A question on aircraft engines

Question

any one av a defination 4 'compression ratio?'

Answer 1

pressure change from intake (manifold) pressure compared to the compressed cylinder pressure.

Answer 2

Perhaps you were also wondering about EPR, engine pressure ratio. This is the ratio of turbine engine inlet pressure to compressor discharge pressure. It is a convenient measure of engine power. Power levers are set according to EPR on most takeoffs.

Answer 3

The ratio of the space in the cylinder when the piston is fully down, compared to the space there is when the piston is fully up.

Answer 4

For piston engines, the compression ratio is as previously noted, the ratio between the volume contained in the cylinder by the piston after filling with fresh fuel-air mixture (generally at the bottom of the piston's travel) and the volume contained when the piston reaches the upper limit of its travel.

For jet engines, the compression ratio is the ratio between ambient air pressure as it enters the engine and the maximum pressure obtained at the end of the compression stages within the engine.