Method for detecting abnormality in reducing agent
AssigneeHino Motors, Ltd.
InventorHironori Narita
Life of this patent
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Abstract
Disclosed is a method for detecting abnormality in a reducing agent 17 replenished to a reducing agent tank 14 in an exhaust emission control device for reduction and removal of NOx through addition of the reducing agent 17 from the tank 14 to a selective reduction catalyst 10 incorporated in an exhaust pipe 9. Presence or absence of NH3 slip is determined when a lowering of NOx removal rate is detected. When the presence of the NH3 slip is detected, it is determined that the selective reduction catalyst 10 is deteriorated; when the absence of the NH3 slip is determined, it is determined that a dilute reducing agent or/and a material other than the reducing agent are replenished into the tank.
Claims2
A method for detecting abnormality in a reducing agent replenished to a reducing agent tank in an exhaust emission control device for reduction and removal of NOx through addition of the reducing agent from said tank to a selective reduction catalyst incorporated in an exhaust pipe, which comprises:
- detecting whether NOx removal rate is lowered;
- elevating a temperature of the selective reduction catalyst after the detecting step to release any hydrocarbon which may have been absorbed by the selective reduction catalyst to obtain a state where no hydrocarbon adsorbed by the selective reduction catalyst remains;
- recording presence or absence of NH3 slip in a driving history after the elevating step;
- conducting a second detection of whether the NOx removal rate is lowered after the recording step and confirming the state where no hydrocarbon adsorbed remains;
- determining a deterioration of the selective reduction catalyst when the presence of the NH3 slip is determinable by the driving history;
- and
- determining that a dilute reducing agent or a material other than the reducing agent are replenished into the tank when the absence of the NH3 slip is determinable by the driving history.
A method for detecting abnormality in a reducing agent replenished to a reducing agent tank in an exhaust emission control device for reduction and removal of NOx through addition of the reducing agent from said tank to a selective reduction catalyst incorporated in an exhaust pipe, which comprises:
- detecting whether NOx removal rate is lowered;
- elevating a temperature of the selective reduction catalyst after the detecting step to release any hydrocarbon which may have been absorbed by the selective reduction catalyst to obtain a state where no hydrocarbon adsorbed by the selective reduction catalyst remains;
- recording presence or absence of NH3 slip in a driving history after the elevating step;
- conducting a second detection of whether the NOx removal rate is lowered after the recording step and confirming the state where no hydrocarbon adsorbed remains;
- determining a deterioration of the selective reduction catalyst when the presence of the NH3 slip is determinable by the driving history;
- and
- determining that a dilute reducing agent and a material other than the reducing agent are replenished into the tank when the absence of the NH3 slip is determinable by the driving history.
Dependencies are inferred from the claim text.