Two engine options are to be offered in a new automobile model. Engine A is naturally...

 

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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 60C and 96 kPa. Engine B is supercharged with after-cooling and has cylinder inlet conditions of 80C 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. [k = 1.35]. Calculate: (a) Temperature at the start of combustion in engine A, using air-standard Otto cycle analysis. [C] (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. [C] 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 60C and 96 kPa. Engine B is supercharged with after-cooling and has cylinder inlet conditions of 80C 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. [k = 1.35]. Calculate: (a) Temperature at the start of combustion in engine A, using air-standard Otto cycle analysis. [C] (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. [C]

Answer rating: 100% (QA)

SOLUTION a Temperature at the start of combustion in engine A using airstandard Otto cycle analysis The airstandard Otto cycle assumes ideal behavior for the working fluid and neglects any heat transf... View the full answer