Analysis On The Multi-body Dynamics Of The Crankshaft Bearing System In High-speed Gasoline Engine

With the lightweight and miniaturization of petrol engine yacht, the rated speed is more and more high, generally about7500r/min to12000r/min. This high speed improves the power performance for the gasoline, but it is a big challenge for its development and manufacture, especially the wear between the moving parts. So to better analyze the wear condition of the high-speed gasoline engine, this paper adopted a good method which is based on the FEM technology and multi-body dynamics to study the multi-body dynamics of the crankshaft-bearing system in high-speed gasoline engine.Firstly, according to the actual circumstance of the crankshaft-bearing system, simplify the model and establish the finite element model of crankshaft and main bearing. Understand the bending stiffness and torsional rigidity of the crankshaft by ABAQUS finite element method to calculate the modal. Then seat the modal reduction of the crankshaft and bearing.Secondly, establish the multi-body dynamics of crankshaft-bearing system and input the corresponding parameters. After completing the simulation in an action cycle, it is concluded that the state of the torsional vibration, lubrication condition and stress distribution. With the consistency between the position of actual bearing wear and the simulated position, it proved the reliability of the multi-body dynamics model. At last by the analysis of dynamic stress response, found out the most dangerous stress points and made the course of its stress, then assessed their fatigue strength.Finally, by changing the key parameters, such as main bearing clearance, oil temperature, oil pressure and oil groove width, to study the effect of these parameters on the crankshaft-bearing system performance. It is concluded that the optimal range of parameters, it provides a powerful technical guarantee for the subsequent optimal design of the high speed gasoline engine crankshaft-bearing system. It has solved the burning phenomenon of the main shell in the high-speed gasoline engine by carrying on the optimization design of the crankshaft system.