发明名称 |
Exhaust emission control system for internal combustion engine |
摘要 |
<p>An exhaust emission control system for an internal combustion engine amounted on an automotive vehicle. The exhaust emission control system comprises a first catalyst disposed in an exhaust gas passage of the engine. The first catalyst functions to store NOx in an atmosphere having an air-fuel ratio leaner than a stoichiometric level and to release NOx in an atmosphere having an air-fuel ratio richer than the stoichiometric level and reduce released NOx in presence of HC and CO. A second catalyst is disposed in the exhaust gas passage upstream of the first catalyst and having an oxygen absorbing ability. A control unit is provided including a first section for accomplishing an enrichment treatment by enriching stepwise an air-fuel ratio of an air-fuel mixture to be supplied to the engine to an enrichment degree at a timing at which a lean operation is changed to a stoichiometric operation in the engine, and recovering the enriched air-fuel ratio to the stoichiometric level at a recovery rate immediately after the enriching the air-fuel ratio. A second section of the control unit is for estimating the oxygen absorbing ability of the second catalyst. A third section of the control unit is for correcting the enrichment degree to decrease in the step wise enricbing as the estimated oxygen absorbing ability decreases. <IMAGE></p> |
申请公布号 |
EP0930425(A2) |
申请公布日期 |
1999.07.21 |
申请号 |
EP19990100657 |
申请日期 |
1999.01.14 |
申请人 |
NISSAN MOTOR COMPANY, LIMITED |
发明人 |
ISHIZUKA, YASUJI;NISHIZAWA, KIMIYOSHI |
分类号 |
F01N3/08;B01D53/94;F01N3/20;F01N3/24;F01N3/28;F01N13/02;F02D41/02;F02D41/04;F02D41/14;(IPC1-7):F02D41/14 |
主分类号 |
F01N3/08 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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