Tribological and environmental impact of silicon dioxide nanoparticles in algae biodiesel fuels for diesel engines

The research evaluates the impact of Sargassum algae methyl ester (SAME20) with 50 and 100 ppm silicon dioxide (SiO 2 ) nanoparticles on the performance and emissions of a single-cylinder, four-stroke diesel engine. SiO 2 nanoparticles were characterized using FTIR, SEM, and TEM. Diesel, SAME20, SAME20 + 50 ppm of SiO 2 , and SAME20 + 100 ppm of SiO 2 blends were tested at 1500 rpm under loads from 25% to 100%. The SAME20 + 100 ppm of SiO 2 blend outperformed others, improving brake thermal efficiency by 1.43% and reducing brake-specific fuel consumption by 5.35% compared to diesel. It also decreased HC, CO, and smoke emissions by 11.12%, 18.1%, and 16.2%, respectively, with a slight NO x increase. Tribological analysis using a four-ball tribometer showed the SAME20 + 100 ppm of SiO 2 blend reduced the coefficient of friction by 76.89% and wear scar diameter by 59.19%. SEM analysis confirmed reduced surface wear and damage, highlighting improved engine and tribological performance.