Abstract: The invention concerns a procedure to determine the sulfur removal of a NOx storage catalytic converter in an exhaust gas aftertreatment system of an internal combustion engine, whereby conditions, in which a surplus of the reducing agent is generated in the internal combustion engine, are adjusted in the internal combustion engine for the sulfur removal, whereby a SOx removal amount is determined in a SOx removal calculation using a model from the reducing agent flow and from additional operating parameters of the internal combustion engine. In so doing, dynamic effects during the desulferization of the NOx storage catalytic converter can be better taken into account for the SOx removal calculation; and in so doing, the subsequent effect of the NOx storage catalytic converter on the reduction of the nitrogen oxides in the exhaust gas can be more accurately predicted, which makes the process management more streamlined and consequently more fuel efficient.

Abstract: A method is described for operating an internal combustion engine, in particular of a motor vehicle. In the method, a lean air/fuel mixture is burned in a combustion chamber; nitrogen oxides contained in the exhaust gas are stored in an accumulator-type catalytic converter; a storage efficiency, with which the accumulator-type catalytic converter stores the nitrogen oxides contained in the exhaust gas, is ascertained; and the storage efficiency is ascertained as a function of an instantaneous space velocity of the exhaust gases in the accumulator-type catalytic converter. Two efficiencies are ascertained at least as a function of the temperature of the accumulator-type catalytic converter and a space velocity. One of the two efficiencies is ascertained for a great space velocity, and the other efficiency is ascertained for a small space velocity. The storage efficiency is ascertained as a function of the instantaneous space velocity from the two efficiencies.

Abstract: The invention concerns a procedure to determine the sulfur removal of a NOx storage catalytic converter in an exhaust gas aftertreatment system of an internal combustion engine, whereby conditions, in which a surplus of the reducing agent is generated in the internal combustion engine, are adjusted in the internal combustion engine for the sulfur removal, whereby a SOx removal amount is determined in a SOx removal calculation using a model from the reducing agent flow and from additional operating parameters of the internal combustion engine. In so doing, dynamic effects during the desulferization of the NOx storage catalytic converter can be better taken into account for the SOx removal calculation; and in so doing, the subsequent effect of the NOx storage catalytic converter on the reduction of the nitrogen oxides in the exhaust gas can be more accurately predicted, which makes the process management more streamlined and consequently more fuel efficient.

Abstract: A method is described for operating an internal combustion engine, in particular of a motor vehicle. In the method, a lean air/fuel mixture is burned in a combustion chamber; nitrogen oxides contained in the exhaust gas are stored in an accumulator-type catalytic converter; a storage efficiency, with which the accumulator-type catalytic converter stores the nitrogen oxides contained in the exhaust gas, is ascertained; and the storage efficiency is ascertained as a function of an instantaneous space velocity of the exhaust gases in the accumulator-type catalytic converter. Two efficiencies are ascertained at least as a function of the temperature of the accumulator-type catalytic converter and a space velocity. One of the two efficiencies is ascertained for a great space velocity, and the other efficiency is ascertained for a small space velocity. The storage efficiency is ascertained as a function of the instantaneous space velocity from the two efficiencies.