On a 2-stroke engine, the upward stroke is the compression stroke.

在2冲程发动机，向上中风是压缩行程。

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However, in a compressed air engine, no additional energy is gained if the air in the cylinder is compressed on the upward stroke of the piston.

然而，在压缩空气引擎，不需要额外的能源是涨，如果空气中的气缸压缩的向上中风活塞。

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This upward leader connects with the downward leader and a return stroke occurs. Five more dart leader-return strokes follow.

上行先导与下行先导连接，于是产生了一次回击，随后又是五次以上的直窜先导型回击。

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