Emissions control system for increasing selective catalytic reduction efficiency

• Main Authors: LIANG, CHO Y, MC COY, STEVEN R
• Format: Patent
• Language: English; French; German
• Published: 23.06.2004
• Edition: 7
• Subjects: BLASTING; CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TOTRANSPORTATION; COMBUSTION ENGINES; CONTROLLING COMBUSTION ENGINES; 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; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS; LIGHTING; MACHINES OR ENGINES IN GENERAL; MECHANICAL ENGINEERING; STEAM ENGINES; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS; TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINSTCLIMATE CHANGE; WEAPONS

An emissions control system (10) is used with a compression ignition engine (12) capable of producing an exhaust gas stream (16) to be treated by a reduction agent which is mixed with the exhaust gas stream (16) to convert the exhaust gas stream (16) prior to being directed into an SCR catalyst (34) capable of reducing NOx in the exhaust gas stream (16). An exhaust gas recirculation valve (18) is associated with the compression ignition engine (12) for directing the exhaust gas stream (16) back into the compression ignition engine (12). An electronic control unit (40) and sensor (46) determine determining whether the temperature of the exhaust gas stream (16) is at a predetermined temperature, and if so control operation of the valve (18) to allow a portion of the exhaust gas stream (16) to be directed into the SCR catalyst (40). A bypass valve (32) may also be provided to prevent the exhaust gas stream (16) from entering into the SCR catalyst (34).