Self-adaptive method for assisting tire inflation

• US 9,783,009 B2
• Filed: 02/25/2014
• Issued: 10/10/2017
• Est. Priority Date: 02/28/2013
• Status: Active Grant

• Current Assignee: Continental Automotive France (Continental AG), Continental Automotive GmbH (Continental AG)
• Original Assignee: Continental Automotive France (Continental AG), Continental Automotive GmbH (Continental AG)
• Inventors: Kessler, Sebastien, Lee, Jerome, De Villardi, Sebastien
• Primary Examiner(s): Mancho, Ronnie
• Application Number:
  US14/765,363
• Publication Number:
  US 20160001614A1
• Time in Patent Office: 1,323 Days
• Field of Search: 701 344
• CPC Class Codes: B60C 23/0408 transmitting the signals by non-mechanical means from the wheel or tyre to a vehicle body mounted receiver
• CPC Class Codes: B60C 23/0437 Means for detecting electromagnetic field changes not being part of the signal transmission per se, e.g. strength, direction, propagation or masking
• CPC Class Codes: B60C 23/0455 Transmission control of wireless signals
• CPC Class Codes: B60C 23/0459 self triggered by motion sensor
• CPC Class Codes: B60C 23/0462 Structure of transmission protocol
• CPC Class Codes: B60C 23/0484 Detecting an ongoing tyre inflation

Abstract

A self-adaptive method for assisting tire inflation enables control of tire inflation. If the vehicle stops, the central unit of a TPMS (Tire Pressure Monitoring System) can change in a self-adaptive manner from the reception configuration of the “moving” mode at a high bit rate to a “stationary” mode at a low bit rate. At the same time, if there is a variation in the pressure of a tire, the corresponding wheel unit is set for transmission in “stationary” mode at a low bit rate. The power Pa received at the central unit varies according to a curve (20) which shows, in the illustrated example, two positions of poor reception. By replacing high bit rate transmission with low bit rate transmission, the signal/noise ratio is improved and there is a gain in reception sensitivity of about 5 dB, and the risks of disturbance of the received power are virtually eliminated.

Claims

1. A self-adaptive method for assisting inflation of the tires of a vehicle, comprising continuously measuring at least the pressure of each tire by means of a wheel unit, transmitting messages, at a high bit rate, on a state of the tires via a wireless link between each wheel unit and a central unit, the central unit analyzing these messages continuously, and then transmitting information relating to the state of the tires to an information module, and continuously measuring a moving/stationary state of the vehicle in order to inform the central unit and the wheel unit of this state, wherein the messages are transmitted, when the vehicle is stationary, at a sufficiently low bit rate to provide an improved signal-to-noise ratio to enable the reception sensitivity of the central unit to avoid virtually any disturbance in reception.

2. The self-adaptive method as claimed in claim 1, wherein, if a stationary state of the vehicle is detected by continuous measurement for more than a specified duration, the central unit is set to two possible configurations of the reception mode, namely a high bit rate “

moving”

mode and a low bit rate “

stationary”

mode, and if, additionally, a pressure variation of a tire is above a specified threshold, the corresponding wheel unit is set for transmission in “

stationary”

mode at a low bit rate, and, additionally, in “

moving”

mode at a high bit rate.

3. The self-adaptive method as claimed in claim 1, wherein the corresponding wheel unit is also set to “

moving”

mode at a high bit rate.

4. The self-adaptive method as claimed in claim 1, wherein the following steps are executed at each wheel unit:

a moving or stationary state of the vehicle is detected by continuous measurement, and if a moving state of the vehicle is detected, the wheel unit sets itself to “

moving”

mode and the messages are transmitted at a high bit rate;

if the continuous measurement detects a stationary state of the vehicle, the wheel unit determines whether the pressure variation of the tire is above a threshold value;

if the pressure variation is below said threshold, the messages are transmitted at a high bit rate;

if the pressure variation is above said threshold, the wheel unit sets itself to “

stationary”

mode, to transmit messages at a low bit rate in this mode while the vehicle remains stationary for longer than a first specified duration.

if the stop is prolonged beyond said first specified duration, the method returns to an initial state at the wheel unit.

