Prediction of Amplitude-Sensitive Dynamic Characteristics of Hydraulic Engine Mount and Experimental Verification

The amplitude-sensitive nonlinear mathematical model of the hydraulic engine mount (HEM) with a free-floating decoupler is deduced through the theory of fluid dynamics. The model considers the amplitude-sensitive characteristics, such as local pressure loss of the inertial track and the decoupler, the amplitude-sensitive dynamic stiffness of main rubber, and the switch mechanism of the decoupler. A new model of decoupler’s switching mechanism is established, which makes parameter identification simpler comparing to the existing analogous models. The finite element method is used to identify parameters of the lumped-parameter model, such as the contact force between the decoupler plate and the cage, the stiffness of the main rubber, the equivalent piston area, the chambers’ compliances, etc. The lumped parameters of fluid track are obtained by fluid mechanics formula. The dynamic characteristics of a hydraulic engine mount under harmonic excitations with various amplitudes are calculated. The comparisons between the calculated results and the experimental results show that the lumped parameter model based on the finite element method can accurately predict the dynamic characteristics of hydraulic engine mount under different-amplitudes excitations. Using the proposed method, the dynamic characteristics of the hydraulic mount can be effectively predicted and the development time can be shortened.