Research On Numerical Simulation Of Shield Parts Noise/sealing Performance And Optimization Design

As the high-speed and high-intensive development of the vehicle and engine products, traditional design methods are facing unprecedented challenges, therefore, the need for efficient, energy saving and low-cost design approaches meeting higher and higher design requirements becomes considering urgent. At the same time, the FEM as the representative of the CAE technology has been widely used in the design of IC engine components, and automotive kinematics, dynamics simulation based on structural optimization and CAE technology are also gradually introduced to the automotive product design. The digital simulation technology can improve products'development of efficiency and quality and make from a comprehensive assessment from different point of views. This paper mainly studies the application of digital simulation methods in predicting and assessing the NVH and sealing performance of the IC engin thin-walled parts.The studies in this paper are based on a kind of diesel oil consumption and NVH performance improvement projects cooperated with Jiangling Motors Co., Ltd. During the project, engin thin-walled parts, such as engine oil pan, water pump shell and cylinder head cover are all redesigned to meet the low-noise target. In addition, taking oil pan gasket leakage into account, we also analysed its sealing performance, and proposed a high surface pressure and low internal stress design. Details are as follows:1) Introduced the subject of the research background, summed up the engine noise control and lightweight technology, the development process and the status of the industry research tools and methods both in and outside of the motherland. And also made a sealing related presentation, in which it concluded the simulation applications using modern design and optimize methods in the automotive industry.2) Described the basic theory in FEM/BEM, as well as the analysing and predicting method of the thin-wall parts radiated noise, then, carried out modal analysis, frequency response analysis and acoustic simulation prediction according to the former analysis.3) In order to provide strong validation to digital simulation analysis, further more, to ensure the accuracy of analysis, we distilled the feature point acceleration in the engine test, and conducted experimental modal analysis to thin-walled parts of diesel engine. In addition, we also did the sound intensity measurement experiment at the front of this engine.4) Based on the simulation results, we selected the graph-topology optimization method to modify the engine oil sump and completed its low-noise design. After that, the radiation noise compare between the oil sump modified and original was proceeded.5) Analysed the static sealing mechanism, and discussed the failure modes in the engine static sealing under micro-state. And on this basis, completed a sump gasket finite element modeling analysis, then presented a structural improvement program, which would improve the gasket sealing performance.