Sensor transponder and procedure for measuring tire contact lengths and wheel load

• US 7,536,903 B2
• Filed: 12/13/2004
• Issued: 05/26/2009
• Est. Priority Date: 12/11/2003
• Status: Active Grant

• Current Assignee: Continental AG, Conti Temic Microelectronic GmbH (Continental AG)
• Original Assignee: Continental AG, Conti Temic Microelectronic GmbH (Continental AG)
• Inventors: Lehmann, Joerg, Cyllik, Adrian, Von Lutz, Rainer, Schillinger, Jakob
• Primary Examiner(s): Allen; Andre J
• Application Number:
  US10/582,538
• Publication Number:
  US 20070107505A1
• Time in Patent Office: 1,625 Days
• Field of Search: 731/46, 731/465, 701/1
• US Class Current: 73/146.5
• 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 23/0411 Piezoelectric generators
• CPC Class Codes: B60C 23/0488 Movement sensor, e.g. for sensing angular speed, acceleration or centripetal force
• CPC Class Codes: B60C 23/064 comprising tyre mounted deformation sensors, e.g. to determine road contact area

Abstract

A sensor transponder (1) with at least one acceleration sensor is arranged on the inner side of a running surface (2) of a tire (9). The signals from the acceleration sensor are compared with prespecified threshold values and then integrated, whereby following the formation of a quotient, the tire contact length (6) is calculated independently of the velocity.

Claims

1. A procedure for calculating a tire contact length (6), whereby a sensor transponder (1) is fitted with at least one acceleration sensor arranged on the inner side of a running surface (2) of a tire (9), the signals from the acceleration sensor are compared with threshold values and are then integrated, and the tire contact length (6) is calculated independently of the velocity using quotient formation.

2. The procedure according to claim 1, characterized in that the tire contact area (tread) is calculated from the tire contact length (6) using tire-specific parameters.

3. The procedure according to claim 2, characterized in that the wheel load is calculated using the tire contact area and the tire pressure.

4. A method of calculating at least a tire contact length of a rotating tire of a vehicle, comprising the steps:

a) as the tire rotates, measuring acceleration data of the tire using an acceleration sensor arranged on the tire;

b) transmitting measured data comprising said acceleration data to a receiver arrangement, and providing said measured data from said receiver arrangement to a central unit comprising an evaluation unit arranged in the vehicle;

c) in said evaluation unit evaluating said acceleration data to determine therefrom a first result dependent on a duration of said acceleration sensor passing through said tire contact length during one rotation of the tire and a second result indicative of a duration of said one rotation of the tire, wherein said evaluating comprises comparing said acceleration data to a threshold and integrating said acceleration data dependent on said comparing; and

d) forming a quotient of said first result relative to said second result to determine said tire contact length relative to a circumference of the tire and independent of a tire rotation speed of the rotation of the tire.

5. The method according to claim 4, further comprising a step of calculating a tire contact area of the tire from said tire contact length and at least one tire-specific parameter of the tire.

6. The method according to claim 5, further comprising measuring an air pressure in the tire and providing corresponding pressure data as part of said measured data to said central unit, and calculating a wheel load of the tire from at least said tire contact area and said pressure data.