Patent ID: 7179430
Filing Date: 2007-02-20
Classification: B01D,F01N

Abstract:
1. In a porous filter body for filtering soot particles from diesel engine exhaust gases, the filter body being a honeycomb wall flow filter body in which interconnected porous filter walls, each of which has a gas inlet surface and a gas outlet surface, define a multiplicity of channels, each channel being closed at one end and neighbouring channels being closed at alternate ends, the filter walls being made of a material based on metallic and/or ceramic particles being bonded together, the porosity of the filter wall being constituted by interconnected voids defined between the metallic and/or ceramic particles, the particles directly defining the pores of the material, the improvement wherein: the filter body has a mean pore size in the range of 30–200 μm for allowing the intrusion of soot particles; a catalytically active material catalyzing oxidation of soot is deposited on at least part of those surface parts of the metallic and/or ceramic particles which are exposed to the voids, and a porous membrane having a mean pore size in the range of 1–50 μm and a thickness in the range of 0.05–0.4 mm is applied to the gas outlet side only of the filter walls.