Abstract: In a method for operating an exhaust-gas cleaning unit of a diesel engine including a particle filter and a nitrogen oxide storage device arranged upstream of the particle filter, wherein sulfur regeneration of the nitrogen oxide storage device is performed periodically at raised exhaust gas temperatures and, in certain phases, with a rich exhaust gas composition, and also soot regeneration of the particle filter is performed at raised exhaust gas temperatures with a lean exhaust gas composition, at least some of the sulfur regeneration and the soot regeneration phases are performed in a combined soot and sulfur regeneration phase, and for the sulfur regeneration, at least temporarily, a rich exhaust-gas composition with a temperature higher than the temperature of the lean exhaust gas composition is provided for the soot regeneration of the particle filter.

Abstract: In a method for operating an exhaust-gas cleaning unit of a diesel engine including a particle filter and a nitrogen oxide storage device arranged upstream of the particle filter, wherein sulfur regeneration of the nitrogen oxide storage device is performed periodically at raised exhaust gas temperatures and, in certain phases, with a rich exhaust gas composition, and also soot regeneration of the particle filter is performed at raised exhaust gas temperatures with a lean exhaust gas composition, at least some of the sulfur regeneration and the soot regeneration phases are performed in a combined soot and sulfur regeneration phase, and for the sulfur regeneration, at least temporarily, a rich exhaust-gas composition with a temperature higher than the temperature of the lean exhaust gas composition is provided for the soot regeneration of the particle filter.

Abstract: The invention relates to a method for operating a diesel engine in which an air ratio (?) of the fuel which is to be burnt and of the combustion air supplied is set by a control unit (14) according to predetermined values. When a value (15) which is predetermined as a switching criterion is recorded, the control unit (14) switches to a special operating mode for regeneration of a catalytic converter (22) and sets the fuel/air ratio according to predetermined values for this operating mode. To achieve more effective regeneration of the catalytic converter, according to the invention it is provided that at least one afterinjection, which is separated in time from a main injection, of fuel which is also to be burnt takes place in the special operating mode.

Abstract: In a method for operating a diesel engine and a diesel engine, wherein engine emission control is provided by switching between a lean mode with superstoichiometric combustion air ratio ?>1 and a rich mode with substoichiometric combustion air ratio ?<1, the engine-torque fluctuations during the switching are determined and engine parameters which influence the engine torque, are adjusted so as to keep the engine torque constant during the switchover.

Abstract: The invention relates to a method for operating a diesel engine in which an air ratio (&lgr;) of the fuel which is to be burnt and of the combustion air supplied is set by a control unit (14) according to predetermined values. When a value (15) which is predetermined as a switching criterion is recorded, the control unit (14) switches to a special operating mode for regeneration of a catalytic converter (22) and sets the fuel/air ratio according to predetermined values for this operating mode.

Abstract: In a method for operating a diesel engine and a diesel engine, wherein engine emission control is provided by switching between a lean mode with superstoichiometric combustion air ratio &lgr;>1 and a rich mode with substoichiometric combustion air ratio &lgr;<1, the engine-torque fluctuations during the switching are determined and engine parameters which influence the engine torque, are adjusted so as to keep the engine torque constant during the switchover.

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: An exhaust-gas cleaning unit includes a particle filter and a nitrogen oxide store disposed upstream of the particle filter. A method for operating the exhaust-gas cleaning unit includes a nitrogen oxide regeneration phase and a sulphur regeneration phase for the nitrogen oxide store and a soot regeneration phase for the particle filter. A longer period is selected for the sulphur regeneration phase than for the nitrogen oxide regeneration phase. At least part of the sulphur regeneration phase and at least part of the soot regeneration phase are performed as a combined regeneration phase, in which the regeneration phases are performed in immediate succession or one regeneration phase is performed intermittently at a number of intervals during the other regeneration phase.