Comparison of Otto, Diesel and Dual cycles

Based on Same Compression Ratio



# The comparison of Otto, Diesel and Dual cycle for the same compression ratio in p-v plot is shown below.

P-v plot

From p-v plot,

1247➡Otto cycle 

1267 ➨Diesel cycle

12357 ➡Dual cycle


# Here the compression ratio ‘r’ is equal for all cycles.

Compression ratio, r = V₂/V₁

Heat rejected is also equal for all cycles.


# We know that the efficiency of cyclic process is given by

η = 1- Q_R/ Q_S

Q_S - Heat supplied or absorbed

Q_R - Heat rejected

For constant heat rejection Q_R , the cycle efficiency increases with increases in the value of heat supplied, Q_S.

# In T-s plot, 

T-s Plot

The area under 1247 represents Q_S for Otto cycle

The area under 1267 represents Q_S for Diesel cycle

The area under 12357 represents Q_S for Dual cycle

Since,  Q_S)_Otto > Q_S)_Dual  > Q_S)_{Diesel ,}

η_Otto > η_Dual  > η_Diesel  , for same compression ratio



Note;

Area under p-v diagram represents Work done during the processes.

Area under T-s diagram represents heat transfer during the processes.

p = C ➡ Constant pressure processes.

v = C ➡ Constant volume processes.

Pv^Ɣ = C ➡ Isentropic processes.