Optimal configuration of a hatchback rear end considering drag and stability objectives

Abstract

Aerodynamic load is recognized as one of the most important factors, which has significant effect on fuel consumption, vehicle performance, and stability. Designing external car body to meet aerodynamic drag and stability requirements is one of the most challenging works in vehicle development process. In this paper, optimum design of rear-end parameters for a hatchback car is studied considering both drag and lift goals. Five geometrical parameters of rear end are chosen as design variables at two levels. Interaction of these factors on drag and lift coefficients is investigated using design of experiments, and optimum level for each parameter is achieved. To reduce the number of case studies, fractional factorial design algorithm is nominated. Then, drag and lift regression equations based on important terms are derived and the relationship of these parameters with objectives are discussed. Finally, aerodynamic performance around the optimal model is reported.