Development of a 1-D CPF Model to Simulate Active Regeneration of a Diesel Particulate Filter 2009-01-1283

A quasi-steady 1-dimensional computer model of a catalyzed particulate filter (CPF) capable of simulating active regeneration of the CPF via diesel fuel injection upstream of a diesel oxidation catalyst (DOC) or other means to increase the exhaust gas temperature has been developed. This model is capable of predicting gaseous species concentrations (HC's, CO, NO and NO₂) and exhaust gas temperatures within and after the CPF, for given input values of gaseous species and PM concentrations before the CPF and other inlet variables such as time-varying temperature of the exhaust gas at the inlet of the CPF and volumetric flow rate of exhaust gas. Also, the model predicts the overall pressure drop across the CPF and its components and the filtration and oxidation processes of PM as functions of axial location in the CPF and time as well as secondary variables that are derived from the equations that are being solved for in the model (such as axial variation of PM cake layer thickness versus time). The mathematical equations and numerical techniques used in the development of this computer model are presented. Results from a comparison of this model to experiments conducted at MTU [1] are presented to validate the model. The model provides further understanding of the processes taking place inside a CPF during active regeneration by calculating various parameters related to the oxidation and filtration processes including the mass of PM in the filter PM cake and substrate wall as functions of axial location and time.