For a modified electric vehicle on the same internal combustion engine (ICE) platform, the primary consideration is to have no change in long member and pendulum type conventional engine mounting system to save development cost and timeline. Electric vehicle (EV) powertrain is comparatively lighter w.r.t the ICE. As a result, the engine mount’s static preload setting point or powertrain centre of gravity under static powertrain load gets changed resulting in a change in stiffness for the same engine mount.
As the static stiffness changes, the dynamic stiffness and modal frequency also change. The 6 degrees of freedom (DOF) modal frequency has almost no impact on powertrain modes as EV powertrain modes, mainly, the motor frequency, is much higher than engine mount Eigen modes.
In this scenario, the gap management gets disturbed due to less static preload, and non-linearity gets affected. This paper will explain a case study on a modified EV, the change in modal map, its impact vis-a-vis ICE, and how this static stiffness progressivity issue is addressed to resolve buzz, squeak and rattle (BSR) noise.