| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an abnormality diagnosis device for an exhaust gas recirculation device capable of certainly suppressing result of abnormality diagnosis from becoming erroneous caused by the fact that an opening degree of an exhaust gas recirculation valve is small in the beginning of diagnosis. <P>SOLUTION: The exhaust gas recirculation device 70 performs correction of the opening for reducing the target opening degree of the exhaust gas recirculation valve 73 as a density of the suction air becomes low. The abnormality diagnosis device for the exhaust gas recirculation device 70 forbids correction of the opening degree when it is determined that the execution condition of abnormality diagnosis is established, and performs valve-opening processing for increasing the opening degree of the exhaust gas recirculation valve 73 from the opening degree at that time to the larger side target opening degree than the smaller side target opening degree. Thereafter, the abnormality diagnosis device performs valve-closing processing for reducing the opening degree of the exhaust gas recirculation valve 73 to the smaller side target opening degree, monitors the variation degree of the suction state amount varied influenced by variation of the exhaust refluxing amount accompanying with execution of the valve-closing processing, and determines that abnormality has occurred in the exhaust gas recirculation device 70 by the fact that the monitored variation degree is smaller than a determination degree. <P>COPYRIGHT: (C)2009,JPO&INPIT |
