多缸内燃机缸体瞬态动力分析

Transient Dynamic Analysis of a Multi-Cylinder Engine

建立了某4缸内燃机缸体的有限元模型,运用完全矩阵法进行了缸体的模态分析及瞬态动力分析。分析中考虑了缸套所受的缸套—活塞间的润滑油膜力、曲轴主轴承处所受的油膜动压作用、燃烧室内气体压力的作用以及缸盖对缸体的作用力。缸套—活塞间的油膜力通过求解平均雷诺方程得到。曲轴主轴承处所受的油膜力由主轴承油膜润滑与活塞—连杆—曲轴系统动力学的耦合分析得到。瞬态动力学分析表明:该型号的内燃机在工作过程中,缸体的受迫振动主要是弯曲振动及沿缸套轴向的伸缩振动。缸体的振动会对缸套—活塞间的油膜润滑产生很大影响。

A FEM model of the cylinder block of a 4cylinder has been built,and its model and transient dynamic analysis were done with ANSYS by considering the lubrication of cylinderpiston pair and crank main bearing.The lubrication of cylinderpiston pair was simulated with an average Reynolds equation by considering the secondvibration of the piston.The oil film forces in crank main bearings were from the result of an analysis of coupling pistonrodcrank system dynamic behavior to crank main bearing lubrication.According to the transient dynamic response of some points on the engine, we found that the blocks vibrations are mostly the bent vibration in the plane of xoy and the vibration in y direction.