Abstract: An internal combustion engine includes an exhaust-gas aftertreatment device, and an operating method is for operating the internal combustion engine. The internal combustion engine is operable with a lean mixture and a rich mixture, the internal combustion engine having an exhaust-gas aftertreatment device, which includes a nitrogen oxide storage catalytic converter and a particle filter. When lean exhaust gas flows through the nitrogen oxide storage catalytic converter, it removes nitrogen oxides from the exhaust gas by storing them, and, when reducing exhaust gas flows through the nitrogen oxide storage catalytic converter, it produces ammonia through reduction of stored and/or supplied nitrogen oxides and releases it to the exhaust gas. Downstream from the nitrogen oxide storage catalytic converter, the exhaust-gas aftertreatment device includes a SCR catalytic converter, which reduces nitrogen oxides contained in the exhaust gas, using ammonia produced by the nitrogen oxide storage catalytic converter.

Abstract: An exhaust-gas aftertreatment device with a nitrogen oxide storage catalytic converter for an internal combustion engine, and a method for operating an exhaust-gas aftertreatment device which is assigned to an internal combustion engine and has a nitrogen oxide storage catalytic converter. An SCR catalytic converter is arranged in the exhaust-gas aftertreatment device, it being possible for the exhaust gas which emerges from the nitrogen oxide storage catalytic converter to be fed to the SCR catalytic converter when the internal combustion engine is in a desulphating operating mode with a reducing exhaust-gas composition, in order for H2S which is formed during the desulphating to be removed.