Method for allocating tire pressure control devices to wheel positions in a tire pressure control system of a motor vehicle

• US 6,435,020 B1
• Filed: 05/08/2000
• Issued: 08/20/2002
• Est. Priority Date: 08/10/1998
• Status: Expired due to Term

• Current Assignee: Continental AG
• Original Assignee: Continental AG
• Inventors: Klodmann, Wolfgang, Oldenettel, Holger, Behrends, Holger, Ernst, Gerhard
• Primary Examiner(s): MCCALL, ERIC SCOTT
• Application Number:
  US09/567,141
• Time in Patent Office: 834 Days
• Field of Search: 731/465, 731/46, 731/463, 731/464, 731/468, 340/445, 340/442, 340/446, 340/447, 340/448
• US Class Current: 73/146.4
• CPC Class Codes: B60C 23/0416 allocating a corresponding wheel position on vehicle, e.g. front/left or rear/right

Abstract

The invention relates to a method for carrying out the allocation of tire pressure control devices (4a to 4d) to wheel positions in a tire pressure control system of a motor vehicle. Each tire pressure control device (4a to 4d) transmits, at certain time intervals, its individual identifier and a lengthened high frequency signal to the central unit (10) of the tire pressure control system. The high frequency signals have an individual trace which is dependent upon the rotational angle of the wheel and on the time because of the geometry of the wheel box and as a consequence of the rotation of the wheel. In the central unit (10), a time point is fixed from two sequential high frequency signals at which the wheel assumes the same angular position in each case with this wheel being the wheel from which the signals were transmitted. The corresponding wheel has made an integer number of revolutions between the two time points. In the central unit (10), with the aid of the signals of the rpm sensors (12a to 12d), the wheel position is determined in which the wheel has made an integer number of revolutions between the two time points. The corresponding wheel position is allocated to the individual identifier transmitted from the tire pressure control device (4a to 4d).

Claims

1. In a tire pressure control system of a motor vehicle having a plurality of wheels at respective wheel positions, a method for allocating tire pressure control devices of the tire pressure control system to the wheel positions of the motor vehicle during the operation of said motor vehicle, the system further including:

a central unit;

said tire pressure control devices being assigned to corresponding ones of said wheels;

each of said tire pressure control devices functioning to transmit an individual identifier to said central unit at time intervals;

a plurality of rpm sensors assigned to corresponding ones of said wheels and said rpm sensors being fixedly mounted at respective ones of said wheel positions with the allocation of said rpm sensors to said wheel positions being known by said central unit; and

,

said central unit storing the allocation (identifier of the tire pressure control device/wheel position) for each of said wheels;

the method comprising the steps of;

causing one of said tire pressure control devices assigned to one of said wheels to transmit to said central unit, at any desired time point, its own individual identifier and a first lengthened high frequency signal, which extends over a first time interval I₁; and

, as a consequence of a rotation of said one wheel, said signal having an individual trace dependent upon at least one of the rotational angle of said one wheel and the time;

causing said one tire pressure control device to transmit to said central unit, at any desired later time point, its own individual identifier and a second lengthened high frequency signal, which extends over a second time interval I₂, said second lengthened high frequency signal having the same individual trace at least segmentwise as said first lengthened high frequency signal, said individual trace of said second lengthened high frequency signal being dependent upon at least one of time and the rotational angle of said one wheel;

in said central unit, determining a first time point at which said one wheel assumes a desired relative angular position from said trace of said first lengthened high frequency signal;

in said central unit, determining a second time point at which said one wheel assumes the same relative angular position as said one wheel assumed at said first time point and said second time point being determined from said trace of said second lengthened high frequency signal;

in said central unit, determining the number of revolutions which said wheels have made in a third time interval I₃ from said first time point to said second time point and the number of revolutions for said wheels being determined from the signals of said rpm sensors;

in said central unit, checking which one of said wheels in which one of said positions had made an integer number of revolutions; and

,

in said central unit, assigning the corresponding wheel position to the individual identifier transmitted from said one tire pressure control device.

2. The method of claim 1, wherein each of said high frequency signals is transmitted from said one tire pressure control device at a constant maximum amplitude, which, as a consequence of the rotation of said one wheel, defines an individual trace in dependence upon at least one of the rotational angle of said one wheel and the time;

and, said one wheel being that wheel from which the lengthened high frequency signal is transmitted.

3. The method of claim 1, wherein each time interval, during which a lengthened high frequency signal is transmitted from one of said wheels, is at least so long that said one wheel makes at least one revolution in said time interval.

4. The method of claim 1, wherein, in each of said tire pressure control devices, a specific length is pregiven which is the same for all lengthened high frequency signals transmitted from said one tire pressure control device.

5. The method of claim 4, wherein each one of said tire pressure control devices has a centrifugal force sensor, which generates a signal above a pregiven number of revolutions of said wheel to which said one tire pressure control device is assigned;

and, said one tire pressure control device transmits a lengthened high frequency signal only when the signal of the centrifugal force sensor is present.

6. The method of claim 1, wherein said tire pressure control system has a central transmitter and each of said tire pressure control devices has a receiver;

and, wherein said method comprises the further steps of;

said central transmitter transmitting a signal to all of said tire pressure control devices; and

,

directly after receiving said signal, each of said tire pressure control devices transmitting a lengthened high frequency signal to said central unit.

7. The method of claim 6, wherein said central transmitter has data as to the length of said lengthened high frequency signal which is to be transmitted by said tire pressure control devices and which is transmitted to said tire pressure control devices.

8. The method of claim 1, wherein said method is started by actuating a switch.

9. The method of claim 1, wherein said method is automatically started after switching on the ignition of said motor vehicle when said ignition was previously switched off for a pregiven time span.

10. The method of claim 1, wherein said signals are amplitude modulated which are transmitted from said tire pressure control devices;

and, each of said lengthened high frequency pulses is a separate signal which is transmitted at a constant maximum amplitude.

11. The method of claim 1, wherein said signals are frequency modulated which are transmitted from said tire pressure control devices and are transmitted at a constant maximum amplitude;

and, the individual identifier is contained in the lengthened high frequency signal.

12. The method of claim 1, wherein said first and second time points whereat said one wheel assumes a coincident relative angular position is determined by cross correlation in said first and second high frequency signals.