compression ratio

American  

noun

Automotive.

1. the ratio of the cylinder volume enclosed by the piston at its outermost position to the volume enclosed by it at its innermost position.

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compression ratio British  

noun

1. the ratio of the volume enclosed by the cylinder of an internal-combustion engine at the beginning of the compression stroke to the volume enclosed at the end of it

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Etymology

Origin of compression ratio

First recorded in 1905–10

Example Sentences

See Examples For:

compression ratio

Formula 1's governing body the FIA said on Saturday that a change to the way the compression ratio was measured would be introduced on 1 June, with a further revision for the 2027 season.

From BBC ● Feb. 28, 2026

Typically, the compression ratio reduces when engines heat up, and the belief was Mercedes had found a way using materials technology to limit this loss.

From BBC ● Feb. 20, 2026

Red Bull's position on the compression ratio argument has not been clear until now, following their entry as a power-unit manufacturer this season.

From BBC ● Feb. 18, 2026

And it's not only on compression ratio, but on other things too.

From BBC ● Feb. 2, 2026

"You've got thirty tons of fuel—you want to find the compression ratio of the number-one firing-tube chamber—so what do you do?"

From Stand by for Mars! by Glanzman, Louis