Zone coated filter, emission treatment systems and methods

摘要

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.

主权项

1. 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.