Patent ID: 8017086
Filing Date: 2011-09-13
Classification: B01D,B01J

Abstract:
1. A catalyst unit configured for reducing NO x compounds in an internal combustion engine's exhaust gas stream, comprising: at least one first zone having a support structure with a first catalytically active material of the silver/alumina type supported by the support structure, and at least one second zone which is located downstream of an immediately preceding first zone, wherein the catalyst unit is arranged such that the exhaust gas stream is conducted through the first zone or zones and the second zone or zones, wherein interaction of the exhaust gas stream with the first catalytically active material produces an unstable intermediate gas species that breaks down into N wherein each second zone is a space that is 1) free of any device that acts on the unstable intermediate gas product in such a way as to foster or promote breakdown of the unstable intermediate gas product into N