Dynamic modeling and optimization for powertrain shake characteristics of electric powertrain system with hydraulic engine mounts

Poor designed powertrain mounting system can lead to severe resonance when road excitation frequency is consistent with the natural frequency of the powertrain mounting system, which results in vertical vibration of the vehicle. In addition, double-layer vibration isolation and hydraulic engine mount (HEM) are widely used for vibration attenuation of electric powertrain. This paper focuses on the vertical vibration of electric vehicles under road excitation. An analytic model of powertrain shake characteristics considering the amplitude-frequency dependent nonlinearity of HEMs is established. Furthermore, the proposed nonlinear model is experimentally validated through rigid body modal test of the powertrain. Numerical simulation is carried out to investigate the influence of HEM parameters on powertrain shake characteristics. Simulation results demonstrate that the effective pumping area, upper chamber stiffness and inertia track effective cross-sectional area, and length of HEM have obvious impact on powertrain shake characteristics. Under the premise of ensuring vibration isolation performance under other conditions, optimization of the above HEM parameters can reduce peak value of car body vibration under road excitation and thus improve ride comfort.