Influence of the Engine Drop-to-Idle Process on Regeneration Temperature, Filtration and Morphology Characteristics of Diesel Particulate Filters

As emission regulations become increasingly stringent, the durability of diesel aftertreatment system is another concern in addition to the excellent purification capacity. Under extreme circumstances, the engine may drop to idle (DTI) sharply and if active regeneration occurs during this period, there is a risk of DPF cracking and melting due to the huge accumulation of soot combustion heat. In this study, regeneration performances, including temperature and transient emission characteristics of cordierite DPF during a DTI process were investigated. The temperature distribution is highly nonuniform, with the peak temperature appearing in the middle ring of the DPF monolith's rear end. As the soot load reached 7 g/L, extensive DPF cracks can be observed and the PN emission dramatically exceeded the regulatory limit. In addition, the evolution of a porous wall's macro morphology and micro pore structure was examined. Numerous microcracks were formed and the wall surface became rougher and more irregular. The substrate's bulk density, average pore diameter, and permeability decreased whilst its total pore volume, total pore area, tortuosity, and porosity increased. The findings contribute to a better comprehension of DPF designs, regeneration strategies and durability improvements.