| As the main source of vibration, the powerstrain system has a great impact on NVH characteristics for modern vehicles. A well-designed powerstrain mounting system can significantly decrease the vibration transmission and improve ride comfort. Hydraulic mounting system is widely used in vibration isolation components presently, and the dynamic characteristics of it are the main research direction of the automotive engine vibration isolation. With the continuous promotion of the structure and performance of hydraulic mounting system, the vibration and noise control to vehicles gets improved constantly.This paper gives an in-depth study on vibration characteristics, principle of design and optimization of mounting system, revolving around vibration isolation and reduction of the powerstrain mounting system. It has also established a six-degree-freedom dynamic model of powerstrain mounting system, derived differential equations of powerstrain mounting system by using Lagrange theorem, built up the inertia and stiffness matrix of powerstrain mounting system after solving the equations mentioned above, and developed an optimization program to vibration characteristics of mounting system—Mount System which offers a convenient and quick way for the initial design of the mounting system. Because of the serious modal coupling phenomenon that appears in the modal matrix of the powerstrain mounting system, this paper applies Sequential quadratic programming optimization algorithm by using fgoalattain function of optimization tools in Matlab toolbox designed for powerstrain mounting system on the basis of energy method of decoupling theory, and integrated the optimization program into the vibration optimization program for mounting system—Mount System.According to the structure of the typical hydraulic mounting engine (HEM), the physical model of it has been established. After the analysis of physical model. of hydraulic mounting engine, a mathematical model of HEM has been obtained by using relative mechanical and hydraulic fluid theories. The means of obtaining HEM parameters receives a detailed analysis and by which the researcher designed and made two sets of HEM. Based on the mathematical model of HEM, the researcher established a simulation computation model for characteristics of HEM by using Matlab/Simulink simulation toolbox, and carried out a simulative computation study of HEM within l-30Hz low-frequency range. In this simulative computation, the dynamic characteristics of HEM got simulated, and a necessary analysis of it was given. The result of analysis tells that there are many factors affecting the stiffness of HEM. The effect to the dynamic stiffness is a combination of spring stiffness, cross-sectional area and length of inertial channel, the volume flexibility of upper chamber of HEM. The lag angle of HEM is mainly affected by hydraulic mechanism. The volume flexibility of lower chamber and the liquid viscosity co efficiency of HEM have only a tiny effect on low-frequency dynamic characteristics, therefore they are not considered in the development and design of HEM.To verify the mathematical model and simulation results, an experimental study was carried out on the hydraulic mounting components. The experiment serves as the basis of the dynamic characteristic curve, and testifies that the experimental curve basically fits the simulation curve, as well as the correctness and applicability for mathematical model and simulation model.The study of the impact of factors of HEM in this paper will certainly play a significant role to improve the vibration and noise of hydraulic mounting system.
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