做功行程：当活塞到达压缩行程的上止点时，火花塞产生电火花。

Power stroke. As the piston reaches TDC on the compression stroke, an electric spark is produced at the spark plug.

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做功行程：当活塞到达压缩行程的上止点时，火花塞产生电火花。

Power stroke. As the piston reaches TDC on the compression stroke, an electric spark is produced at the spark plug.

youdao