Piston rings require an oil film between ring and liner and between ring and piston groove to seal against these high pressures and to prevent blowby.是什么意思_Piston rings require an oil film between ring and liner and between ring and piston groove to seal against these high pressures and to prevent blowby.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句