The piston is essentially a cylindrical plug that moves up and down in the engine cylinder. It is equipped with piston rings to provide a good seal between the cylinder wall and piston.

• 实质上活塞是一个在气缸中上下移动的圓筒状的塞子。上面装有活塞环,从而使活塞和气缸壁之间具有良好的密封性。