Arrangement for monitoring at least one parameter for a number of motor vehicle wheels

• US 20040008108A1
• Filed: 06/25/2003
• Published: 01/15/2004
• Est. Priority Date: 07/01/2002
• Status: Active Grant

• Current Assignee: Continental Automotive GmbH (Continental AG)
• Original Assignee: Siemens AG
• Inventors: Spotka, Jurgen, Prenninger, Martin, Kroitzsch, Johannes
• Granted Patent: US 6,980,099 B2
• Time in Patent Office: Days
• US Class Current: 340/442
• CPC Class Codes: B60C 23/0416 allocating a corresponding wheel position on vehicle, e.g. front/left or rear/right
• CPC Class Codes: B60C 23/0433 Radio signals
• CPC Class Codes: B60R 25/24 using electronic identifiers containing a code not memorised by the user

Abstract

The arrangement for monitoring at least one parameter for a number of motor vehicle wheels uses at least one receive antenna that features a directional characteristic such that at least the signals which are transmitted by detector units located at two different vehicle wheels can be uniquely assigned to the relevant wheel positions as a result of the different receive level. The use of a number of receive antennas allows either the number of distinguishable detector units to be increased or a redundancy to be created to improve the reliability of the detection.

Claims

1. Arrangement to monitor at least one parameter for a number of motor vehicle wheels, comprising:

a) a number of detector units, each of which is assigned to a wheel, whereby each detector unit comprises a sensor for recording the at least one parameter and a transmit unit with a transmit antenna,

b) at least one receive antenna comprising a directional characteristic positioned in such a way in the vehicle that, in connection with the field strengths of the signals sent by the individual transmit units at the location of the at least one receive antenna produces receive signals of different power in each case for at least two of the transmit units,

c) a central evaluation unit which comprises a receive unit, wherein the receive unit is connected to the at least one receive antenna; and

d) an evaluation unit coupled with the central evaluation unit which compares the receive power of a received signals with stored threshold values or ranges of values assigned to one wheel position in each case and assigns the received signal to a wheel position, if the threshold value assigned to this wheel position is exceeded or the receive power lies within the range of values assigned to this wheel position.

2. Arrangement in accordance with claim 1, further comprising means for creating the directional characteristic of the at least one receive antenna such that, starting from the position of the receive antenna, they each produce sensitivities in the direction of the transmit antennas of the at least two signals to be distinguished of the relevant transmit units, for which the difference is greater than a predefined value, in which case this value is selected to enable a clear distinction to be made between the signals using the detected receive power of the two signals.

3. Arrangement in accordance with claim 1, wherein for a vehicle with four wheels two receive antennas are provided.

4. Arrangement in accordance with claim 3, wherein one receive antenna is provided in a position in the area of the front wheel and one receive antenna is provided in a position in the area of the rear wheel, preferably in the area above the wheel arch.

5. Arrangement in accordance with claim 4, wherein the directional characteristic of the receive antenna at least in the direction of the further wheel of the same lengthwise side of the vehicle shows a low or high sensitivity and in the direction of the further front or rear wheel a high or low sensitivity, so that the evaluation unit can use one receive antenna in each case to undertake at least one unique assignment of the signals of the transmit units at the wheel positions in the direction of the low and high sensitivity.

6. Arrangement in accordance with claim 5, wherein the directional characteristic of the receive antennas is created so that the signal of the transmit unit in the area of the same wheel creates the highest receive power in each case, which is clearly distinguishably higher than the receive power on reception of a signal from the transmit unit in the direction of the high sensitivity of the directional characteristic.

7. Arrangement in accordance with claim 1, wherein the transmit antennas or the entire transmit units or detector units are identical in design.

8. Arrangement in accordance with claim 1, wherein in the receive unit there is provision for a further receive antenna and wherein the receive unit is positioned adjacent to a transmit unit in such a way that this receive antenna receives the signal of the adjacent transmit unit with the greatest signal power.

9. Arrangement in accordance with claim 1, wherein the evaluation unit comprises means for undertaking the assignment of the signals to wheel positions on request or at regular intervals as part of an assignment mode and when doing so assigns a characteristic identifier for the detected wheel position transmitted by one of the transmit units in each case and stores it and wherein the means in normal operation assign the received signals to the wheel positions using a comparison between the identifier transmitted by the transmit units and the stored assignment information (identifier for wheel position).

10. Arrangement in accordance with claim 1, wherein the receive unit comprises a controllable switch that in each case connects one of a number of receive antennas with downstream components of receive unit.

11. Method for monitoring at least one parameter for a number of motor vehicle wheels, comprising the steps of:

a) recording the at least one parameter;

b) transmitting the at least one parameter with a transmit antenna, positioned at least one receive antenna in such a way in the vehicle that, in connection with the field strengths of the signals sent by the individual transmit units at the location of the at least one receive antenna produces receive signals of different power in each case for at least two of the transmit units; and

c) comparing the receive power of a received signals with stored threshold values or ranges of values assigned to one wheel position in each case and assigning the received signal to a wheel position, if the threshold value assigned to this wheel position is exceeded or the receive power lies within the range of values assigned to this wheel position.

12. The method in accordance with claim 11, further comprising the steps of:

starting from the position of the receive antenna, distinguishing at least two signals of the relevant transmit units by producing sensitivities in the direction of each of the transmit antennas, for which the difference is greater than a predefined value, in which case this value is selected to enable a clear distinction to be made between the signals using the detected receive power of the two signals.

13. The method in accordance with claim 12, further comprising the step of providing one receive antenna in a position in the area of a front wheel and one receive antenna in a position in the area of a rear wheel, preferably in the area above the wheel arch.

14. The method in accordance with claim 13, wherein the directional characteristic of the receive antenna at least in the direction of the further wheel of the same lengthwise side of the vehicle shows a low or high sensitivity and in the direction of the further front or rear wheel a high or low sensitivity, so that the evaluation unit can use one receive antenna in each case to undertake at least one unique assignment of the signals of the transmit units at the wheel positions in the direction of the low and high sensitivity.

15. The method in accordance with claim 14, further comprising the step of creating the directional characteristic of the receive antennas in such a way that the signal of the transmit unit in the area of the same wheel creates the highest receive power in each case, which is clearly distinguishably higher than the receive power on reception of a signal from the transmit unit in the direction of the high sensitivity of the directional characteristic.

16. The method in accordance with claim 11, further comprising the steps of:

providing for a further receive antenna in the receive unit and positioning the receive unit adjacent to a transmit unit in such a way that this receive antenna receives the signal of the adjacent transmit unit with the greatest signal power.

17. The method in accordance with claim 11, wherein the evaluation unit undertakes the assignment of the signals to wheel positions on request or at regular intervals as part of an assignment mode and when doing so assigns a characteristic identifier for the detected wheel position transmitted by one of the transmit units in each case and stores it and the evaluation unit in normal operation assigns the received signals to the wheel positions using a comparison between the identifier transmitted by the transmit units and the stored assignment information (identifier for wheel position).

18. The method in accordance with claim 11, further comprising the step of connecting one of a number of receive antennas with downstream components of the receive unit by means of a switch.