The top of the piston is shaped to give the incoming mixture an upward movement. This helps to sweep the Burned gases ahead and out through the exhaust port.

活塞顶部的形状使进入气缸的可燃混合气向上运动，这样有助于扫气，引导燃烧过的废气向上运动并从排气口排出。

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The caucus is "very concerned" that violence not sweep through the capital of Port-au-Prince and that the democratic process "is not further compromised, " he said.

CNN: Dems slam White House on Haiti policy