Method for operating a direct injection engine

Process for operating a direct injection I.C. engine containing a catalyst system with a nitrogen oxides storage catalyst comprises storing nitrogen oxides in the storage catalyst under a first operating condition, and releasing the nitrogen oxides from the catalyst under a second operating condition. A predetermined maximum time duration is assigned to each point in a load rotational speed mapping for each first operating condition which then switches to a second operating condition assigned to this point. The first operating condition comprises a lean operation, especially a shift operation and/or homogeneous lean operation. The lambda value for an air-fuel ratio in the first operating condition is more than 1.1. The second operating condition comprises a stoichiometric operation with a lambda value for an air-fuel ratio equal to 1. The predetermined maximum time duration is 0-20 seconds, preferably 0-5 seconds.