During testing of single cylinder two stroke oil engine, following data was obtained :

Brake torque \(=640\) N.m, Cylinder diameter \(=21 \mathrm{~cm}\), Speed \(=350 \mathrm{rpm}\), Stroke \(=28 \mathrm{~cm}\), mean effective pressure \(=5.6 \mathrm{bar}\), oil consumption \(=8.16 \mathrm{~kg} / \mathrm{h}\), Calorific value of oil \(=42705 \mathrm{~kJ} / \mathrm{kg}\)

Determine

(a) mechanical efficiency,

(b) indicated thermal efficiency,

(c) brake thermal efficiency, and

(d) brake specific fuel consumption.