Characterization of the soot generated by an internal combustion engine using blends of biodiesel through Raman spectroscopy

Biodiesel serves as a biodegradable, non-toxic, and renewable fuel option that offers an alternative to traditional fossil fuels. This study aimed to examine the impact of elevating biodiesel content to 20% and 50% within regular diesel, with a focus on comprehending how these fuel mixtures influence variations in soot composition using Raman spectroscopy. The soot samples under analysis originated from commercial S10 diesel, as well as fuel blends containing 20% and 50% portions of sunflower and macaúba biodiesel, whereupon the use of this methodology for these fuels characterizes the novelty of this work. The outcomes derived from analyzing the soot samples revealed distinct characteristics in the G, D1, D3, and D4 bands. The ratio between the intensities of these D and G bands is closely indicative of the soot's structure. Consequently, this ratio was analyzed in this investigation to assess the effects of biodiesel concentration and engine rotation speed on soot characteristics. The conclusions found in this study indicated that there was minimal variation in the spectral characteristics of the soot samples across the different fuels and varying engine speeds. As a result, it is inferred that increasing the proportion of biodiesel in commercial diesel S10 did not have a significant impact on the structural composition of soot.