Oxygen storage control of engine exhaust gas purification catalyst

• Main Authors: KOBAYASHI HIDEAKI, KAKIZAKI SHIGEAKI
• Format: Patent
• Language: English
• Published: 20.03.2003
• 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

A three-way catalyst (10) is provided in the exhaust passage (9) of an engine (1) which stores and releases oxygen according to the oxygen concentration in the exhaust gas. A controller (2) calculates an oxygen storage amount of the catalyst (10) by accumulating a variation rate of the oxygen storage amount of the catalyst (10) based on the oxygen amount in the exhaust gas (S3-S5). A target oxygen amount in the exhaust gas is calculated which reduces the difference of the oxygen storage amount from a target oxygen storage amount (S6). A target air/fuel ratio is calculated based on a catalyst deterioration coefficient, an exhaust gas flowrate and the target oxygen amount (S7). Due to this process, it is possible to increase the speed and accuracy of control of the oxygen storage amount of the catalyst (10) towards the target oxygen storage amount.