It links the piston and crank, piston top face in the role of the gas expansion of the crank to enable the movement to the piston into the rotation of the crank movement.

• 连杆是柴油机中非常重要的一个部件，它连接了活塞与曲轴，把作用在活塞顶面的气体膨胀的力传给了曲轴，使活塞的往复运动变为了曲轴的旋转运动。