Dynamic Analysis Of 8L265 Internal Combustion Engine Block Under Multiple Excitation

The internal combustion engine, as a major power machinery, plays an important role in the modern society. The research on the dynamic response characteristics of the internal combustion engine is an important content for the development of new engine. It has great influence on the vibration, noise, structural strength and fatigue life and other performance of internal combustion engine. And the engine block accounts for a large proposition in the whole engine. Also, it is the important support of other parts of engine.In this paper, based on the model of new inline 8 cylinder engine developed by the CNR, it does the calculation of the dynamics response of engine block. Under the guidance of finite element analysis (FEA) and the modal analysis theory, it establishes the FEM model and multi body dynamic model (MBD). Then the free modes and constraint modes are simulated to know about the inherent dynamic characteristics of the engine block. Establishing the multi-body dynamics model of the crankshaft, connecting rod and piston system, the curve of the main load in the time domain is researched. After the simulation calculation presented already, the transient dynamics of engine block is on the studying under the main load, including gas pressure, piston side force and bearing load. Then get the dynamic response of the vibration and stress signal and do further analysis of time-frequency analysis and spectrum analysis. This is to identify the main frequency of vibration signals of engine block surface in every direction. At last, the approach of reducing the vibration amplitude, the dynamic stress and force frequency as a goal is put forward to make the optimization.