Exhaust system for internal combustion engine

摘要

In an exemplary embodiment of the invention an exhaust gas after treatment system for an internal combustion engine comprises an exhaust gas conduit configured to transport exhaust gas from the internal combustion engine to exhaust treatment devices of the exhaust gas treatment system. A controller in signal communication with the exhaust gas aftertreatment system is configured to monitor the temperature of a selective catalytic reduction device, wherein the controller is operable to move a valve assembly to an open position when the selective catalytic reduction device is at or above an operating temperature and to move the valve assembly to a closed position when the selective catalytic reduction device is below the operating temperature for entrainment of NOx constituents from the exhaust gas.