Granted Patent B2

US 7,302,329 · App. 11/106,116 · Granted Nov 27, 2007

Assignee: GM Global Technology Operations, Inc.

Abstract

Claims (58)

1. A controller for monitoring and diagnosing the coil temperature of a magnetorheological (MR) clutch connected to a power steering pump of a vehicle, the controller comprising:

a processing circuit; and

a storage medium, readable by the processing circuit, for storing instructions for execution by the processing circuit for:

receiving a plurality of input signals representative of dynamic operating conditions relating to the vehicle;

using the input signals to generate an output signal representative of a temperature of the coil of the MR clutch;

determining from the output signal whether the temperature of the coil exceeds a threshold limit; and

in response to the temperature of the coil exceeding a threshold limit, triggering at least one of a remedial action and a data storage algorithm.

2. The controller of claim 1 , wherein:

the output signal is representative of an estimated temperature of the MR clutch coil absent a need for a physical temperature sensor at the coil.

3. The controller of claim 1 , wherein the plurality of input signals comprises:

a first signal representative of a supply voltage of the vehicle;

a second signal representative of a duty cycle of the MR clutch coil; and

a third signal representative of a current through the MR clutch coil.

4. The controller of claim 1 , further comprising a storage medium, readable by the processing circuit, for storing instructions for execution by the processing circuit for:

using a look-up table, an equation, a transfer function, or any combination comprising at least one of the foregoing, for determining whether the temperature of the coil exceeds a threshold limit.

5. The controller of claim 1 , further comprising a storage medium, readable by the processing circuit, for storing instructions for execution by the processing circuit for:

using a three-dimensional look-up table for estimating the temperature of the coil; and

using the estimated temperature to determine whether the temperature of the coil exceeds a threshold limit.

6. The controller of claim 1 , further comprising:

a storage medium, readable by the processing circuit, for storing instructions for execution by the processing circuit for generating a control signal; and

a current amplifier responsive to the control signal and in signal communication with the MR clutch coil.

7. A magnetorheological (MR) power steering pump system for a vehicle, the system comprising:

a MR clutch having an excitation coil;

a power steering pump in operable communication with the MR clutch; and

a controller in operable communication with the MR clutch, the controller comprising:

a processing circuit; and

a storage medium, readable by the processing circuit, for storing instructions for execution by the processing circuit for:

receiving a plurality of input signals representative of dynamic operating conditions relating to the vehicle;

using the input signals to generate an output signal representative of a temperature of the coil of the MR clutch;

determining from the output signal whether the temperature of the coil exceeds a threshold limit; and

in response to the temperature of the coil exceeding a threshold limit, triggering a remedial action, a data storage algorithm, or both.

8. The system of claim 7 , wherein:

the output signal is representative of an estimated temperature of the MR clutch coil absent a need for a physical temperature sensor at the coil;

the plurality of input signals comprises a first signal representative of a supply voltage of the vehicle, a second signal representative of a duty cycle of the MR clutch coil, and a third signal representative of a current through the MR clutch coil; and

further comprising a storage medium, readable by the processing circuit, for storing instructions for execution by the processing circuit for:

using a look-up table, an equation, a transfer function, or any combination comprising at least one of the foregoing, for estimating the temperature of the coil then determining whether the estimated coil temperature exceeds a threshold limit.

9. A method for monitoring and diagnosing the coil temperature of a magnetorheological (MR) clutch connected to a power steering pump of a vehicle, the method comprising:

receiving a plurality of input signals representative of dynamic operating conditions relating to the vehicle;

using the input signals to generate an output signal representative of a temperature of the coil of the MR clutch;

determining from the output signal whether the temperature of the coil exceeds a threshold limit; and

in response to the temperature of the coil exceeding a threshold limit, triggering a remedial action, a data storage algorithm, or both.

10. The method of claim 9 , wherein:

the output signal is representative of an estimated temperature of the MR clutch coil absent a need for a physical temperature sensor at the coil;

the plurality of input signals comprises a first signal representative of a supply voltage of the vehicle, a second signal representative of a duty cycle of the MR clutch coil, and a third signal representative of a current through the MR clutch coil; and

further comprising:

using a look-up table, an equation, a transfer function, or any combination comprising at least one of the foregoing, to estimate the temperature of the coil; and

using a diagnostic algorithm to decide if the estimated coil temperature exceeds a threshold value.

11. A method for calibrating a look-up table used for monitoring and diagnosing the coil temperature of a magnetorheological (MR) clutch connected to a power steering pump of a vehicle, the method comprising:

receiving a first signal representative of a supply voltage of the vehicle;

receiving a second signal representative of a duty cycle of the MR clutch coil;

receiving a third signal representative of a current through the MR clutch coil;

receiving a fourth signal representative of a sensed temperature of the MR clutch coil; and

populating a multi-dimensional look-up table by relating information associated with the fourth signal to information associated with the first, second and third signals.

12. The method of claim 11 , wherein the first, second, third and fourth, signals are steady state signals.

13. The method of claim 11 , further comprising:

generating the first, second, third and fourth, signals under simulated or test vehicle conditions such that the look-up table includes information relating to substantially all operating conditions likely to be experienced by an actual vehicle.

14. The method of claim 11 , further comprising:

acquiring and interpreting the data associated with the first, second, third and fourth, signals prior to populating the multi-dimensional look-up table.

Assignments (12)

Continuity (1)