Patent ID: 7530220

Claim:
A method for enabling and initiating regeneration of a NOx adsorber catalyst that has adsorbed NOx in exhaust gas passing through an exhaust system of an internal combustion engine that propels a motor vehicle to release adsorbed NOx by catalytic-aided chemical conversion of the NOx into other gases that entrain with flow passing out of the exhaust system, the method comprising: processing, in an engine control system processor, while the engine is operating to propel the vehicle, data indicative of NOx adsorption efficiency of the NOx adsorber catalyst, data indicative of temperature of exhaust gas passing through the NOx adsorber catalyst, data indicative of speed of the motor vehicle, and data indicative of engine torque according to an algorithm that will enable regeneration to be initiated upon concurrence of the data indicative of NOx adsorption efficiency indicating an efficiency less than a defined efficiency, of the data indicative of temperature of exhaust gas passing through the NOx adsorber catalyst indicating a temperature suitable for initiating regeneration, of the data indicative of speed of the motor vehicle indicating vehicle speed suitable for initiating regeneration, and of the data indicative of engine torque indicating engine torque suitable for initiating regeneration; upon such concurrence, enabling regeneration of the NOx adsorber catalyst to be initiated; and after regeneration has been enabled, initiating regeneration by increasing the amount of carbon monoxide in the exhaust gas passing through the NOx adsorber catalyst; wherein the processor repeatedly iterates the algorithm and includes a delay function that conditions actual initiation of regeneration upon successive iterations of the algorithm disclosing such concurrence.