Method of diagnosing regeneration failure of exhaust emission control device

摘要

Provided is a method of diagnosing regeneration failure of an exhaust emission control device including filter regenerating means for forcibly heating a particulate filter 13 so as to burn off captured particulates. An exhaust flow rate to the particulate filter 13 and a differential pressure between entry and exit sides of the particulate filter 13 are obtained to calculate a gradient of change in the differential pressure relative to change in the exhaust flow rate. The calculated gradient is compared with a predetermined reference gradient to diagnose the particulate filter 13 as having regeneration failure when the calculated gradient exceeds the reference gradient.

主权项

1. A method of diagnosing regeneration failure of an exhaust emission control device including filter regenerating means for forcibly heating a particulate filter so as to burn off captured particulates, the method comprising:
obtaining an exhaust flow rate to the particulate filter and a differential pressure between entry and exit sides of the particulate filter to calculate a gradient of change in the differential pressure relative to change in the exhaust flow rate, the calculated gradient being compared with a predetermined reference gradient to diagnose the particulate filter as having regeneration failure when the calculated gradient exceeds the reference gradient, wherein the diagnosis of regeneration failure of the particulate filter is performed only when the exhaust flow rate exceeds a predetermined flow rate, and wherein the particulate filter is diagnosed as having regeneration failure when a frequency of the calculated gradient exceeding the reference gradient becomes greater than a predetermined frequency.