Analysis of the Effect of Vehicle, Driving and Road Parameters on the Transient Performance and Emissions of a Turbocharged Truck

In this paper, a fundamental analysis of the effects of various influential parameters on the performance and emissions of a turbocharged truck operating under transient conditions is presented. The results derive from a detailed vehicle model that comprises two parts. The first is an engine performance and emissions module that follows a mapping approach, with experimentally derived correction coefficients employed to account for transient discrepancies; this is then coupled to a comprehensive vehicle model that takes into account various vehicle operation attributes such as gearbox, tires, tire slip, etc. Soot, as well as nitrogen monoxide, are the examined engine-out pollutants, together with fuel consumption and carbon dioxide. The parameters examined are vehicular (mass and gearbox), driving (driver 'aggressiveness' and gear-shift profile) and road (type and grade). From the range of values investigated, the most critical parameters for the emission of NO and soot are vehicle mass, driving 'aggressiveness' and the exact gear-change profile. Vehicle mass, driving 'aggressiveness' and road-grade were identified as the most influential parameters for the emission of CO2. A notable statistical correlation was established between pollutant emissions (NO, soot) and vehicle mass or road-tire friction, as well as between fueling/CO2 and vehicle mass, road-tire friction and road grade. It is believed that the results obtained shed light into the effect of critical operating parameters on the engine-out emissions of a truck/bus, underlining at the same time the peculiarities of transient operating conditions.