对1.5 L增压直喷汽油机主轴承孔变形进行优化，借助有限元仿真分析手段，分析主轴承盖止口过盈量、螺栓轴力及缸体材料塑性因素等对主轴承孔变形的影响。研究结果表明：对于该机型，主轴承盖螺栓轴力及夹紧区材料塑性变形是主轴承孔变形的主要影响因素，通过降低螺栓轴力可大幅降低主轴承孔变形；对于降低螺栓轴力优化方案，实测与仿真主轴承孔变形结果改善趋势一致，说明该主轴承孔变形仿真分析方法可实际工程应用。

The main bearing hole deformation of a 1.5 L supercharged GDI gasoline engine was optimized by using the finite element simulation and analysis method. The effects of interference of main bearing cap, bolt pretention force and material plasticity of cylinder block were mainly analyzed. The results show that the bolt pretention force of main bearing cap and the plastic deformation of material in the clamping zone were the main factors affecting the main bearing hole deformation. Reducing bolt pretention force could improve the main bearing hole deformation greatly. For the optimization scheme of reducing bolt pretention force, the improvement trend of measured and simulated results was consistent, the simulation analysis method of hole deformation hence could be applied in the engineering application.