Abstract
Biodiesel molecular structure (Saturated, Unsaturated Fatty Acids and Carbon chain length) have a predominant effect on itsproperties and NOX emission. Bio-mixture fuel is a novel approach to prepare third generation biofuel which have higher saturation, lower unsaturation fatty acids and longer carbon chain length as compared to single feedstock biodiesel. To produce Bio-mixture fuel, four different bio-diesels were mixed together based on the degree of saturation and unsaturation of the composition in v/v% to form Bio-mixture. In the mixture, two is edible and two is non-edible. Two sample of bio-mixture fuel were prepared Bio-mix-I, Bio-mix-II and experimental investigation conducted on the four-stroke single cylinder, water cooled, Variable Compression Ratio (VCR) diesel engine under four different load(0N-m, 5N-m,10N-m, 20N-m) at constant speed of 1500rpm with compression ratio 17.5:1. Results showed that; brake specific fuel consumption (BSFC) and brake thermal efficiency (BTE) of the Bio-mixturewas higher than diesel fuel. With longer carbon chain length, CO, HC and smoke increased whereas NOx was reduced. Longer chain length improves cetane number (CN) which reduced ignition delay. A shorter ignition delay shifts pre-mixed combustion towards diffusion combustion which in-turn reduced in-cylinder pressure and temperature, therefore lowering NOx. NOx is strongly related to temperature.
Keywords: Biodiesel,Bio-Mix fuel, Performance, Combustion, Emission