Fault detection in a motor vehicle charging system
First Claim
1. A fault detection method for a motor vehicle charging system including a generator and an electrical component coupled to receive electrical current from an output of said generator, said method comprising the steps of:
- (a) sensing a first voltage at an output of said generator;
(b) sensing a second voltage at said electrical component; and
(c) comparing a difference of said first voltage and said second voltage to a predetermined voltage, said predetermined voltage indicative of a high resistance connection between said output of said generator and said component; and
(d) if said difference is greater than said predetermined voltage, reducing or suspending output of electrical current from said generator.
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Abstract
A fault detection method is disclosed for a motor vehicle charging system including a generator and an electrical component coupled to receive electrical current from the generator. In one embodiment, the method comprises sensing a first voltage at an output of the generator and sensing a second voltage at the electrical component and, if the first voltage and the second voltage differ by more than a predetermined amount, reducing or suspending output of electrical current from the generator. One advantage of the method disclosed herein is in its ability to diagnose a fault in an electrical connection at the output of a motor vehicle generator, where the fault manifests itself as a high resistance connection.
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Citations
20 Claims
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1. A fault detection method for a motor vehicle charging system including a generator and an electrical component coupled to receive electrical current from an output of said generator, said method comprising the steps of:
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(a) sensing a first voltage at an output of said generator;
(b) sensing a second voltage at said electrical component; and
(c) comparing a difference of said first voltage and said second voltage to a predetermined voltage, said predetermined voltage indicative of a high resistance connection between said output of said generator and said component; and
(d) if said difference is greater than said predetermined voltage, reducing or suspending output of electrical current from said generator. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
(e) a predetermined period of time after reducing or suspending output of electrical power from said generator, ending said reduction or suspension and repeating said steps (a) through (d).
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3. A fault detection method as recited in claim 2, further comprising:
after performing said step (e) for a predetermined number of times, logging a diagnostic code in memory and/or illuminating a diagnostic indicator.
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4. A fault detection method as recited in claim 2, wherein said electrical component is a battery.
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5. A fault detection method as recited in claim 2, wherein:
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said generator is controlled by a voltage regulator which is responsively coupled to a powertrain controller; and
said step of reducing or suspending output of electrical current from said generator comprises the powertrain controller providing a signal to the voltage regulator commanding such reduction or suspension.
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6. A fault detection method as recited in claim 2, wherein:
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said generator is controlled by a voltage regulator which receives a commanded voltage from a powertrain controller; and
said step of reducing or suspending output of electrical current from said generator comprises the powertrain controller reducing said commanded voltage.
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7. A fault detection method as recited in claim 6, wherein:
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said steps (a) and (b) are performed by said voltage regulator; and
if said first voltage and said second voltage differ by more than said predetermined amount, said voltage regulator provides a fault signal to said powertrain controller.
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8. A fault detection method as recited in claim 2, wherein:
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said generator is controlled by a voltage regulator which receives a commanded voltage from a powertrain controller;
said steps (a) and (b) are performed by said voltage regulator; and
if said first voltage and said second voltage differ by more than said predetermined amount, said voltage regulator provides a fault signal to said powertrain controller.
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9. A fault detection method as recited in claim 2, wherein said predetermined amount is a function of an output current of said generator.
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10. A fault detection method as recited in claim 5, wherein said predetermined amount is a function of an output current of said alternator.
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11. A fault detection method as recited in claim 7, wherein said predetermined amount is a function of an output current of said alternator.
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12. A fault detection method for a motor vehicle charging system including a generator and an electrical component coupled to receive electrical current from said generator, said method comprising the steps of:
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(a) sensing a first voltage at an output of said generator;
(b) sensing a second voltage at said electrical component; and
(c) if said first voltage and said second voltage differ by more than a predetermined amount, said predetermined amount being a function of an output current of said generator, reducing or suspending output of electrical current from said generator. - View Dependent Claims (13, 14, 15, 16)
(d) a predetermined time after reducing or suspending output of electrical power from said generator, ending said reduction or suspension and repeating said steps (a) through (c).
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14. A fault detection method as recited in claim 13, wherein:
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said generator is controlled by a voltage regulator which is responsively coupled to a powertrain controller; and
said step of reducing or suspending output of electrical current from said generator comprises the powertrain controller providing a signal to the voltage regulator commanding such reduction or suspension.
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15. A fault detection method as recited in claim 14, wherein:
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said steps (a) and (b) are performed by said voltage regulator; and
if said first voltage and said second voltage differ by more than said predetermined amount, said voltage regulator provides a fault signal to said powertrain controller.
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16. A fault detection method as recited in claim 15, further comprising:
after performing said step (d) for a predetermined number of times, logging a diagnostic code in memory and/or illuminating a diagnostic indicator.
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17. A fault detection method for a motor vehicle charging system including a generator, a voltage regulator operatively coupled to said generator, an electrical component coupled to receive electrical current from said generator and a powertrain controller, said method comprising the steps of:
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(a) if said charging system has an operational fault, providing a fault indicating signal from said voltage regulator to said powertrain controller indicative of said operational fault; and
(b) if said signal intermittently indicates said operational fault, providing a first charging system control signal from said powertrain controller to said voltage regulator to limit or suspend output of said generator. - View Dependent Claims (18, 19, 20)
(d) providing a second charging system control signal from said powertrain controller to said voltage regulator to end said limiting or suspension of output of said generator; and
continuing to perform steps (a) through (c).
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20. A method as recited in claim 19, wherein said fault-indicating signal, said first charging system control signal and said second charging system control signal are pulse-width modulated.
Specification