SYSTEM, DATA CARRIERS, READER AND METHOD FOR DETERMINING THE PERIPHERAL WHEEL SPEED AND DISTANCE

• US 20090224899A1
• Filed: 11/30/2005
• Published: 09/10/2009
• Est. Priority Date: 12/06/2004
• Status: Active Grant

• Current Assignee: NXP B.V. (NXP Semiconductors NV)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Wieser, Stefan
• Granted Patent: US 7,782,183 B2
• Time in Patent Office: Days
• US Class Current: 340/444
• CPC Class Codes: B60C 23/0433 Radio signals
• 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: G01P 3/48 by measuring frequency of generated current or voltage in general G01R23/00

Abstract

A system comprises at least one contactless readable data carrier (1) which can be attached to a wheel (100) of a vehicle and a reader (10) which can be arranged on the vehicle to receive electromagnetic signals (ES) emitted by the data carrier (1). The reader (10) is designed to determine the revolutions of the wheel (100) from the field strength fluctuation of the received electromagnetic signals (ES), the reader (10) having calculation means (19) designed to calculate from the revolutions and a wheel periphery reference value (RU) determined by the reader and allocated to the wheel (100), such as circumference, diameter or radius, a distance covered by a point on the wheel periphery and/or values derivable therefrom such as the peripheral speed (UV) of the wheel (100).

Claims

1. A system comprising at least one contactless readable data carrier which can be mounted on a wheel of a vehicle and a reader which can be arranged on the vehicle for receiving electromagnetic signals emitted by the data carrier, the reader being designed to determine the wheel revolutions from the field strength fluctuations of the electromagnetic signals received, where the reader has calculation means designed to calculate, from the revolutions and a wheel periphery reference size that is allocated to the wheel can be determined by the reader, such as the circumference, diameter or radius, a distance covered by a point on the wheel periphery and/or values derivable therefrom such as the peripheral speed of the wheel.

2. A system as claimed in claim 1, where the data carrier is designed to send a wheel periphery reference value of the allocated wheel as an electromagnetic signal and the reader is designed to extract the wheel periphery reference value from the electromagnetic signals received from the data carrier and provide these to the calculation means.

3. A system as claimed in claim 1, where the reader has a data memory communicating with the calculation means for storing at least one wheel periphery reference value and where applicable the reference codes allocated to the wheel periphery reference values.

4. A system as claimed in claim 3, where the reader has a user interface for input of the wheel periphery reference values and where applicable the reference codes for storage in the data memory.

5. A system as claimed in claim 3, where the reference codes comprise unique identification codes of the data carrier.

6. A system as claimed in claim 4, where the reference codes comprise pressure values and the data carrier is designed to determine the tire pressure of the allocated wheel tire and send this as a reference code to the reader.

7. A system as claimed in claim 1, where the reader is designed to send to the data carrier data derivable from the distance covered by a point on the wheel periphery or the peripheral speed of the wheel, such as distance traveled, operating hours, average speed, and the data carrier comprises a non-volatile memory for storage of the data received.

8. A system as claimed in claim 7, where the reader is designed to determine the distance traveled from the distance covered by a point on the wheel periphery or the peripheral speed of the wheel, and determine furthermore the tire wear from the distance traveled, and where applicable store this in the data memory.

9. A system as claimed in claim 1, where the reader communicates with a wheel load sensor which senses the wheel load caused by the weight of the vehicle and its load, where the calculation means the reader are designed to send the wheel load to the data carrier and/or calculate from a deformation of the wheel caused by the wheel load the associated change in effective wheel diameter and in the calculation take into account the distance covered by a point on the wheel periphery or the wheel peripheral speed.

10. A system as claimed in claim 1, where the reader is integrated in a mobile phone.

11. A contactless readable data carrier for mounting in a wheel tire, where the data carrier has a tire pressure sensor and furthermore in the data carrier in a non-volatile memory is stored a table which contains the allocations of tire pressures to effective wheel periphery reference values such as circumference, diameter or radius, and the data carrier is designed to determine, using the table, from a tire pressured measured by the tire pressure sensor the associated effective wheel periphery reference value and emit this as an electromagnetic signal.

12. A reader with a receiver for receiving electromagnetic signals emitted by a contactless readable data carrier attached to a wheel of a vehicle, the reader being designed to determine the revolutions of the wheel from a field strength fluctuation of the electromagnetic signals received, where the reader has calculation means designed to calculate, from the revolutions and a wheel periphery reference value allocated to the wheel and which can be determined by the reader, such as circumference, diameter or radius, a distance covered by a point on the wheel periphery and/or values derivable therefrom such as the peripheral speed of the wheel.

13. A reader as claimed in claim 12, where the reader has data read means which extract the wheel periphery reference value from the electromagnetic signals received from the data carrier and present these to the calculation means.

14. A reader as claimed in claim 12, where the reader has a data memory communicating with the calculation means for storing at least one wheel periphery reference value and where applicable the reference codes allocated to the wheel periphery reference values.

15. A reader as claimed in claim 14, where a user interface is provided for input of the wheel periphery reference values and where applicable the reference codes and for storage in a data memory.

16. A reader as claimed in claim 14, where the reference codes comprise one or more unique identification codes of the data carrier, tire pressure values and wear values.

17. A reader as claimed in claim 12, where the calculation means are designed to send to the data carrier data derivable from the distance covered by a point on the wheel periphery or the peripheral speed of the wheel such as distance covered, operating hours, average speed.

18. A reader as claimed in claim 17, where the calculation means are designed to determine the distance traveled from the distance covered by a point on the wheel periphery or the peripheral speed of the wheel and determine the tire wear from the distance traveled and store this in the data carrier.

19. A reader as claimed in claim 12, where a wheel load sensor is provided which senses the wheel load caused by the weight of the vehicle and its load and transmits this to the calculation means, where the calculation means are designed to send the wheel load to a data carrier and/or calculate from a deformation of the wheel caused by the wheel load the associated change in effective wheel diameter and take this into account in the calculation of the distance covered by a point on the wheel periphery or the peripheral speed of the wheel.

20. A mobile telephone in which is integrated a reader as claimed in claim 12.

21. A method for determining a distance covered by a point on the periphery of a wheel of a vehicle, where on the wheel is attached a contactless readable data carrier that emits electromagnetic signals, comprising the determination of a field strength fluctuation, caused by the wheel rotation, of the electromagnetic signals received by the reader, determination of the revolutions of the wheel from the field strength fluctuation, determination of a wheel periphery reference value allocated to the wheel such as circumference, diameter or radius, and from the revolutions and the wheel periphery reference value calculation of a distance covered by a point on the wheel periphery and/or values derivable therefrom such as the peripheral speed of the wheel.

22. A method as claimed in claim 21, where the data carrier emits a wheel periphery reference value of its allocated wheel as an electromagnetic signal.

23. A method as claimed in claim 21, where at least one wheel peripheral reference value and where applicable the reference code allocated to the wheel peripheral reference value are stored in the reader.

24. A method as claimed in claim 23, where the reference codes comprise unique identification codes of the data carrier and/or tire pressure values and/or tire wear values.

25. A method as claimed in claim 21, where with a wheel load sensor the wheel load caused by the weight of the vehicle and its load is sensed and from the deformation of the wheel caused by the wheel load the associated change in effective wheel diameter is calculated and taken into account in calculation of the distance covered by a point on the wheel periphery and the wheel peripheral speed.