Study On Hangers’ Location And Static&Dynamic Characteristics Of An Automotive Exhaust System

As an important part of the vehicle, exhaust system play an important role in controlling exhaust emissions and noise pollution from engine. As a result, its performances of the purification, noise reduction and static&dynamic performance have drawn extensive attention. For the exhaust attachs directly to the engine and body, its performance will directly influence on the performance of riding amenity. Reasonable design of hangers’location can effectively isolate the vibration energy transmitting from the engine to the body, enhancing the level of the whole vehicle’s noise and vibration, and improving the fatigue durability of the exhaust system. Therefore, it is very necessary to study and discuss the hangs’position and its vibration characteristics.In this paper, based on the exhaust of a vehicle, first of all, its numerical analysis model was established through simplifying and modeling each component of the exhaust system. Then the numerical modal analysis was carried out on the exhaust system and compared with experimental modal analysis results. This two analysis results coincided highly with each other, verified the accuracy and reasionality of the established numerical analysis model of the exhaust system.Secondly, on the basis of the numerical modal analysis, the hangers’location was selected and designed according to the average driving degree of freedom displacement method. Then the static anslysis, constraint modal analysis and dynamic analysis were carried on the exhaust system. The analysis results showed that the force on every hanger was equal, met the system requirement of the stress. What’s more, the natural frequencies of exhaust system kept away from the engine idle excitation frequency and the dynamic response force which transmitted to the body by the hangers was within the limitation. Thus further verified the rationality of the design of the hanging position and also got the vibration characteristic of the exhaust system.Finally, the influence on the exhaust system’ modal characteristic made by the parameter changes of key components was studied through the sensitivity analysis. This played a significance guiding role on the optimization of modal characteristic of the exhaust system.