METHOD OF DESULFATING AN NOX STORAGE CATALYST

摘要

The invention relates to a method of desulfating an NOx storage catalyst that is mounted downstream of a lean-mix internal combustion engine. The charge condition of the catalyst is determined by means of sulfur and is compared with a predetermined maximally permissible sulfur charge. If said value is exceeded, the method provides for a check of the safety-relevant components for their proper functioning and the actual drive conditions for observance of predetermined drive parameters in order to decide whether a desulfation is permissible. It is also checked whether it is possible to carry out a desulfation by observing predetermined desulfation parameters. If such a desulfation is permissible, the required desulfation parameters are adjusted and a desulfation process is initiated which lasts until either a predetermined desulfation degree is reached or the actual results of the permissibility check require a premature termination or disruption of the desulfation. In addition to this procedure, the exhaust gases are monitored in order to detect any irregularities in the catalyst performance. If the emission values are impermissibly high, desulfation is advanced to remove potential sulfur-related damages. If the emission values are exceptionally low, a possibly required desulfation is specifically suppressed until certain maximally permissible emission values are reached.