Method of Vehicle Dynamics Analysis by Means of Equivalent Cornering Stiffness for Aerodynamic Forces and Moments

The dynamic performance of a vehicle traveling at high speeds is affected by the aerodynamic characteristics consisting of lift on front and rear axles, side force, and yawing moment. In order to enable consideration of these aerodynamic characteristics from the early stages of the vehicle development process, it is required that the characteristics are replaced by simple development indices. The study discussed in this paper introduced the concept of equivalent cornering stiffness to analyze these aerodynamic characteristics from the viewpoint of vehicle dynamics. Using this method, it is possible to integrate four aerodynamic characteristics into two variables which are very important to vehicle dynamics. As a result, the interaction between each aerodynamic characteristic is simply expressed in the equations of motion. Moreover the aerodynamic characteristics are dealt with as the same variables which are commonly used in other chassis systems such as suspensions and tires. It can hereby simplify to allocate the various chassis characteristics including aerodynamics to fulfill the high requirements for the vehicle dynamics performance, such as minimizing running resistance in keeping with appropriate lateral dynamics.