Performance and emission improvements of diesel engine run on biodiesel with green synthesized copper oxide nanoparticles

Abstract Biomass‐based biodiesel is an environmentally friendly and renewable alternative energy source that has the potential to achieve carbon neutrality. This research focuses on the influence of green‐synthesized copper oxide (CuO) nanoparticles extracted from neem leaves on the performance and emission characteristics of Chlorophyta green algae biodiesel in a diesel engine. Two different concentrations of CuO nanoparticles (25 and 50 mg/L) were mixed with 20% algae biodiesel‐diesel fuel (CB20) and tested under various engine loads. The CB20CuO50 blend resulted in a 1.66% increase in brake thermal efficiency and a 14.73% reduction in specific fuel consumption. The combined effect of CuO nanoparticles and the oxygenated nature of the biodiesel blend led to significant emission reductions, with carbon monoxide (CO) and hydrocarbon (HC) emissions decreasing by 20.81% and 14.49%, respectively, compared to diesel fuel. Response Surface Methodology (RSM) optimization showed a minimum SFC of 0.302 kg/kWh, HC emission of 63 ppm, and CO concentration of 0.1349% under optimal CB20CuO50 conditions. These results indicate that CuO nanoparticles synthesized through green chemistry have strong potential to enhance combustion efficiency and reduce emissions, aligning with the goals of sustainable and clean energy (SDG 7) and climate action (SDG 13).