System and method for detection of pressure drop in a tire

• US 6,907,776 B2
• Filed: 09/09/2002
• Issued: 06/21/2005
• Est. Priority Date: 09/10/2001
• Status: Active Grant

• Current Assignee: Continental Automotive GmbH (Continental AG)
• Original Assignee: Siemens AG
• Inventors: Fischer, Martin, Hillenmayer, Franz, Fuessel, Dominik
• Primary Examiner(s): Lefkowitz, Edward
• Assistant Examiner(s): ALLEN, ANDRE J
• Application Number:
  US10/237,124
• Publication Number:
  US 20030070477A1
• Time in Patent Office: 1,016 Days
• Field of Search: 731/46, 340/440, 340/442, 340/444
• US Class Current: 73/146
• CPC Class Codes: B60C 23/0408 transmitting the signals by non-mechanical means from the wheel or tyre to a vehicle body mounted receiver

Abstract

The present invention comprises a system for the detection of a pressure drop in a tire. Herein an evaluating unit determines the temporal modification of the temperature in the tire and produces an alerting signal if the temporal modification of the temperature falls short of a predetermined temperature modification threshold value. In presence of an evaluating signal, the evaluating unit determines the temporal modification of the air pressure and produces an alerting signal, if the temporal modification of the air pressure exceeds an air pressure modification threshold value.

Claims

1. A method for detecting pressure drop in a tire of a vehicle, comprising the steps of:

measuring air pressure and temperature within said tire,

determining a temporal modification of said temperature and whether said modification is below a predetermined temperature modification threshold,

if said temperature temporal modification is below a predetermined threshold, generating an alarm if temporal modification of measured air pressure exceeds an air pressure modification threshold value, and

decreasing said air pressure modification threshold value with increasing range between measured air pressure and target air pressure.

2. The method according to claim 1, wherein said temporal modification of said air pressure is only evaluated if said vehicle is stationary.

3. The method according to one of the claim 1, wherein said measured air pressure is corrected according to measured temperature.

4. The method according to one of the claim 2, wherein said measured air pressure is corrected according to measured temperature.

5. The method according to claim 1, further comprising the steps of:

extrapolating various degrees of operating safety levels of said tire;

determining if measured air pressure falls below any one of said safety levels; and

generating an alarm if said air pressure falls below any one of said safety levels.

6. The method according to claim 5, further comprising the steps of:

determining rate in which said air pressure falls below a highest of said safety levels;

extrapolating from said rate a time when said air pressure falls below a lowest of said safety levels; and

displaying said time when said alarm is generated.

7. The method according to claim 1, further comprising the steps of:

determining said tire deformation; and

modifying measured air pressure according to tire deformation.

8. The method according to claim 1, further comprising the steps of:

determining said vehicle speed; and

modifying measured air pressure according to vehicle speed.

9. A system for the detection of a pressure drop in a tire of a vehicle, comprising:

an air pressure sensor for detecting air pressure in said tire,

a temperature sensor for detecting temperature in said tire;

an alarm unit for generating a human detectable alarm;

an evaluating unit electrically connected to said air pressure sensor, temperature sensor and alarm unit, said unit further comprising means for;

determining temporal modification of detected temperature and producing an evaluating signal if said temporal modification falls below a predetermined temperature modification threshold value; and

determining said temporal modification of air pressure in the presence of said evaluating signal and producing an alarm signal in said alarm unit if temporal modification of detected air pressure exceeds an air pressure modification threshold value; and

means for decreasing said air pressure modification threshold value with increasing range between detected air pressure and target air pressure.

10. The system according to claim 9, further comprising:

a vehicle immobilization sensor for detecting whether a vehicle is in motion, said immobilization sensor connected to said evaluating unit; and

said evaluating unit further comprising means for determining temporal modification of detected air pressure in regard to production of an alerting signal only when output from said immobilization sensor indicates that said vehicle is stationary.

11. The system according to claim 9, further comprising an ambient air pressure sensor for detecting ambient air pressure, said ambient air pressure sensor connected to said evaluation unit, and said evaluating unit further comprising means for correcting measured air pressure according to detected ambient air pressure.

12. The system according to claim 10, further comprising an ambient air pressure sensor for detecting ambient air pressure, said ambient air pressure sensor connected to said evaluation unit, and said evaluating unit further comprising means for correcting measured air pressure according to detected ambient air pressure.

13. The system according to claim 9, further comprising a velocity sensor for detecting vehicle operating speed, and said evaluating unit further comprising means for correcting measured air pressure according to said operating speed.

14. The system according to one of the claim 10, wherein said unit further comprises means for correcting measured air pressure according to measured temperature.

15. The system according to one of the claim 11, wherein said unit further comprises means for correcting measured air pressure according to measured temperature.

16. The system according to one of the claim 12, wherein said unit further comprises means for correcting measured air pressure according to measured temperature.

17. The system according to one of the claim 13, wherein said unit further comprises means for correcting measured air pressure a according to measured temperature.

18. The system according to claim 9, wherein said evaluation means further comprises means for:

extrapolating various degrees of operating safety levels of said tire;

determining if measured air pressure falls below any one of said safety levels; and

generating an alarm if said air pressure falls below any one of said safety levels.

19. The system according to claim 18, wherein said evaluating unit further comprises means for:

determining rate in which said air pressure falls below a highest of said safety levels;

extrapolating from said rate a time when said air pressure falls below a lowest of said safety levels; and

displaying said time when said alarm is generated.

20. The system according to claim 9, further comprising means for measuring tire deformation in communication with said evaluating means, and wherein said evaluating unit further comprises means for modifying measured air pressure according to tire deformation.

21. The system according to claim 9, further comprising means for detecting vehicle operating speed and wherein said evaluating unit further comprises means for modifying measured air pressure according to vehicle operating speed.