Optimized Design Of Structure For Exhaust System Of Engine Based On Lightweight

Firstly, the research background of exhaust system of automobile is introduced in this thesis. Combining with the development trend of exhaust and the enterprise's actual requirements, the necessity and urgency as well as the main purpose and significances of the research are discussed. In a detailed analysis of study statuses of exhaust system at home and abroad, the principal contents of this thesis and research approach are put forward.Then, the overall structure of exhaust system is analyzed in brief. In addition, main construction members, structural features and working condition of exhaust system are introduced, especially for exhaust manifold, exhaust adapter and cover of the exhaust manifold. The connect relationship between them are also introduced.Afterwards, giving the main theory which may be used in this paper, established the rationale for it.According to the relevant parameter supplied by the enterprise, calculated the entry condition of the exhaust manifold by GT-Power, obtained the pressure curve, temperature curve and mass flow curve. Based on these curves, calculated temperature field of the front exhaust pipe, and its'thermal stress later.Next, improvement measure put forward after calculating the modal of whole exhaust system, that's shorten the pipe's length between front exhaust pipe and supercharger. After the improvement, the requirement of lightweight achieved.And then analyzed the modal for the cover of the exhaust manifold and heat shield, reduce the mass of the structure to the minimum with the first modal frequency not changed too much.The result shows that the cover of the exhaust manifold and heat shield reduce0.22kg and0.15kg, which as about29.8%and28.4%of each original structure.Finally, the effect of the lightweight is analyzed, though whole mass reduced not much, it takes a big rate on original structure. And because of affected effect, bigger benefit will be generated.All studies in this thesis combined lightweight and fluid structure interaction together on exhaust system improvement, a creative way to solve the problem of exhaust system design. Not only supplied some reference and basis, but also figure out enterprise's practical problems. Providing practical tool for optimization of exhaust system as well as new idea and possible ways for exhaust system research, and have a fine practical significance.