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

To give it considerably more punch, Mr. Allen applied age-old engine modifications, including increasing the engine’s compression ratio and its displacement.

From New York Times

To achieve this, Nissan said it strengthened in-cylinder gas flow and ignition, which burns a more diluted air-fuel mixture at a high compression ratio.

From Reuters

The fuel system works in synergy with a range of variables, including ignition timing, supercharger boost, compression ratio, clutch application rate and more.

From New York Times

The power bump is thanks in part to a redesigned exhaust manifold and new pistons designed to increase the engine’s compression ratio.

From Fox News

It’s a turbocharged four-cylinder with a variable compression ratio.

From Fox News