DE4240426A1 - Ignition key protection system for centralised locking of motor vehicle - uses interrogation signal and detected response to unlock locked vehicle when ignition key is still inside - Google Patents

Abstract

The protection system uses an electronic circuit which detects when the ignition key has been left in the vehicle upon the driver leaving the vehicle and operating the centralised locking to initiate automatic unlocking so that the ignition key can be retrieved. The electronic circuit has two parts respectively incorporated in the vehicle and in the ignition key. The first part provides a radio, or acoustic, signal upon the vehicle being locked for initiating a response signal from the second part. When the ignition key is still in the vehicle, detected by the first part to initiate automatic unlocking. ADVANTAGE - Prevents ignition key being left in locked vehicle.

Description

The invention complements central door locking systems, as mainly in Motor vehicles are used and how, for example, from the Publication DE 35 19 743 A1, patent classification E 05 B 65/36 known are.

The invention solves the problem faced by all motorists who the locked car door thrown in the lock and the ignition key in the Have forgotten the interior of the vehicle.

This is often done by reaching around the B-pillar of the car in order to trigger the central locking system using the button on the driver's door (instead of using to do the key), but also by putting the key aside while clearing or searching in the trunk. The system works regardless of where the key is in the car.

This problem is solved by the invention described here as follows:

Drawings 1 and 2 schematically show the structure of this system. Here Drawing 1 contains the vehicle-side system part, drawing 2 the key-side system part.

There is always a dialogue between the two system parts after the "question and answer "pattern instead if the ignition key is forgotten in the vehicle has been.

The "question" in the form of a radio or sound signal is answered by the vehicle-side system part (which is permanently installed in the car and connected to the car battery is connected) and sent from the key system part with a Radio or sound signal of another frequency "answered". To do this, it is necessary to use the key-side system part Miniaturization - to be placed in the key handle of the ignition key, at least as a trailer with the ignition key. In addition, the "question and answer" signals can be additionally encoded to to achieve greater operational security.

The radio or soundproofing property of the vehicle body is functionally exploited: the key system part can be used by the Vehicle system part can only be reached if it is in the vehicle located.

Drawing 1 shows the vehicle-side system part, which is divided into three modules breaks down:

- Assembly A starts the entire system part shown in drawing 1 and switches it off again, only controlled by the doors, the case lid and the central locking system.
Module B is the transmitter and
Module C the receiver, which also unlocks and locks the vehicle.

A -Baugruppe registers whether a door or the trunk lid has been thrown and the central locking system via the contact "Close" (Contact "S" on the switch 1 c) has been operated. The door contact switch by switches with the designations 1 a₁. . . 1 a₄ and the input Ein I, and the contact switch of the trunk lid represented by switch 1 b and input Ein II. These two input signals are linked in the first of the two logic gates 2 a with a "or" condition (see drawing 1), so that there is always a signal via flip-flop 2 b to gate 2 c when a door or the case lid is thrown has been.

Input A III and switch 1 c are used here to represent the contact of the central locking system which is coupled to the lock cylinder and the locking button of the driver's door. "S" is the make contact and "Ö" the make contact. The signal arriving at A III is switched via flip-flop 2 d to logic gate 2 c (“and” condition), which in turn is connected downstream of gate 2 a via memory flip-flop 2 b (see drawing 1).
At the other input of gate 2 c is the output of flip-flop 2 b.
Flip-flop memory module 2 b receives the switching state supplied by 2 a on gate 2 c until it is automatically reset via input “R” when gate 2 c is switched through.

The slamming of a door or the case lid is defined here as a "1" signal, which is delivered as an I or an II through the door contact switch or the case lid switch to the gate 2 a. Furthermore, the closing operation ("S" on switch 1 c) of the central locking system is defined both as a "1" signal by the key on the driver's door and by pressing the button on the driver's door, which is designated as a III by the Switch 1 c and contact "S" via memory flip-flop 2 d is supplied to gate 2 c (see drawing 1). Here, module 2 d maintains the switching state on the input of gate 2 c until it is reset by opening the central locking (switch 1 c, contact "Ö").

Diodes 2 e and 2 f prevent the currents supplied as reset signals from flip-flop 2 b and switch 1 c / contact "Ö" to relay 13 c in the logic circuit ( 2 a... 2 d) from causing interference. These are explained in a later section.

