| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide an abnormality diagnostic system of a secondary air supply device capable of accurately diagnosing failure. <P>SOLUTION: This secondary air supply device 200 is arranged on the upstream side of a catalyst 112, and supplies secondary air to an exhaust manifold 110. The secondary air supply device 200 has an air pump 210 for forcibly feeding the secondary air in an operation state, a secondary air passage (a first air passage 212, and a second air passage 220) for supplying the secondary air forcibly fed from the air pump 210 to the exhaust manifold 110, and an ASV 214 for opening and closing the secondary air passage 212. An ECU 300 diagnoses abnormality of the air pump 210 and the ASV 214 on the basis of secondary air passage pressure detected by a pressure sensor 306 arranged in the secondary air passage 212. The ECU 300 stops a diagnosis of the abnormality when back pressure is a predetermined value or more. Thus, an erroneous diagnosis is avoided on closing failure of the ASV 214. <P>COPYRIGHT: (C)2006,JPO&NCIPI</p> |
