A comparative study on the effect of nano-additives on performance and emission characteristics of CI engine run on castor biodiesel blended fuel

Biodiesel is a promising alternative fuel because of its renewable status, biodegradability, non-toxicity, and low pollution levels. However, other limitations such as high viscosity, low thermal energy content, poor atomization, greater densities, and higher (NOx) exhaust emissions hinder its adoption as a prospective diesel alternative. The current study focuses on comparing and analyzing the performance and emission effects of introducing single and hybrid cerium oxide (CeO2) and aluminum oxide (Al2O3) nanoparticles to a fuel blend of 20% castor biodiesel and 80% diesel (CB20) made from castor seed oil. The pulsed plasma in liquid technique, a straightforward one-step procedure, was used to create cerium oxide (CeO2) nanoparticles. When Al2O3 nanoparticles were added to the CB20, the cylinder pressure and rate of heat release increased. Therefore, in this study single and hybrid cerium oxide (CeO2) and aluminum oxide (Al2O3) nanoparticles are introduced. The tests were conducted on a single cylinder compression ignition engine at varied engine speeds between 1250 and 3200 rpm while keeping a constant engine load. Using a water bath and sonication, two concentrations of the nanoparticles—80 and 100 ppm—were introduced to the fuel blends, along with Tween 80 and span 80 surfactants to improve blend stability. Different tested fuel samples, including pure diesel CB0, CB20, CB20C100, CB20C80, CB20A100, CB20A80, CB20A40C40, and CB20A50C50, were examined for their physiochemical properties, such as density, viscosity, cloud point, pour point, flash point, and fire points, as well as engine performance parameters, including torque, power, fuel consumption, BTE, and EGT. CB20A50C50 and CB20A40C40 both had an average brake power that was higher than diesel fuel by 6.14% and 1.25 percent, respectively. The average brake-specific fuel consumption decreased by 3.21% to 8.29% when using hybrid and single nano-additive blended fuels compared to CB20. CB20A50C50 exhibited a 20.38% higher brake thermal efficiency than CB20. Notably, CB20C100 showed a 29.52% reduction in HC and a 38.32% reduction in CO, while CB20A50C50 demonstrated a 10.24% decrease in NOx compared to CB20. Overall, the results of this study indicate that the generated fuel blends combining castor biodiesel and aluminum oxide/cerium oxide nanoparticles hold promise as alternate fuels for diesel engines, with positive impacts on engine performance and emissions.