METHOD FOR EXHAUST-GAS AFTERTREATMENT IN INTERNAL COMBUSTION ENGINES, AND APPARATUS FOR CARRYING OUT THIS METHOD

摘要

The present invention relates to a method for exhaust-gas aftertreatment in internal combustion engines, in which method nitrogen is removed from the exhaust gas by a NOx storage catalytic converter (10, 12) which is arranged in the exhaust-gas section (8). There is provision for nitrogen to be removed from exhaust gas in two consecutive steps in a first NOx storage catalytic converter (10) which is arranged near the engine and subsequently in a second NOx storage catalytic converter (12) which is arranged away from the engine. In cold starting and part load operation, the NOx storage catalytic converter (10) which is near the engine operates in a favourable operating window and assumes the greater proportion of the nitrogen removal. In full load operation, the NOx storage catalytic converter (12) which is arranged away from the engine operates in a favourable operating window, with the result that it assumes the greater proportion of the nitrogen removal in this mode of operation. In this way, the operating window of the overall arrangement is increased considerably in comparison with individual NOx storage catalytic converters.