System for monitoring and for signaling by radio the pressure in pneumatic tires on motor vehicles

• US 20020113692A1
• Filed: 02/22/2002
• Published: 08/22/2002
• Est. Priority Date: 08/23/1999
• Status: Active Grant

• Current Assignee: Andreas Kuhnle, Gunter Lothar Schulzer, Norbert Normann, Ralf Kessler
• Original Assignee: Andreas Kuhnle, Gunter Lothar Schulzer, Norbert Normann, Ralf Kessler
• Inventors: Normann, Norbert, Kessler, Ralf, Schulzer, Gunter Lothar, Kuhnle, Andreas
• Granted Patent: US 6,828,905 B2
• Time in Patent Office: Days
• US Class Current: 340/442
• 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: G08C 17/02 using a radio link

Abstract

The system for monitoring and signalling by radio a pressure or a change in pressure in pneumatic tires of wheels (1) on vehicles (2) consists of a receiver unit (9) provided in or on the vehicle (1) to which at least one antenna (6, 7) is associated, and of a unit (3), arranged in the pneumatic tire, for measuring, evaluating and transmitting tire pressure signals, hereinafter referred to as “wheel-mounted electronic unit”, the latter comprising

battery (24) as current source,

a pressure sensor for picking up the pressure prevailing in the pneumatic tire,

an evaluation circuit for evaluating the measured pressure signals supplied by the pressure sensor,

and a transmitter (21) which is controlled by the evaluation circuit and which transmits to the receiver unit (9) signals that contain information regarding the pressure in the tire and/or the condition of the wheel-mounted electronic unit (3),

the wheel-mounted electronic unit (3) being activated at time intervals (t₀) for a period of time (T₁) shorter than the time intervals (t₀) and remaining otherwise in a current-saving state. An interrogator (14) is provided on the vehicle (1), and there is associated to the wheel-mounted electronic unit (3) on the same wheel (1) a receiver (4) which is responsive to interrogation signals sent out by the interrogator (14) and which draws the energy required for its function not from the battery (24) but from the interrogation signals as such, and the receiver (4) has a trigger circuit (25) the output of which is connected to a trigger input of the wheel-mounted electronic unit (3) so that the latter is activated by triggering and returns to its current-saving state at the end of the before-mentioned period of time (T₁).

Claims

1. System for monitoring and signalling by radio a pressure or a change in pressure in pneumatic tires of wheels (1) on vehicles (2), consisting of a receiver unit (9) provided in or on the vehicle (1) to which at least one antenna (6, 7), is associated, and of a unit (3), arranged in the pneumatic tire, for measuring, evaluating and transmitting tire pressure signals, hereinafter referred to as “

wheel-mounted electronic unit”

, comprising

a battery (24) as current source,

a pressure sensor for picking up the pressure prevailing in the pneumatic tire,

an evaluation circuit for evaluating the measured pressure signals supplied by the pressure sensor,

and a transmitter (21) which is controlled by the evaluation circuit and which transmits to the receiver unit (9) signals that contain information regarding the pressure in the tire and/or the condition of the wheel-mounted electronic unit (3),

the wheel-mounted electronic unit (3) being activated at time intervals (t₀) for a period of time (T₁) shorter than the time intervals (t₀) and remaining otherwise in a current-saving state, characterised in that an interrogator (14) is provided on the vehicle (1) and that there is associated to the wheel-mounted electronic unit (3) on the same wheel (1) a receiver (4) which is responsive to interrogation signals sent out by the interrogator (14) and which draws the energy required for its function not from the battery (24) but from the interrogation signals as such,

and that the receiver (4) has a trigger circuit (25) the output of which is connected to a trigger input of the wheel-mounted electronic unit (3) so that the latter is activated by triggering and returns to its current-saving state at the end of the before-mentioned period of time (T₁).

2. The system as defined in claim 1, where the current-saving state of the wheel-mounted electronic unit (3) is characterised in that it is kept in a responsive state only for the reception of the trigger signal and is kept under voltage, if necessary, only for saving data in a volatile memory, its internal clock being switched off in that state.

3. The system as defined in claim 1 or claim 2, characterised in that the interrogator 14 and the receiver unit (9) are connected with the locking system or the ignition lock of the vehicle (2) in such a way that the interrogator (4) and the receiver unit (9) become switched off when the ignition is switched off or when the vehicle (2) is locked, and become switched on when the ignition key is operated or when the ignition is switched on or when the vehicle (2) is unlocked.

4. The system as defined in claim 1 to 3, characterised in that the wheel-mounted electronic unit (3) is adjusted so as to ensure that once an interrogation signal is received by it, it performs consecutively a plurality of measurements and evaluation cycles during its active period of time (T₁) commencing at that moment.

5. The system as defined in claim 4, characterised in that measurements are carried out at intervals (t₀) of 2 s to 4 s.

6. The system as defined in claim 4 or claim 5, characterised in that the active period of time (T₁) is 0.5 min. to 10 min., preferably 3 min. to 5 min.

7. The system as defined in any of the preceding claims, characterised in that a single-channel RF receiver with a modulator is arranged near each antenna (6, 7) of the receiver unit (9) and that lines (8), leading from these antennas (6, 7) to the receiver unit (9), carry LF signals rather than RF signals.

8. The system as defined in claim 7, characterised in that an interrogator (14) is arranged near each antenna (6, 7) associated to the receiver unit (9).

9. The system as defined in any of the preceding claims, characterised in that the wheel-mounted electronic unit (3) comprises a centrifugal sensor, with the aid of which the measuring rate and the transmission rate of the wheel-mounted electronic unit (3) can be varied.

10. The system as defined in any of the preceding claims, characterised in that the measuring and/or transmission rate of the wheel-mounted electronic unit (3) can be varied by an evaluation and control circuit provided in the wheel-mounted electronic unit, in response to the pressure and/or the change of the pressure occurring over time.