What does compression ratio mean?
Glad you asked...
The term you are referring to, combustion ratio, describes the comparison of the cylinder volume to the combustion chamber volume of an engine. It is used to know how well the engine will perform.
chickiemomma1961, Shopping Expert
Then again, this answer might help you...
Compression ratio referring to an internal combustion engine is a value representing the ratio of uncompressed fuel/air mixture to compressed fuel/air mixture just prior to ignition.
Scootsalot, Shopping Expert