The air flow to a four cylinder four-stroke engine is 2.15 m³/min. During a test on the engine the following data were recorded: Bore 10.5cm; stroke 12.5cm; engine speed 1200 rpm, torque 150 N.m, fuel consumption 5.5 kg/h, calorific value of fuel, 43124 kJ/kg, ambient temperature and pressure are 20°C and 1.03 bars. Calculate: 1- The brake thermal efficiency. 2- The brakes mean effective pressure. 3- The volumetric efficiency.