Removing nitrogen oxides during a lean-burn engine cold start

An apparatus and method for removing NOx from an exhaust stream of a lean-burn engine during an engine cold start is provided. The apparatus includes a close-coupled LNT coupled to a main LNT by a hollow conduit. NOx from the cold exhaust is initially stored on the close-coupled LNT. As the engine e...

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Bibliographische Detailangaben
Hauptverfasser:	LI WEI, MONROE DAVID R
Format:	Patent
Sprache:	eng
Schlagworte:	BLASTING ENGINE PLANTS IN GENERAL GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNALCOMBUSTION ENGINES GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES ORENGINES IN GENERAL GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS HEATING LIGHTING MACHINES OR ENGINES IN GENERAL MECHANICAL ENGINEERING STEAM ENGINES TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINSTCLIMATE CHANGE WEAPONS
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Beschreibung
Zusammenfassung:	An apparatus and method for removing NOx from an exhaust stream of a lean-burn engine during an engine cold start is provided. The apparatus includes a close-coupled LNT coupled to a main LNT by a hollow conduit. NOx from the cold exhaust is initially stored on the close-coupled LNT. As the engine exhaust warms up, the close-coupled LNT reaches its operating temperature and reduces the stored NOx to N2. When the temperature of the close-coupled LNT reaches approximately 350° C., NOx is released from the close-coupled LNT, is absorbed on the main LNT, and is converted to N2 during fuel-rich conditions. The close-coupled LNT can be regenerated after the engine is turned off by providing heat. The released NOx during the regeneration of the closed-coupled LNT is absorbed by the main LNT. The stored NOx on the main LNT can be reduced to N2 during the next vehicle operation.