Desulfurizing nitrogen oxides storage catalyst in exhaust gas channel of I.C. engine involves determining rich lambda value for desulfurization depending on nitrogen oxides storage rate of catalyst

摘要

Desulfurizing a NOx storage catalyst in an exhaust gas channel of an I.C. engine involves impinging the storage catalyst with a rich exhaust gas atmosphere with a given rich lambda value during a desulfurization phase; and determining the rich lambda value for desulfurization depending on a NOx storage rate of the storage catalyst or a value derived from it, where the NOx storage rate is a proportion of the NOx amount flowing into the catalyst. Process for desulfurizing a NOx storage catalyst (16) arranged in an exhaust gas channel (12) of an I.C. engine comprises impinging the storage catalyst with a rich exhaust gas atmosphere having a prescribed rich lambda value during a desulfurization phase; and determining the rich lambda value for desulfurization depending on a NOx storage rate of the storage catalyst or a value derived from it, in which the NOx storage rate is a proportion of the NOx amount flowing into the catalyst. An Independent claim is also included for a device for desulfurizing a NOx storage catalyst comprising a control device (24) for acquiring a NOx storage rate of the storage catalyst in the lean phase and determining the rich lambda value for desulfurization. Preferred Features: The NOx amount is determined based on a NOx amount measured by a sensor (20) arranged downstream of the storage catalyst.