Exhaust-gas cleaning unit with particle filter and nitrogen oxygen store, and operating method therefor

摘要

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.