Patent ID: 6502387
Filing Date: 2003-01-07
Classification: F01N,F02D,Y02T

Abstract:
A method for controlling a purge time cycle and a fill time cycle of an emission control device that receives exhaust gas generated by an internal combustion engine, wherein the device is filled with a constituent gas of the exhaust gas during a first engine operating condition and is purged of constituent gas during a second engine operating condition, the method comprising:selecting, in a normal open-loop mode of operation, a fill time and a purge time from a set of predetermined values as a function of an engine operating condition; cyclically filling and purging the device based on the selected fill and purge times; after a predetermined number of fill and purge cycles, determining a first value representative of current total device capacity, and a second value representative of a quantity of oxygen stored in the device; updating at least one of the predetermined values as a function of the first and second values; and periodically optimizing a selected purge time associated with a selected fill time by: filling the device for the selected fill time; purging the device for the selected purge time; generating a third value representative of oxygen concentration present in the exhaust flowing through the device during a predetermined sampling period which includes at least an end portion of the purge time; comparing the third value to a predetermined reference value, wherein the reference value is based on an optimized value for device capacity utilization; and generating an adaption value for modifying the selected purge time as a function of any error between the third value and the reference value.