An air-standard Diesel cycle has a compression ratio of 17 and a cutoff ratio of 2. At the beginning of the compression process, air is at 95 kPa and 27°C. Take c, = 0.716 kJ/kg K, C, = 1.0 kJ/kg K. Determine the: 1. temperature after the heat-addition process. 2. thermal efficiency. 3. mean effective pressure. 4. temperature after compression. 5. pressure after compression

A 4 stroke spark ignition engine operates on an ideal Otto cycle with a compression ratio of 8.5. This engine compresses the fresh air-fuel mixture from its initial volume to a final volume of 75cm. The air is at 101kPa and 20°C prior to the compression stroke. Temperature at the end of isentropic expansion is 750K. Make air standard assumption to solve this problem. Air properties: cp = 1.005KJ/kg.K; cy = 0.718KJ/kg.K; R = 0.287KJ/kg.K. Determine, • Mass of air in the engine (in kg). (answer to 4 decimals) (Hint: treat air as ideal gas at start of intake stroke - point 1 on P-V diagram) Isentropic Isentropic * Iout BDC TDC