- Starting from point 1, the air is compressed adiabatically to point 2.
- Fuel injection begins at 2, and heat is added to the cycle partly at constant volume 2-3, and partly at constant pressure 3-4.
- At 3, expansion begins and continues adiabatically till point 5.
- Then the heat is rejected to the exhaust at constant volume 5-1.
Note: Otto cycle has highest regards to fuel consumption as it rejects minimum heat but highest pressure is high. Dual cycle has least economy in fuel consumption but maximum pressure is low. Dual cycle falls between these two cycles i.e. fuel consumption is not very high as well as peak pressure is within limits.
