Patent ID: 8522530

Claim:
A reducing agent injection valve abnormality detection device for detecting, in a reducing agent injection device equipped with a storage tank that houses a reducing agent, a pump that pressure-feeds the reducing agent, a reducing agent injection valve that injects the reducing agent pressure-fed by the pump into the inside of an exhaust pipe of an internal combustion engine, a supply path that interconnects the pump and the reducing agent injection valve, and a pressure sensor that is disposed in the supply path, clogging of the reducing agent injection valve, the reducing agent injection valve abnormality detection device comprising: a pressure detection component that detects the pressure inside the supply path on the basis of a sensor value of the pressure sensor; a pump control component that fixes the output of the pump in a state where the pressure inside the supply path has become a value in a predetermined range; a reducing agent injection valve control component that opens the reducing agent injection valve for a predetermined amount of time in a state where the output of the pump has been fixed; and a clogging determination component that determines the extent of clogging of the reducing agent injection valve by comparing, with plural threshold values, the pressure, or a pressure drop quantity, inside the supply path when the reducing agent injection valve has been opened for the predetermined amount of time, wherein the reducing agent injection valve is a multiple injection hole-type injection valve having plural injection holes, and the number of the plural threshold values is the same as the number of the injection holes.