Abstract: Based on the thermohydrodynamic lubrication theory of dynamically loaded bearing, researches on the lubrication of internal combustion engine(ICE)’s main bearing considering thermal deformation effects are presented combining with thermal deformation matrix method. Basic theory and govern-ing equations adopted here are described. Influences on main bearing’s lubrication performance from thermal deformation are also discussed here, such as on journal orbit, oil flow rate, maximum film pressure and minimum film thickness, etc. A simulation analysis example with ICE’s main bearing is pre-sented. Simulation results show that the orbit of journal has a large change with considering thermal deformation effects. And the average flow rate and maximum film pressure in one load cycle are increased evidently. While the minimum film thick-ness in one load cycle is decreased distinctly. The rise of oil temperature in one load cycle has just a little change. It points out that, thermal deformation will appear in ICE’s main bearing when it works due to many kinds of heat factors and this de-formation should be considered seriously in the design of main bearing and ICE’s lubrication system.

Key words: Internal combustion engine’s main bearing, Simulation, Thermal deformation, Thermohydrodynamic lubrication