METHOD AND APPARATUS TO MONITOR A TEMPERATURE SENSING DEVICE

• US 20080181280A1
• Filed: 01/31/2007
• Published: 07/31/2008
• Est. Priority Date: 01/31/2007
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations Incorporated (Motors Liquidation Co. GUC Trust)
• Inventors: West, Stephen T., Wu, Peter E., Wang, Wei D., Bauer, Harry J., Gataric, Slobodan
• Granted Patent: US 7,555,411 B2
• Time in Patent Office: Days
• US Class Current: 374/1
• CPC Class Codes: G01K 15/00 Testing or calibrating of thermometers
• CPC Class Codes: G01K 15/007 Testing

Abstract

A method and an article of manufacture are provided to monitor a temperature sensing circuit and detect a fault therein. The method comprises monitoring sensor readings output from a plurality of temperature sensing circuits. An average sensor reading is determined, calculated from the sensor readings output from a subset of the temperature sensing circuits. Each of the sensor readings is compared to the average sensor reading. A fault is identified when one of the sensor readings deviates from the average sensor reading by an amount greater than a threshold, more particularly when one of the sensor readings deviates from the average sensor reading by an amount greater than the threshold at least a quantity of X times out of Y sensor readings.

Claims

1. (canceled)

5. Method to detect a fault in a temperature sensing circuit, comprising:

monitoring sensor readings output from a plurality of temperature sensing circuits operative to monitor an electrical machine and machine control circuits,

calculating an average sensor reading from the sensor readings output from a subset consisting of the temperature sensing circuits operative to monitor the machine control circuits;

comparing each of the sensor readings to the average sensor reading; and

determining when one of the sensor readings deviates from the average sensor reading by an amount greater than a threshold.

2. The method of claim 5, further comprising

setting a fault increment when one of the sensor readings deviates from the average sensor reading by an amount greater than the threshold, and

determining at least a quantity of X fault increments out of Y sensor readings output from one of the temperature sensing circuits.

3. The method of claim 2, further comprising identifying a fault in one of the temperature sensing circuits when one of the sensor readings deviates from the average sensor reading by an amount greater than the threshold during a substantial portion of the sensor readings output from the one of the temperature sensing circuits.

4. The method of claim 5, comprising monitoring sensor readings output from a plurality of substantially contiguous sensing circuits operative to monitor temperatures in a device.

6. The method of claim 5, further comprising:

selectively omitting the one of the sensor readings that deviates from the average sensor reading;

determining a second average sensor reading calculated from a subset consisting of less than all of the remaining sensor readings;

comparing each remaining sensor reading to the second average sensor reading; and

,

setting a fault increment when one of the remaining sensor readings deviates from the second average sensor reading by an amount greater than a threshold.

7. The method of claim 6, further comprising determining at least a quantity of X fault increments out of Y sensor readings output from one of the temperature sensing circuits.

8. Method for monitoring temperatures of an electrical machine and a machine control circuit, comprising:

monitoring sensor readings output from a plurality of temperature sensors operative to monitor the electrical machine and the machine control circuit;

determining an average sensor reading calculated from the sensor readings output from a subset consisting of less than all of the temperature sensors;

identifying a fault in one of the temperature sensors when one of the sensor readings deviates from the average sensor reading by an amount greater than a threshold.

9. The method of claim 8, wherein identifying a fault in one of the temperature sensors further comprises:

regularly monitoring the sensor readings output from the temperature sensors;

setting a fault increment when one of the sensor readings deviates from the average sensor reading by an amount greater than the threshold; and

,

identifying a fault in one of the temperature sensors when there are at least a quantity of X fault increments out of Y sensor readings output from one of the temperature sensors.

10. The method of claim 9, further comprising identifying a fault in one of the temperature sensors when one of the sensor readings deviates from the average sensor reading by an amount greater than the threshold during a substantial portion of the sensor readings output from the one of the temperature sensors.

11. The method of claim 8, wherein determining the average sensor reading calculated from the sensor readings output from the subset of the temperature sensors comprises calculating an average sensor reading from the sensor readings output from the temperature sensors operative to monitor the machine control circuit.

12. The method of claim 8, further comprising determining one of the sensing circuits is functioning acceptably when the sensor reading for the sensing circuit is within range of the average sensor reading.

13. The method of claim 8, further comprising regularly monitoring the sensor readings after a cold start event.

14. Article of manufacture, comprising a storage medium having machine-executable code encoded therein for effecting a method to monitor a plurality of temperature sensing circuits operative to monitor temperature of electrical power control circuits and an electrical machine, the code comprising:

code to monitor sensor readings output from the temperature sensing circuits;

code to determine an average sensor reading calculated from a subset consisting of less than all of the monitored sensor readings;

code to identify a fault in one of the temperature sensing circuits when one of the monitored sensor readings deviates from the average sensor reading by an amount greater than a threshold.

15. The article of manufacture of claim 14, wherein each temperature sensing circuit comprises:

a temperature sensing device operative to monitor one of the electrical power control circuits and the electrical machine; and

,

an electrical circuit effective to communicate an output signal from the temperature sensing device.

16. The article of manufacture of claim 14, wherein the code to identify a fault in one of the temperature sensing circuits further comprises:

code to regularly monitor the temperature sensor readings; and

,

code to identify a fault in one of the temperature sensing circuits when the sensor reading deviates from the average sensor reading by an amount greater than the threshold at least a quantity of X fault increments out of Y samples of the sensor readings output from the one of the temperature sensing circuits.

17. The article of manufacture of claim 14, wherein the electrical power control circuits are substantially contiguous.

18. The article of manufacture of claim 14, further comprising code to determine one of the sensing circuits is functioning acceptably when the sensor reading output from the one of the temperature sensing circuits is within range of the average sensor reading.

19. The article of manufacture of claim 14, further comprising:

code to selectively omit the one of the sensor readings that deviates from the average sensor reading;

code to determine a second average sensor reading calculated from a subset consisting of the remaining sensor readings;

code to compare each remaining sensor reading to the second average sensor reading; and

,

code to set a fault increment when one of the remaining sensor readings deviates from the second average sensor reading by an amount greater than a threshold.

20. The article of manufacture of claim 19, further comprising code to determine at least a quantity of X fault increments out of Y samples of the sensor readings output from one of the temperature sensing circuits.