EXHAUST GAS PURIFICATION SYSTEM

摘要

The exhaust gas purification system includes a SCR, an NOx sensor which is provided on a downstream side of the SCR, and an NOx purifying controller which controls an amount of urea water being ejected to the SCR and performs an abnormality diagnosis based on a detection value of the NOx sensor, wherein the exhaust gas purification system includes an exhaust gas temperature sensor which acquires temperature of the exhaust gas flowing into the SCR, a temperature increasing rate calculating unit which calculates a temperature increasing rate at which the exhaust gas temperature acquired by the exhaust gas temperature sensor reaches a second temperature from a predetermined first temperature, and a prohibiting unit which prohibits abnormality diagnosis by the NOx purifying controller in a case in which the temperature increasing rate calculated by the temperature increasing rate calculating unit is higher than a predetermined determination threshold value.

主权项

1. An exhaust gas purification system comprising:
a selective catalytic reduction which is provided on an exhaust gas passage of an internal combustion engine and purifies NOx in exhaust gas by using ammonia generated from urea water as a reducing agent; an NOx sensor which is provided on the exhaust gas passage on downstream side further than the selective catalytic reduction; control means for controlling an amount of urea water being ejected to the selective catalytic reduction and performing an abnormality diagnosis based on a detection value of the NOx sensor, exhaust gas temperature acquiring means for acquiring temperature of the exhaust gas flowing into the selective catalytic reduction; temperature increasing rate calculating means for calculating a temperature increasing rate at which an exhaust gas temperature acquired by the exhaust gas temperature acquiring means reaches a predetermined second temperature, which is higher than a predetermined first temperature, from the first temperature; and prohibiting means for prohibiting the abnormality diagnosis by the control means in a case in which the temperature increasing rate calculated by the temperature increasing rate calculating means is higher than a predetermined determination threshold value.