Research Of Lubricating Property Of The U-Shape Connecting Rod Big Bearing

Energy saving and emission reduction of the internal combustion engines has become the strategic needs of the country. So all kinds of technology appear such as direct injection and homogeneous combustion in cylinder, etc. Among them, the internal combustion engine bearing lubrication as an important influence factor of the operating performance has been widely researched. And the higher requirement for the reliability of the engine components has raised with the strengthen of the internal combustion engine performance indicators. So studying crankshaft bearing lubrication has important significance for the engine working reliability and durability. The thesis mainly research the influence of the U-shape connecting rod bearing and journal on the bearing lubrication property based on a four cylinders diesel engines, considering the installation deformation of bearings and the OSL.Firstly, study the development of the theory of fluid lubrication including the found of the fluid dynamic pressure and the perfect of Elasto-hydrodynamic. List the average Reynolds equation, oil film thickness equation and elastic deformation needed for solving the bearing lubrication and relevant boundary conditions. Then explain the meaning of the parameters. Analyze the formation and solving of the bearing oil film that will lay the theoretical foundation for the analysis of crankshaft bearing lubrication.Secondly, study the multi-body dynamics theory, give the control equation of flexible multi-body. Divide the model into body element and connecting element considering the linear and nonlinear of the structure. In order to improve the calculation efficiency, reduce degree of freedom of body. Then get the files containing stiffness matrix, mass matrix and damping matrix.Then carry out multi-body dynamics and elastic hydrodynamic lubrication coupling calculation based on the four cylinders diesel engine. Adopt the flexile body and EHD2 bearing unit. Consider the influence of bearing installation deformation, surface roughness and OSL. Results show that U-shape connecting rod bearing and journal has more advantages over the traditional connecting rod bearing and journal. Peak oil film pressure and rough peak contact pressure reduce. The minimum oil film thickness and oil film flow increase. The bearing heat road improves. All of these improve the performance of the bearing lubrication.Bearing lubrication is also affected by speed, load, supply oil pressure, oil hole position and bearing structure. In this paper, study the influence of different structure of main bearing, connecting rod journal oil hole location and oil type on the bearing lubrication. This will provide a good direction for bearing lubrication design.