| 摘要 |
PROBLEM TO BE SOLVED: To restrain exhaust of emission in a state of reducing oxygen storage capacity of a catalyst, in an air-fuel ratio control device of an internal combustion engine. SOLUTION: A fuel injection quantity is controlled so that the air-fuel ratio of exhaust gas flowing in the catalyst, vibrates by sandwiching the stoichiometric air-fuel ratio. When estimating that the oxygen storage capacity of the catalyst is reduced more than predetermined reference capacity, amplitude of the air-fuel ratio is reduced by control of the fuel injection quantity. A degree of the oxygen storage capacity of the catalyst can be estimated from amplitude of an output signal of an oxygen sensor arranged on the downstream side of the catalyst. COPYRIGHT: (C)2008,JPO&INPIT
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