Analysis Of Dynamic Characteristics Of Exhaust System Under Pavement Excitation

Along with development of Vehicle performance and engine Power, the problem of vehicle exhaust, vehicle noise and vehicle vibration are increasingly serious. Automotive exhaust system play a very important role in tail gas treatment, noise control and comfort of vehicle. Because automotive exhaust system works in the complex environment, resonance of exhaust system has impact on service life of exhaust exhaust system such as engine excitation, road excitation, engine air excitation, sound vibration, vibration of car body. Then it is important guiding significance to analysis vibration characteristics of automotive exhaust system..The paper illustrate the basic theory of automobile exhause system, from the engin’s exhause noise, the compotion of exhause system, the assessment index of exhause system, and the vibration sources of exhause system. The paper explain the basic theory and ananly procedure of model analysis and harmonic response analysis. At first we use UG software to establish the three-dimensional models of automotive exhaust system. Because its structure is very complex, we simplify the simulation model. Secondly the model is introduced into ANSYS Workbench for data analytics about the free mode, constraint mode, and harmonic response analysis.Research results show that:We get the exhaust system’s natural frequencies and mode shapes, and find that the maximum deformation is main in the bellows. Because exhaust system constraints natural frequencies and mode of engine idle speed and no economic speed excitation frequency coincides, the exhaust system is not resonant with the engine speed of the two major incentives occur. Harmonic frequency response of the exhaust system and road excitation frequencies coincide, so description incentive pavement will affect the life of the use of the exhaust system. With model analysis and harmonic response analysis, we prove the point when the muffler hanging200mm when moving forward and then adjusted to optimize the stiffness of the rubber pad10is a reasonable solution. At the same time, we learn that it is convenient to analyze the mode analysis and harmonic response analysis by ANSYS Workbench.