Unlocking the potential of low concentration biodiesel blended with green synthesized novel carbon black nanoparticles from Ricinus communis outer shell: An experimental study under different compression ratios and EGR concentrations

The outer prickly shells of the Ricinus communis (castor plant) have intrigued researchers interested in the synthesis of carbon black (CB) nanoparticles because of their excellent biocompatibility, low toxicity, and widespread availability. Both chemical and physical synthesis methods, such as pyrolysis and ball milling, are employed to obtain the fine-sized CB nanoparticles. The ball milling process is done for 5 h to reduce the size of the biochar from the pyrolysis process. The as-synthesized CB nanoparticles are characterized using Fourier transform infrared spectroscopy, x-ray diffraction, and field emission scanning electron microscopy analysis. The energy dispersive spectrum also confirmed that the nanoparticles are highly composed of carbon and oxygen. CB nanoparticles made from green materials are added to a low-concentrated biodiesel blend of waste fried edible oil at a rate of 100 ppm. The experiment was performed in a single-cylinder diesel engine under varying compression ratios (CRs) (16:1–18:1), loads (0–16 kg), and exhaust gas recirculation (EGR) rates (0%, 15%, and 25%). The results revealed that the existence of carbon in nanoparticles increased the mean gas temperature, and the mass fraction burned was also slightly higher than diesel. Raising both CR (16:1–17:1 and 16:1–18:1) and EGR (25%) boosted the cylinder pressure of CBB30 (1.844% and 10.391%, respectively). In contrast, it lowered the net heat release rate (7.88% and 14.56%, respectively). Similar to this, smoke emissions decreased by 6.38% and 15.02%, respectively, at the same CR and EGR parameters. On the other hand, brake thermal efficiency slumped by 7.22% and 10.13% concurrently.