Compression method
I. Isothermal compression: A compression method in which the temperature is always constant when the gas is compressed.
II. Adiabatic compression: A compression method in an adiabatic state that neither heats nor removes heat from the outside.
III. Polygonal curve compression (compression method actually used): It is a compression method that dissipates a part of the generated heat, exchanges heat with the outside, and is different from isothermal compression and adiabatic compression.