Study on the Filter Structure of SiC-DPF with Gas Permeability for Emission Control

The pore structure of DPF (Diesel Particulate Filter) is one of the key factors in contributing the fuel consumption and the emission control performance of a vehicle. The pressure loss of mini samples (1 in. in diameter, 2 in. in length) with various pore structures was measured at relatively low filtration velocity (< 5 cm/sec). Then the obtained data were evaluated by using an index of “permeability”. As a result, among the parameters which characterize the pore structure, it was found that the size of the pore diameter and the sharpness of pore distribution were the most contributing factors in reducing pressure loss which in turn is related to the fuel consumption performance when the cell structure was fixed. On the other hand, it was found that the gas permeability was not affected significantly by any parameter when the catalyst was coated because the coating caused a broadening of the pore distribution. In addition, it was found that any parameter prior to the catalyst coating did not have a real impact on the gas purification efficiency. It is considered that the catalyst coating should be selectively applied to pores to sharpen the pore distribution for decreasing the pressure loss and increasing the emission control performance after coating the catalyst.