A citybus engine has the following characteristics: Engine displacement: 12.9 liters 6 cylinders, in-line placement; Fuel: Diesel Compression ratio: 18.5:1 Cut-off ratio: 2.5 The engine's inlet conditions are 20C and 1 bar Maximum engine pressure: 5 MPa Using an ideal air-standard Diesel cycle, calculate the following and remember to show all your calculations: a. the temperature and pressure at state points 1, 2, 3, and 4. (15) b. the heat and work transferred in each of the four processes. (20) c. The cycle's thermal efficiency. (5)