Low-frequency emission electronic unit emitting to a mobile wheel electronic unit of a vehicle and associated low-frequency signal transmission method

• US 9,669,667 B2
• Filed: 12/14/2015
• Issued: 06/06/2017
• Est. Priority Date: 12/17/2014
• Status: Active Grant

• Current Assignee: Continental Automotive France (Continental AG), Continental Automotive GmbH (Continental AG)
• Original Assignee: Continental Automotive France (Continental AG), Continental Automotive GmbH (Continental AG)
• Inventors: Kessler, Sebastien, Cheikh, Mohamed
• Primary Examiner(s): Bugg, George
• Assistant Examiner(s): AKKI, MUNEAR T
• Application Number:
  US14/968,035
• Publication Number:
  US 20160176247A1
• Time in Patent Office: 540 Days
• Field of Search: 340447, 340445, 340442, 34042633, 32420716, 32420725, 343711, 343713, 343787, 343788, 343741, 343748, 343866, 343867, 343742, 116 34 R, 116 34 A, 73 48, 73146-1468
• CPC Class Codes: B60C 23/044 Near field triggers, e.g. magnets or triggers with 125 KHz
• CPC Class Codes: B60C 23/0444 Antenna structures, control or arrangements thereof, e.g. for directional antennas, diversity antenna, antenna multiplexing or antennas integrated in fenders
• CPC Class Codes: B60C 23/0452 Antenna structure, control or arrangement vehicle tyre mounted antennas H01Q1/2241
• CPC Class Codes: B60C 23/0483 Wireless routers between wheel mounted transmitters and chassis mounted receivers
• CPC Class Codes: H01Q 1/2241 used in or for vehicle tyres

Abstract

A low-frequency emission electronic unit (20′) includes two low-frequency antennas (B1, B2). The second antenna (B2) is passive and resonant, oriented along the main axis (Y) of the first low-frequency antenna (B1) and is adapted to generate two low-frequency fields (D2, D2′) at right angles to the field (D1) emitted by the first antenna (B1). The low-frequency emission electronic unit (20′) makes it possible to reduce the zones of rupture of reception of the low-frequency signals by the wheel unit (13) situated in proximity in which the low-frequency signals emitted by the low-frequency emission electronic unit are not received by the closest wheel unit (13). A low-frequency signal transmission method alternating the emissions of waves by the two antennas (B1, B2) is also described.

Claims

1. A low-frequency emission electronic unit (20′

) emitting to a mobile wheel electronic unit (13) of a vehicle (V), fixed to said wheel (11), said low-frequency emission electronic unit comprising;

a microcontroller (30)

a first low-frequency (f) emission antenna (B1), oriented along an axis (Y), connected to the microcontroller (30), having a power supply voltage (Vdd), and emitting a first low-frequency field (D1, D1′

),

said low-frequency emission electronic unit (20′

) further comprising;

a second passive low-frequency antenna (B2) arranged along the axis (Y) of the first antenna (B1), situated in a zone of reception of the first low-frequency field (D1, D1′

), regardless of the power supply voltage of the first antenna (B1), and comprising a first part (B2a) and a second part (B2b), electrically linked together, separated by a gap (E) having a length (l), the two parts (B2a, B2b) being adapted to emit low-frequency fields of opposite directions (C2a, C2b), and directed toward one another,

means (M1) for adapting a frequency (f′

) of the second antenna (B2) to the frequency (f) of the first antenna (B1),

means (M2) for regulating the power supply voltage (Vdd) of the first antenna (B1).

2. The low-frequency emission electronic unit (20′

) as claimed in claim 1, wherein the first antenna (B1) and the second antenna (B2) are coaxial and wound around the same ferrite (F′

).

