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

From 1 June, the compression ratio will be measured at 130C as well as ambient temperature, and from next year only at 130C.

From BBC ● Feb. 28, 2026

The compression ratio is a measurement of the cylinder displacement between the two extremes of the piston stroke.

From BBC ● Feb. 18, 2026

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

From BBC ● Feb. 2, 2026

Audi, Ferrari and Honda have complained to governing body the FIA because they believe Mercedes have found a loophole in the rule regarding compression ratio.

From BBC ● Feb. 2, 2026

Any desired ideal efficiency may be obtained from any of the cycles by selecting a suitable compression ratio.

From Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 4 "G" to "Gaskell, Elizabeth" by Various