Air-fuel ratio control apparatus of internal combu

专利名称：Air-fuel ratio control apparatus of internal

combustion engine

发明人：Akira Kamoto,Toshinari Nagai,Akihiro

Katayama,Naoto Kato

申请号：US09956992申请日：20010921

公开号：US20020040577A1公开日：20020411

专利附图：

摘要：An air-fuel ratio control apparatus of an internal combustion engine accordingto the present invention is provided with oxygen storage amount estimating means for

estimating an oxygen storage amount of an exhaust purifying catalyst and air-fuel ratiocontrol means for controlling an air-fuel ratio, based on the oxygen storage amount. Anupper threshold and a lower threshold are set for the oxygen storage amount, and theair-fuel ratio control means performs such control that, when the oxygen storageamount is larger than the upper threshold, the control means controls the air-fuel ratioto a rich region and that, when the oxygen storage amount is smaller than the lowerthreshold, the control means controls the air-fuel ratio to a lean region. Since this controlmakes the oxygen storage amount vary between the upper threshold and the lowerthreshold (within a predetermined range), it is feasible to promote activation of theexhaust purifying catalyst, so as to keep purification performance of the exhaust purifyingcatalyst high, and to implement stable control of air-fuel ratio.

申请人：TOYOTA JIDOSHA KABUSHIKI KAISHA

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