Which option is not part of the Diesel cycle?

Which option is not part of the Diesel cycle?

• A. Adiabatic compression
• B. Isothermal compression
• C. Isobaric heat addition
• D. Isochoric heat rejection

Answer: (B)

Diesel cycle involves four specific thermodynamic steps: compression happens adiabatically (no heat transfer), heat addition occurs at constant pressure, expansion is adiabatic, and heat rejection occurs at constant volume. Isothermal compression would require heat transfer to keep temperature constant during compression, which is not how the Diesel cycle operates. So isothermal compression isn’t part of the Diesel cycle, while adiabatic compression, constant-pressure heat addition, and adiabatic expansion with constant-volume heat rejection are.

Diesel cycle involves four specific thermodynamic steps: compression happens adiabatically (no heat transfer), heat addition occurs at constant pressure, expansion is adiabatic, and heat rejection occurs at constant volume. Isothermal compression would require heat transfer to keep temperature constant during compression, which is not how the Diesel cycle operates. So isothermal compression isn’t part of the Diesel cycle, while adiabatic compression, constant-pressure heat addition, and adiabatic expansion with constant-volume heat rejection are.