DEVICE FOR DETECTING FAILURE OF FILTER

摘要

PROBLEM TO BE SOLVED: To improve accuracy in detecting a failure of a filter using an output value of a particulate matter (PM) sensor, in a configuration where a NOx selective reduction-type catalyst is provided between the filter and the PM sensor in an exhaust passage.

SOLUTION: A device for detecting a failure of a filter includes the steps of: calculating an oxidation amount of the PM deposited on the PM sensor on the basis of a nitrous oxide concentration or nitrous oxide content of the downstream exhaust gas of the NOx selective reduction-type catalyst; correcting the PM deposition amount in the PM sensor which is calculated by assuming that the filter is in a predetermined state on the basis of the PM oxidation amount; and determining whether the filter is in failure or not on the basis of the output value of the PM sensor on condition that the corrected PM deposition amount in the PM sensor is more than a predetermined amount.

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