Pressure sensor fault detection
First Claim
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1. A diagnostic system for a pressure sensor, comprising:
- a cavity configured to receive an applied pressure, the cavity having a first and a second wall;
a deflectable diaphragm in the cavity configured to form a first and a second capacitance with the first wall and a third and a fourth capacitance with the second wall which change in response to the applied pressure, the first and third capacitances forming a first transfer function and the second and the fourth capacitances forming a second transfer function; and
circuitry coupled to the first, second, third and fourth capacitance having a diagnostic output as a function of the first and second transfer functions which is related to a diagnostic condition of the pressure sensor.
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Abstract
A diagnostic system for a pressure sensor having a cavity configured to receive on applied pressure is provided. The cavity has a first and a second wall. A deflectable diaphragm is positioned in the cavity and configured to form a first and a second capacitance with the first wall and a third and a fourth capacitance with the second wall which change in response to the applied pressure. The capacitances form a first transfer function and a second transfer function. Changes in the first transfer function relative to the second transfer function are detected to provide a diagnostic output.
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Citations
20 Claims
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1. A diagnostic system for a pressure sensor, comprising:
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a cavity configured to receive an applied pressure, the cavity having a first and a second wall; a deflectable diaphragm in the cavity configured to form a first and a second capacitance with the first wall and a third and a fourth capacitance with the second wall which change in response to the applied pressure, the first and third capacitances forming a first transfer function and the second and the fourth capacitances forming a second transfer function; and circuitry coupled to the first, second, third and fourth capacitance having a diagnostic output as a function of the first and second transfer functions which is related to a diagnostic condition of the pressure sensor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method of diagnosing operation of a pressure sensor, comprising:
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measuring first, second, third, and fourth capacitances of the pressure sensor; calculating a present value of H based upon the measured first, second, third and fourth capacitances; diagnosing operation of the pressure sensor based upon changes in the calculated value; and providing a diagnostic output based upon the step of diagnosing. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification