Patent ID: 7926263

Claim:
A method for regenerating a particulate filter, desulfating a lean NOx trap, desulfating a reduction catalyst, regenerating a reduction catalyst, or a combination thereof, comprising: providing an oxidation catalyst downstream of an internal combustion engine and upstream of the particulate filter, lean NOx trap, and reduction catalyst; providing a first oxygen sensor upstream of the oxidation catalyst providing engine-out oxygen concentration; providing a second oxygen sensor immediately downstream of the oxidation catalyst providing oxygen concentration exiting the oxidation catalyst; determining a change in oxygen concentration across the oxidation catalyst based on the engine-out oxygen concentration and the oxygen concentration exiting the oxidation catalyst; providing a temperature control loop including a temperature error function based upon an actual temperature of an exhaust stream exiting the oxidation catalyst and a desired temperature of the exhaust stream exiting the oxidation catalyst; providing a processor for selecting and maintaining a desired change in oxygen concentration across the oxidation catalyst for a selected period of time to provide the desired temperature of the exhaust stream exiting the oxidation catalyst, wherein the desired change in oxygen concentration is based upon the temperature error function and a mean change in oxygen concentration, and compared with the change in oxygen concentration across the oxidation catalyst to maintain the desired change in oxygen concentration across the oxidation catalyst; regenerating the particulate filter by passing the exhaust stream exiting the oxidation catalyst through the particulate filter, wherein the temperature of the exhaust stream passing through the particulate filter and the selected period of time are sufficient to regenerate the particulate filter; desulfating the lean NOx trap by passing the exhaust stream exiting the oxidation catalyst through the lean NOx trap, wherein the temperature of the exhaust stream passing through the lean NOx trap and the selected period of time are sufficient to desulfate the lean NOx trap; and desulfating or regenerating the reduction catalyst by passing the exhaust stream exiting the oxidation catalyst through the reduction catalyst, wherein the temperature of the exhaust stream passing through the reduction catalyst and the selected period of time are sufficient to desulfate or regenerate the reduction catalyst.