Correlational studies of vibration characteristics theory of exhaust system, optimization design of idling vibration control and the noise test analysis were conducted to solve the problems of body vibration and exhaust noise under idling condition. Firstly, the analysis of vibration mode, dynamic response and vibration transfer of exhaust system were carried out by using the simulation analysis, and the location of the exhaust system hangers were verified. Furthermore, the structure optimization schemes of exhaust system were proposed for exhaust noise reduction under idling condition based on control of local stiffness optimization, constraint location optimization and system global stiffness optimization. Finally, the interior and exhaust noise and system vibration of optimization schemes were tested under idling condition, and the exhaust noise was verified under rapid acceleration condition respectively. Meanwhile, the vibration response of exhaust system was analyzed. Results showed that the optimization schemes had better noise attenuation effect than the original scheme under idling and rapid acceleration conditions, indicating that it was necessary not only to effectively avoid the idling frequency interval of engine, but also to improve the structural stiffness and the vibration of local structure according to the vibration mode, and minimize the modification of the internal structure of the exhaust system.

Aiming at the problem of excessive low-frequency noise inside a minibus, the interior noise control scheme was studied to improve the NVH (Noise, Vibration, and Harshness) performance of the vehicle based on the characteristics of the structural acoustic radiation. With acoustic contribution as the evaluation index, the ability of the structure to radiate noise to the vehicle was studied from the perspective of modal participation and panel contribution. In this study, the legacy finite element model of the vehicle was firstly established, and the model was validated through the modal test of the BIW (Body in White), and the noise transfer function analysis was carried out to identify the critical frequency points. Furthermore, the improved super element method (SEM) was used to establish the super element simulation model of the vehicle, the simulation analysis of the modal contribution and panel contribution was carried out for the critical frequency points, and the panels that provide the main contribution were determined. In addition, a single-factor experimental study was carried out on the position of the critical panel by using the dynamic vibration absorbers with different performance parameters, so as to verify the accuracy of the simulation results of the panel acoustic contribution for the critical frequency. Finally, the structural optimization schemes of the critical panels were designed and verified by experiments. It was indicated that optimizing the acoustic radiation characteristics of the structure by improving the body panel structure to reduce interior noise was feasible.