【摘要】 以四缸发动机为例 ,建立发动机活塞 -轴系的三维装配实体 ,选取不同的曲轴转角对其进行动特性分析 .计算结果表明 ,不同角度时活塞 -轴系的频率和振型略有不同 ,这种差异导致单一曲轴转角的动特性计算和物理样机实验结果的不确定性 ,所以对发动机不同曲轴转角下的动特性分析 ,更能够从本质上反映发动机所具有的特性更多还原

【Abstract】 The 3 D assembly model of a four cylinder engine with piston crankshaft system and block is established with the I DEAS software, then the whole dynamic characteristics analysis is carried out using FEM method in different crank angle. The result indicates that the inherent frequencies and the mode shapes of piston crankshaft system are appreciably different in different crank angle, which leads the result of inaccurateness in the physical prototype experiment and dynamic characteristic analysis of single crank angle. So the method of dynamic characteristic analysis in cycles reflects the inherent characteristics of engine in essence.更多还原