Brake Based Torque Vectoring for Sport Vehicle Performance Improvement

The most common automotive drivelines transmit the engine torque to the driven axle through a differential. Semi-active versions of this device ([4], [5], [6]) have been recently conceived to improve vehicle handling at limit and under particular conditions; these differentials are based on the structural scheme of the passive one but they try to manipulate the vehicle dynamics by controlling the distribution of the driving torque on the wheels of the same axle thus generating a yaw moment. Unfortunately a semi-active differential is not able to perform a complete yaw control since the torque can only be transferred from the faster wheel to the slower one; on the other hand, active differentials ([11], [12], [13]) allow to generate the most appropriate yaw moment controlling both the amount of transferred torque and its direction. The application presented in this the paper aims at enhancing the dynamic behaviour (in terms of handling performance) of a rear-driven sport vehicle by creating the required yaw moment through brakes actuation and throttle control; the examined car is equipped with free differential, thus the proposed system does not require the introduction of additional devices. The feasibility study of the proposed concept is based on the comparison with a semi-active and active differential model.