Computational Investigation Of Soot Load And Active And Passive Regeneration Characteristics In Catalytic Particulate Filter

Particulate Matter (PM) in diesel exhaust can do great harm to human’srespiratory system. As an effective way of promoting the passive regeneration ofPM， CPF（Catalytic Particular Filter） has already been developed and drew muchattention by the internal combustion engine researchers。 In this paper, a CPFnumerical model was proposed with experimental verification. The paper introducedPM catalytic regeneration percentage() as a criterion of CPF catalytic efficiency andinvestigated the influence of inlet conditions and physical parameter on catalyticefficiency to select catalyst loading based on certain catalytic efficiency range；Several factors that affected formation of soot layer and pressure drop of a filterwere analyzed, which involved in various wall permeability, cell density, channeldiameter ratio (inlet to outlet)；In addition, the effect of different shapes of channel,wall permeability and soot permeability on pressure drop, frequency of activeregeneration and maximum regeneration temperature were investigated；In the sametime，the influence of the ash on the pressure drop of an empty filter is investigatedfor different physical parameters of ash. The results show that:(1)For the continuous passive regeneration of soot layer and cake layer, in somecontidions reaches the best CPF catalytic efficiency and high initial particlemass,channel diameter ratio causes high catalytic efficiency. For the depth layer thesoot mass was burned from657K to710K.In addition the catalytic efficiency isrelated to temperature instead of exhaust components(2)The physical parameters of CPF such as porosity and the import and exportratio have little impact on the efficiency of catalyst.(3)With the increase of wall permeability, PM tends to deposit on axial ends offilter and distribute more uniform; With the increase of cell density and channeldiameter ratio, the initial time of cake layer formation is earlier.(4)The active regeneration frequency drops under the condition of hexagonchannel compared with the square channel and octagonal channel; the maximumactive regeneration temperature is low under the condition of square channelcompared with the hexagon channel and octagonal channel.(5)Under the condition of square channel，in high wall permeability and highsoot permeability the total pressure is small and the active regeneration frequency is low; in high wall permeability and low soot permeability the low maximum activeregeneration temperature is good at prolonging the service life of the diesel engine.(6)The low initial ash and high ash distribution factor cause the low pressuredrop. The active regeneration frequency drops under the condition of the low initialash and the high ash distribution factor; the maximum active regeneration temperatureis low under the condition of the high ash distribution factor and high ashpermeability.