Patent ID: 7325394

Claim:
In an apparatus having an internal combustion engine and a catalytic device for treating NO x emissions from the internal combustion engine, a method of operating the engine, comprising: accumulating sulfur in the catalytic device for a first interval by operating the engine in such a manner as to store and reduce NO x emissions in the catalytic device during the first interval; ending the first Interval when a first measure of sulfur is accumulated in the catalytic device; desulfating the catalytic device for a second interval by operating the engine in such a manner as to remove a portion of sulfur from the catalytic device during the second interval, wherein sulfur is removed at a higher rate during the second interval than during an interval used to fully desulfate the catalytic device via a single desulfation process; and, ending the second interval when a second measure of sulfur remains in the catalytic device, wherein the second measure corresponds to a substantial portion of sulfur remaining in the catalytic device.