Research of automotive exhaust system hanger location

Under the excitation of the engine and road surface, the vibration energy of the exhaust system which will result in the vibration of the body and produce the structure noise transfers to the body from the hanger. This will seriously affect the noise, vibration and harshness (NVH) performance of the vehicle. Average driving degree of freedom (DOF) displacement (ADDOFD) is applied to select hanger locations of the automotive exhaust system in this paper. The numerical model of the normal modal analysis of the exhaust system has been studied; several numerical models have been analyzed with the test correlation technology; and the accurate numerical model has been found. Exhaust systempsilas free-free mode and sum of its eigenvectors are offered using MSC.Nastran. Hanger locations are recommended at the position where the ADDOFD is relatively lower. Then static analysis and dynamic analysis of the exhaust system are done, and finally hanger locations of the exhaust system are selected. When the reasonable hanger positions have been decided, the vibration level of the body and the internal noise would have been decreased. This method can effectively select better NVH performance hanger locations in the earlier vehicle development process.