Combined effects of water emulsion and diethyl ether additive on combustion performance and emissions of a compression ignition engine using biodiesel blends

In the present study, the effects of water emulsion and diethyl ether additive on the combustion performance and emissions of a compression ignition engine using biodiesel blends are investigated on a four stroke, single cylinder diesel engine. The emulsification technique is used to reduce the oxides of nitrogen emission. Biodiesel is produced from waste cooking oil and blended with mineral diesel to form different blend compositions. The water in oil emulsion is prepared by adding 5% (vol) water in the presence of 2% Span 80 surfactant. Diethyl ether is used to improve the combustion efficiency of the emulsified blends. The results show that, compared to biodiesel operation, the brake thermal efficiency of the emulsified fuel increases slightly with the composition of diethyl ether, and the maximum brake thermal efficiency is obtained at 2% diethyl ether. Lower oxides of nitrogen are observed for all emulsion fuels compared to biodiesel operation for all load conditions. Lower emissions of carbon monoxide, hydrocarbon and smoke are observed for emulsions, and minimum values are obtained for a 2% diethyl ether composition. The use of water emulsion reduces the oxides of nitrogen whereas the oxygenated fuel additive is responsible for the reduction of other emissions. (C) 2019 Elsevier Ltd. All rights reserved.