Brake force distributions optimised with regard to energy recovery for electric vehicles with single front‐wheel drive or rear‐wheel drive

Energy recovery by means of braking with the electric machine helps to extend the cruising range of electric vehicles. By optimising the recuperation system, the total energy efficiency is increased. In general, using a usual brake force distribution the capability for recuperation is not equal for every type of drive train. Usually, four-wheel drives are advantageous in comparison to drive trains with only one driven axle. Regarding the single drives, generally, a front-wheel drive provides a higher capability for recuperation than a rear-wheel drive. This is mainly due to the dynamic axle load shift, which occurs during decelerations. In order to increase the energy recovery of electric vehicles with single drive, an adaptive brake force distribution is presented and compared with other brake force distributions in this study. It uses the knowledge of the currently available adhesion coefficient between tyre and road. The positive effect on the recuperation without impairing the braking performance on a straight road is demonstrated based on simulations. In curves, the lateral forces additionally need to be considered to guarantee the stability of the vehicle, especially relating to electric vehicles having a rear-wheel drive.