Performance and emission interaction analysis of biodiesel–diesel blends with CeO₂ nanoparticles and diethyl ether in a compression ignition engine

This study aimed to evaluate the effect of adding 75 ppm cerium oxide nanoparticles (CeO2 NPs) with 2% diethyl ether (DEE) to castor biodiesel diesel blends on the performance and emissions of a single-cylinder, four-stroke CI engine operated at 80% load across 1700–3000 rpm, revealing that the nano-additive improved brake torque, brake power, thermal efficiency, and reduced carbon monoxide (CO), hydrocarbons (HC), and soot emissions, with only marginal changes in nitrogen oxides (NOx) compared to blends without CeO₂. The results indicate that the addition of CeO2 NPs led to an increase in brake torque to 15.5 Nm (95% CI: 15.0–16.0 Nm) and brake power to 3.7 kW (95% CI: 3.6–3.8 kW). Furthermore, BSFC decreased to 250 g/kWh at (95% confidence interval (CI): 240–260 g/kWh), enhancing thermal efficiency to 38% (95% CI: 37–39%). Emission analysis revealed a reduction in CO levels to 0.425%V (95% CI: 0.400–0.450%V), HC emissions to 47.5 ppm (95% CI: 45.0–50.0 ppm), and NOx emissions to 80 ppm (95% CI: 75–85 ppm). These findings demonstrate the potential of CeO2 NPs to enhance engine efficiency while reducing harmful emissions, making them a promising candidate for cleaner combustion technologies.