Analysis of Changes in Disc-Brake Squeal Characteristic due to Regenerative Braking Simulation on Brake-Inertia-Dynamometer

Brake is very crucial functional part of automobile, therefore need a robust testing for validation in order to ensure its failsafe functionality under harsh circumstances. For performance testing and foundation brake system design optimization purpose Brake-Inertia-Dynamometer (BID) being used extensively since its inception, and from last two decades for optimization of brake Noise, Vibration, and Harshness (NVH) performance too. In brake NVH the major issue is brake squeal or squeak generation, which is very difficult to predict its occurrences and standardized its prerequisite conditions. Since, brake is the only device which is designed for power absorption in automobile and therefore the regenerative braking concept come to the picture for energy conservation. The loss of energy in braking in case of Hybrid Electric Vehicle (HEV) and Electric Vehicle (EV) is more crucial and hence implementation of regenerative-braking is more discernible in HEVs and EVs to enhance the efficiency. Furthermore, the propensity of brake squeal generation plays very important role as its gain more attention by occupants and rise questions against vehicle’s level of sophistication especially in case of HEVs and EVs, since squeal is very annoying in perception. Above reasons motivate to investigate the squeal performance of conventional friction disc brake when it is subjected to the regenerative braking. The regenerative braking has been simulated on BID through blending of braking torques of electric (regenerative) brake and friction brake using electrical inertia simulation technology in which, part of inertia acting as a resisting rotational torque which is equivalent to that of utilizing to conserve energy through regeneration. In this paper, the disc-brake squeal noise occurrence has been characterized without and with regenerative braking respectively. Also emphasis the changes in squeal characteristic for the same disc brake through comparison. Brake squeal noise occurrence has been evaluated using SAEJ2521 test cycle.