Hot passenger car emissions modelling as a function of instantaneous speed and acceleration

As part of the EC DRIVE programme, a study was carried out to determine the most important vehicle parameters that influence the emissions and fuel consumption of passenger cars. Emission measurements have been conducted in the three laboratories in France, Germany and UK on the basis of 14 driving cycles specially designed to cover the whole range of vehicle speed and acceleration in urban traffic. One hundred and fifty vehicles, representing the European 1 995 fleet, were tested, and the emissions of CO, HC, NOx and CO2 continuously recorded. Subsequently, a model was developed to calculate emissions during an urban trip as a function of the vehicle type and its instantaneous speed and acceleration. Average unit emissions are presented as a function of average speed and vehicle type. The model is given in the form of a two-dimensional junction with the variables, speed and speed times acceleration, for all vehicle types. An attempt to test this model with an on-board sampling system was made but without success. The paper briefly describes some typical applications.