Multi-Degree-of-Freedom Modeling for Electric Powertrains: Inertia Effect of Engine Mounting System

It has been widely acknowledged over the last couple of decades that the vibroacoustic characteristics of electric powertrains assembled to engine mounting systems are significantly different from internal combustion engines. These distinctions necessitate the modeling of inertial properties of the mounting system in order to account for internal resonances and wave effects. This paper presents a spatial model with three degrees-of-freedom that can be used to capture internal resonances of the engine mount system at frequencies well above 1 kHz. Such a model could significantly enhance the understanding of the vibroacoustic performance of the system while being specifically beneficial for electric powertrains. Results indicate that the model is successful in capturing internal resonances up to 10 kHz while also representing the lower order eigenmodes of the powertrain. The iterative capability of the model renders it specifically beneficial for experimental characterization and model correlation. It is observed that force transmissibility is highly sensitive to the design parameters that govern the effective stiffness of the engine mounts. The model presented in this paper can be used for the optimization of engine mount systems for electric powertrains.