Performance Design And Optimization Of Nvh For Powertrain Suspension System

Powertrain is one of the main sources of vehicle interior vibration and noise.Suspension system is the main way to isolate engine vibration from vehicle body.The powertrain reduces the transmission of vibration to the vehicle body through necessary measures of vibration reduction and isolation,which becomes an important task in the process of vehicle development.The development and matching of mounting system determines the performance of vehicle NVH to a great extent.Therefore,the reasonable matching of powertrain mounting system plays an important role in reducing vehicle vibration and improving vehicle NVH performance.In this paper,a six-degree-of-freedom mathematical model of power assembly-mount system is established,and the differential equation of the overall vibration of power assembly expressed by stiffness matrix and mass matrix is obtained.The natural frequency and energy distribution matrix program of powertrain mounting system is compiled by using MATLAB software,and the correctness of the model simulation program is established in ADAMS.Design analysis and optimization verification of powertrain mounting system take a domestic car as the research object,carrying powertrain 1.6L+5MT.The inertia parameter test of power assembly,stiffness test of mounting element,working condition analysis of mounting system,simulation analysis and test of mounting attachment point IPI(dynamic stiffness of origin)and NTF(acoustic and vibration transfer function)are completed respectively.In the whole design and development process,the mounting position and stiffness of mounting elements are taken as design variables,and the rigid body modal decoupling and reasonable modal frequency matching of powertrain mounting system are taken as objective functions to optimize the design.The optimized suspension system was verified by a prototype vehicle,and the actual vibration data of the suspension system were tested.Finally,the evaluation criterion of the research results is based on the linearity of the suspension vibration isolation rate,the vibration climbing with the speed and the subjective evaluation in the vehicle under idling and accelerating conditions of the test prototype vehicle.The results show that the optimization of mounting stiffness can effectively improve the decoupling rate of the mounting system,thereby improving the NVH performance of the system.The actual vehicle verifies that the vibration isolationrate of the whole suspension system is good,and the vibration linearity under acceleration condition is good.The level of noise and vibration in the vehicle reaches the upper level of the same level in the industry and achieves the purpose of analysis and optimization.