A two-litre, four-cylinder, four-stroke, spark ignition engine operates on an Otto cycle with the throttling valve...

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A two-litre, four-cylinder, four-stroke, spark ignition engine operates on an Otto cycle with the throttling valve partially open. It uses petrol with a heating value of 41,000 kJ/kg at an air-fuel ratio of 11. The engine speed is 2500 RPM and its compression ratio is 9.5. It has a combustion efficiency of 98% and a mechanical efficiency of 86%. At the end of the expansion process, conditions in the combustion chamber are at 550 kPa and 1800 °C. It is assumed that there is 5% exhaust residual for the next cycle. Determine (ii) (iii) (iv) the temperature [°C] and pressure [kPa] at each state of the cycle. the torque of the engine. [Nm] the mass flow rate of unburnt fuel exhausted to the atmosphere. [g/s] the rate of waste heat discharged by the engine. [kJ/s] A two-litre, four-cylinder, four-stroke, spark ignition engine operates on an Otto cycle with the throttling valve partially open. It uses petrol with a heating value of 41,000 kJ/kg at an air-fuel ratio of 11. The engine speed is 2500 RPM and its compression ratio is 9.5. It has a combustion efficiency of 98% and a mechanical efficiency of 86%. At the end of the expansion process, conditions in the combustion chamber are at 550 kPa and 1800 °C. It is assumed that there is 5% exhaust residual for the next cycle. Determine (ii) (iii) (iv) the temperature [°C] and pressure [kPa] at each state of the cycle. the torque of the engine. [Nm] the mass flow rate of unburnt fuel exhausted to the atmosphere. [g/s] the rate of waste heat discharged by the engine. [kJ/s]

Answer rating: 100% (QA)

SOLUTION i Temperature and pressure at each state of the cycle 1 Intake stroke Pressure 1013 kPa atmospheric pressure Temperature 20C ambient temperature 2 Compression stroke Pressure 9512 kPa compres... View the full answer