Patent ID: 7191591

Claim:
A method for regenerating a NOx adsorber in an exhaust system of an internal combustion engine that is fueled in accordance with a data value for desired engine fueling, the method comprising: a) processing data values of certain parameters to develop a data value for desired engine fueling for causing the engine to develop a corresponding desired output torque without conditioning engine exhaust passing into the exhaust system for NOx adsorber regeneration; b) processing data values of various parameters indicative of conditions relevant to initiation of NOx adsorber regeneration; and c) after the processing of step b) has disclosed that NOx adsorber regeneration can be initiated, initiating NOx adsorber regeneration by changing engine fueling so as to condition engine exhaust passing into the exhaust system for regenerating the NOx adsorber, including developing a data value for desired engine fueling that is effective to condition the exhaust gas for NOx adsorber regeneration at a given engine speed while striving to maintain the output torque at the corresponding output torque that desired engine fueling would develop at the given engine speed without conditioning engine exhaust passing into the exhaust system for NOx adsorber regeneration, by processing data values for i) the desired engine fueling that would develop that corresponding output torque without conditioning engine exhaust passing into the exhaust system for NOx adsorber regeneration, ii) engine speed, and iii) actual air-fuel ratio at which the engine is operating according to a control algorithm that, for a given data value for i) provides a data value for desired engine fueling that is correlated with both a data value for ii) and a data value for iii) and that conditions the exhaust gas for NOx adsorber regeneration while striving to maintain the output torque at the corresponding output torque that would be developed without conditioning the exhaust gas for NOx adsorber regeneration.