A 6-cylinder, 4-stroke, single acting petrol engine develops \(50 \mathrm{~kW}\) brake power at \(4200 \mathrm{rpm}\) and brake thermal efficiency is \(22 \%\). The temperature and pressure at the end of suction stroke are \(60^{\circ} \mathrm{C}\) and 0.85 bar respectively. The following data are available :

Calculate bore and stroke of engine.

Volumetric efficiency Mechanical efficiency Theoretical A: Fratio Air supplied C.V. of fuel Density of petrol vapour Stroke/bore ratio = 80% = 82% = 14.5:1 =25% excess than theoretical = 46 MJ/kg = 2 density of air = 1.25