| 摘要 |
A device for determining clogging of a reducing agent path and method of determining clogging of reducing agent path, which, when there is clogging at any position in both a supply line and a return line, accurately detects the clogging and estimates the position of the clogging. The device for determining clogging of a reducing agent path has pump drive control means for performing DUTY control of a pump so that a pressure value is maintained at a predetermined level; drive DUTY determination means for determining whether a drive DUTY of the pump is less than a predetermined threshold corresponding to the degree of opening of a reducing agent injection valve; pressure reduction amount calculation means which, when the drive DUTY of the pump is determined to be less than the threshold, stops the pump, fully opens the reducing agent injection valve, and then calculates a pressure reduction amount detected by a pressure sensor and representing the amount of reduction in pressure in a predetermined time; and clogging determination means for determining, based on the pressure reduction amount calculated by the pressure reduction amount calculation means, whether there is clogging in a first reducing agent path or a second reducing agent path.
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