OUTSIDE AIR TEMPERATURE SENSOR DIAGNOSTIC SYSTEMS FOR A VEHICLE

• US 20120051388A1
• Filed: 10/13/2010
• Published: 03/01/2012
• Est. Priority Date: 08/27/2010
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations Incorporated (General Motors Company)
• Inventors: Hamama, Wajdi B., Wiggins, Layne K., Wang, Wenbo, Horner, Robert J., Van Gilder, John F., Lindsey, Keith M. Jr., Wagner, Robert D.
• Granted Patent: US 8,608,374 B2
• Time in Patent Office: Days
• US Class Current: 374/1
• CPC Class Codes: F02D 2200/0414 Air temperature
• CPC Class Codes: F02D 41/222 relating to the failure of sensors or parameter detection devices
• CPC Class Codes: F02D 41/2403 using essentially up/down counters
• CPC Class Codes: G01K 15/007 Testing
• CPC Class Codes: G01K 2205/00 Application of thermometers in motors, e.g. of a vehicle
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

An outside air temperature (OAT) diagnostic system includes an ambient temperature monitoring module that receives (i) an OAT signal from an OAT sensor and (ii) an intake air temperature (IAT) signal from an IAT sensor of an engine. The ambient temperature monitoring module compares the OAT signal to an IAT signal and generates a first difference signal. A performance reporting module determines whether the OAT sensor is exhibiting a fault and generates an OAT performance signal based on the first difference signal.

Claims

1. An outside air temperature (OAT) diagnostic system comprising:

an ambient temperature monitoring module that receives (i) an OAT signal from an OAT sensor and (ii) an intake air temperature (IAT) signal from an IAT sensor of an engine,

wherein the ambient temperature monitoring module compares the OAT signal to an IAT signal and generates a first difference signal; and

a performance reporting module that determines whether the OAT sensor is exhibiting a fault and generates an OAT performance signal based on the first difference signal.

2. The OAT diagnostic system of claim 1, wherein:

the ambient temperature monitoring module subtracts the IAT signal from the OAT signal to generate the first difference signal;

the ambient temperature monitoring module subtracts the OAT signal from the IAT signal to generate a second difference signal; and

the performance reporting module determines whether the OAT sensor is exhibiting a fault and generates the OAT performance signal based on the second difference signal.

3. The OAT diagnostic system of claim 1, further comprising an engine temperature module that generates a second difference signal based on (i) an engine coolant temperature (ECT) signal received from an ECT sensor and (ii) the IAT signal,

wherein the performance reporting module determines whether the OAT sensor is exhibiting a fault and generates the OAT performance signal based on the second difference signal.

4. The OAT diagnostic system of claim 3, wherein the performance reporting module determines whether the OAT sensor is exhibiting a fault and generates the OAT performance signal:

based on the first difference signal and the second difference signal when the engine is deactivated; and

based on the second difference signal and not the first difference signal when the engine is activated.

5. The OAT diagnostic system of claim 1, further comprising an engine monitoring module that determines whether the engine is activated and stores an engine OFF count and an engine ON count based on whether the engine is activated,

wherein the performance reporting module determines whether the OAT sensor is exhibiting a fault and generates the OAT performance signal based on the engine OFF count and the engine ON count.

6. The OAT diagnostic system of claim 5, wherein the performance reporting module determines whether the OAT sensor is exhibiting a fault and generates the OAT performance signal based on (i) a first comparison between the engine OFF count and a first count minimum and (ii) a second comparison between the engine ON count and a second count minimum.

7. The OAT diagnostic system of claim 1, further comprising an engine adjustment module that:

determines an OFF count adjustment value based on an engine OFF count minimum and adjusts an OFF count by the OFF count adjustment value when the engine is OFF; and

determines an ON count adjustment value based on an engine ON count minimum and adjusts an ON count by the ON count adjustment value when the engine is ON,

wherein the performance reporting module determines whether the OAT sensor is exhibiting a fault and generates the OAT performance signal based on (i) the OFF count when the engine is OFF and (ii) the ON count when the engine is ON.

8. The OAT diagnostic system of claim 1, wherein the performance reporting module determines that the OAT signal is skewed one of high and low relative to an estimated OAT based on the first difference signal.