3. The low-frequency emission electronic unit (20′

) as claimed in claim 1, wherein the voltage regulation means (M2) comprise

a first two-way switch (S1), connected on one side to a voltage generator (G) incorporated in the microcontroller (30), and connected on the other side to;

a first circuit of nominal voltage, comprising a first resistor (R1),

a second circuit of voltage lower than the nominal voltage, comprising a second resistor (R2);

the first switch (S1) having a first position in which the first antenna (B1) is connected to the first circuit and a second position in which the first antenna (B2) is connected to the second circuit.

4. The low-frequency emission electronic unit (20′

) as claimed in claim 1, wherein the adaptation means (M1) comprise;

a second switch (S2),

a frequency adaptation circuit comprising;

a capacitor (C2),

a third resistor (R3),

the second switch (S2) having a closed position in which the second antenna (B2) is connected to the adaptation circuit and an open position in which the second antenna (B2) is disconnected from the adaptation circuit.

5. The low-frequency emission electronic unit (20′

) as claimed in claim 1, wherein a length (l1) of the first part (B2a) is equal to a length (l2) of the second part (B2b) and the length (l) of the gap (E) is between ⅛

^th and ⅝

^th of the length (l1) of the first part (B2a) or of the length (l2) of the second part (B2b).

8. A system for monitoring the pressure of the tires, comprising the low-frequency emission electronic unit (20′

) as claimed in claim 1, a central unit (12), and at least one wheel electronic unit (13).

9. A motor vehicle in combination with the low-frequency emission electronic unit (20′

) as claimed in claim 1.

6. A method for transmitting low-frequency signals to a mobile wheel electronic unit (13) of a vehicle (V), fixed to said wheel (11), comprising:

in a preliminary step, using a low-frequency emission electronic unit (20′

) comprising a microcontroller (30), first low-frequency emission antenna (B1) of frequency f, oriented along an axis (Y), connected to the microcontroller (30), having a power supply voltage (Vdd), and emitting a first low-frequency field (D1, D1′

), a second passive low-frequency antenna (B2) arranged along the axis (Y) of the first antenna (B1), situated in a zone of reception of the first low-frequency field (D1, D1′

), regardless of the power supply voltage of the first antenna (B1), and comprising a first part (B2a) and a second part (B2b), electrically linked together, separated by a gap (E) having a length (l), the two parts (B2a, B2b) being adapted to emit low-frequency fields of opposite directions (C2a, C2b), and directed toward one another, adapting a frequency (f′

) of the second antenna (B2) to the frequency (f) of the first antenna (B1), regulating the power supply voltage (Vdd) of the first antenna (B1) making it possible to regulate the power supply voltage of the first antenna (B1) either to a nominal voltage, or to a voltage lower than the nominal voltage, and

said method comprises the following steps;

step 1;

activation of a regulation means (M2) in order to power the first antenna (B1) with a nominal voltage for a first predetermined duration (t1),

step 2;

deactivation of the regulation means (M2),

step 3;

activation of the regulation means (M2) in order to power the first antenna (B1) with a voltage lower than the nominal voltage and activation of an adaptation means (M1) simultaneously for a second predetermined duration (t2),

step 4;

deactivation of the regulation means (M2) and deactivation of the adaptation means (M1) simultaneously,

step 5;

repetition of the steps 1 to 4.

7. The transmission method as claimed in claim 6, wherein the means for adapting a frequency (M1) comprise:

a second switch (S2);

a frequency adaptation circuit comprising;

a capacitor (C2), and a third resistor (R3), the second switch (S2) ving a closed position in which the second antenna (B2) is connected to the adaptation circuit and an open position in which the second antenna (B2) is disconnected from the adaptation circuit, and wherein;

step 1 consists in connecting the first switch (S1) to the circuit of nominal voltage,

step 2 consists in disconnecting the first switch (S1) from the circuit of nominal voltage,

step 3 consists in connecting the first switch (S1) to the circuit of voltage lower than the nominal voltage and in closing the second switch (S2),

step 4 consists in disconnecting the first switch (S1) from the circuit of voltage lower than the nominal voltage simultaneously with the opening of the second switch (S2).