上部的活塞环用来阻止压缩空气泄露；而下部的活塞环用来控制气缸壁上存留下来的机油数量。

The upper ring or rings are to prevent compression leakage; the lower ring or rings control the amount of oil being deposited on the cylinder wall.

youdao

窜气，基本上是被压缩的空燃混合气和燃烧后的气体的泄漏，它通过活塞环进入曲轴箱。

Blowby is basically the leakage of compressed air-fuel mixture and burned gases past the piston rings into the crankase.

youdao

对压缩机汽缸的科学设计以及电机、活塞环、传动系统质量的控制，能够大幅提高单位功率下的产气量。

Compressor cylinder to the scientific design and motor, piston, transmission system of quality control, can greatly improve the gas production unit power.

youdao