Diesel combustion characteristics of single compositions of fatty acid methyl esters

The diesel combustion characteristics and the exhaust emissions of biodiesel are affected by the composition of fatty acid methyl esters (FAMEs). In this study, the combustion characteristics and the exhaust emissions from single compositions of FAMEs, such as methyl palmitate, methyl oleate and the others, are investigated by using a single cylinder DI diesel engine. Experimental five FAME fuels are neat methyl oleate and the rest are blended mixtures based on methyl oleate. From the experimental results, the ignition delays of saturated FAMEs decrease with longer straight chain of the hydrocarbon molecules while in the same carbon number FAMEs, the ignition delays increase by increasing carbon-carbon double bonds. The break thermal efficiencies of the five FAME fuels and the gas oil are almost the same. The NOx emission from methyl palmitate and methyl oleate mixture is the least and the smoke emission from methyl laurate and methyl oleate mixture is the lowest, in the five FAMEs fuels. The smoke emission decreases by increasing the oxygen content in the FAMEs.