Patent ID: 7722829
Filing Date: 2010-05-25
Classification: B01D,B01J,F01N

Abstract:
1. A catalyzed soot filter, comprising: a wall flow substrate comprising an inlet end, an outlet end, a substrate axial length extending between the inlet end and the outlet end, and a plurality of passages defined by internal walls of the wall flow substrate; wherein the plurality of passages comprise inlet passages having an open inlet end and a closed outlet end, and outlet passages having a closed inlet end and an open outlet end; wherein the internal walls of the inlet passages comprise a first inlet coating that extends from the inlet end to a first inlet coating end, thereby defining a first inlet coating length, wherein the first inlet coating length is less than the substrate axial length; wherein the internal walls of the outlet passages comprise an outlet coating that extends from the outlet end to a outlet coating end, thereby defining a outlet coating length, wherein the outlet coating length is less than the substrate axial length; wherein the sum of the first inlet coating and outlet coating lengths is substantially equal to the substrate axial length; wherein the first inlet coating length defines an upstream zone and the outlet coating length defines a downstream zone; wherein the first inlet coating comprises at least one first inlet platinum group metal component; wherein the outlet coating comprises at least one outlet coating platinum group metal component; and, wherein at least 50% of the platinum group metal components are present in the upstream zone.