| 摘要 |
PROBLEM TO BE SOLVED: To provide a device for determining whether a particulate filter provided in an exhaust passage of an internal combustion engine is abnormal, capable of preventing fault diagnosis even if a pressure difference between an inlet side and an outlet side of the filter varies depending on the number of times of regeneration of the filter.SOLUTION: An abnormality determination unit constituting an abnormality determination device determines whether an abnormality occurs to a particulate filter on the basis of a result of comparison between a correlation value of a pressure difference between an inlet side and an outlet side of the particulate filter and a predetermined first threshold &Dgr;Pth1 acquired at an exhaust gas flow volume V that is not smaller than a predetermined first flow volume Vc if the number of times of regeneration of the filter is smaller than a predetermined number in view of the fact that the pressure difference between the inlet side and the outlet side of the filter varies depending on the number of times of regenerating the filter relatively to the exhaust gas flow volume V. On the other hand, the abnormality determination unit determines whether an abnormality occurs to the particulate filter on the basis of a result of comparison between the correlation value of the pressure difference between the inlet side and the outlet side of the filter and a predetermined second threshold &Dgr;Pth2 acquired at the exhaust gas flow volume V that is not smaller than a predetermined second flow volume Vb smaller than the first flow volume Vc if the number of times of regenerating the filter is not smaller than the predetermined number.SELECTED DRAWING: Figure 5 |