5. The self-adaptive method as claimed in claim 4, wherein the following steps are executed for the wheel unit, when it is in “

stationary”

mode;

the wheel unit continues to transmit at a low bit rate while the vehicle remains stationary and while the pressure variation, measured by a pressure test, is above a pressure threshold;

if the pressure variation measured by this pressure test is below this threshold, the method remains in “

stationary”

mode until the expiry of said first duration;

if a moving state of the vehicle is detected, the wheel unit sets itself to “

moving”

mode, and the messages are transmitted at a high bit rate.

6. The self-adaptive method as claimed in claim 4, wherein the wheel unit, in “

stationary”

mode, also transmits messages at a high bit rate.

7. The self-adaptive method as claimed in claim 4, wherein the wheel unit, in “

moving”

mode, does not transmit any message.

8. The self-adaptive method as claimed in claim 5, wherein the following steps are executed at the central unit:

a moving or stationary state of the vehicle is detected by continuous measurement, and if a moving state of the vehicle is detected, the messages are received at a high bit rate;

if the continuous measurement detects a stationary state of the vehicle for longer than a second predetermined duration, the central unit is set to “

stationary”

reception mode at a low bit rate;

if said second specified duration has not expired, but a pressure variation of the tire is above a specified threshold, the central unit is set to “

stationary”

reception mode at a low bit rate;

if the pressure variation remains below said predetermined value, the central unit remains set to “

moving”

reception mode at a high bit rate.

9. The self-adaptive method as claimed in claim 8, wherein the central unit, in “

stationary”

mode, also receives messages at a high bit rate.

10. The self-adaptive method as claimed in claim 8, wherein the central unit, in “

moving”

mode, also receives messages at a low bit rate.

11. The self-adaptive method as claimed in claim 8, wherein the first and second durations may be different for the central unit and for each wheel unit.

12. The self-adaptive method as claimed in claim 1, wherein the low bit rate is chosen according to a compromise between the desired sensitivity and the duration of the messages to be transmitted.

13. The self-adaptive method as claimed in claim 1, wherein the messages transmitted at a low bit rate are limited to information concerning the identification of a wheel unit and the measurement of the pressure of the corresponding tire.

14. The self-adaptive method as claimed in claim 2, wherein the corresponding wheel unit is also set to “

moving”

mode at a high bit rate.

15. The self-adaptive method as claimed in claim 6, wherein the wheel unit, in “

stationary”

mode, also transmits messages at a high bit rate.

16. The self-adaptive method as claimed in claim 5, wherein the wheel unit, in “

moving”

mode, does not transmit any message.

17. The self-adaptive method as claimed in claim 1, wherein the following steps are executed at the central unit:

a moving or stationary state of the vehicle is detected by continuous measurement, and if a moving state of the vehicle is detected, the messages are received at a high bit rate;

if the continuous measurement detects a stationary state of the vehicle for longer than a second predetermined duration, the central unit is set to “

stationary”

reception mode at a low bit rate;

if said second specified duration has not expired, but a pressure variation of the tire is above a specified threshold, the central unit is set to “

stationary”

reception mode at a low bit rate;

if the pressure variation remains below said predetermined value, the central unit remains set to “

moving”

reception mode at a high bit rate.

18. The self-adaptive method as claimed in claim 17, wherein the central unit, in “

stationary”

mode, also receives messages at a high bit rate.

19. The self-adaptive method as claimed in claim 17, wherein the central unit, in “

moving”

mode, also receives messages at a low bit rate.

20. The self-adaptive method as claimed in claim 18, wherein the central unit, in “

moving”

mode, also receives messages at a low bit rate.