Compressor Volumetric Efficiency & Clearance Calculator
Determine cylinder volumetric efficiency ($E_v$), clearance pocket throughput modulation, and discharge gas temperature ($T_2$) during compression.
Operating Pressures & Clearance
Efficiency & Discharge Temperature
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Cylinder Clearance & Volumetric Efficiency
At the end of a compression stroke, a small volume of high-pressure gas remains trapped in the cylinder clearance space (valve pockets, piston-to-head clearance, counterbores). As the piston withdraws on the suction stroke, this compressed gas must expand back down to suction pressure before the suction valves can crack open to admit fresh gas.
Capacity Control via Clearance Pockets
To modulate compressor throughput without energy-wasting bypass recycle, cylinders are equipped with manually or pneumatically operated variable clearance pockets. Opening a clearance pocket increases $C$, intentionally expanding the re-expansion stroke and reducing volumetric efficiency ($E_v$), dialing down flow while reducing driver horsepower.