THE WORKING PRINCIPLE OF THE DISTURBING PLATE IN HYDRAULIC ENGINE MOUNT

For two types of HEMs with different orifices, shapes and cross-sectional areas, this paper performs experimental investigation and parameter identification. This study verifies the following issues: the fixed points on the dynamic characteristics, the constant value on amplitude-dependent dynamic stiffness in-phase at higher bands, the nonlinear lumped parameter model (LPM) for hydraulic engine mount (HEM) and the parameter identification method. It is indicated that the fluid flow through an orifice can be modeled as a fluid flow through an equivalent inertia track. So the nonlinear LPMs for these two types of HEMs, i.e. the HEM with an orifice and the one with an inertia track, can be united. Finally this paper develops a parameter identification method for the local losing factor of fluid flow. The experimental and simulation results show that: the disturbing plate can lower dynamic stiffness markedly at higher bands because it enhance the turbulent-flow-induced energy loss, i.e. the quadratic nonlinear fluid damping is enhanced, so the resonance of the fluid flow through the inertia track is attenuated. This is a useful step to explain the working principle of the disturbing plate.