In a diesel engine compresses pure air in a cylinder so that the temperature of
ID: 1819264 • Letter: I
Question
In a diesel engine compresses pure air in a cylinder so that the temperature of the air increases. Just before the compression is completed, is the fuel injected under high pressure into the cylinder. The fuel itself antennas because of the high air temperature in the cylinder.a) A diesel engine develops 110 kW and uses 0.245 kg of fuel per kWh effective. The fuel-efficient heating value is 42,500 kJ / kg. Calculate the engine's efficiency.
b) A diesel engine uses 0.258 kg fuel per effective hkh. The fuel-efficient heating value is 42,000 kJ / kg. What percentage of the energy is supplied from the fuel leaves the engine through the exhaust, if the cooling water losses are 28% and losses in the auxiliary machinery by radiation is 6%?
Explanation / Answer
Case a) efficiency = Work/Heat Supplied 1 kWhr = 1000W * 36000s Therefore in 3600 sec, fuel consumption is 0.245 kg, For 1kWhr effective work , fuel consumption is 0.245kg efficiency = 1000*3600/(0.245*42500*1000) = 0.34573 Case b) for 1kWhr work done (power supplied) fuel consumption is 0.258 kg what percentage of supplied heat goes as power = 1000W *3600s / (0.258*42000*1000) =0.33222 Heat supplied for exhaust = (1-0.28-0.06-0.33222)*0.258*42000 = 3551.76 kJ