Abstract: A method for the desulfurization of a nitrogen oxide adsorber of an exhaust gas purification device for a combustion system employs desulfurization phases that are intermittently implemented by a desulfurization control unit. During each desulfurization phase, the carbon monoxide concentration and/or the lambda value of the exhaust gas stream exiting the nitrogen oxide adsorber is recorded. A localized maximum that appears in the recorded course of the carbon monoxide concentration over time, or a downward slope that appears in the established course of the lambda value over time, falling from a temporary plateau value, is employed as criterion for terminating the desulfurization phase. The method may be used, for example, in exhaust gas purification devices in primarily lean-burning vehicle combustion engines.

Abstract: A method for the desulfurization of a nitrogen oxide adsorber of an exhaust gas purification device for a combustion system employs desulfurization phases that are intermittently implemented by a desulfurization control unit. During each desulfurization phase, the carbon monoxide concentration and/or the lambda value of the exhaust gas stream exiting the nitrogen oxide adsorber is recorded. A localized maximum that appears in the recorded course of the carbon monoxide concentration over time, or a downward slope that appears in the established course of the lambda value over time, falling from a temporary plateau value, is employed as criterion for terminating the desulfurization phase. The method may be used, for example, in exhaust gas purification devices in primarily lean-burning vehicle combustion engines.

Abstract: A method for operating an exhaust-gas cleaning system having an NOx adsorption accumulator and an SOx trap, includes, in normal operating phases, feeding the exhaust gas to be cleaned first via the SOx trap and then via the NOx adsorption accumulator. The normal operating phases are from time to time interrupted by desulphurization phases for desulphurizing the SOx trap. Means are provided for controlling the direction of flow of the exhaust stream so that it optionally passes firstly via the SOx trap and then via the NOx adsorption accumulator, or firstly via the NOx adsorption accumulator and then via the SOx trap, so that during the desulphurization phases the exhaust gas can be passed firstly via the NOx adsorption accumulator and then via the SOx trap.

Abstract: A method and apparatus for periodically desulphating a nitrogen oxide or sulphur oxide storage vessel of an exhaust emission control system of a multi-cylinder internal combustion engine, in which an engine exhaust emission containing reducing agent and oxygen is fed to the nitrogen oxide or sulphur oxide storage vessel by setting a rich fuel/air ratio for a first subset of the engine cylinders and a fuel/air ratio which is, in comparison, leaner for the other cylinders. The distance between the fuel/air ratio for the first subset of the engine cylinders and that for the second subset of the engine cylinders is set higher in an initial storage vessel heating-up phase than in the subsequent desulphation mode, and/or control errors of the entire fuel/air ratio are eliminated by a predefinable set point value by modifying the fuel/air ratio either of just the first subset or just the second subset of the engine cylinders. Used, for example, in motor vehicles.

Abstract: A method for operating an exhaust-gas cleaning system having an NOX adsorption accumulator and an SOX trap, includes, in normal operating phases, feeding the exhaust gas to be cleaned first via the SOX trap and then via the NOX adsorption accumulator. The normal operating phases are from time to time interrupted by desulphurization phases for desulphurizing the SOX trap. Means are provided for controlling the direction of flow of the exhaust stream so that it optionally passes firstly via the SOX trap and then via the NOX adsorption accumulator, or firstly via the NOX adsorption accumulator and then via the SOX trap, so that during the desulphurization phases the exhaust gas can be passed firstly via the NOX adsorption accumulator and then via the SOX trap.

Abstract: A method and an apparatus are provided for operating a diesel engine with an exhaust feedback device located between the exhaust line and the intake air line, with an adjusting element that can be operated by an adjusting drive actuated by an auxiliary force to operate the exhaust feedback device as a function of signals from an electronic control device. An engine regulator permits rich/lean regulation of the diesel engine as a function of its operating parameters. A storage catalyst is located in the exhaust line, in which catalyst oxides of nitrogen (NO.sub.x) can be adsorbed, desorbed, and reduced. A sensor is located downstream from the storage catalyst for detecting the NO.sub.x concentration in the exhaust stream in such fashion that when an NO.sub.x storage threshold value is reached that varies in terms of its characteristics as a function of the rpm and the load, a switch is made from operation with a lambda value of larger than 1 to operation with a lambda value of less than 1.