Modeling catalytic regeneration of diesel particulate filters, taking intoaccount adsorbed hydrocarbon oxidation

Initiation of the regeneration of porous ceramic diesel particulate filters at low exhaust gas temperatures and the subsequent control of the soot oxi dation rate is necessary in order to allow a wide applicability of filter s ystems in diesel-powered vehicles. The use of catalysts in this respect, in particular catalytic fuel additives; has been proven to be successful, lea ding to a minimization of the system's cost and additional fuel consumption . Better understanding and modeling of the catalytic activity at low temper atures necessitates that one takes into account the oxidation not only of d ry particulate but also of the volatile hydrocarbons adsorbed on the partic ulate. In this paper, the oxidation of the hydrocarbons adsorbed on the par ticulate is modeled, to allow a better understanding of the filter regenera tion behavior at very low temperatures (150-300 degrees C). A simplified re action scheme and tunable kinetics are employed in the description of adsor bed hydrocarbon oxidation. The mechanism is incorporated in an existing mat hematical model, and specific computational case studies are invoked to exp lain and to model regeneration at low temperatures. The results compare wel l with experimental evidence and indicate certain directions for further re search to better understand this complex process which is essential to the successful application of diesel particulate filters.