Energy and Exergy Analyses of a Diesel Engine Running on Biodiesel Fuel

Availability analysis is an effective approach to studying energy conversion in systems and identifying inefficiency. In the present study, a single-zone model was used to examine energy performance parameters and heat release rates. The governing equation of availability analysis was applied in the model, and the possibility of using biodiesel produced from sunflower oil as diesel engine was investigated via mathematical simulation. The different exergy components of pure diesel fuel and pure biodiesel were compared at different crank angles. Results indicated that combining the examined diesel engine with biodiesel fuel would decrease the energy and exergy efficiencies by about 2.72% and 2.61%, respectively. As a result, work exergy and heat transfer exergy decrease and exhaust gas exergy and irreversibility would increase. When biodiesel is replaced with diesel fuel, carbon monoxide decreases, carbon dioxide formation increases, and nitrogen oxide formation remains constant. However, considering the negligible decrease in the first- and second-law efficiencies of biodiesel fuel compared with the decrease in diesel fuel efficiencies, the former is regarded as a renewable fuel that produces less carbon monoxide. It can therefore serve as a substitute for diesel fuel.