HUMIDITY SENSOR DIAGNOSTICS
First Claim
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1. A method, comprising:
- indicating degradation of a humidity sensor based on an output from the humidity sensor and an output from an intake gas composition sensor, wherein indicating degradation further comprises indicating degradation of the humidity sensor based on the humidity sensor output and the output from the intake gas composition sensor while exhaust gas recirculation (EGR) is off and responsive to output from the humidity sensor changing more than a threshold amount, wherein indicating degradation based on the humidity sensor output and the output from the intake gas composition sensor further comprises, if the humidity sensor output decreases by more than the threshold amount, indicating degradation of the humidity sensor if the output from the intake gas composition sensor does not increase above a second threshold amount.
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Abstract
Embodiments for testing a humidity sensor are provided. One example method comprises indicating degradation of a humidity sensor based on a humidity sensor output and output from an intake gas composition sensor. In this way, output from the intake gas composition sensor may be used to determine if the humidity sensor is degraded.
52 Citations
18 Claims
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1. A method, comprising:
indicating degradation of a humidity sensor based on an output from the humidity sensor and an output from an intake gas composition sensor, wherein indicating degradation further comprises indicating degradation of the humidity sensor based on the humidity sensor output and the output from the intake gas composition sensor while exhaust gas recirculation (EGR) is off and responsive to output from the humidity sensor changing more than a threshold amount, wherein indicating degradation based on the humidity sensor output and the output from the intake gas composition sensor further comprises, if the humidity sensor output decreases by more than the threshold amount, indicating degradation of the humidity sensor if the output from the intake gas composition sensor does not increase above a second threshold amount. - View Dependent Claims (2, 3, 5, 6, 7)
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4. A method, comprising:
indicating degradation of a humidity sensor based on an output from the humidity sensor and an output from an intake gas composition sensor, wherein indicating degradation further comprises indicating degradation of the humidity sensor based on the humidity sensor output and the output from the intake gas composition sensor while exhaust gas recirculation (EGR) is off and responsive to output from the humidity sensor changing more than a threshold amount, wherein indicating degradation of the humidity sensor based on the humidity sensor output and the output from the intake gas composition sensor further comprises, if the humidity sensor output increases by more than the threshold amount, indicating degradation of the humidity sensor if the output from the intake gas composition sensor does not decrease below a second threshold amount. - View Dependent Claims (8, 9, 10)
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11. A system, comprising:
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an exhaust gas recirculation (EGR) system; a humidity sensor disposed in an engine intake system; a turbocharger having a compressor coupled in the engine intake system and a compressor bypass; an intake gas composition sensor disposed in the engine intake system downstream of the humidity sensor; and a controller including instructions to; when EGR is disabled and if output from the humidity sensor changes by more than a threshold amount, indicate humidity sensor degradation based on the humidity sensor output and output from the intake gas composition sensor. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18)
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Specification