An internal combustion engine with clearance volume of 60 cm3 and compression ratio of 8.5 is modeled using the following four processes:
Process 1-2: Polytropic compression with n = 1.2
Process 2-3: Constant volume heat addition
Process 3-4: Polytropic expansion with n = 1.3
Process 4-1: Constant volume heat rejection
Consider air in the cylinder is at 100 kPa and 77 degrees C at the start of compression and that the maximum temperature during the cycle is 1700 K. Consider variable specific heats for air.
(a) Find the pressure (kPa), volume (cm3), and temperature (K) at all states in the cycle.
(b) Calculate thermal efficiency (%) of the cycle.
(c) Show the cycle on P-v diagram. Label states and show property values.