EXHAUST EMISSION PURIFYING APPARATUS FOR ENGINE

摘要

A technology for purifying an exhaust emission from an engine is provided, in which a misjudgment caused by a time lag between the abnormality detection and an abnormality judgment is avoided, in the case where a plurality of abnormalities is judged on the aqueous solution of a reducing agent or the like. After a first abnormality judgment (Femp=1: the time t2) is made, when a second abnormality is detected as a result that the concentration Dn as a state parameter is directly shifted from a first region A to a second region C (the time t3), the first abnormality judgment is maintained for a predetermined period of time PRD after the second abnormality detection.