对置活塞二冲程汽油机曲柄连杆动力学分析

Crank-rod Dynamics Analysis for Two Stroke Gasoline Engine

为分析对置活塞二冲程汽油机的动力学特性,对不同连杆比的分析结果表明,连杆比越小,发动机两缸活塞运动加速度的矢量和越小,即机构的平衡性越好。由于对置活塞二冲程汽油机本身具有的结构特点,两个同步曲轴存在一定的相位差,对不同曲轴相位差的分析可知,曲轴相位差越小,发动机两缸活塞运动加速度的矢量和越小。左侧曲柄连杆受到的力要比右边曲柄连杆机构受到的力小些。竖直方向的分力要比气缸轴线方向的分力小很多,而且竖直方向的分力呈现近似三角函数的规律,水平方向的受力由于惯性力和气体作用力的双重影响,变化规律比较复杂。

In order to analyze the dynamic characteristics of opposed piston two stroke gasoline engines, different crank rods are analyzed. It is found that the smaller connecting rod ratio will obtain less piston acceleration, namely better balance of me-chanical structure. For its characteristics, the two synchronous crankshafts exist phase difference. With the analysis of different phase, it is found that the less phase difference will decrease the vectorial acceleration of the two pistons. The force of left crank connecting rod is less than the right one. The vertical force is much less than the cylinder axis direction and the compo-nent force of vertical direction express as trigonometric function. The force in horizon direction is more complex as it is af-fected by the inertia force and the in-cylinder force.