The size, weight, and cost of the engine per horsepower are therefore less, and two-stroke-cycle engines are used in motorcycles and smaller machines (e. g. , lawnmowers and power rakes).
2
二冲程发动机没有移动的阀,火花塞每次点火活塞到达循环顶端。
A two-stroke engine has no moving valves, and the spark plug fires each time the piston hits the top of its cycle.