An internal combustion engine includes first and second sets combustion chambers fluidly coupled to respective first and second aftertreatment devices. A third aftertreatment device including a supplemental heating device is fluidly coupled to outlets of the first and second aftertreatment devices. The first set of combustion chambers is operated rich and the second set of combustion chambers is operated lean. The supplemental heating device is operated to transfer thermal energy to the exhaust gas feedstream.