Patent ID: 7662197
Filing Date: 2010-02-16
Classification: B01D,F01N,F02D,Y02A,Y02C,Y02T

Abstract:
1. A method for operating an exhaust-gas cleaning unit of a diesel engine with exhaust gas recirculation including a particle filter and a nitrogen oxide storage device arranged upstream of the particle filter, wherein, in phases, sulfur regeneration of the nitrogen oxide storage device is performed periodically at raised exhaust gas temperatures and, at least in certain phases, with a rich exhaust gas composition, and soot regeneration of the particle filter is performed, for certain phases, at raised exhaust gas temperatures with a lean exhaust gas composition, the method comprising the steps of: performing at least some of the sulfur regeneration and the soot regeneration phases in the form of a combined soot and sulfur regeneration phase, and providing, during the combined sulfur and soot regeneration phase, 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 which is provided for the period of soot regeneration of the particle filter, and, during the soot regeneration period, deactivating the exhaust gas recirculation, and intermittently regenerating the nitrogen oxide storage device for shorter periods and at lower exhaust gas temperatures than are employed for the sulfur regeneration just for the removal of the nitrogen oxides by an exhaust gas having, at least for a predetermined time, a rich composition.