Abstract

The aim of this work is to study the effect of properties of Karanja (Pongamia pinnata) methyl ester on combustion, and NOx (oxides of nitrogen) emissions of a diesel engine. The properties of the karanja methyl ester such as viscosity, density, bulk modulus, calorific value, iodine value, cetane number, saturation% and oxygen% are considered for this study. Experiments were conducted in a naturally aspirated, single cylinder, four-stroke, stationary, water cooled, constant rpm, in-line (fuel pump- pressure tube-fuel injector) direct injection diesel engine. The engine tests were conducted with karanja methyl ester (with and without preheating), and baseline fossil diesel. The peak pressures and peak heat release rates for methyl ester was slightly higher than diesel fuel. The crank angles for peak pressure of the karanja methyl ester are very close to top dead center. This is probably due to dynamic injection advance caused by their higher bulk modulus. However, the peak cylinder pressures for preheated methyl ester decreases, due to late injection and faster evaporation of the fuel. It was observed that, at full load the oxides of nitrogen emissions of karanja methyl ester are increased by 6%. A significant reduction in oxides of nitrogen emission is observed with preheated methyl ester.

Key words: Bulk modulus, combustion, diesel engine, effect, Karanja, methyl ester, NOx, properties, preheating, Pongamia pinnata