| The vibration-acoustic research on the vehicle, combined with the study on the passengers'objective feeling and response to the vibration and noise, forms the vehicle NVH(Noise, Vibration, Harshness) problem. NVH performance which directly reflects the dynamic characteristics and performance of the vehicle has become a comprehensive technical indicator. The vibration-acoustic optimization techniques of entire vehicle from the angle of NVH is one of the core competitive powers of vehicle top-down design and the key matter of vibration-acoustic performance improvement of existing type of vehicle.In this paper, the research content and method of vehicle exhaust system are introduced firstly. Based on the vibration, noise and flow field analysis of exhuast system of certain type vehicle, the mothod of validating one each another with experice and simulation is been used.. This paper includes the followings:The vibration and noise testing and optimizing program is built with the program language VB and MATLAB. Combining with the sigal adoption equipment, forms a vibration and noise testing and optimizing system of automation exhaust system.The apparatus B&K 3560D system for vibration and noise test, the 4508B acceleration sensor, the 4506B acceleration sensor and the package of PULSE analytical software are adopted to implement mode test for exhaust system under free condition and installation condition.The finite element analysis and optimization of vehicle exhaust system:according to the real dimensions, the 3D model of emission system is built and imported into ANSYS preparing for the next vibration, noise and harmonic response analysis.The internal flow field has been analysis and got the velocity and pressure distribution in the muffler with the software of FLUENT.The internal sound field has been analysis and got the sound pressure distribution with the software of SYSNOISE, then compare the transmit loss with flow and without flow.
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