Reducing agent injection valve abnormality detection device and abnormality detection method

Abstract

A reducing agent injection valve abnormality detection device for detecting clogging of a reducing agent injection valve in a reducing agent injection device has a pressure detection component that detects the pressure inside a supply path based on a sensor value of a pressure sensor, a pump control component that fixes the output of a pump in a state where the pressure inside the supply path hasbecome a value in a predetermined range, a reducing agent injection valve control component that opens the 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 valve has been opened for the predetermined amount of time.

Description

technical field [0001] The present invention relates to an abnormality detection device and an abnormality detection method for detecting abnormality of a reducing agent injection valve. [0002] In particular, an abnormality detection device and an abnormality detection method for detecting a predetermined clogging phenomenon occurring in a reducing agent injection valve for injecting a reducing agent for purifying nitrogen oxides in exhaust gas into an exhaust pipe . Background technique [0003] Nitrogen oxides (NO X ). Purify the NO as a reduction X One of the exhaust gas purification devices has the following structure, that is: the exhaust pipe of the internal combustion engine is equipped with X purify the catalyst, and the NO X A reducing agent such as urea aqueous solution or unburned fuel is injected on the upstream side of the purification catalyst. [0004] In such an exhaust purification device, through the NO X Purification catalyst promotes reducing age...

AI Technical Summary

Problems solved by technology

[0018] That is, although the clogging determination methods of Patent Document 1 and Patent Document 2 can obtain a rough determination result of whether a clogging has occurred, they cannot obtain a detailed determination result of what degree of clogging has occurred.

[0019] Therefore, if the degree of clogging cannot be accurately determined, it will be difficult to accurately correct the reducing agent injection amount due to clogging.

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