中文摘要：

以某四行程四缸内燃机为对象,在内燃机试验台架上进行多工况下的内燃机曲轴主轴承三维（即同时包括轴颈在轴承截面中的平面运动和轴线方向运动）轴心轨迹实际测量。轴颈在曲轴轴承中的位置采用电涡流传感器测量并通过后处理计算获得。结果表明,内燃机工作中,曲轴轴承轴颈存在沿轴线方向的运动;实际内燃机曲轴轴承的轴心轨迹为三维空间曲线;一个内燃机工作循环的曲轴轴承轴心轨迹曲线是不封闭曲线;曲轴轴承轴颈沿轴线方向存在较大的移动量,其数值大于轴承径向间隙;随内燃机转速和负荷增加,轴颈的轴向移动量增大;内燃机转速较低时,轴承轴颈的轴向运动在一个内燃机工作循环中的变化规律具有一定的周期性,变化周期数等于内燃机的气缸个数,而高转速情况下没有明显的变化规律性。

英文摘要：

A four-cylinder four-stroke internal combustion engine is taken as the object,the 3D trajectory（including the plane motion of the journal in the cross-section of bearing and the movement of the journal at axial direction） of the journal center of crankshaft main bearing in the internal combustion engine is measured under a number of operating conditions.The position of the journal in bearing is obtained by the data measured using eddy current sensors and after-processed.The results show that,there is the movement of the journal of crankshaft bearing along the axial direction in internal combustion engine,the real trajectory of journal center of crankshaft bearing is a three-dimensional spatial curve,the trajectory of the journal center of crankshaft bearing in one working cycle is not a closed curve,there is the relatively large movement of the journal of crankshaft bearing along the axial direction,and its value is greater than the radial clearance of bearing.The more the speed and load of engine,the larger the axial movement of journal is.There is the periodic variation of the axial movement of the journal of bearing in one engine working cycle at low speed,and the variation periodicity is equal to the cylinder number of internal combustion engine.However,there is not the obvious variation regularity at high speed.