Development of a quasi-two-dimensional model for analysing continuous regeneration-diesel particulate filter states during continuous and active regeneration

A quasi-two-dimensional model for describing regeneration events in the continuous regeneration-diesel particulate filter (CR-DPF) is presented, in which computational grids of the diesel particulate filter are provided in the discretization of physical domains in the axial and wall thickness directions. In the model, gas and particle flows, pressures, temperatures, and soot distributions in the inlet/outlet channels and wall, together with both continuous regeneration and active regeneration reactions, are considered. Rate constants of the chemical reactions are calibrated using results of soot oxidation tests in a mini flow reactor and engine bench tests. The distributions of loaded soot mass, filter temperature, and pressure during both continuous and active regenerations have been analysed using this model. The analysis shows that the predicted pressure drop across the diesel particulate filter is in good agreement with the data obtained in an engine bench test. The processes of soot loading including the deep wall filtration phase and the subsequent soot cake layer formation phase have been successfully predicted by calculation based on the model. It is also shown that soot accumulates mainly in the upstream area in the filter wall and at the front and rear parts in the axial direction when the soot accumulation amount is small. The reason for this uneven accumulation is presumed to result from the large pressure differences between the inlet and outlet channels at these locations.