An internal combustion engine of a car is operating at a brake power of 150 kW. The indicated thermal efficiency of the engine is 30%, and the mechanical efficiency is 85%. The fuel used has a calorific value of 44,000 kJ/kg. Calculate the following: Indicated Power of the engine. Brake Specific Fuel Consumption (BSFC). Fuel consumption rate in kg/hr. Given Data: Brake Power (BP) = 150 kW Indicated Thermal Efficiency = 30% or 0.30 Mechanical Efficiency = 85% or 0.85 Calorific Value of fuel = 44,000 kJ/kg

Use the following conversions where necessary:1hp = 745.7W; ρwater = 1000 kg/m3; ρmercury = 13600 kg/m3; 1 atm = 101.325 kPa; Cp (water) = 4.18 kJ/kg °C; g = 9.81m/s2; For properties of air, use R = 0.287 kJ/kg K; Cv (air) = 0.718 kJ/kg K; Cp (air) =1.005 kJ/kg K Warm air is contained in a piston-cylinder assembly oriented horizontally. The air cools slowly from an initial volume of 0.003 m3 to a final volume of 0.002 m3. During the process, the spring exerts a force that varies linearly from an initial value of 900 N to a final value of zero. The atmospheric pressure is 100 kPa, and the area of the piston face is 0.018 m2 . Friction between the piston and the cylinder wall can be neglected. For the air in the piston-cylinder assembly, determine the initial and final pressures, each in kPa and atm.

2 A six-cylinder, four-stroke, direct-injection oil engine is to deliver 120 kW at 1600 rpm. The fuel to be used has a calorific value of 43 MJ/kg and its percentage composition by mass is carbon 86.0%, hydrogen 13.0%, non combustibles 1.0%. The absolute volumetric efficiency is assumed to 80%, the indicated thermal efficiency 40% and the mechan- ical efficiency 80%. The air consumption to be 110% in excess of that required for theoretically correct combustion. (i) Estimate the volumetric composition of dry exhaust gas (ii) Determine the bore and stroke of the engine, taking a stroke to bore ratio as 1.5. Assume the volume of 1 kg of air at the given conditions as 0.77 m³. Oxygen in air is 23% by mass and 21% by volume.

The fuel efficiency for Vehicle 1 is modelled by A(t) = t+4 / t+2, and vehicle 2, by A(t) = t-2/ t-4. At what operating time(s) will Vehicle 1 have a lower fuel efficiency than Vehicle 2?