Question

. A diesel engine uses 54.5 kg of fuel oil per hour of calorific value 45 MJ/kg. The thermal efficiency of the engine is 25 per cent. Determine the power output of the engine in kilowatts

Answer 1

Input fuel to engine is 54.5kg/hour

and input power to engine is $54.5\times 45 \times 10^6$ joules/hour

efficiency of engine is 25%

Hence output power of engine is $\cfrac{2452.5}{4}\times 10^6$ Joules/hour

In kilowatts, output power is $\cfrac{613.1}{3600}\times 10^3$ Kilo-joules/sec

or 170.3 kilowatts.