Hydraulic Engine Mounts (HEMs)

In vehicles, hydraulic engine mounts (HEMs) are installed to isolate the vibrations of the engine and to establish comfortable and quiet driving. Hydromounts consist of a rubber chamber filled with viscous fluid. Here a model is presented to predict the high frequency dynamic response (1-1000 Hz) of HEMs including all non-linear effects like hyperelastic material behavior, wall contact and the fluid flow by itself.  A good agreement is found in comparison of simulated predicted responses to experimental data. Using additional built in components, the simulation predicts the correct influence on the dynamic response.

The fluid is confined in the rubber chamber. The fluid can pass a throttle plate and reach a second chamber (top of image).  When applying various excitation frequencies the HEM response differs: Fig. 1 shows a low frequency excitation, where the fluid can pass the throttle plate. Fig. 2 presents the high frequency response where plate is dynamically closed.  

Figure 3: 3D configuration with 2 chambers

Fig. 3 shows a 3D HEM with two fluid chambers connected via a channel. The yellow section corresponds to the rubber and the holder. The fluid is transported from one chamber to the other.