This gets back to Seymour's vacuum analogy. A 1950s-style cylindervacuum provides the best comparison.
这样，我们就又回到了西摩关于吸尘器的类比，20世纪50年代风格的圆筒真空吸尘器是最好的类比物了。
2
Intake stroke: the camshaft opens the intake valve and the piston moves down the cylinder. This creates vacuum and sucks in air and fuel into the combustion chamber above the piston.
进气行程：凸轮轴打开进气阀，活塞在汽缸中向下运动，产生一段真空。
3
The brake booster USES vacuum from the engine to multiply the force that your foot applies to the master cylinder.