Toward sustainable transportation: Experimental insights into Chlorella vulgaris algae biodiesel with titanium oxide nano-enhancements

Biodiesel, an environmentally friendly alternative to diesel fuel, is commonly used in compression-ignition engines. In this research, an attempt has been made to evaluate the performance, combustion, and emission characteristics of Chlorella vulgaris algae methyl ester (CVAME) blended with diesel fuel containing titanium oxide nanoparticles as a fuel additive in a single-cylinder four-stroke diesel engine under various operating conditions. The morphology of the synthesized titanium oxide nanoparticles was investigated by EDX, SEM, and TEM. The fuel samples used for testing were CVAME20, CVAME20 + 50 ppm of TiO 2 , and CVAME20 + 100 ppm of TiO 2 . The fuel samples were analyzed for their physicochemical characteristics in accordance with ASTM procedures. From experimental results obtained, it was found that CVAME20 with 100 ppm of TiO 2 offered the highest reduction in the brake-specific fuel consumption (BSFC). Further, this blend showed a 2.96% increase in brake thermal efficiency (BTE) over CVAME20. However, CVAME20 containing 100 ppm TiO 2 had the highest heat release rate (HRR) value among all the samples at 45.41 J/° CA and the highest cylinder pressure at 70.72 bar. Under peak load, the CVAME20 + 100 ppm of TiO 2 fuel blend exhibited reductions of 35.1% for CO, 31.5% for HC, and 9.04% for smoke in emissions compared to CVAME20. Conversely, NO x emissions were increased by 7.36% in comparison to CVAME20. A four-ball tester was utilized to investigate the tribological characteristics of different biodiesel blends under conditions of 1200 r/min, 75 °C, and 40 kg for a duration of 1 hour. The addition of 100 ppm TiO 2 into CVAME20 led to a 32.62% reduction in the wear scar diameter (WSD) and a 16.51% decrease in friction compared to CVAME20. It can also be observed from the SEM analysis that the biodiesel blends with nano-additives have lower wear rates as compared to CVAME20.