The impact of adding nanoparticles to biodiesel fuel prepared from waste sunflower oil on the performance and emission of diesel engines

Although biodiesel has attracted much attention because of its ability to reduce engine emissions, its lower performance in diesel engines and the need to find renewable sources for its production limit its adoption. Thus, this work investigated the use of the trans-esterification method to convert waste sunflower oil to biodiesel (BD) and the impact of mixing it with TiO₂ and CuO nanoparticles on the performance and emissions of a four-stroke engine at three engine torques (2, 4, and 6 N·m) compared with petroleum diesel (PD). The fuel performance was evaluated by calculating the brake-specific fuel consumption (BSFC), brake-specific energy consumption (BSEC), brake thermal efficiency (BTE), and noise intensity of the engine. The exhaust emissions were measured to identify hydrocarbons (HC), CO, particulate matters (PM), CO₂, and NO_x emissions. The results show that BD reduces the BSFC, BSEC, and BTE up to 20.1%, 6.1%, and 6.9%, respectively. In contrast, when TiO₂ is used, the percentages are 11.8%, 0.77%, and 4.4%, and when CuO is used, the percentages are 15.7%, 3.9%, and 5.4%, respectively. In addition, the emission results show that BD reduces HC, CO, and PM up to 91.0%, while the use of TiO₂ reduces them up to 93.0%, and CuO reduces them up to 92.0%. However, this decrease is associated with increasing CO₂ and NO_x emissions by up to 42.9% and 82.9%, respectively, with the use of BD, while the use of TiO₂ increases them by up to 53.7% and 65.5%, and the use of CuO increases them by up to 51.5% and 60.6%, respectively.