Method to control the purging of a Nitric oxygen trap

摘要

The method involves comparing a part of nitrogen oxide content to a reference value, and controlling purging of nitrogen oxide trap according to a comparison result. A constant target value of purging efficiency of nitrogen oxide trap to be attained is stored in a memory. An assembly of temperature and regular speed values is stored. A cartography representing an assembly of reference values is established for the stored target value according to the stored assembly of temperature and regular speed values. An independent claim is also included for a computer program comprising instructions to execute steps of a nitrogen oxide trap purging controlling method.