Forensics of soot: C5-related nanostructure as a diagnostic of in-cylinder chemistry

We report observations of nanoscale microstructural changes in soot from an experimental light-duty diesel engine, produced with varying levels of biodiesel fuel blending. Based on these observations and current information in the literature, we propose a mechanistic hypothesis to explain the effects of biodiesel blending. Our underlying assumption is that particulate nanostructure is closely coupled to the local chemistry at the time the soot is formed. In the context of in-cylinder soot formation, this implies that changes in nanostructure may aid in diagnosing important changes in fuel–air mixing.