The Otto cycle given by Dr. Nikolaus August Otto. This cycle consists of four processes, two isoentropic and two isochoric processes. In this cycle heat is supplied and rejected during the isochoric process.
The entire modern petrol engine works on the Otto cycle.
Here we will try to understand this cycle with the help of its P-V and T-S diagram.
1-2: Adiabatic compression
2-3: Isochoric heat addition
3-4: Adiabatic expansion
4-1: Isochoric heat rejection
Heat supplied during constant volume process 2-3
Heat rejected during constant volume process 4-1
The thermal efficiency of the Otto cycle given by the formula