Method for determining a state of aging of an NOx storage catalyst of an exhaust gas aftertreatment system of an internal combustion engine designed for

摘要

In a method for determining a state of ageing of a NOx storage catalyst, eg LNT, (5, fig.1) of an exhaust gas aftertreatment system (3) of an internal com­bustion engine (1) designed for lean-mixture operation, eg a diesel engine or a direct injection spark-ignition engine, an ageing parameter of the NO storage catalyst is determined on the basis of a function measurement of the NO storage catalyst, wherein the state of ageing is determined repeatedly and a state of ageing of the NO storage catalyst is determined from a plurality of values of the ageing parameter determined within an averaging interval. The inven­tion also relates to a corresponding control device for an exhaust gas aftertreatment system (3) of an internal combustion engine (1) designed for lean-mixture operation. The ageing parameter may be determined on the basis of oxygen absorption of the NOx storage catalyst or air ratio downstream of the catalyst. The function measurement may be carried out in time relationship with a regeneration phase.