Isentropic Expansion (2-3)
The second stage (2-3) involves a reversible adiabatic expansion of the fluid back to its original pressure. It can be determined for an isentropic process that the second law of thermodynamics results in the following:
Where for this specific cycle. The first law of thermodynamics results in the following for this expansion process: because for an adiabatic process: 
Read more about this topic: Lenoir Cycle
Famous quotes containing the word expansion:
“Artistic genius is an expansion of monkey imitativeness.”
—W. Winwood Reade (1838–1875)