Method to infer engine coolant temperature in cylinder head temperature sensor equipped vehicles

• US RE40,262 E1
• Filed: 04/16/2001
• Issued: 04/29/2008
• Est. Priority Date: 03/10/1998
• Status: Expired due to Fees

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Betki, Randy Adam, Holmes, John William, Cullen, Michael John
• Primary Examiner(s): MCCALL, ERIC SCOTT
• Application Number:
  US09/835,926
• Time in Patent Office: 2,570 Days
• Field of Search: 731/16, 731/172, 731/173, 731/181, 731/19.R, 123/41.15, 340/449, 374/145
• US Class Current: 73/117.03
• CPC Class Codes: F01P 11/16 concerning coolant temperature F01P11/20 takes precedence
• CPC Class Codes: F01P 2023/08 Microprocessor; Microcomputer
• CPC Class Codes: F01P 2025/33 Cylinder head temperature
• CPC Class Codes: F01P 2025/64 Number of revolutions

Abstract

The present invention provides a method of inferring the engine coolant temperature in cylinder head temperature sensor equipped vehicles including the steps of measuring the cylinder head temperature, calculating the engine coolant temperature from the measured cylinder head temperature as a function of at least one vehicle operational state, generating a signal for the calculated engine coolant temperature, and sending the generated signal to a display.

Claims

1. A method of inferring engine coolant temperature in cylinder head temperature sensor equipped vehicles comprising the steps of:

measuring the cylinder head temperature;

calculating the engine coolant temperature from the measured cylinder head temperature as a function of at least one vehicle operational state;

generating a signal for the calculated engine coolant temperature; and

sending the generated signal to a display .

2. A method according to claim 1, wherein the vehicle operational state is includes engine revolutions per minute.

3. A method according to claim 2, wherein the vehicle operational state is includes cylinder air charge temperature.

4. A method according to claim 1, wherein the vehicle operational states are both engine revolutions per minute and cylinder air charge temperature.

5. A method according to claim 1, further including the step of filtering the calculated engine coolant temperature so as to prevent inaccurate display readings resulting from sudden changes in vehicle operational states, the filter step performed prior to the step of generating a signal.

6. A method according to claim 5, further including the step of recording determining the difference between the measured cylinder head temperature and the filtered engine coolant temperature and recording said difference.

7. A method according to claim 6, further including the step of storing the recorded difference in keep alive memory.

8. A method according to claim 7, further including the steps of:

decaying the difference between the measured cylinder head temperature and the filtered engine coolant temperature as an exponential function of soak time upon vehicle startup;

generating an initial, startup signal by subtracting the measured cylinder head temperature from the last recorded difference stored in keep alive memory; and

sending an initial, startup signal to the display.

19. The method according to claim 1, further comprising the step of sending the generated signal to a display.

9. A method of inferring engine coolant temperature in cylinder head temperature sensor equipped vehicles comprising the steps of:

measuring the cylinder head temperature;

calculating the engine coolant temperature from the measured cylinder head temperature as a function of engine revolutions per minute and cylinder air charge temperature;

generating a signal for the calculated engine coolant temperature; and

sending the generated signal to a display.

10. A method according to claim 9, further including the step of filtering the calculated engine coolant temperature so as to prevent inaccurate display readings resulting from sudden changes in revolutions per minute and air charge temperature, the filtering step performed prior to the step of generating a signal.

11. A method according to claim 10, further including the step of recording determining the difference between the measured cylinder head temperature and the filtered engine coolant temperature and recording said difference.

12. A method according to claim 11, further including the step of storing the recorded difference in keep alive memory.

13. A method according to claim 12, further including the steps of:

decaying the difference between the measured cylinder head temperature and the filtered engine coolant temperature as an exponential function of soak time upon vehicle startup;

generating an initial, startup signal by subtracting the measured cylinder head temperature from the last recorded difference stored in keep alive memory; and

sending an initial, startup signal to the display.

14. A system for inferring engine coolant temperature in cylinder head temperature sensor equipped vehicles comprising:

a cylinder head temperature sensor; and

a controller for calculating the engine coolant temperature from the measured cylinder head temperature as a function of engine revolutions per minute and cylinder air charge temperature, wherein the controller generates a signal for the calculated engine coolant temperature and sends the generated signal to a display.

15. A system according to claim 14, wherein the controller further filters the calculated engine coolant temperature so as to prevent inaccurate display readings resulting from sudden changes in revolutions per minute and air charge temperature, the filtering performed prior to generation of the signal.

16. A system according to claim 15, wherein the controller further records determines the difference between the measured cylinder head temperature and the filtered engine coolant temperature and records said difference.

17. A system according to claim 16, wherein the controller further stores the recorded differences in keep alive memory.

18. A system according to claim 17, wherein the controller further:

decays the difference between the measured cylinder head temperature and the filtered engine coolant temperature as an exponential function of soak time if determined that the cylinder head temperature measurement was taken at vehicle startup;

generates an initial, startup signal by subtracting the measured cylinder head temperature from the last recorded difference stored in keep alive memory; and

sends an initial, startup signal to the display.

20. A method of operating a motor vehicle having an internal combustion engine, comprising:

measuring a cylinder head temperature;

inferring an engine coolant temperature from the measured cylinder head temperature; and

generating a signal for the inferred engine coolant temperature.

21. The method according to claim 20, further comprising sending the generated signal to a display.

22. The method according to claim 21, further including the step of filtering the inferred engine coolant temperature so as to prevent inaccurate display readings resulting from sudden changes in vehicle operational states, the filter step performed prior to the step of generating a signal.

23. The method according to claim 22, further including the step of determining the difference between the measured cylinder head temperature and the filtered engine coolant temperature and recording said difference.

24. A method according to claim 23, further including the step of storing the recorded difference in keep alive memory.

25. A method according to claim 24, further including the steps of:

decaying the difference between the measured cylinder head temperature and the filtered engine coolant temperature as an exponential function of soak time upon vehicle startup;

generating an initial, startup signal by subtracting the measured cylinder head temperature from the last recorded difference stored in keep alive memory; and

sending an initial, startup signal to the display.