| Crankshaft main bearing is one of primary friction pair of internal combustion engine,which will form a dynamic load radial lubricating oil film during the work process.Its work condition will not only directly affect the reliability and economic of internal combustion engine,but also affect the work life of internal combustion engine.In this paper,researched on high-speed boat gasoline engine,combined with flexible multi-body system dynamic model and radial sliding bearing elastic system model,analyzed crankshaft-bearing system lubrication performance under different system parameters and optimized the system parameters value which impacts crankshaft-bearing lubrication system.Firstly,the multi-body dynamic models are established for crankshaft bearing system of high-speed gasoline engine.Meanwhile,we added the relevant parameters,reduced the modal then completed the simulation results.By analyzing and comparing the results,the easiest wearing position and the regional form of bearing are consistent with actual situation in the experiment,which has verified the correctness and veracity of the simulation model.We can get the results that the lubrication conditions are worst when the main bearing at the speed of 4000r/min,the fourth Main bearing is most likely to wear.So the following research and optimization will proceed in the fourth Main bearing.Secondly,by analyzing the influence factors of the main bearing lubrication characteristics which includes the main bearing clearance,oil supply pressure,lubricating oil temperature,oil groove width,bearing surface roughness and the effect of various factors on the lubrication characteristics of the main bearing of the internal combustion engine,we can get the optimum parameter value under this circumstance.Finally,the experiment was designed to analyze the effect of the optimal parameters of the main bearing clearance,oil supply pressure,lubricating oil temperature,oil groove width and bearing surface roughness by using the optimal Latin hypercube(OLH).Calculated the maximum oil film pressure and the minimum oil film thickness,figured out the average friction power in the AVL_EXCITE model,then established an approximate model based on the radial basis neural network method.Meanwhile,the oil film thickness minimum and the oil film pressure range maximum was considered as the optimal constraint condition,the smallest of the oil film pressure,the largest of the oil film thickness,the minimum of the average friction power consumption were aimed,and the multi-objective optimization was adopted with multi-island genetic algorithm.The results showed that the lubrication characteristics of the main bearing was improved at a certain extent. |
