Turbocharged And Intercooled Diesel Engine Bearing Lubrication Factors

As the continuous improvement of the ICE intensive index, its operating conditions become more and more serious. Such puts forward some more strict requirements for ICE bearings. Both the main bearing and the connecting rod big end bearing are the key frictions in ICE. Their lubrication performance is good or not directly affects the operating performance of ICE. On the research of the lubrication conditions of bearings, we can predict the performance of bearings. Thus provide reliable theory reasons for reasonable optimizing of bearings.In this paper, taking a four-cylinder turbocharged intercooled diesel as the research object, combining the elastohydrodynamic lubrication (EHD) theory and the muti-body dynamic theory (MBD), considering the elastic deformations of bearing shell and bearing seat, surface conditions of bearing shell and journal,and the oil supplying characteristics comprehensively. Discuss the lubrication performance of main bearings and conrod big end bearing respectively. Next, assess the bearing lubrication conditions. Furthermore, applying orthogonal experimental method, design Orthogonal projects for main bearings and conrod big end bearing. Then, calculating and analyzing them. Research the effect of bearing clearance, bearing width, the oil drilling position and oil diameter on the lubrication performance. Finally, optimize those design schemes.The results show that in range of engine speeds, the lubrication conditions of main bearings and connecting rod big end bearing are all well. The ratio between their minimum oil film thickness and bearing roughness is bigger than1. Every assessing index is satisfied with the designing requirements. Compared with other bearings, the oil film thickness of fifth main bearing is smallest. It occurs a slight eccentric wear phenomenon.In addition, compared the bearing lubrication results of diesel engine before and after reinforcement. The results show that no matter before strengthened or after strengthed, the main bearings and conrod big end bearings of diesel engine are all meet with the designing requirements.By means of analyzing the orthogonal experimental schemes, select the best one affected the lubrication performance. Compared with the original scheme, after optimizing the bearing parameters, the average of bearing load decreased by4.61%, the average of bearing moment decreased by4.72%, the minimum oil film thickness increased by27.43%, the peak oil film pressure decreased by16.79%, the average of total friction power loss decreased by21.68%, the average of oil outflow increased by50.79%. Select the best scheme of connecting rod big end bearing. Compared with the original scheme, after optimizing the bearing parameters, the average of bearing load changed a little, the minimum oil film thickness increased by54.3%, the peak oil film pressure decreased by6.1%, the peak aspect contact pressure decreased by98.5%, the average of total friction power loss increased by13.2%, the average of oil outflow decreased by36.2%.Besides, by the way of analyzing the effect of those various factors on the bearing lubrication performance, then, get a primary and secondary order. It is found that the bearing clearance, width, oil position and oil diameter are all owed significant effects on the bearing lubrication performance, and Bearing clearance and width have the most significant effect on the bearing lubrication performance.