Answer Happy

1- Two engine options are to be offered in a new automobile model. Engine A is naturally aspirated with a compression ratio of 10.5:1 and cylinder inlet conditions of 60°C and 96kPa. Engine B is supercharged with aftercooling and has cylinder inlet conditions of 80°C and 130 kPa. To avoid knock problems, it is desirable to have the air-fuel temperature at the start of combustion in engine B to be the same as in engine A. Calculate a. Temperature at start of combustion in engine A, using air-standard Otto cycle analysis. b. Compression ratio of engine B which would give the same temperature at the start of combustion. c. Temperature reduction in the aftercooler of engine B if the compressor has an isentropic efficiency of 82% and inlet conditions are the same as in engine A.