| Today diesel engines are widely used in industry. But with the enhancement of environmental protection consciousness in the world, the problem of vibration and noise of the diesel engine is deeply concerned. At the same time, pursuing the weightlessness and higher efficiency of the diesel engines, their blocks are needed to be made stronger and stronger. So low noise and high intension design has become one of the developing tendencies of the diesel engine design.Meanwhile, with the development of science and technology, the diesel engine design not only in theory but also in application changes greatly. Computers and Finite Element Method (FEM) technique have been used more and more popular, which made the technique of modal analysis, vibration and noise control, temperature and stress analysis enter into a new developing period.In this thesis, FEM technique is mainly concentrated and used to do thermal, modal and transient analysis on 4120SG diesel engine, which is useful to future design and amelioration.First, 3-D model based on the 2-D drawing of 4120SG diesel engine is established by software of PROE. Second, many factors acting on cylinder head, temperature field and thermal & mechanical stress field are calculated separately, all kinds of factors influencing cylinder heads' intension are researched and compared, and weakness of the structure is also analysed. Third, modal analysis under both free condition and restricted condition is calculated, the parts needed to be improved are proposed, the advantages and disadvantages are compared to offer the reference for dummy machine design. Finally, the transient analysis of the engine block is calculated based on the original modal analysis, and in the course of analysis, various loads are calculated.All kinds of factors being considered, static and dynamic analysis on 4120SG diesel engine using FEM method not only can be used to enhance engine design, to improve engine quality and to shorten its research period, but also can offer valuable data and modernized design experiences for the enterprise. The successful work isalso verified the feasibility of virtual designing technique, and it is demonstrated that FEM technology used in enterprise and product explore is very important. |
