Air standard cycles employs air as the working fluid assuming air to behave as a perfect gas.

Types of air cycles are.

1. Carnot Cycle
2. Otto Cycle
3. Diesel Cycle

Carnot Cycle:

Carnot cycle consists of four operations.

• Isothermal expansion
• Adiabatic expansion
• Isothermal compression
• Adiabatic compression

Otto Cycle:

Otto cycle is additionally referred to as constant volume cycle. In this Otto cycle four operations are there.

1. Adiabatic compression
2. Addition of heat at constant volume
3. Adiabatic expansion
4. Rejection of heat at constant volume

• 1 – 2 = Adiabatic compression
• 2 – 3 = Addition of heat
• 3 – 4 = Adiabatic expansion
• 4 – 1 = Rejection of heat

Diesel cycle:

Diesel cycle is additionally referred to as constant pressure cycle. The diesel cycle consist of

• 1 – 2 = Adiabatic compression
• 2 – 3 = Addition of heating at constant pressure
• 3 – 4 = Adiabatic expansion
• 4 – 1 = Rejection of heat