Word forms: (regular plural) compression ratios
( Automotive engineering : Vehicle components , Engine, transmission, and exhaust ) compression1, compression2
The compression ratio
in an engine is the ratio of the volume of the cylinder plus combustion chamber
at the bottom
of the stroke (when the volume is greatest
) to the volume at the top
of the stroke (when the volume is least.)
This design has the facility to tilt the cylinder head slightly, so that the compression ratio can be altered automatically according to engine load and revs.
Not all engines have the same compression ratio, and an engine with a ratio set for a 95RON fuel will usually gain no benefit from
using 98RON fuel since the pistons will not compress the fuel to its maximum.
To determine the compression ratio of an internal combustion engine, compare the greatest volume of the piston cylinder
to the lowest volume.
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