9. The OAT diagnostic system of claim 1, further comprising:

at least one of (i) an out-of-range high and low module that generates a first fault pending signal based on the OAT signal and an OAT limit and (ii) an intermittent fault module that generates a second fault pending signal based on an intermittent count and an intermittent maximum;

a count module that increments one of a pass count and a fail count based on at least one of the first fault pending signal and the second fault pending signal; and

a monitoring module that determines whether the OAT sensor is exhibiting a fault based on at least one of the pass count and the fail count.

10. The OAT diagnostic system of claim 9, further comprising a false pass and fail module that:

stores (i) a maximum fail on pass count limit and (ii) a maximum pass on fail count limit; and

performs one of (i) a first comparison between the fail count and the maximum fail on pass count limit and (ii) a second comparison between the pass count and the maximum pass on fail count limit,

wherein the count module resets the fail count and the pass count based on the first comparison and the second comparison.

11. An outside air temperature (OAT) diagnostic system comprising:

an ambient temperature monitoring module that receives an OAT signal from an OAT sensor of a vehicle;

at least one of (i) an out-of-range high and low module that generates a first fault pending signal based on the OAT signal and a first OAT limit and (ii) an intermittent fault module that generates a second fault pending signal based on an intermittent count and an intermittent maximum;

a count module that increments one of a first pass count and a first fail count based on at least one of the first fault pending signal and the second fault pending signal; and

a monitoring module that determines whether the OAT sensor is exhibiting a fault based on at least one of the first pass count and the first fail count.

12. The OAT diagnostic system of claim 11, wherein:

the out-of-range high and low module generates the first fault pending signal based on the OAT signal and the first OAT limit;

the count module increments one of a first pass count and a first fail count based on the first fault pending signal; and

the count module determines whether the first fail count is greater than a first predetermined fail count limit and generates a first status signal.

13. The OAT diagnostic system of claim 12, wherein:

the out-of-range high and low module generates the first fault pending signal based on a second OAT limit, wherein the second OAT limit is less than the first OAT limit;

the pass and fail count module determines whether a second fail count is greater than a second predetermined fail count limit and generates a second status signal; and

the monitoring module determines whether the OAT sensor is exhibiting a fault based on the second status signal.

14. The OAT diagnostic system of claim 12, wherein the monitoring module determines whether the OAT sensor has a circuit that is at least one of (i) open, (ii) shorted to ground and (iii) shorted to a source voltage based on the first status signal.

15. The OAT diagnostic system of claim 11, further comprising:

a count comparison module that compares the intermittent count to an intermittent limit and generates a limit result signal; and

a sample count module that stores a sample count based on the limit result signal,

wherein the intermittent fault module generates the second fault pending signal based on the intermittent count and the intermittent maximum,

wherein the count module increments one of a first pass count and a first fail count based on the second fault pending signal, and

wherein the monitoring module determines whether the OAT sensor is exhibiting a fault based on the sample count, an intermittent fail count limit, and a sample count limit.

16. The OAT diagnostic system of claim 15, the monitoring module determines whether the OAT sensor is exhibiting a fault based on (i) a first comparison between the sample count and the sample count limit and (ii) a second comparison between the fail count and the fail count limit.

17. The OAT diagnostic system of claim 11, further comprising:

an intermittent integral module that stores an intermittent count; and

an absolute value module that determines an absolute value of a difference between a current OAT and a pervious OAT,

wherein the absolute value module add the absolute value to the intermittent count, and

wherein the monitoring module determines whether the OAT sensor is exhibiting a fault based on the intermittent count.

18. The OAT diagnostic system of claim 17, further comprising an intermittent comparison module that compares the intermittent count to an intermittent limit and generates a resultant signal,

wherein the intermittent integral module increments the intermittent count based on the resultant signal.

19. The OAT diagnostic system of claim 18, further comprising a sample count module that (i) stores a sample count and (ii) increments the sample count based on the resultant signal,

wherein the monitoring module determines whether the OAT sensor is exhibiting a fault based on the sample count.

20. The OAT diagnostic system of claim 11, further comprising a false pass and fail module that:

stores (i) a maximum fail on pass count limit and (ii) a maximum pass on fail count limit; and

performs one of (i) a first comparison between the fail count and the maximum fail on pass count limit and (ii) a second comparison between the pass count and the maximum pass on fail count limit,

wherein the count module resets the fail count and the pass count based on the first comparison and the second comparison.