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US 8,800,268 B2Granted
Zone coated filter, emission treatment systems and methods
AssigneeBASF SE
InventorsKenneth Voss, Ingemar Gottberg, Steve Truesdail, Marius Vaarkamp
Life of this patent
Estimating the term…
Abstract
Exhaust treatment filters, systems, and methods are disclosed. According to one or more embodiments, a particulate filter is zone coated with an oxidation catalyst and is used in an emission treatment system or method including a NOx reducing catalyst and an optional NH3 destruction catalyst.
Claims32
An emission treatment system for treatment of an exhaust stream
- comprising NOx and particulate matter, the emission treatment system comprising:
- a filter comprising a substrate having a plurality of passages and elements for trapping particulate contained in an exhaust stream flowing through the filter, the substrate having an inlet end and an outlet end defining an axial length, the inlet end of the substrate having a quantity of platinum group metal composition comprising platinum and palladium disposed thereon and extending for less than 50% of the axial length to periodically light off fuel at a temperature of less than about 300° C. and to produce an exotherm sufficient to burn off trapped particulate in the filter, wherein active regeneration of the filter can be accomplished by the filter alone, without a separate upstream, light-off oxidation catalyst;
- and
- a NOx reducing catalyst located downstream from the particulate filter.
1 more element
An emission treatment system for treatment of an exhaust stream comprising NOx and particulate matter, the emission treatment system comprising:
- a particulate filter having an axial length and elements for trapping particulate matter contained in an exhaust stream flowing through the filter and a light-off oxidation catalyst composition comprising platinum and palladium extending from the inlet end towards the outlet end to a length that is less than the axial length of the walls to provide an inlet zone in an amount sufficient to periodically light-off fuel at less than about 300° C. and generate an exotherm to burn soot trapped in the filter, wherein active regeneration of the filter can be accomplished by the filter alone, without a separate upstream, light-off oxidation catalyst;
- and
- a NOx reducing catalyst located downstream from the particulate filter.
An emission treatment system for treatment of an exhaust stream comprising NOx and particulate matter, the emission treatment system comprising:
- a filter comprising a wall flow monolith disposed within the exhaust stream and having a plurality of longitudinally extending passages bounded by longitudinally extending walls, the passages comprising 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, the walls having a porosity of at least 40% with an average pore size of at least 5 microns and the wall flow monolith comprising a quantity of a light-off oxidation catalyst composition comprising platinum and palladium permeating the walls and extending from the inlet end towards the outlet end to a length that is less than the axial length of the walls to provide an inlet zone in an amount sufficient to periodically light-off fuel at less than about 300° C. and generate an exotherm to burn soot trapped in the filter, wherein active regeneration of the filter can be accomplished by the filter alone, without a separate upstream, light-off oxidation catalyst;
- an SCR catalyst located downstream from the wall flow monolith;
- and
- an injector for injecting ammonia or ammonia precursor into the exhaust gas stream upstream of the SCR catalyst.
1 more element
A method of treating exhaust stream from a diesel engine comprising:
- disposing within the exhaust stream containing particulate matter a wall flow monolith and having a plurality of longitudinally extending passages bounded by longitudinally extending walls, the passages comprising 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, the walls having a porosity of at least 40% with an average pore size of at least 5 microns and the wall flow monolith comprising a light-off oxidation catalyst composition comprising platinum and palladium permeating the walls and extending from the inlet end towards the outlet end to a length that is less than the axial length of the walls to provide an inlet zone in an amount sufficient to periodically light off fuel at less than about 300° C. and generate an exotherm to burn soot trapped in the wall flow monolith, wherein active regeneration of the wall flow monolith can be accomplished by the wall flow monolith alone, without a separate upstream, light off oxidation catalyst;
- disposing a NOx reducing catalyst downstream from the wall flow monolith;
- and
- periodically introducing an exotherm-producing agent upstream of the wall flow monolith to generate an exotherm in the wall flow monolith sufficient to combust particulate matter trapped within the wall flow monolith.
1 more element
An emission treatment system for treatment of an exhaust stream comprising NOx and particulate matter, the emission treatment system comprising:
- a substrate in the form of a wall flow monolith having a plurality of passages and elements for trapping particulate contained in an exhaust stream flowing through the filter, the substrate having an inlet end and an outlet end, the inlet end of the substrate having a quantity of platinum group metal composition comprising platinum and palladium disposed thereon present in a loading amount of at least about 40 g/ft3 and extending for less than about 50% of the axial length of the filter to periodically light off fuel at a temperature of less than about 300° C. and to produce an exotherm sufficient to burn off trapped particulate in the wall flow monolith;
- and
- a NOx reducing catalyst located downstream from the wall flow monolith.
Dependencies are inferred from the claim text.