Method for detecting failure of a relay
First Claim
1. A method for detecting failure of a relay operating in a vehicle having an ignition switch, a power supply, a capacitor, and a pre-charge circuit to pre-charge the capacitor with the relay switching power from the power supply to the pre-charged capacitor, the method comprising the step of:
- performing a capacitor discharge test, wherein the step of performing a capacitor discharge test includes the steps of;
opening the relay to disconnect the power supply from the capacitor;
checking the capacitor for a discharged over-voltage condition; and
delaying opening the relay to disconnect the power supply from the capacitor for a predetermined discharge time period and wherein the step of checking the capacitor for a discharged over-voltage condition is performed after the predetermined discharge time period has elapsed.
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Accused Products
Abstract
A method for detecting failure of a relay operating in a vehicle having an ignition switch, a power supply, a capacitor, and a pre-charge circuit to pre-charge the capacitor with the relay switching power from the power supply to the pre-charged capacitor, the method comprising the steps of: performing a capacitor pre-charge test; and performing a capacitor discharge test. Preferably, the capacitor pre-charge test is performed when the ignition is switched ON and the capacitor discharge test is performed when the ignition is switched OFF.
73 Citations
9 Claims
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1. A method for detecting failure of a relay operating in a vehicle having an ignition switch, a power supply, a capacitor, and a pre-charge circuit to pre-charge the capacitor with the relay switching power from the power supply to the pre-charged capacitor, the method comprising the step of:
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performing a capacitor discharge test, wherein the step of performing a capacitor discharge test includes the steps of;
opening the relay to disconnect the power supply from the capacitor;
checking the capacitor for a discharged over-voltage condition; and
delaying opening the relay to disconnect the power supply from the capacitor for a predetermined discharge time period and wherein the step of checking the capacitor for a discharged over-voltage condition is performed after the predetermined discharge time period has elapsed. - View Dependent Claims (2)
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3. A method for detecting failure of a relay operating in a vehicle having an ignition switch, a power supply, a capacitor, and a pre-charge circuit to pre-charge the capacitor with the relay switching power from the power supply to the pre-charged capacitor, the method comprising the steps of:
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performing a capacitor discharge test, and performing a capacitor pre-charge test, wherein the step of performing a capacitor pre-charge test includes the steps of;
activating the pre-charge circuit to initiate pre-charging of the capacitor;
checking the capacitor for a pre-charge over-voltage condition;
checking the capacitor for a pre-charge under-voltage condition;
deactivating the pre-charge circuit;
closing the relay to provide power from the power supply to the capacitor; and
checking the capacitor for a post-charged under-voltage condition. - View Dependent Claims (4, 5, 6, 7)
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8. A method for detecting failure of a relay operating in a vehicle having an ignition switch, a power supply, a capacitor, and a pre-charge circuit to pre-charge the capacitor with the relay switching power from the power supply to the pre-charged capacitor, the method comprising the steps of:
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performing a capacitor discharge test;
activating the pre-charge circuit to initiate pre-charging of the capacitor;
deactivating the pre-charge circuit;
closing the relay to provide power from the power supply to the capacitor;
checking the capacitor for a post-charged under-voltage condition;
checking the capacitor for a pre-charge over-voltage condition; and
checking the capacitor for a pre-charge under-voltage condition, wherein the step of checking the capacitor for a pre-charge over-voltage condition further includes repetitively checking the capacitor for a pre-charge over-voltage condition for a predetermined pre-charging time period. - View Dependent Claims (9)
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Specification