The influence of engine demand map design on vehicle perceived performance

This paper reports a study into the influence of the steady state engine demand map on perceived performance. Analysis of the results of a survey of 24 C and C/D class 1600cc cars is presented and shows that the primary parameters are mean wide-open throttle acceleration, throttle progression, and part-throttle rate of change of acceleration with engine speed. These results are used to design a factorial experiment to investigate these parameters using an electronic throttle system. This approach eliminates problems of inter-vehicle variations in noise, comfort or general image, allowing subjective ratings to be attributed directly to the demand map changes. The results are discussed in terms of the significant main effects and interactions and as response surfaces, from which optimum setups can be determined.