If this gate circuit registers the slamming of a door or the trunk lid and the central locking of the vehicle, the triggerable mono-flop module 3 connected downstream of the gate 2 b is activated and in turn switches the power supply of the subsequent modules for a certain amount via the relay 4 a Time one.

Mono-flop module 3 ensures that the vehicle is as burglar-proof as vehicles without an "electronic ignition key safe", since the system, after being switched off again by component 3 , cannot be influenced by strong transmitters from outside.

The switch 4 b in the instrument panel of the car is intended to enable the occupants to paralyze the vehicle system by interrupting the power supply to the following assemblies. This makes it possible to lock yourself in the vehicle (with the ignition key) (e.g. during a rest).

Module B is composed of an astable flip-flop 5 , a frequency generator 6 and an antenna 7 a or optionally a loudspeaker 7 b, depending on whether the device is to work with radio or acoustic signals.
The signals ("question") sent via antenna 7 a or loudspeaker 7 b to the key-side system part are generated in frequency generator 6 . Component 5 switches the frequency generator on and off at regular intervals, so as to avoid interference between radio waves and sound waves that are transmitted and can be received by module C from the key-side system part.

Module C receives the "answer" from the key-side system part via antenna 8 a or microphone 8 b.
Through the bandpass 9 a, only the signal to amplifier 9 b is passed on, which the key-side system part emits as a "response". If this signal is received, it is passed through the bandpass 9 a to the amplifier 9 b, which simultaneously stores the memory flip-flop 10 a, the relay 11 , the mono-flop 12 a and the triggerable mono-flop module 13 activated.

Once it was found b so by the "reply" signal and amplifier 9, that the ignition key is located in the interior of the car is determined by memory 10a and relay 10 b module B disconnected from the power supply, so that as long as no "question" signals more are sent until 10 a is reset (by slamming another door) (at input "R" of flip-flop 10 a).

Relay 11 switches the output off Ia of the circuit, which in turn switches the opening operation of the central locking (= switch 1 c bridges to contact "Ö"), and thus unlocks the vehicle.

In addition, the mono-flop 12 a and relay 12 b on output Aus Ib emit a short reminder signal to the outside via the car horn (or a special noise source). This warning is intended to alert the owner to his mistake, which he might otherwise not notice until he returns.

Mono-flop module 13 a activates relay 13 b after the time set for it to lock the vehicle again via output Off II. This prevents the car from being left open if the owner has missed the reminder signal.

After that, the vehicle can only be opened with a second key.

In addition, the mechanical self-holding and electronically resettable relay 13 c is switched simultaneously with 13 b via mono-flop 13 a. This prevents feedback, which can always occur if the owner has not responded to the reminder signal, because then the feedback loop is closed by closing Ia and Ein III when the central locking system in the vehicle system part opens automatically and the "question -and-answer "procedure would be restarted across all assemblies.

Simultaneously with the reclosing, the power supply of the modules B and C is interrupted by 13 c in order to break the previously described feedback circuit.

The relay 13 c must be mechanically self-holding, since it separates itself from the power supply.

In addition, 13 c must be resetable via its reset input "R" both from the "Ö" contact of the switch 1 c and from the output of the flip-flop 2 b:

• - Via switch 1 c / contact "Ö", the entire system is automatically ready for use again when the vehicle is opened with a second key.
• - By flip-flop 2 b, the relay 13 c is always reset when doors on the locked vehicle are thrown one after the other at longer intervals and the key is still in the vehicle. To ensure that in this case the system is activated again after the last door has been slammed, flip-flop 2 b relay 13 c must be able to be reset.

If diode 2 f were missing, the reset signal from switch 1 c / contact "Ö" for 13 c would result in a "1" signal on gate 2 b, as if a door or the case lid had been slammed shut. If 2 e were missing, the reset signal from component 2 b for 13 c would result in the simultaneous reset of flip-flop 2 d, which would not even allow the entire system part in drawing 1 to take effect.

Drawing 2 shows how the key-side system part works clearly that is powered by its own small battery. It can be on Ignition keys are carried as a trailer, or - if appropriate Miniaturization - be housed in the ignition key handle.

The antenna 16 a and the microphone 16 b deliver their received signal to the bandpass filter 17 , which is set to the frequency emitted by module B in drawing 1. When this frequency reaches bandpass 17 , it sends a signal to amplifier 18 , which turns on mono-flop 21 . This activates the frequency generator 20 for the time set for it, which then sends back its "answer" signal via antenna 19 a or loudspeaker 19 b to module C in drawing 1.

