There is no "unit". It is a ratio. Just pick a unit. Since you're likely talking about engine displacement, liters are a good unit to use.
Engines are described in litres, but individual cylinder volumes are normally expressed in cubic centimetres (c.c.), but the compression-ratio is the same irrespective of measurement units because a ratio is dimensionless.
Compression ratio simply means the difference in size of the original vs compressed unit. Compression ratio is a commonly used term for internal combustion engine piston/cylinder compression and file compression. Ratios differ depending on the type of engine or the type of file being compressed. In file compression, 7zip has the highest compression ratio.
Mechanically To put it as simply as possible. The cubic inches of a cylinder and the amount of space your compressing it into is the compression ratio.
A conversion factor.
The lowest compression ratio of a compression-ignition engine that allows a specific fuel to be ignited by compression ignition.
23:1 compression ratio
The compression ratio for the 1995 Mustang is: 9.0:1
The compression ratio for NASCAR engines is limited to 12.0:1.
compression ratio=uncompressed image size/compressed size
compression ratio = compressed size / uncompressed size the ratio should be between 1 and 0 (multiply with 100 to get the ratio in percent) a ratio greater than 1 means, the compressed size is actually greater than the uncompressed size a ratio just below 1 means bad compression the lower the ratio, the better the compression
8.4:1 is the compression ratio for 04-07 STi's.
"600 psi" is not a compression ratio; it's a pressure. For a RATIO, you need to compare TWO different numbers.
The compression ratio is simply the ratio of the absolute stage discharge pressure to the absolute stage suction pressure.