near the injection temperature, the SCR catalytic conversion efficiency is low during re-starting or acceleration, especially when the urea is not in the injection state, leading to high NO_x emissions. After a congestion-related stop, the SCR temperature significantly decreases, and the longer the stop duration cause higher NO_x emissions. Under the same stop duration, the full load scenario has significantly higher cumulative particulate matter (PN) emissions and the specific emissions compared to the no-load scenario, while stop duration has little impact on it. As the vehicle load increases, the brake-specific fuel consumption (BSFC) and the CO₂-specific emissions decrease to some extent, while the cumulative PN emissions and the NO_x emissions increase. The cumulative NO_x emissions and the specific emissions show an initial increase followed by a decrease with the increase in vehicle load.

Key words: heavy duty diesel vehicles, pollutant emissions, traffic flow scenarios, engine-in-the-loop (EIL), selective catalytic reducer (SCR), brake specific fuel consumption (BSFC)