目前有些工厂正在制造三曲轴的二冲程船用发动机.在机构上曲轴之间是用齿轮连接把发出的功率都传给下面那根和轴系相联的曲轴.发动机的三只气缸是布装在曲轴中心线的垂直平面内,每个气缸有二个活塞(见图1).为了要保证良好的换气过程,任意二个活塞之间都有一个提前角 At present, some factories are making three-crankshaft two-stroke marine engines, in which the crankshafts are connected with gears to transmit the power they generate to the crankshaft associated with the shaft system. The three cylinders of the engine are mounted on Crankshaft centerline in the vertical plane, each cylinder has two pistons (see Figure 1) In order to ensure a good ventilation process, there is an advance between any two pistons