Knock sensor diagnostic system and method
First Claim
Patent Images
1. A knock sensor diagnostic system comprising:
- a knock sensor;
a bias circuit that applies a bias voltage to said knock sensor;
a first input circuit that receives a first input signal based on said bias voltage;
a control module that indicates a short circuit associated with said knock sensor based on said first input signal;
a signal generator that generates and applies a test signal with a predetermined frequency to said knock sensor; and
a second input circuit that receives a second input signal based on said test signal,wherein said control module detects an amplitude of said test signal based on an engine speed and indicates an open circuit associated with said knock sensor based on said second input signal.
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Abstract
A knock sensor diagnostic system may include a knock sensor. A bias circuit applies a bias voltage to the knock sensor. An input circuit receives an input signal based on the bias voltage. A control module indicates a short circuit associated with the knock sensor based on the input signal. A knock sensor diagnostic system may also or alternatively include a signal generator that generates and applies a test signal with a predetermined frequency to the knock sensor. Another input circuit receives another input signal that is based on the test signal. A control module indicates an open circuit associated with the knock sensor based on the other input signal.
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Citations
16 Claims
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1. A knock sensor diagnostic system comprising:
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a knock sensor; a bias circuit that applies a bias voltage to said knock sensor; a first input circuit that receives a first input signal based on said bias voltage; a control module that indicates a short circuit associated with said knock sensor based on said first input signal; a signal generator that generates and applies a test signal with a predetermined frequency to said knock sensor; and a second input circuit that receives a second input signal based on said test signal, wherein said control module detects an amplitude of said test signal based on an engine speed and indicates an open circuit associated with said knock sensor based on said second input signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A knock sensor diagnostic system comprising:
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a knock sensor; a bias circuit that applies a bias voltage to said knock sensor; a signal generator that generates and applies a test signal with a predetermined frequency to said knock sensor; an input circuit that receives an input signal based on said test signal; and a control module that detects an amplitude of said test signal based on an engine speed and indicates an open circuit associated with said knock sensor based on said input signal.
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16. A knock sensor diagnostic system comprising:
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a knock sensor; a bias circuit that applies a bias voltage to said knock sensor; a first input circuit that receives a first input signal based on said bias voltage; a control module that indicates a short circuit associated with said knock sensor based on said first input signal; a signal generator that generates and applies a test signal with a predetermined frequency to said knock sensor; and a second input circuit that receives a second input signal based on said test signal, wherein said control module indicates an open circuit associated with said knock sensor based on said second input signal, and wherein said test signal has a frequency level that is outside a frequency range associated with at least one of knock detection and engine background noise.
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Specification