Compression ratio

Japanese: 圧縮比 - あっしゅくひ（英語表記）compression ratio

In internal combustion engines and compressors, the ratio of the volume at the start of compression to the volume after compression. The piston position when the cylinder volume is smallest during its reciprocating motion is called the top dead center, and the volume at that position is called the clearance volume _Vc . The piston position at which the volume is maximum is called the bottom dead center, and the volume between these two dead centers is called the stroke volume _Vs. The compression ratio is expressed as the ratio ( _Vc + _Vs )/ _Vc . It is an important design factor that directly affects the engine performance and combustion.

Source: Encyclopaedia Britannica Concise Encyclopedia About Encyclopaedia Britannica Concise Encyclopedia Information

Japanese:

内燃機関や圧縮機において，圧縮始めの容積と圧縮後の容積との比。ピストンの往復運動中シリンダ内容積が最小になるときのピストン位置を上死点，その容積をすきま容積 V_c といい，最大容積になるピストン位置を下死点，両死点間の容積を行程容積 V_s といい，圧縮比は (V_c＋V_s)/V_c という比で表わされる。機関の性能や燃焼に直接影響する重要な設計因子である。

出典　ブリタニカ国際大百科事典小項目事典ブリタニカ国際大百科事典小項目事典について　情報

<<: Assur; Ashur

>>: Compressed air - Compressed air