| 摘要 |
<P>PROBLEM TO BE SOLVED: To specify a block abnormal cylinder even when knocking is not detected per unit of cylinder. <P>SOLUTION: A diagnostic apparatus of an internal combustion engine includes: an EGR device having a plurality of branch EGR passages for distributing and supplying an EGR gas to each branch intake passage per cylinder; a means for changing an ignition timing per cylinder; a means for detecting knocking; a means for detecting block abnormality in which any of the branch EGR passages of the cylinders is blocked during an EGR execution; and a means for specifying an abnormal cylinder in which the block abnormality has occurred during the EGR execution. The specifying means retards the ignition timing for each of a predetermined number of cylinders in order and alternately, calculates a knocking reduction amount before and after retarding per the retard, and designates one cylinder of which knocking reduction amount exceeds a predetermined value as the abnormal cylinder on the basis of a calculated plurality of knocking reduction amounts. <P>COPYRIGHT: (C)2012,JPO&INPIT |
