An exhaust aftertreatment system for an engine includes an exhaust valve assembly having a first port, a second port, and a third port, the exhaust valve assembly being configured to effect selective fluid communication between the first port, the second port, and the third port; an exhaust conduit fluidly coupled to an exhaust port of the engine and fluidly coupled to the first port of the exhaust valve assembly; an exhaust aftertreatment device fluidly coupled to the second port of the exhaust valve assembly; a bypass conduit fluidly coupled to the third port of the exhaust valve assembly, the bypass conduit configured to bypass a flow of exhaust around the exhaust aftertreatment device; a reductant supply in selective fluid communication with the exhaust conduit; and a controller operatively coupled to the exhaust valve assembly and the reductant supply.