INTAKE AIR TEMPERATURE DIAGNOSTIC SYSTEM

• US 20090138154A1
• Filed: 11/27/2007
• Published: 05/28/2009
• Est. Priority Date: 11/27/2007
• 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: Wang, Wenbo, Mc Lain, Kurt D.
• Granted Patent: US 8,234,038 B2
• Time in Patent Office: Days
• US Class Current: 701/34
• CPC Class Codes: F02D 2200/0414 Air temperature
• CPC Class Codes: F02D 2200/0416 Estimation of air temperature
• CPC Class Codes: F02D 41/187 using a hot wire flow sensor
• CPC Class Codes: F02D 41/222 relating to the failure of sensors or parameter detection devices
• CPC Class Codes: G01K 13/02 for measuring temperature of moving fluids or granular materials capable of flow
• CPC Class Codes: G01K 15/00 Testing or calibrating of thermometers
• CPC Class Codes: G01K 15/007 Testing
• CPC Class Codes: G01M 15/042 by monitoring a single specific parameter not covered by groups G01M15/06 - G01M15/12
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

A method of evaluating intake air temperature (IAT) sensor rationality may include measuring a first intake air temperature associated with an engine using an IAT sensor when the engine is in a non-operating condition, determining a second intake air temperature associated with the engine using a hot wire air flow meter when the engine is in the non-operating condition, and indicating an IAT sensor fault when a difference between the first and second intake air temperatures exceeds a predetermined temperature limit.

Claims

1. A method comprising:

measuring a first intake air temperature (IAT) associated with an engine using an IAT sensor when said engine is in a non-operating condition;

determining a second intake air temperature associated with said engine using a hot wire air flow meter when said engine is in said non-operating condition; and

indicating an IAT sensor fault when a difference between said first and second intake air temperatures exceeds a predetermined temperature limit.

2. The method of claim 1, wherein said hot wire air flow meter includes a mass air flow (MAF) sensor located in an intake system of said engine.

3. The method of claim 1, wherein said hot wire air flow meter produces a pulse modulated signal to determine said second intake air temperature during said non-operating condition.

4. The method of claim 3, further comprising determining a frequency of said signal and using said frequency to determine said second intake air temperature.

5. The method of claim 4, wherein said frequency is linearly related to said second intake air temperature.

6. The method of claim 5, wherein said frequency is indirectly proportional to said second intake air temperature.

7. The method of claim 4, wherein said determining said second intake air temperature includes referencing a look-up table including said second intake air temperature as a function of said frequency.

8. The method of claim 1, further comprising waiting a predetermined time period after operation of said engine before said measuring and said determining.

9. A method comprising:

determining a mass air flow (MAF) rate into an engine during operation thereof using a hot wire air flow meter;

measuring a first intake air temperature using an intake air temperature (IAT) sensor when said engine is in a non-operating condition;

determining a second intake air temperature using said hot wire air flow meter when said engine is in said non-operating condition; and

indicating an IAT sensor fault when a difference between said first and second intake air temperatures exceeds a predetermined temperature limit.

10. The method of claim 9, wherein said hot wire air flow meter includes a MAF sensor located in an intake system of said engine.

11. The method of claim 9, wherein said hot wire air flow meter produces a pulse modulated signal to determine said second intake air temperature during said non-operating condition.

12. The method of claim 11, further comprising determining a frequency of said signal and using said frequency to determine said second intake air temperature.

13. The method of claim 12, wherein said frequency is linearly related to said second intake air temperature.

14. The method of claim 13, wherein said frequency is indirectly proportional to said second intake air temperature.

15. A control module comprising:

an intake air temperature (IAT) sensor temperature determination module that determines a first intake air temperature measurement associated with an engine using an IAT sensor when said engine is in a non-operating condition;

a mass air flow (MAF) sensor temperature determination module that determines a second intake air temperature associated with said engine using a hot wire air flow sensor when said engine is in a non-operating condition;

an intake temperature evaluation module in communication with said IAT sensor temperature determination module and said MAF sensor temperature determination module that determines a difference between said first and second intake air temperatures; and

an IAT sensor fault determination module in communication with said intake temperature evaluation module that indicates an IAT sensor fault when said difference exceeds a predetermined temperature limit.

16. The control module of claim 15, wherein said hot wire air flow sensor is located in an intake system of said engine and determines an air flow into said engine when said engine is in an operating condition.

17. The control module of claim 15, wherein said MAF sensor temperature determination module receives a pulse width modulated signal from said hot wire air flow sensor and determines said second intake air temperature based thereon.

18. The control module of claim 17, wherein said MAF sensor temperature determination module determines a frequency of said signal and determines said second intake air temperature based thereon.

19. The control module of claim 18, wherein said frequency is linearly related to said second intake air temperature.

20. The control module of claim 18, wherein said MAF sensor temperature determination module includes a look-up table including said second intake air temperature as a function of said frequency.