The car was powered by a four cylinder air-cooled engine.

这辆汽车是由一个四缸气冷式发动机驱动的。

《柯林斯英汉双解大词典》

The engine, as it cooled itself, sucked in air through the outlet hose, producing suction in the vacuum chamber, and so drawing the plunger down and compressing the spring.

当引擎冷却时，通过出口软管吸入空气，在真空管产生吸气，导致柱塞向下挤压弹簧。

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Beetles of that era came in two body styles — hard-top and cabriolet — and with one powertrain option: air-cooled, rear-engine, three-speed manual transmission.

那个时代的甲壳虫有硬顶式和敞篷式两种车身造型，不过动力系统却没得选，只有一款风冷后驱发动机，搭配三速手动变速箱。

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By the early 20th century Syracuse became famous for production of Smith Corona typewriters, Syracuse China, Nettleton shoes, bicycles, wax candles and the Franklin, an ahead-of-its-time automobile with an air-cooled engine.

FORBES: Willis Carrier's Ghost