SYSTEMS AND METHODS FOR DIAGNOSING SELECTIVE CATALYTIC REDUCTION SYSTEMS
First Claim
1. An aftertreatment system, comprising:
- a selective catalytic reduction system structured to decompose constituents of an exhaust gas produced by an engine;
an engine out NOx (EONOx) adjustment system; and
a controller configured to;
when the selective catalytic reduction system is in a diagnostic enabling condition, instruct the engine out NOx adjustment system to adjust an EONOx amount between a high EONOx level for a first predetermined time and a low EONOx level for a second predetermined time, the EONOx amount comprising an amount of NOx gases included in the exhaust gas emitted by the engine;
determine a selective catalytic reductions system out NOx (SONOx) amount, the SONOx amount comprising an amount of NOx gases included in the exhaust gas after passing through the selective catalytic reduction system;
determine an efficiency parameter of the selective catalytic reduction system from the SONOx amount when the EONOx amount transitions from the low EONOx level to the high EONOx level;
determine if the efficiency parameter satisfies a predetermined threshold; and
in response to the efficiency parameter not satisfying the predetermined threshold, determine that the selective catalytic reduction system has failed.
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Accused Products
Abstract
An aftertreatment system comprises a SCR system, an engine out NOx (EONOx) adjustment system and a controller. The controller is configured to instruct the EONOx adjustment system to adjust an EONOx amount between a high EONOx level for a first predetermined time and a low EONOx level for a second predetermined time when the SCR system is in a diagnostic enabling condition. The controller determines a SCR system out NOx (SONOx) amount. The controller determines an efficiency parameter of the SCR system from the SONOx amount when the EONOx amount transitions from the low EONOx level to the high EONOx level and if the efficiency parameter satisfies a predetermined threshold. In response to the efficiency parameter not satisfying the predetermined threshold, the controller determines that the SCR system has failed.
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Citations
29 Claims
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1. An aftertreatment system, comprising:
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a selective catalytic reduction system structured to decompose constituents of an exhaust gas produced by an engine; an engine out NOx (EONOx) adjustment system; and a controller configured to; when the selective catalytic reduction system is in a diagnostic enabling condition, instruct the engine out NOx adjustment system to adjust an EONOx amount between a high EONOx level for a first predetermined time and a low EONOx level for a second predetermined time, the EONOx amount comprising an amount of NOx gases included in the exhaust gas emitted by the engine; determine a selective catalytic reductions system out NOx (SONOx) amount, the SONOx amount comprising an amount of NOx gases included in the exhaust gas after passing through the selective catalytic reduction system; determine an efficiency parameter of the selective catalytic reduction system from the SONOx amount when the EONOx amount transitions from the low EONOx level to the high EONOx level; determine if the efficiency parameter satisfies a predetermined threshold; and in response to the efficiency parameter not satisfying the predetermined threshold, determine that the selective catalytic reduction system has failed. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A control circuitry for diagnosing a catalytic conversion efficiency of a selective catalytic reduction system of an aftertreatment system, comprising:
a controller configured to be operatively coupled to the aftertreatment system, the controller comprising; an engine out NOx (EONOx) adjustment circuitry configured to instruct an engine out NOx adjustment system of the aftertreatment system to adjust an EONOx amount between a high EONOx level for a first predetermined time and a low EONOx level for a second predetermined time when the selective catalytic reduction system is in a diagnostic enabling condition, the EONOx amount comprising an amount of NOx gases included in the exhaust gas emitted by the engine; a NOx determination circuitry configured to determine a selective catalytic reduction system out NOx (SONOx) amount, the SONOx amount comprising an amount of NOx gases included in the exhaust gas after passing through the selective catalytic reduction system; and an efficiency parameter determination circuitry configured to; determine an efficiency parameter of the selective catalytic reduction system from the SONOx amount when the EONOx amount transitions from the low EONOx level to the high EONOx level; determine if the efficiency parameter satisfies a predetermined threshold; in response to the efficiency parameter not satisfying the predetermined threshold, determine that the selective catalytic reduction system has failed; and indicate to a user that the selective catalytic reduction system has failed. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22)
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23. A method for diagnosing a conversion efficiency of a selective catalytic reduction system of an aftertreatment system receiving an exhaust gas from an engine, the method comprising:
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determining if a diagnostic enabling condition is satisfied; in response to the diagnostic enabling condition being satisfied, adjusting an engine out NOx (EONOx) amount between a high EONOx level for a first predetermined time and a low EONOx level for a second predetermined time, the EONOx amount comprising an amount of NOx gases included in the exhaust gas emitted by the engine; determining a selective catalytic reduction system out NOx (SONOx) amount, the SONOx amount comprising an amount of NOx gases included in the exhaust gas after passing through the selective catalytic reduction system; determining an efficiency parameter of the selective catalytic reduction system from the SONOx amount when the EONOx amount transitions from the low EONOx level to the high EONOx level; determining if the efficiency parameter satisfies a predetermined threshold; in response to the efficiency parameter not satisfying the predetermined threshold; determining that the selective catalytic reduction system has failed, and indicating to a user that the selective catalytic reduction system has failed. - View Dependent Claims (24, 25, 26, 27, 28, 29)
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Specification