I.C. ENGINES Practical No: 7 (5 May, 2014)

Fuel Consumption Objective To calculate thermal efficiency of the engine Apparatus Engine test bench Accurate measuring tank Flow meter Stop watch (min time should be not less than two minutes)

Fuel Consumption Procedure Use test tank with hook gauges Or calibrated glass measuring cylinder Measuring glass shaped so that fuel falls fast at the points of calibration where time finished and finishes An other method is to use flow meter

Fuel Consumption

Calculation To convert milliliter (ml) or liters ( l) to mass ( kg) 1000 ml = 1 litre Since 1 litre of water has a mass of 1 kg 1 litre of fuel has a mass of 1 x relative density of fuel (kg) X litre of fuel has a mass of : X x relative density of fuel ( kg)

Fuel Consumption

Example A Morse test on an engine gave the following results: P b All cylinder working 100 kW P b No 1 cylinder cut out 69 kW P b No 1 cylinder cut out 71 kW P b No 1 cylinder cut out 68.5 kW P b No 1 cylinder cut out 71.5 kW Find P i, P f and Mechanical efficiency

Example Formula P i = (A x 4) - (B 1 +B 2 +B 3 + B 4 ) Sol P i = (100 x4) – ( ) = 400 – 280 P i = 120 kW P f = P i - P b = 120 – 100 P f = 20 kW

Example