FAULT DIAGNOSIS DEVICE FOR REDUCING AGENT SUPPLY DEVICE, AND REDUCING AGENT SUPPLY DEVICE

摘要

[Problem] To provide a reducing agent supply apparatus abnormality diagnosis unit that can reduce the limitation on when to perform abnormality diagnosis and on the applicability of abnormality diagnosis to facilitate the implementation of abnormality diagnosis of a reducing agent supply apparatus and to provide the reducing agent supply apparatus. [Means for Resolution] The reducing agent supply apparatus abnormality diagnosis unit includes: a reducing agent injection valve controller for determining an energization on/off duty ratio according to an instructed injection amount of the reducing agent to issue an instruction for driving the reducing agent injection valve; a pump controller for determining an energization on/off duty ratio to issue an instruction for driving the pump so that the pressure in the reducing agent passage is maintained at a predetermined system pressure, based on the difference between the detected pressure in the reducing agent passage and the system pressure; and an abnormality determiner for performing abnormality determination of the reducing agent supply apparatus based on the duty ratio of the reducing agent injection valve and the duty ratio of the pump in a predetermined period.