Abstract: The crankshaft rotates and moves along the axis in internal combustion engine. A crankshaft-bearing system of a four-stroke four-cylinder internal combustion engine is taken as the object, lubrication analysis of main bearing considering axial movement of crankshaft and deformation of crankshaft under load are based on the three-dimensional hydrodynamic lubrication model. In the analysis, the axial movement of the crankshaft is measured by internal combustion engine test bench. Crankshaft main bearing load and crankshaft deformation of internal combustion engine is calculated by the whole crankshaft solid-element FE method. Lubrication of crankshaft main bearing is analyzed by dynamic method. The result show that the journal center trajectory of crankshaft main bearing is an unclosed and three-dimensional spatial curve when the axial movement of crankshaft is considered, and the minimum oil film thickness, maximum oil film pressure, frictional power loss and end leakage flow-rate of main bearing is changed obviously at some times of an internal combustion engine working cycle comparing with not considering the axial movement. The influence of crankshaft axial movement on the lubrication performance of main bearings of internal combustion engine is not always adverse. Therefore, in order to be more reasonable and closer to reality, it is necessary to take into account the influence of axial movement of crankshaft in the analysis of lubrication performance of crankshaft main bearing.

Key words: IC engine, main bearing, lubrication, axial movement of crankshaft, journal misalignment