3D Finite Element Modelling of a Hydraulic Engine Mount and Identifying its Dynamic Characteristics

Demands to economic and more powerful cars, have raised some NVH (Noise, Vibration and Harshness) issues in the passengers' compartment in the recent years. Controlling of vibration andnoise in cars is a challenging and difficult procedure because cars have several sources of vibration and noise (like engine) which are interrelated and speed dependent. Engine mounts are equipments to isolate power-train vibrations. The car engine mounting system, generally, consists of an engineand several mounts connected to the car structure. The modern engine mounting systems have beensuccessfully used to isolate the passengers' compartment from both noise and vibration generated by the engine. In modern passenger cars usually tow type of passive engine mounts are used: elastomericengine mounts and hydraulic engine mounts (HEMs). Achieving very restricted NVH targetsmakes using the HEM crucial. Hydraulic engine mounts have both solid and fluid media in their structures that make theirbehaviour complex to figure out. In addition to elastomeric material which has nonlinear and frequency and amplitude dependent characteristics, the fluid behaviour and the interaction between fluid and solid make the modelling of HEMs difficult. The real engine mount is a three dimensional media with its internal resonances and receives forces from all directions. Therefore, in this paper a three dimensional (3D) model of HEM with using finite element (FE) is presenting that encompass elastomeric materials nonlinearity, fluids nonlinearity and fluid solid interaction (FSI). To validate the model, the models behaviour is compared with real hydraulic engine mounts behaviour that derived from several modal tests.

Keywords:

finite element modelling , hydraulic engine mount , dynamic characteristic , NVH