System and method for monitoring an electrical power relay in a hybrid electric vehicle
First Claim
1. System for monitoring an electrical relay operable to conduct electrical power from a source to a load device in an operator controlled vehicle, comprising:
- an electrical relay including a pair of electrical contacts controllably opened and closed;
a resistive device, permanently electrically connected across the pair of electrical contacts such that when the pair of electrical contacts is closed the resistive device is substantially shorted by the closed electrical contacts and when the pair of electrical contacts is open the resistive device is in circuit between the open electrical contacts;
a controllable electrical load device electrically connected to an electrical power source through the resistive device when the pair of electrical contacts is open and primarily through the pair of electrical contacts when the pair of electrical contacts is closed and the resistive device is substantially shorted by the closed electrical contacts;
at least one sensing device measuring one of a) voltage across the resistive device and b) actual current supplied to the controllable electrical load device; and
,a controller identifying a vehicle shutdown command from the operator,commanding the controllable electrical load device to operate at a known current draw level,commanding the relay to open the pair of electrical contacts, anddetermining from the measured one of a) voltage across the resistive device and b) actual current supplied to the controllable electrical load device, and a corresponding voltage threshold and current threshold, respectively, whether the pair of electrical contacts has opened.
12 Assignments
0 Petitions
Accused Products
Abstract
A method and system to monitor a high voltage power relay operable to conduct electrical power from a source to a load, during each vehicle shutdown event. The system includes the electrical relay with a resistive device, electrically connected in parallel circuit, a controllable electrical load device, and a sensing device. A controller is connected to the electrical relay and each sensing device, and operable to identify a low electrical load condition at the load. The controller commands the load to operate at a known current draw level, commands the relay open, and monitors a change in power to the load device when the relay is commanded open. The electrical relay is functioning properly when the change in electrical power to the load exhibits a known profile over time, when the electrical relay is controlled to the commanded-open position.
42 Citations
15 Claims
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1. System for monitoring an electrical relay operable to conduct electrical power from a source to a load device in an operator controlled vehicle, comprising:
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an electrical relay including a pair of electrical contacts controllably opened and closed; a resistive device, permanently electrically connected across the pair of electrical contacts such that when the pair of electrical contacts is closed the resistive device is substantially shorted by the closed electrical contacts and when the pair of electrical contacts is open the resistive device is in circuit between the open electrical contacts; a controllable electrical load device electrically connected to an electrical power source through the resistive device when the pair of electrical contacts is open and primarily through the pair of electrical contacts when the pair of electrical contacts is closed and the resistive device is substantially shorted by the closed electrical contacts; at least one sensing device measuring one of a) voltage across the resistive device and b) actual current supplied to the controllable electrical load device; and
,a controller identifying a vehicle shutdown command from the operator, commanding the controllable electrical load device to operate at a known current draw level, commanding the relay to open the pair of electrical contacts, and determining from the measured one of a) voltage across the resistive device and b) actual current supplied to the controllable electrical load device, and a corresponding voltage threshold and current threshold, respectively, whether the pair of electrical contacts has opened. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. Method to monitor a pair of electrical contacts of an electrical relay in a circuit conducting current from an electrical storage device to a controllable electrical load device in an operator controlled vehicle, comprising:
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a. equipping the electrical relay with a resistive device permanently electrically connected across the pair of electrical contacts such that when the pair of electrical contacts is closed the resistive device is substantially shorted by the closed electrical contacts and when the pair of electrical contacts is open the resistive device is in circuit between the open electrical contacts; b. identifying a vehicle shut down command from the operator; c. commanding the controllable electrical load device to operate at a known current draw level simultaneously while the electric relay is commanded to open the pair of electrical contacts; d. measuring one of a) voltage across the resistive device and b) actual current supplied to the controllable electrical load device; and e. diagnosing from the measured one of a) voltage across the resistive device and b) actual current supplied to the controllable electrical load device, and a corresponding voltage threshold and current threshold, respectively, whether the pair of electrical contacts has opened. - View Dependent Claims (13, 14, 15)
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Specification