Variation modes of vehicle acceleration and development of ideal vehicle acceleration

Abstract

Vehicle acceleration is one of the key characteristics that influence customer satisfaction. Pedal displacements and vehicle speeds are necessary to represent the performance of acceleration: how much acceleration a vehicle is capable of if the acceleration pedal is displaced at a certain speed. The result of varying the acceleration pedal is called the acceleration response surface in three-dimensions. The current approach utilizes a few discrete levels of acceleration response surface for engineering specification because of the three-dimensional nature of the acceleration response surface (ARS), and thus may under-represent the entire acceleration response surface. The underlying variation modes of the acceleration response surface among 92 vehicles are identified by applying principal component analysis in which the entire ARS is analyzed. The 92 vehicles are specifically between the 2006- and 2007-model years with automatic transmission and 4-, 6-, and 8-cylinder engines. Two variation modes are identified, which differentiate vehicles from each other: how fast a vehicle can accelerate overall and how quickly a vehicle reaches its peak acceleration at launch with short or long pedal displacement. The association between the two variation modes and buyer satisfaction from mail surveys similar to Consumer Reports is analysed. Finally the ideal shape of the acceleration response surface is developed.