A Numerical Study on Uncontrolled Regeneration Processes in Diesel Particulate Filters

An effective regeneration is needed to remove the accumulated soot in a Diesel Particulate Filter (DPF). However, the sudden heat release by soot oxidation during an uncontrolled thermal regeneration process may cause the substrate of a DPF to overheat. The consequent thermal stress could even result in structural failure. In this paper, a cone-dimensional transient model was employed to describe the exhaust flow, heat transfer, and chemical reaction processes within the DPF substrate during regeneration. The model was validated preliminarily against the experimental data of previous researchers. By using this mode, a variety of uncontrolled regeneration processes were simulated to analyze the different mechanisms of DPF overheating. The results show that the exhaust temperature, oxygen concentration, and PM loading are three major factors that effect DPF overheating. Furthermore, the tendency of uncontrolled thermal runaway could be reduced by changing either the thermal runaway could be reduced by changing either the thermal properties or the structure of the DPF substrate.