Performance and emission characteristics of a diesel engine fuelled by neem oil blended with alcohols

Fuel crisis and environmental concerns have led researchers to look for alternative fuels of bio-origin sources such as vegetable oils, which can be produced from forests and oil-bearing biomass materials. Vegetable oils have energy content comparable to that of diesel fuel. Straight vegetable oils posed several operational problems and durability problems when subjected to long-term usage in compression ignition engine. These problems are attributed to higher viscosity and lower volatility. In this study, performance and emission parameters of a diesel engine operating on neem oil and its blends of 5, 10, 15 and 20 vol% with ethanol, 1-propanol, 1-butanol and 1-pentanol are evaluated and compared with diesel operation. The results indicate that the brake thermal efficiency is improved with the use of neem oil-alcohol blends with respect to those of neat neem oil. The smoke intensity, CO and HC emissions with neem oil-alcohol blends are observed to be lower with respect to those of neat neem oil at higher loads. The NOx emission is very slightly reduced with the use of neem oil-alcohol blends except for the neem oil-ethanol blend compared with that of neat neem oil.