A novel emulsion fuel containing aqueous nano cerium oxide additive in diesel-biodiesel blends to improve diesel engines performance and reduce exhaust emissions: Part II - Exergetic analysis

This survey was aimed at determining exergy-based sustainability parameters of a single cylinder DI diesel engine in response to various fuel blends and engine loads at a fixed engine speed of 1000 rpm. Engine tests were conducted at four engine loads (25%-100%) using a 95% diesel + 5%biodiesel blend (B5) emulsified with water (3, 5, and 7 w/w%). All the prepared emulsions were stabilized with a 2:1 combination of Span 80 and Tween 80 (overall 7.5 w/w% surfactant). Two levels of cerium oxide nanoparticle concentrations (0 and 90 ppm) were also applied. The results showed that engine load and fuel type profoundly affected the exergy-based sustainability indices of the engine. Generally, increasing engine load steadily decreased exergy efficiency, while normalized exergy destruction declined by up to 75% under full load condition. Among the fuel blends prepared, the B5 blend containing 3 w/w% water and 90 ppm cerium oxide nanoparticles (B5W3m) showed the best exergy-based sustainability parameters at all the studied engine loads as its respective performance approached that of the basal petro-diesel. More specifically, among the fuel blends prepared the highest exergetic efficiency and the lowest normalized exergy destruction at full load condition were achieved using the selected fuel blend at 28.26% and 1.52, respectively. These values stood at 28.36% and 1.69 for neat diesel, respectively. However, the selected emulsified fuel blend represented a remarkably better environmental performance compared with diesel fuel. In conclusion, the B5W3m fuel blend might be effectively applied as substitute to mineral diesel fuel without any change in the existing engine structure.