(b) The pressure, volume and temperature at the beginning of compression of a four stroke petrol engine are 105kN/m²,0.0005m³ and 25°C respectively. The maximum temperature of the cycle is 1400°C. The volume ratio of the engine is 8:1. i) Calculate the mean effective pressure in the cylinder.

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.

A The compression ratio of a diesel cycle is 15.5, and the cutoff occurs at 10% of the stroke. 14 psia and 600 K characterize state 1. Calculate the following for the hot-air standard with k= 1.34 and a starting volume of 2 cu ft: Qin a. Find T2 , P2 , V2 , T3 , V3 , P4 , and T4 3 P = P, b. Compute the heat added (QA), Wout heat rejected (Qr), work (W) and the cycle efficiency (e). P. c. for a rate of circulation of 1000 cfm, Qout compute the horsepower.