Synergistic effects of magnesium oxide nanoparticles on tribology and emissions in Datura stramonium L. biodiesel-fueled diesel engines

The present study investigates the effects of magnesium oxide (MgO) nanoparticles on the performance and emissions of a single-cylinder diesel engine fueled by Datura stramonium L. methyl ester (DSLME) under constant speed and varying load conditions. SEM, TEM, and EDX spectroscopy were used to characterize the MgO nanoparticles. Experimental results showed that compared to DSLME20, the addition of 50 ppm MgO led to a 9.5% reduction in brake-specific fuel consumption and a 6.03% increase in brake thermal efficiency, highlighting the beneficial impact of MgO on thermal efficiency, aside from diesel fuel. Emissions analysis demonstrated significant reductions in carbon monoxide (CO), unburned hydrocarbons (HC), and smoke emissions. At full engine load, the DSLME20 + 50 ppm of MgO blend reduced CO by 7.9%, HC by 10.8%, and smoke by 8.7%, compared to DSLME20. However, nitrogen oxide (NO_x) emissions increased by 6.3%. Additionally, tribological tests conducted using a four-ball tribometer at 1200 rpm, 75 °C, and a 40-kg load for 1 h revealed that the wear scar diameter for the DSLME20 + 50 ppm of MgO blend decreased by 15.74%, along with a 24.5% reduction in the coefficient of friction compared to the DSLME20. These findings suggest that MgO nanoparticles improve fuel efficiency, reduce emissions, and enhance engine durability and wear resistance in diesel engine applications.