UTILIZATION OF MICRO- EMULSION OF DIESEL IN SMALL CAPACITY DIESEL ENGINE- PERFORMANCE AND EMISSION STUDIES

Abstract

Diesel Engines are considered work horse in India economy and are used extensively in agriculture, transport and power sector. They, however, also pollute the environment significantly. The emissions from diesel engine include CO, HC, NOx and particulate matter. As growing concern about degradation of environment from diesel engine have gained momentum and also stricter emission norms have been mandated, there is an urgent need to reduce emissions from diesel engine either by fuel modification or engine modification. The engine modification in Indian context is a tedious job due to large investment required; fuel modification appears to be the best solution to reduce pollutants. In this context, emulsions of diesel and water are often considered as being able of simultaneously reducing emissions of both oxides of nitrogen (NOx) and particulate matter from diesel engines.

In the present work diesel water emulsions having 5 and 10% water were prepared using a surfactant (mixture of Tween80 & Span80). The stable emulsion was formed and its physic-chemical characterization was carried out. The performance and emission characteristics of a medium capacity diesel engine on the two diesel water emulsion was carried and results being compared with baseline data of diesel. Higher brake thermal efficiency with simultaneous increase in brake specific fuel consumption was observed. The reason for the higher BTE of diesel/water emulsion as compared to diesel is that the presence of water and in particular the presence of oil water interface with very low interfaced tension leads to a finer atomization of fuel during injection. The water in fuel improves the combustion process. Microexplosion accelerates the diffusion of combustion through the cylinder, decrease the time required for combustion and increasing combustion efficiency which result in better BTE. Higher bsfc observed in case of diesel/water emulsion is attributed to lower heating value of these fuels. The NOx, HC and smoke opacity were found to decrease for diesel water emulsion, however, CO was found to increase.