Research on noise control of automobile exhaust system under idling condition based on modal analysis

Abstract

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.