Patent ID: 6941748

Claim:
A method for desulfurization of an NO x storage catalyst arranged in an exhaust duct of a combustion engine, at least one lambda probe arranged downstream from the NO x storage catalyst, comprising the steps of: alternatingly operating the combustion engine in a lean operating mode and a rich operating mode; and monitoring progress of desulfurization in accordance with a characteristic curve of a size of intervals during the desulfurization process; wherein the interval lasts from a beginning of a rich operating phase to a point that a lambda value downstream from the NO x storage catalyst falls below a specifiable lambda threshold value, the specifiable threshold value having a value less than 1 and greater than a preselected lambda value in front of the NO x storage catalyst; and wherein, during desulfurization, a temperature of the NO x storage catalyst one of equals and exceeds a minimum desulfurization temperature.