Performance of a diesel engine with water emulsified diesel prepared with optimized process parameters

An attempt has been made to produce stable water-diesel emulsion with optimal formulation and process parameters and to evaluate the performance and emission characteristics of diesel engine using this stable water-diesel emulsion. A total of 54 samples were prepared with varying water/diesel ratio, surfactant amount and stirring speed and water separation was recorded after 24 and 48 hr of emulsification. The recorded data were used in artificial neural network (ANN)-particle swarm optimization (PSO) technique to find the optimal parameters to produce water-diesel emulsion for engine testing. The predicted optimal parameters were found as 20% water to diesel ratio, 0.9% surfactant and 2200 rpm of stirrer for a water separation of 14.33% in one day with a variation of 6.54% against the actual value of water separation. Water-diesel emulsion fuel exhibited similar fuel properties as base fuel. The peak cylinder gas pressure, peak pressure rise rate and peak heat release rate for water-diesel were found higher as compared to diesel at medium to full engine loads. The improved air-fuel mixing in water-diesel emulsion enhanced brake thermal efficiency (BTE) of engine. The absorption of heat by water droplets present in water-diesel emulsion led to reduced exhaust gas temperature (EGT). With water-diesel emulsion fuel, the mean carbon monoxide (CO), unburned hydrocarbon and oxides of nitrogen (NOx) emissions reduced by 8.80, 39.60, and 26.11%, respectively as compared to diesel.