General

The frequency of the "response" signal sent by the key system part is different from that sent by assembly B.

It is conceivable that the system achieves a higher level of functional reliability if it not only works in a frequency-bound manner, but at the same time sends and receives coded signals on the respective frequencies. For this purpose, the frequency generators ( 5 b, 20 ) with encoders, the bandpass filters ( 9 a, 17 ) with decoders must also be combined in series.

The antenna pairs 7 a and 8 a and the loudspeaker-microphone pairs 7 b and 8 b shown in assemblies B and C must each be installed at least twice in a vehicle: at least one pair is installed in the passenger compartment, while at least a second one Pair in the trunk so that it can not be covered by luggage.

The system described here complements the locking system of a car Central locking, d. H. the owner does not need to change his habits change, still significantly affect the handling of new switches or Adjust instruments. The system can also be retrofitted to older vehicles, provided that they have a Central locking are equipped. For some types of central locking systems, however, an actuator is in retrofit the driver's door.

Claims (13)

1. Electronic ignition key safe, which supplements central locking systems, as they are mainly installed in motor vehicles and are known, for example, from published patent application DE 35 19 743 A1, patent classification E 05 B 65/36,
characterized by
that a vehicle whose doors are locked after getting out of the vehicle is checked for whether the ignition key has been forgotten in the vehicle. If this is the case, the system automatically unlocks again. 2. Electronic ignition key safe according to claim 1, characterized, that the entire vehicle interior thereupon by sound or radio waves it is checked whether the ignition key has been forgotten in the car. 3. Electronic ignition key safe according to claims 1 and 2, characterized, that the system is in two parts. A system part is permanently installed in the vehicle (system part on the vehicle side) other system part is housed in the ignition key handle, or as Key chain connected to the ignition key (key side System part). 4. Electronic ignition key safe according to claims 2 and 3, characterized, that the vehicle-side system part with at least two transmit and Receiving units (2 pairs of antennas / 2 pairs of loudspeakers and microphones) see above is equipped that at least one pair the passenger compartment and at least one Couple checked the trunk of the car. 5. Electronic ignition key safe according to claim 3, characterized in that between the vehicle-side system part and the key-side system part, a dialogue according to the "question and answer" pattern comes about as follows:
A radio or sound signal of a certain frequency is sent by the vehicle-side system part ("question"), and is "answered" on another frequency by the key-side system part, provided that the key-side system part (the ignition key) is inside the vehicle. 6. Electronic ignition key safe according to claim 5, characterized, that the "question-and-answer" signals alternating between the two system parts can also be coded, resulting in higher operational reliability. 7. Electronic ignition key safe according to claims 2 and 5, characterized, that the sound and radio wave insulating property of the vehicle body causes that as a "question" signal from the vehicle system part sent signal can only reach the key-side system part if the latter is located inside the vehicle. 8. Electronic ignition key safe according to claim 1, characterized, that the vehicle-side system part automatically only through the contact switch of the doors and the case lid and the contacts of the central locking system is switched on. This part of the system comes into action every time the Central locking is on "lock" and a door or the case lid thrown into the castle. 9. Electronic ignition key safe according to claim 8, characterized, that the entire vehicle-side system part after a certain time is switched off to prevent the intrusion protection inherent in the vehicle restrict. (Otherwise the central locking would be with a strong transmitter the correct frequency from the outside). 10. Electronic ignition key safe according to claim 1, characterized, that simultaneously with the automatic opening of the central locking system by the on-board system (i.e., the ignition key was forgotten in the car) Reminder signal (e.g. a short horn signal) is sent to the outside to alert the owner of his mistake. 11. Electronic ignition key safe according to claim 10, characterized, that the vehicle-side system part the car after a time over the Central locking automatically locked, the reminder should not or the key has not been removed from the car. This prevents the vehicle from remaining unlocked.   12. Electronic ignition key safe according to claim 11, characterized, that the entire on-board system part after reclosing is turned off to avoid feedback (The entire system would otherwise do this according to the "question and answer" pattern Unlock vehicle. . . close. . . unlock. . . and so on.) 13. Electronic ignition key safe according to claim 8, characterized, that the entire vehicle-side system part by one on the dashboard attached switch can be turned off to linger in the to allow locked trolleys (with keys).