中重型柴油机扩缸前后缸套变形的数值分析

降低缸套壁厚可以在保持发动机紧凑性的同时提高排量，而缸套变形是限制许用厚度的主要瓶颈，针对这一问题，选择缸套壁厚和材料作为变量，缸套变形圆柱度和傅里叶展开系数作为评判指标，研究了薄壁湿式气缸套的可行性。通过对某型柴油机进行有限元分析，发现缸套壁厚从8．25 mm 降低到6．25 mm 后缸套变形明显变大，而改用钢质材料后缸套变形与原机相当，证明了通过降低缸套壁厚同时采用弹性模量更高的材料是一种可行的扩缸方法。

Numerical Analysis of Liner Deformation of Medium and Heavy Duty Diesel Engine before and after Cylinder Enlargement

The radial reduction of cylinder liner wall would increase engine swept volume without the change of engine size , but was difficult to carry out due to the restricted allowance thickness by liner deformation .For the bottleneck ,the feasibility of wet thin‐wall cylinder liner was researched by defining the liner wall thickness and material as the variables and choosing cylin‐dricity and Fourier expansion coefficient as the evaluation indexes .According to the finite element analysis of a diesel engine , the liner deformation became serious when the wall thickness decreased from 8 .25 mm to 6 .25 mm ,but improved and compared to the original liner when the steel wall was applied .It was proved that the radial reduction of liner wall and the application of higher elastic material was a feasible way to enlarge cylinder bore .