Performance and emission characteristics of a diesel engine using water-emulsified fuels: an experimental assessment

Emission regulations are steadily becoming more stringent, compelling researchers to adopt extra precautions to minimize the release of pollutants into the environment. For this purpose, many methods are employed by researchers. Among these, Water-Emulsified Fuels (WEFs) stand out as an effective solution for obtaining decrement on nitrogen oxide (NOx) and Particulate Matter (PM) emissions, concurrently. In this study, emulsion fuels were prepared using diesel, sunflower biodiesel, distilled water, and surfactants (Span 80 + Tween 80). The fuels are denoted as D (diesel), DW5 (93% diesel + 5% water + 2% surfactants), DW10 (88% diesel + 10% water + 2% surfactants), B (biodiesel), BW5 (93% biodiesel + 5% water + 2% surfactants), and BW10 (88% biodiesel + 10% water + 2% surfactants). Test fuels were prepared by stirring the emulsion mixture at a speed of 1500 rpm using a magnetic stirrer at room temperature for one hour, and the fuel properties were then specified. Finally, performance and emission tests were performed on a turbocharged, water-cooled, 4-stroke, and 4-cylinder diesel engine. WEFs led to decreased engine torque and brake power values, along with lowered carbon monoxide (CO) and nitrogen oxide (NOx) emissions. DW5 and DW10 reduced engine torque by 6.27% and 9.82%, and brake power by 6.49% and 10.31%, respectively, compared to D. Similarly, BW5 and BW10 decreased engine torque by 4.63% and 8.12%, and brake power by 4.73% and 8.38%, respectively, compared to B. Additionally, DW5 and DW10 fuels reduced CO emissions by 1.61% and 2.85%, and NOx emissions by 8% and 12.61%, respectively. BW5 and BW10 fuels lowered CO emissions by 1.56% and 3.67%, and NOx emissions by 3.87% and 10.47%, respectively.