Pressure drop model of DPF considering ash factor at different capture stages

Abstract

In this paper, a pressure drop model of diesel particulate filter (DPF) is established on diesel bench loading tests and simulation studies. A proposed DPF soot loading prediction model takes into account the different factors and calculation methods of pressure drop formation in different capture stages, including deep bed capture stage, transitional capture stage and soot cake capture stage. Further, a pressure drop model of DPF is improved, and the model for different filter wall permeability in different capture stages is discussed. The calculated results of the model are verified with the experimental results. Finally, the influence of ash factor on the modification of DPF pressure drop model was investigated.The results show that, when the ash layer is 0.05 mm–0.15 mm in the deep bed capture stage, the modified values of filtration wall permeability are 8.2%–43.8% of the original values. In the transitional capture stage, the ash layer with thickness of 0.01 mm–0.05 mm needs to modify 0.75 g/L∼1.5 g/L soot loading. The DPF pressure drop and the particle soot cake layer thickness increase linearly with time in the soot cake capture stage. When the ash layer changes in the range of 0.05 mm–0.15 mm, the soot loading is modified to 13.4%–36.8% of the original value. When the axial scale of the ash plug is 1/5,1/4 and 1/3 of the DPF length, the soot loading is corrected to 33.3%, 37.3% and 45.1%.