The Optimization Design And Dynamic Characteristic Analysis Of Powertrain Mount System

Powertrain mount system connects powertrain and vehicle body, is an important component to isolate vibration. The vibration transmission between powertrain and vehicle body can be reduced through design and matching the parameters of powertrain mount system. And noise inside the car can be lowered to improve ride comfort and NVH (Noise vibration and harshness) performance.The thesis is based on the sub-project"Control Technology for vibration and noise of powertrain"of"Vehicle Integrated development Advanced Technology-Control: Control Technology on Vehicle NVH", a project of"National Advanced-Tech Research and Development Plan". This dissertation makes optimal design on powertrain mount system, and has research on the characteristic of each mount. The result is of great value in engineering application.First, based on theory of powertrain mount system, model of the system is made by two ways: writing program by mathematical software MATLAB and modeling by mechanical system dynamics analysis software ADAMS. The simulation result validates accuracy of the model. And natural frequency, energy distribution and stress state are analyzed.Second, this dissertation aims at the energy decoupling, takes the stiffness of each mount as variable, considers the natural frequency distribution and vibration displacement and uses Genetic Algorithm to optimize the mount system. The result shows that decoupling degree of the system is increased, and frequency distribution is more reasonable. The performance curve of each mount is designed to make sure that the displacement of powertrain is satisfactory in all work condition. The isolation performance of mount system is analyzed in full vehicle model.Third, performance of the mount is analyzed with finite-element method. Nonlinear finite-element method is used for the nonlinearity of rubber material. The finite element model of Hydraulic Engine Mount (HEM) was established based on the Fluid Structure Interaction theory. The system parameters are calculated, and the static characteristic and dynamic characteristic are simulated.