Patent ID: 6973775
Filing Date: 2005-12-13
Classification: B01D,F01N,F02D

Abstract:
1. A method for desulfating a nitrogen oxide storage catalyst, wherein said nitrogen oxide storage catalyst contains stored nitrogen oxides and sulfur oxides and is a component of an exhaust gas purification system of a lean-burn engine, said method comprising: (i) increasing the temperature of the catalyst under lean exhaust conditions to a temperature at which thermal desorption of the nitrogen oxides sets in; and (ii) enriching the air/fuel mixture, wherein said enriching is commenced at the onset of said thermal desorption, thereby causing desulfating of the nitrogen oxide storage catalyst; wherein the onset of thermal desorption of the nitrogen oxides during heating of the storage catalyst is determined with the aid of a nitrogen oxide sensor that is inserted into the exhaust gas purification system downstream of the nitrogen oxide storage catalyst.