压缩比的定义就是气缸内活塞的最大行程容积与最小行程容积的比值。目前采用的“往复式发动机”,就发动机某个气缸而言,当活塞运行到距曲轴中心最远点,此时的位置称为下止点,整个气缸包括燃烧室所形成的容积便是最大行程容积,当活塞反向运动,距曲轴中心最近点时,这个位置称为上 The compression ratio is defined as the ratio of the maximum stroke volume of the piston in the cylinder to the minimum stroke volume. The current “reciprocating engine”, in terms of a cylinder of the engine, when the piston runs to the furthest point from the center of the crankshaft, the position at this time is called bottom dead center, and the volume formed by the entire cylinder including the combustion chamber is the largest Stroke volume, when the piston reverse motion, the closest point from the center of the crankshaft, this position is called