A 700 kg sports car is powered with a 1.6 litre, 4-stroke, 6-cylinder engine. At 5,000 rpm, the engine produces 100 kW o

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A 700 Kg Sports Car Is Powered With A 1 6 Litre 4 Stroke 6 Cylinder Engine At 5 000 Rpm The Engine Produces 100 Kw O 1 (105.74 KiB) Viewed 54 times

A 700 kg sports car is powered with a 1.6 litre, 4-stroke, 6-cylinder engine. At 5,000 rpm, the engine produces 100 kW of power. The engine has an overall efficiency of 46% and the breathing and mechanical efficiencies are 90% and 82% respectively. We will model this as an Otto cycle operating on an ideal gas and you may assume that Rg = 0.287 kJ/kg/K and y = 1.4, where y is the adiabatic index. (a) Determine the compression ratio, brake work and net work output per cylinder, per cycle. (10 marks) (b) At the intake, the air pressure and temperature are P1 = 101 kPa and T1 = 288 K. Determine the temperature at each stage in the process, the work done during compression and expansion and the heat rejection per cylinder per cycle. (8 marks) (c) Suggest two ways in which the thermal efficiency of the engine could be improved and briefly explain how each method works. (2 marks) (d) The air-fuel mix consists of 1.6% petrol by mass and petrol has a density of 0.8 kg/litre. Assuming the car travels at 70 mph (112 km/hour) in 6th gear at 5000 rpm, determine the fuel economy of the engine in km/litre. (5 marks)