Environmental Impact Mitigation in Diesel Engines Using Emulsified Water-in-Diesel Fuel Blended with Al₂O₃ Nanoparticles

The primary objective of this work is to conduct an in-depth investigation into the performance, combustion, and emission characteristics of a diesel engine using Water-in-Diesel Emulsions (WiDE) with alumina oxide (Al2O3) nanoparticles to reduce harmful pollutants and enhance efficiency amid increasingly stringent environmental regulations. Emulsified fuels were prepared as containing 5%, 10%, and 15% water by volume. Furthermore, 100 ppm of Al2O3 nanoparticles were uniformly dispersed in the blends to enhance atomization and improve combustion characteristics. Engine testing was carried out from no load to full load to assess the performance, combustion behavior, and emission characteristics of the prepared fuel blends. The most important results obtained from this research show that the WiDE blends give higher brake thermal efficiency and significantly lower emissions with respect to diesel. Among all, the best behavior was shown by WiDE10, which showed a 7.14% increase in brake thermal efficiency and reductions in HC by 50.00%, CO by 16.67%, NOX by 66.67%, and smoke by 46.88%. In combustion analysis, it was observed that diesel shows a peak pressure of 62.74 bar at 366°CA, whereas WiDE blends produce smoother combustion with a lower heat release rate due to water-induced micro-explosions. The importance of the obtained results is to demonstrate that the synergistic effects of water emulsification and Al₂O₃ nanoparticles enhance the processes of atomization and reduce peak temperatures, thus allowing cleaner comb