Patent ID: 7412823

Claim:
A method of desulfating a LNT configured downstream of a fuel reformer, comprising: operating an internal combustion engine to produce exhaust; introducing the exhaust to a fuel reformer; heating the fuel reformer to a temperature at least about 50° C. hotter than the exhaust; providing fuel to the exhaust to make the exhaust rich for a first period over which the reformer heats by at least about 75° C.; reducing or terminating the provision of fuel to the exhaust to make the exhaust lean for a second period over which the reformer cools by at least about 75° C. while remaining at least about 50° C. hotter than the exhaust; and while the reformer remains at least about 50° C. hotter than the exhaust, repeating the actions of making the exhaust rich for a period over which the reformer heats by at least about 75° C. and making the exhaust lean for a period over which the reformer cools by at least about 75° C.