Abstract: The inventors' concept relates to controlling a power generation system having an exhaust aftertreatment system comprising a fuel reformer and an LNT in series. Over the course of a desulfation, a fuel injection upstream of the fuel reformer is pulsed to create alternating lean and rich phases and control the LNT temperature. The LNT temperature is controlled by manipulating a minimum temperature for the fuel reformer at the end of the lean phase, a length of the lean phase, or a pulse frequency. Preferably, the rich phases end when the fuel reformer reaches a predetermined maximum temperature. The method is effective in regulating the fuel reformer temperature while accurately controlling the LNT temperature.