DEVICE FOR MONITORING A VEHICLE WHEEL AND CORRESPONDING COMMUNICATION METHOD

• US 20120274461A1
• Filed: 12/15/2010
• Published: 11/01/2012
• Est. Priority Date: 12/18/2009
• Status: Abandoned Application

• Current Assignee: Eltek SpA
• Original Assignee: Eltek SpA
• Inventors: Colombo, Paolo, Cantarelli, Domenico
• Application Number:
  US13/516,123
• Publication Number:
  US 20120274461A1
• Time in Patent Office: Days
• US Class Current: 340/447
• 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 23/0462 Structure of transmission protocol
• CPC Class Codes: B60C 23/0481 System diagnostic, e.g. monitoring battery voltage, detecting hardware detachments or identifying wireless transmission failures
• CPC Class Codes: B60C 23/0494 Valve stem attachments positioned inside the tyre chamber
• CPC Class Codes: H04L 25/4902 Pulse width modulation; Pulse position modulation

Abstract

A device for monitoring a vehicle wheel (1) is provided for:—detecting a value indicating the tyre inflating pressure of a wheel;—converting the value detected into a bit sequence;—associating to each bit sequence, via an encoding, a respective symbol of a pulse-code modulation, where the encoding is such that in the passage between two consecutive symbols of the modulation there is always the variation of just one bit; and—transmitting the symbols of the pulse-code modulation.

Claims

1. Device for monitoring a vehicle wheel, configured for detecting and transmitting to a receiver, by a wireless connection (C), information relating to at least one characteristic quantity of the wheel status, such as the inflation pressure of a wheel tyre, the device comprising:

at least one sensor for detecting at least one value indicative of the said characteristic quantity, such as the tyre inflation pressure,

means for converting said at least one value into a sequence of bits (IB),

means for associating to each sequence of bits (IB), by means of a coding, a respective symbol (S) of a pulse-code modulation, wherein said means for associating are configured such that a single bit change occurs when passing between two consecutive symbols (S) of said modulation,

means for transmitting said symbol (S) of said pulse-code modulation.

2. Device according to claim 1, wherein said pulse-code modulation is a pulse-position modulation, such as for example a 16 PPM or a 256 PPM pulse-position modulation.

3. Device according to claim 1, wherein said means for transmitting said symbols (S) of said modulation comprise:

means for converting each symbol (S) into a low frequency pulse sequence, preferably comprising a start pulse (SB) and a data pulse (DB) wherein the time interval between said start pulse and said data pulse is determined based on said symbol (S).

4. Device according to claim 3, wherein

a time interval having a length comprised between 5 and 15 microseconds, particularly about 9.45 microseconds, is associated to each symbol (S);

and

the length of said data pulse (DB) is comprised between 1 and 5 microseconds, particularly about 3.3 microseconds.

5. Device according to claim 3, wherein said means for transmitting said symbols (S) of said modulation comprises:

a generator for generating a high frequency carrier signal, and

a circuit for creating transmission pulse series or burst (SB, DB) by combining said low frequency pulse sequence with said high frequency carrier signal.

6. Device according to claim 5, wherein said generator comprises an oscillator, particularly a quartz oscillator.

7. Device according to claim 1, wherein said means for transmitting said symbols (S) of said modulation are configured for transmitting said symbols (S) by means of a transmission frame (F) comprising a preamble (P) identifying a new transmission frame (F) followed by said symbols (S).

8. Device according to claim 7, wherein

said transmission frame (F) comprises a correction code, and/or

said means for transmitting said symbols (S) are configured for transmitting said transmission frame (F) at least twice, with a randomly chosen time interval.

9. Device for monitoring a vehicle wheel, configured for receiving data from a transmitter, comprising:

means for receiving symbols (S) of a pulse-code modulation,

means for associating to each symbol (S) of said pulse-code modulation, by means of a coding, a respective sequence of bits, wherein said means for associating are configured such that a single bit change occurs when passing between two consecutive symbols (S) of said modulation, and

means for detecting said data in said sequence of bits.

10. System for monitoring a vehicle wheel, comprising

a first device configured for detecting and transmitting, by a wireless connection (C), information relating to at least one characteristic quantity of the wheel status, such as the inflation pressure of a wheel tyre,

a second device configured for receiving, by a wireless connection (C), the information relating to the at least one characteristic quantity of the wheel status,

the first and the second device each comprising at least one of a transmission circuit arrangement and a reception circuit arrangement, wherein

the transmission circuit arrangement comprises:

means for converting data to be transmitted into a sequence of bits (IB),

means for associating to each sequence of bits (IB), by means of a coding, a respective symbol (S) of a pulse-code modulation, wherein said means for associating are configured such that a single bit change occurs when passing between two consecutive symbols (S) of said modulation,

means for transmitting said symbol (S) of said pulse-code modulation,

the reception circuit arrangement comprises;

means for receiving symbols (S) of a pulse-code modulation,

means for associating to each symbol (S) of said pulse-code modulation, by means of a coding, a respective sequence of bits, wherein said means for associating are configured such that a single bit change occurs when passing between two consecutive symbols (S) of said modulation,

means for detecting data to be received in said sequence of bits.

11. Method for communicating through a wireless connection (C) information relating to at least one characteristic quantity of the status of a vehicle wheel, such as the inflation pressure of a wheel tyre, the method comprising:

detecting at least one value indicative of the said characteristic quantity, such as the tyre inflation pressure,

converting said at least one value into a sequence of bits,

associating to each sequence of bits (IB), by means of a coding, a respective symbol (S) of a pulse-coded modulation, wherein said coding is such that a single bit change occurs when passing between two consecutive symbols (S) of said modulation, and

transmitting said symbols (S) of said pulse-code modulation.

12. Method according to claim 11, wherein said pulse-code modulation is a pulse-position modulation, such as for example a 16 PPM or a 256 PPM pulse-position modulation.

13. Method according to claim 11, comprising the operation of converting each symbol (S) into a low frequency pulse sequence preferably comprising a start pulse and a data pulse, wherein the time interval between said start pulse and said data pulse is determined based on said symbol (S).

14. Method according to claim 13, comprising

generating a high frequency carrier signal by means of a quarts oscillator, and

creating transmission pulse series or burst (SB, DB) by combining said low frequency pulse sequence with said high frequency carrier signal.

15. A computer program product loadable into the memory of a computer and including software instructions or code portions adapted for performing the steps of the method of claim 11 when the product is run on a computer.