| CPC F01N 11/005 (2013.01) [F02D 41/0235 (2013.01)] | 7 Claims |
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1. A controller for an internal combustion engine, wherein
an exhaust purification device is disposed in an exhaust passage of the internal combustion engine,
the internal combustion engine is configured to execute a fuel cutoff operation in which an engine output shaft is rotated with fuel supply stopped,
the controller comprises processing circuitry,
the processing circuitry is configured to execute a first change amount calculating process, a second change amount calculating process, a determination process, and an anomaly diagnosing process,
the first change amount calculating process is a process of calculating a first change amount that is a change amount per unit time of an upstream-side temperature, the upstream-side temperature being a temperature of exhaust gas on an upstream side of the exhaust purification device,
the second change amount calculating process is a process of calculating a second change amount that is a change amount per unit time of a downstream-side temperature, the downstream-side temperature being a temperature of exhaust gas on a downstream side of the exhaust purification device,
the determination process is a process of determining that a deviation between the first change amount during the fuel cutoff operation and the second change amount during the fuel cutoff operation is less than or equal to a threshold, and
the anomaly diagnosing process is a process of determining that the exhaust purification device is in a detached state when it is determined in the determination process that the deviation is less than or equal to the threshold.
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