Combustion and performance characteristics of a diesel engine using emulsified diesel prepared by ultrasonicator

Use of water emulsified diesel (WED) has overcome the difficulties of simultaneous reduction of both nitrogen oxides (NOx) and particulate matter (PM) emission from diesel engines. Its application in CI engines also reduces the emission of other pollutants like hydrocarbon (HC), carbon monoxide (CO) and smoke. In this article, the authors have studied the combustion and performance characteristics of WED containing 0 and 10% of water using in a single-cylinder, four-stroke diesel engine. WED has been produced using both mechanical homogenizer as well as ultrasonicator. The water particle sizes in the emulsion, stability, density and viscosity of the WED have been compared obtained by those methods. The observations show that the ultrasonication is more favourable than mechanical homogenization for emulsification. In case of performance analysis, pure diesel and WED are comparable with respect to power, brake thermal efficiency and brake specific fuel consumption (BSFC). At higher load, increased brake thermal efficiency and decreased neat BSFC were found. The combustion characteristics show that the peak in-cylinder pressure and net heat release rate are higher for WED than that of pure diesel. Longer ignition delay is found for WED than that of pure diesel. However, the combustion duration is shorter. Thus the comprehensive analysis of the experimental results suggests that WED can be considered as a greener fuel for diesel engine.