(644d) Performance of Microemulsions As an Alternative Fuel in Constant Speed Diesel Engine

There is an urgent need for sustainable alternative fuels due to the limited stocks of and increasing demand for fossil fuels, as well as evermore increasingly-stringent environmental regulations. Microemulsions are alternatives which could possibly be used without any modifications to current engines and storage-transportation-supply infrastructure. Our current work attempts to measure the usability of alcohol-diesel-water microemulsion fuels in a diesel engine. A small percentage of water is desirable in microemulsions, as it reduces the combustion temperature which, in turn, reduces the NO_x- and smoke-emissions. An alcohol was used which acted both as a surfactant as well as a co-surfactant, thereby making the entire process facile and economical. The microemulsion regions were mapped out in ternary phase diagrams, and the fuel was characterized as per ASTM D975, and further examined for its performance in a diesel engine. The microemulsions formulated, as such, satisfied the ASTM standards, and had properties (density, viscosity, flash points, and cloud and pour points) close to those of neat diesel. The percentage change in property ‘ɛ’ was calculated as [(ɛ_diesel-ɛ_{microemulsion})/ɛ_diesel]×100 . The calorific value for the microemulsion fuel containing 70% diesel was lower by 8.31% compared to that of neat diesel. However, the brake thermal efficiency was higher by 15.55% for the microemulsion fuel relative to that of neat diesel (2% higher overall efficiency of the engine). The brake specific fuel consumption was also lower by 5.04% with respect to the value for neat diesel. The experimental investigation thus suggested that the microemulsions could be used as a sustainable alternative to diesel.

Keywords: Diesel replacement, microemulsion, sustainable fuel, diesel engine.