Lean NOx storage estimation based on oxygen concentration corrected for water gas shift reaction

摘要

A method for estimating the amount of NOx stored in a lean NOx trap. The method includes determining a change in the oxygen concentration between an exhaust air/fuel ratio entering the lean NOx trap and exiting the lean NOx trap to determine the amount of NOx absorbed in the trap and correcting such determination for water gas shift reaction effects in such change in oxygen concentration determination.