During testing of single cylinder two-stroke petrol engine following data were obtained. Brake torque \(=640 \mathrm{Nm}\), cylinder diameter 21 \(\mathrm{cm}\), speed \(350 \mathrm{rpm}\), stroke length \(=28 \mathrm{~cm}\), mean effective pressure \(=5.6 \mathrm{bar}\), oil consumption \(=8.16 \mathrm{~kg} / \mathrm{h}\), calorific value of the fuel \(=42,705 \mathrm{~kJ} / \mathrm{kg}\). Determine: (i) mechanical efficiency, (ii) Indicated thermal efficiency, (iii) Brake thermal efficiency, and (iv) brake specific fuel consumption.