The temperature at the end of combustion in an Otto cycle is 2200 K. The excess...

Transcribed Image Text:

The temperature at the end of combustion in an Otto cycle is 2200 K. The excess air coefficient is 1.2. The fuel used is gasoline (C7.76H13.1). Calculate the volume percentages of CO2, H2O, O2 and N2 gases in the exhaust gases. Problem 7 In a binary cycle for a compression ignition engine, the temperature and pressure at the start of compression are 340 K and 150 kPa, respectively. The compression ratio is 20. The polytropic gas constant during compression is 1.35, and the polytropic gas constant during expansion is 1.25. At the end of combustion, the temperature and pressure are 2000 K and 13000 kPa respectively. The fuel used is C12H26. The excess air coefficient is 2. Find the average effective pressure of the cycle. Problem 8 The brake specific fuel consumption of the 4-stroke, 2-liter spark ignition engine operating at 3000 rpm is 250 g / HP-hour. Volumetric efficiency is 70%. Fuel used C7.76H13.1 Excess air coefficient is 0.9 Calculate the power of the engine (Pstd = 101.325 kPa and Tstd = 20 o C) Problem 9 A car with a total mass of 1550 kg moves at a speed of 100 km/h on a flat road with only the driver (70 kg). The car has a frontal projected area of 3.2 m2. Rolling resistance coefficient CR = 0.015 and drag coefficient CD = 0.3. Assuming that the brake thermal efficiency is 30% and the engine power is approximately equal to the road power, how many liters of gasoline will the vehicle need to travel 500 km? The heating value of the fuel is 44 MJ / kg. and the density of the fuel is 0.73 g/cc. (Pstd = 101.325 kPa and Tstd = 20 C) Problem 10 A newly designed car is expected to move at a top speed of 250 km/h at maximum power at a nominal speed of 6000 rpm with only the driver (70 kg). The curb weight of the car is 1700 kg, the front cross-sectional area is 3.0 m2, the rolling resistance coefficient is 0.012 and the drag coefficient is 0.3. What should be the size (total scavenged volume) of a 4-stroke engine for an average brake pressure of 1000 kPa? (Pstd = 101.325 kPa and Tstd = 20 C) Problem 11 If the turning radius of the racing car making a turn is 150 m and its constant speed throughout the return home is 300 km/h, how many "g" is the lateral acceleration on the driver? Problem 12 If the weight of a car weighing 1200 kg and the distance between its axles is 3.5 m, if the weight on the front wheels is 350 kg and the weight on the rear wheels is 250 kg, how far is the center of gravity of the car from the rear axle? Problem 13 The center of gravity of a car weighing 2500 kg is 90 cm behind its front axle. If the wheelbase of the car is 350 cm, what is the vertical force acting on the front and rear wheels? The temperature at the end of combustion in an Otto cycle is 2200 K. The excess air coefficient is 1.2. The fuel used is gasoline (C7.76H13.1). Calculate the volume percentages of CO2, H2O, O2 and N2 gases in the exhaust gases. Problem 7 In a binary cycle for a compression ignition engine, the temperature and pressure at the start of compression are 340 K and 150 kPa, respectively. The compression ratio is 20. The polytropic gas constant during compression is 1.35, and the polytropic gas constant during expansion is 1.25. At the end of combustion, the temperature and pressure are 2000 K and 13000 kPa respectively. The fuel used is C12H26. The excess air coefficient is 2. Find the average effective pressure of the cycle. Problem 8 The brake specific fuel consumption of the 4-stroke, 2-liter spark ignition engine operating at 3000 rpm is 250 g / HP-hour. Volumetric efficiency is 70%. Fuel used C7.76H13.1 Excess air coefficient is 0.9 Calculate the power of the engine (Pstd = 101.325 kPa and Tstd = 20 o C) Problem 9 A car with a total mass of 1550 kg moves at a speed of 100 km/h on a flat road with only the driver (70 kg). The car has a frontal projected area of 3.2 m2. Rolling resistance coefficient CR = 0.015 and drag coefficient CD = 0.3. Assuming that the brake thermal efficiency is 30% and the engine power is approximately equal to the road power, how many liters of gasoline will the vehicle need to travel 500 km? The heating value of the fuel is 44 MJ / kg. and the density of the fuel is 0.73 g/cc. (Pstd = 101.325 kPa and Tstd = 20 C) Problem 10 A newly designed car is expected to move at a top speed of 250 km/h at maximum power at a nominal speed of 6000 rpm with only the driver (70 kg). The curb weight of the car is 1700 kg, the front cross-sectional area is 3.0 m2, the rolling resistance coefficient is 0.012 and the drag coefficient is 0.3. What should be the size (total scavenged volume) of a 4-stroke engine for an average brake pressure of 1000 kPa? (Pstd = 101.325 kPa and Tstd = 20 C) Problem 11 If the turning radius of the racing car making a turn is 150 m and its constant speed throughout the return home is 300 km/h, how many "g" is the lateral acceleration on the driver? Problem 12 If the weight of a car weighing 1200 kg and the distance between its axles is 3.5 m, if the weight on the front wheels is 350 kg and the weight on the rear wheels is 250 kg, how far is the center of gravity of the car from the rear axle? Problem 13 The center of gravity of a car weighing 2500 kg is 90 cm behind its front axle. If the wheelbase of the car is 350 cm, what is the vertical force acting on the front and rear wheels?