Vehicle speed sensor abnormality detection device
First Claim
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1. In a systema first sensor for sensing the magnitude of a first operational parameter;
- a second sensor for sensing said magnitude of said first operational parameter;
a control circuit which receives the outputs of said first and second sensors and which produces a control signal, said control circuit including means for diagnosing the normality of said first and second sensors, said diagnosing means including circuitry for;
comparing the output of said first sensor with a predetermined value;
comparing the output of said second sensor with said predetermined value;
indicating that said second sensor is malfunctioning in the event that the output of said first sensor is above said predetermined value and the output of said second sensor is below said predetermined value; and
indicating that said first sensor is malfunctioning in the event that the output of said first sensor is below said predetermined value and the output of said second sensor is above said predetermined value.
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Abstract
In order to detect a sensor malfunction, the outputs of two sensors which sense the same operational parameter are both compared with a predetermined value. When the outputs of the sensors fall on either side of the predetermined value the one having the lower value is assumed to be inoperative. The comparison is continually repeated and the operative/inoperative status of the sensors continually updated.
28 Citations
10 Claims
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1. In a system
a first sensor for sensing the magnitude of a first operational parameter; -
a second sensor for sensing said magnitude of said first operational parameter; a control circuit which receives the outputs of said first and second sensors and which produces a control signal, said control circuit including means for diagnosing the normality of said first and second sensors, said diagnosing means including circuitry for; comparing the output of said first sensor with a predetermined value; comparing the output of said second sensor with said predetermined value; indicating that said second sensor is malfunctioning in the event that the output of said first sensor is above said predetermined value and the output of said second sensor is below said predetermined value; and indicating that said first sensor is malfunctioning in the event that the output of said first sensor is below said predetermined value and the output of said second sensor is above said predetermined value. - View Dependent Claims (2, 3)
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4. In a system
a first sensor for sensing the magnitude of a first operational parameter; -
a second sensor for sensing said magnitude of said first operational parameter; a third sensor, said third sensor sensing the magnitude of a second operational parameter; a control circuit which receives the outputs of said first and second sensors and which produces a control signal, said control circuit including means for diagnosing the normality of said first and second sensors, said diagnosing means including circuitry for; comparing the output of said first sensor with a predetermined value; comparing the output of said second sensor with said predetermined value; indicating that said second sensor is malfunctioning in the event that the output of said first sensor is above said predetermined value and the output of second sensor is below said predetermined value; and using the output of said third sensor in combination with one of the outputs of said first and second sensors to develop said control signal, said control circuit preferentially using the output of said first sensor for developing said control signal and utilizing the output of said second sensor only when said diagnosing means indicates the said first sensor is malfunctioning. - View Dependent Claims (5, 6)
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7. In a control method the steps of:
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using a first sensor for sensing the magnitude of a first operational parameter; using a second sensor for sensing said magnitude of said first operational parameter; diagnosing the normality of said first and second sensors by; comparing the output of said first sensor with a predetermined value; comparing the output of said second sensor with said predetermined value; indicating that said second sensor is malfunctioning in the event that the output of said first sensor is above said predetermined value and the output of said second sensor is below said predetermined value; and indicating that said first sensor is malfunctioning in the event that the output of said first sensor is below said predetermined value and the output of said second sensor is above said predetermined value. - View Dependent Claims (8)
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9. In a control method the steps of:
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using a first sensor for sensing the magnitude of a first operational parameter; using a second sensor for sensing said magnitude of said first operational parameter; diagnosing the normality of said first and second sensors by; comparing the output of said first sensor with a predetermined value; comparing the output of said second sensor with said predetermined value; indicating that said second sensor is malfunctioning in the event that the output of said first sensor is above said predetermined value and the output of said second sensor is below said predetermined value; indicating that said first sensor is malfunctioning in the event that the output of said first sensor is below said predetermined value and the output of said second sensor is above said predetermined value; using a third sensor for sensing the magnitude of a second operational parameter; using the output of said third sensor in combination with one of the outputs of said first and second sensors to develop said control signal; preferentially using the output of said first sensor for developing said control signal; and utilizing the output of said second sensor only when said diagnosing step indicates the said first sensor is malfunctioning.
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10. In a system
first sensor, serving as a primary sensor, for sensing the magnitude of a first operational parameter and producing an output which is normally used as an output signal; -
a second sensor, for serving as a secondary sensor, for sensing said magnitude of said first operational parameter and producing an output; a control circuit which receives the outputs of said first and second sensors and which produces a control signal, said control circuit including means for diagnosing the normality of said first and second sensors, said diagnosing means including circuitry for; comparing the output of said first sensor with a predetermined value; comparing the output of said second sensor with said predetermined value; indicating that said first sensor is malfunctioning in the event that the output of said first sensor is below said predetermined value and the output of said second sensor is above said predetermined value; utilizing the output of said second sensor in place of the output of said first sensor as said output signal; and maintaining said second sensor output as said output signal until a difference between the outputs of said first and second sensors becomes smaller than a preset value.
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Specification