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Q2. A compression ignition engine working on the ideal dual combustion cycle has a volume compression ratio of 14:1.

The pressure and temperature at the beginning of compression are 0.95 bar and 30℃ respectively. The maximum pressure of the cycle is 44 bar and the constant pressure heat transfer takes place for 1/18 of the stroke.

(a) Sketch the cycle on Pressure-Volume and Temperature-specific entropy diagrams. (4)

(b) Calculate EACH of the following per unit mass of air:

(i) the heat supply; (6)

(ii) the heat rejected; (2)

(iii) the net work output; (2)

(iv) the thermal efficiency. (2)

Note:  For air C_p = 1.005 kJ/kg K C_v = 0.718 kJ/kg K