An internal combustion engine includes first and second exhaust paths, and a first NO_x adsorber located in the first exhaust path. A flow control valve controls the relative amounts of exhaust gas flowing through the first and second exhaust paths. A first injector injects a reductant into the exhaust gas stream. The injector is located so as to inject the reductant at a location adjacent to the flow control valve to cause mixing of the reductant and the exhaust gas and to allow regeneration of the first NO_x adsorber.