Investigation of the effects of different diesel fuel cetane numbers on exhaust emissions in a single cylinder direct injection diesel engine

There are limited studies to reveal the effect of local diesel fuel types especially in Kurdistan region of conducted to evaluate the effect of different types of diesel fuel having different cetane number, which are from Kirkuk, Dura, Basra refineries and with ethanol blended diesel fuel 8%. The other samples of diesel fuel are from crude oil in TaqTaq oil field in Koya, refined in both Kar and Bazyan refineries. For this purpose the fuel with different value of cetane number were tested in a direct injection diesel engine at variable speed and load. The study showed that the concentration emission of co, NOx and HC are reduced by 6%, 7% and 16%, respectively, while CO2 are increased by 3% for fuel cetane number 50. The reason of decreasing emissions are due to complete combustion of these fuel. Result also show that Koya diesel fuel gives the worst harmful emissions of CO. The result shows that the exhaust emission of co is in general decreased with increasing cetane number, and its value is increased at maximum engine torque for all engine speeds. Ethanol blended fuel with cetane number 54 gives minimum emission of CO at engine speed n= 2200 rpm. NOx emissions of the higher cetane number fuel are decreased by 20% and co of this fuel is reduced to 58%. In general the ethanol blended fuel gives slightly lower HC and CO.