Performance and Emission Characteristics of a Diesel Engine Burning Unstabilized Emulsions of Diesel Fuel with Water, Methanol, and Ethanol

This study was performed to compare the effects of water, methanol, and ethanol as internal phases in the unstabilized emulsions of diesel fuel formed in the injection line on the performance and exhaust emission characteristics of a compression-ignition engine. The experiments were performed with a single cylinder, direct injection, air-cooled engine and the various emulsions were tested under practically identical operational conditions. The results indicate that (a) thermal efficiency decreases when diesel fuel is emulsified with water or ethanol and slightly increases when it is emulsified with methanol and (b) among the liquids tried, water is the most suitable internal-phase for curtailing particulates and CO in the exhaust, whereas ethanol is the best internal-phase for decreasing the emissions of NO_X and UBHC.