EXHAUST AFTERTREATMENT SYSTEM WITH LOW-TEMPERATURE SCR

摘要

An aftertreatment system may treat exhaust gas discharged from an engine. The system may include first and second selective-catalytic-reduction (SCR) catalysts and a valve. The valve may be disposed upstream of the first SCR catalyst and at least one of an oxidation catalyst and a particulate filter. The valve is connected to first and second exhaust flow paths and is movable between a first position allowing exhaust gas to flow through the first flow path and bypass the second flow path and a second position allowing exhaust gas to flow through the second flow path and bypass the first flow path. The second SCR catalyst may be a low-temperature SCR catalyst and may be disposed in the second flow path. A control module may cause the valve to move between the first and second positions based on a temperature of the exhaust gas and/or a temperature of the engine.

主权项

1. An aftertreatment system for treating exhaust gas discharged from a combustion engine, the aftertreatment system comprising:
at least one of an oxidation catalyst and a particulate filter configured to receive exhaust gas; first and second selective-catalytic-reduction catalysts; a valve disposed upstream of the first selective-catalytic-reduction catalyst and the at least one of the oxidation catalyst and particulate filter, the valve connected to first and second exhaust flow paths and movable between a first position allowing exhaust gas to flow through the first exhaust flow path and bypass the second exhaust flow path and a second position allowing exhaust gas to flow through the second exhaust flow path and bypass the first exhaust flow path, the second selective-catalytic-reduction catalyst is a low-temperature selective-catalytic-reduction catalyst and is disposed in the second exhaust flow path; and a control module in communication with the valve and configured to cause the valve to move between the first and second positions based on an operating parameter of the combustion engine.