Method and apparatus for diagnosing exhaust gas aftertreatment component degradation
First Claim
1. A system for diagnosing operation of an exhaust gas aftertreatment component for an internal combustion engine, the system comprising:
- a NOx sensor producing a NOx signal indicative of NOx content of exhaust gas exiting the aftertreatment component, and a control circuit estimating as a function of a number of engine operating conditions a NOx inlet content corresponding to a NOx content of exhaust gas produced by the engine and entering the aftertreatment component, the control circuit determining a NOx conversion efficiency of the aftertreatment component as a function of the NOx signal and of the NOx inlet content and determining that the aftertreatment component is degraded if the NOx conversion efficiency is below a threshold value.
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Abstract
A system is provided for diagnosing operation of an exhaust gas aftertreatment component for an internal combustion engine. The system includes a NOx sensor producing a NOx signal indicative of NOx content of exhaust gas exiting the aftertreatment component, and a control circuit configured to estimate as a function of a number of engine operating conditions a NOx inlet content corresponding to a NOx content of exhaust gas produced by the engine and entering the aftertreatment component. The control circuit is configured to determine a NOx conversion efficiency of the aftertreatment component as a function of the NOx signal and of the NOx inlet content, and to determine that the aftertreatment component is degraded if the NOx conversion efficiency is below a threshold value for at least a first predefined time period.
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Citations
34 Claims
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1. A system for diagnosing operation of an exhaust gas aftertreatment component for an internal combustion engine, the system comprising:
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a NOx sensor producing a NOx signal indicative of NOx content of exhaust gas exiting the aftertreatment component, and a control circuit estimating as a function of a number of engine operating conditions a NOx inlet content corresponding to a NOx content of exhaust gas produced by the engine and entering the aftertreatment component, the control circuit determining a NOx conversion efficiency of the aftertreatment component as a function of the NOx signal and of the NOx inlet content and determining that the aftertreatment component is degraded if the NOx conversion efficiency is below a threshold value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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23. A method for diagnosing operation of an exhaust gas aftertreatment component for an internal combustion engine, the method comprising:
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determining from information provided by a NOx sensor a NOx outlet value corresponding to a NOx content of exhaust gas exiting the aftertreatment component, estimating as a function of a number of engine operating conditions a NOx inlet value corresponding to a NOx content of exhaust gas produced by the engine and entering the aftertreatment component, determining a NOx conversion efficiency of the aftertreatment component as a function of the NOx outlet value and of the NOx inlet value, and determining that the aftertreatment component is degraded if the NOx conversion efficiency is below a threshold value. - View Dependent Claims (24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34)
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Specification