piston

The mechanic removed a damaged piston from the engine. ▶

机修工从发动机中拆下了一个损坏的活塞。

In a conventional engine, expanding gases push each piston, converting energy from fuel into mechanical motion.

在传统发动机中，膨胀的气体推动每个活塞，将燃料的能量转化为机械运动。