| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an apparatus for diagnosing malfunctions of an air-fuel ratio sensor which can suppress emissions as much as possible while diagnosing malfunctions of an air-fuel ratio sensor more accurately than existing apparatuses. <P>SOLUTION: The apparatus is configured to obtain a parameter corresponding to the responsiveness of an air-fuel ratio sensor when an air-fuel ratio is changed by an active air-fuel ratio control means, and based on the obtained value, diagnose malfunctions of the air-fuel ratio sensor. The active air-fuel ratio control means controls an air-fuel ratio of an exhaust gas so that a deviation from a theoretical air-fuel ratio of an air-fuel ratio at a first time that is immediately after the air-fuel ratio being forcibly changed to one of a rich side and a lean side is larger than a deviation from a theoretical air-fuel ratio of an air-fuel ratio at a second time that is after the first time and before the air-fuel being forcibly changed to the other of the rich side and the lean side in the following turn. <P>COPYRIGHT: (C)2013,JPO&INPIT |
