The Finite Element Analysis Of The Whole Engine Of The 4D25G Diesel Engine

This paper takes the 4D25G diesel engine as specific research objects, analyzing mainly from the structure noise and strength of it. Among them, the works of the structure noise are mainly doing the modal and dynamic response analysis, and the works of the strength mainly doing the static analysis. The research results would be lessons and referring value to analysis and control vibration and noise of the whole diesel.First we establish the three-dimensional solid model of the diesel engine block, the cylinder head, the oil pan, the gear room cover and the cylinder cover parts , and then assemble on them. This is the basis and premise of a series of the later simulation analysis.Then, we do the modal analysis of the diesel engine block, the cylinder head, the oil pan and assembly. The analysis shows that in the three main components, the stiffness of the cylinder head is the largest and the engine block is the second and the oil pan is the smallest. Through the analysis of the modal natural frequency and vibration mode, we can learn their vibration characteristics. These, not only provide sufficient basis for the improvement of the structure, but also lay the necessary foundation for subsequent research of this paper.And then we do the static analysis of the engine block. Through the establishment of the finite element model, imposing appropriate load, and the constraint of consistent actual situations, we finally get the deformation and stress of the engine block in each cylinder maximum breakout pressure moment. Through the static analysis of the engine block, it proves the feasibility and reliability of structure of the engine block.Finally, we do the dynamic response analysis of the combination of the engine block and the cylinder head. Through the establishment of the finite element model of the combination, calculating the size of combustion pressure, the piston lateral force and the main bearing load, imposing appropriate constraint, we could do the dynamic response of the combination of diesel engine in a work cycle time, getting its relationship curves between the surface vibration displacement and speed and the time, and the picture at different time. These lay the foundation for the radiation noise prediction with the boundary element method, providing the basis for the improvement and optimization of the structure.