DE19711901C1 - Theft protection system for motor vehicle - Google Patents

Abstract

The system includes several code signal generators (3) which transmit respectively code signals, through which one or several safety devices (8, 9) are locked or unlocked when a successful authentification through the received code signals has o, if, after locking of one or several safety device (8) with another code signal generator, the generator is recognized in the nearby area of the motor vehicle. The code signal generator in the motor vehicle is released after unlocking of one or several safety device with the other code signal generator.

Description

The invention relates to an anti-theft system for a Motor vehicle, in particular a keyless remote control Central locking and an electronic immobilizer.

A known anti-theft system (DE 41 23 654 A1) has a code signal generator, the egg by pressing nes switch triggered question-answer dialog a code signal sends to unlock the doors to the motor vehicle. After About Checking the authorization of the code signal are the doors unlocked. When locking, the question-answer- Dialogue carried out. However, the lock is only then performed when it is detected that the code signal generator is located outside the motor vehicle.

If the code signal generator in such an anti-theft system stem is carried by the front passenger and the front passenger between getting out of the vehicle without closing the vehicle lock, the driver can no longer lock his vehicle lock. If so, the ignition is switched off, the ignition can no longer be switched on be switched because there is no code signal transmitter in the vehicle that is.

In addition, meh rere antennas needed, both on the interior of the Motor vehicle as well as the outside space around the motor vehicle are directed. With these antennas, a distinction must be made whether a code signal generator is located outside or inside. There through the theft protection system becomes very complex, because the The range of antennas depends on the motor vehicle must be tuned.  

Another known theft protection system (DE 195 29 666 C1) has several code signal transmitters, each one code send signal. By the code signal one or more Other safety devices locked or unlocked if through the received code signals a successful authentication has taken place in a control unit.

From the published patent application DE 42 40 426 A1 it is known unlock the doors after getting out, if the Locked doors when getting out of the motor vehicle and the ignition key in the motor vehicle has been forgotten.  

The invention is based on the problem of theft protection system for a motor vehicle to create the safe against unauthorized use of the motor vehicle and that at simple structure offers a high level of user comfort.

According to the invention, this problem is solved by the features of Claim 1 solved. Everyone is protected against theft stem assigned several code signal transmitters, each at Be may send out a code signal. With this code signal Door locks or other locking points locked or unlocked as well as an electronic immobilizer can be released if the code signal is authenticated successfully. When a Code signal generator remains in the vehicle during the ignition is switched off, this code signal transmitter is blocked, as soon as a door of the motor vehicle is closed or a Lock is locked with another code signal generator. Of the Code signal generator is released again when after opening one door or another to unlock a lock Close-up code signal generator outside the motor vehicle is recognized.

Thus, a code signal generator can remain in the vehicle nevertheless security is guaranteed. The one in the vehicle The existing code signal generator is blocked until a additional code signal generator on request outside the vehicle stuff is recognized.

The code signal generator located in the motor vehicle can also after expiry of a quantity or time limit automa be locked table.

Advantageous embodiments of the invention are the Un Described claims. So every code signal generator can a conventional mechanical key or on one  Chip card can be arranged. Thus the code signal generator easily taken by the user. Arranged outside in or on the motor vehicle a transmitting and receiving antenna is more advantageous wise on the outside of the driver's door and the passenger door or in the Outside mirrors arranged. Coils are used as the antenna det, whose range is very small, so that only the immediate outside space is detected by the antennas. About ranges are avoided. Farther away As a result, code signal transmitters are not addressed.

A code signal transmitter can be placed in a cradle while driving inside the tool. As long as the ignition is on is switched on, a lock prevents the code from being unplugged signal generator. The code signal generator can have keys after whose actuation code signals are sent wirelessly. in the A trigger switch can be arranged in the area of the door handle be triggered by a request signal if necessary is sent from the vehicle to the code signal generator. The code signal transmitter then sends its code signal back. The user therefore does not need his code signal generator to bring out his pocket when he gets into his vehicle want to rise.

There is an ignition switch in the area to switch on the ignition the steering wheel of the dashboard provided by the level if a request signal is generated. If the Codesi gnalgeber receives the request signal, it sends then his code signal back.

Exemplary embodiments of the invention are described below the drawings explained in more detail. Show it:

Fig. 1: a block diagram of the anti-theft protection system according to the invention and

Fig. 2: a flowchart describing the operation of the anti-theft protection system according to Fig. 1.

An anti-theft system according to the invention for a motor vehicle has a control unit 1 ( FIG. 1), by means of which one or more security devices in the motor vehicle can be locked or unlocked. The Steuerein unit 1 is at least connected to a transmitting and receiving antenna 2 , which is arranged for example as a coil in the motor vehicle door or in an outside mirror (the outer limit of the motor vehicle is indicated by the dashed line in Fig. 1). Via this transmitting and receiving antenna 2 , a request signal can be transmitted inductively and code signals from one or more portable Codesignalge transmitters 3 can be received inductively.

The control unit 1 is connected to a trigger switch 4 , which is located in the region of the door handle on the outside of the motor vehicle. When the trigger switch 4 is actuated, the control unit 1 causes the request signal to be transmitted via the transmitting and receiving antenna 2 .

Furthermore, the control unit 1 is connected to state sensors 5 which, for example, detect whether the door or the windows are open or closed. The state sensors 5 can also recognize the state of the transmission or of (brake, gas) pedals.

The control unit 1 can also be connected to a receiver 6 which can receive code signals (infrared or radio signals) emitted by a code signal transmitter 3 from a greater distance. The code signals are then fed to the control unit 1 for evaluation.

A recording device 7 for a code signal generator 3 is arranged in the vehicle interior in the area of the steering wheel, the dashboard or the center console. In the receiving device 7 , a transmitting and receiving unit with a transmitting and receiving coil 7 'is arranged, which transmits signals to the code signal generator 3 in the receiving device 7 as well as receives signals from it and forwards them to the control unit 1 for evaluation. If the code signal transmitter 3 is inserted in the receiving device 7 , it sends its code signal to the control unit 1 upon request or actuation of a key 10 , which is checked there for its authorization (authentication).

If the code signal is recognized as authorized, one or more security devices, such as central locking system 8 (door locks, trunk locks), glove locks, fuel cap locks, engine compartment locks, etc. are locked or unlocked. Likewise, an electronic immobilizer 9 and an electronic steering lock can be locked or unlocked with the code signal.

The operation of the anti-theft system is explained in more detail in the following using the flow diagram of FIG. 2 ( FIGS. 2a, 2b and 2c result in FIG. 2). First of all, the vehicle is in its rest position, ie the central locking system 8 is closed and the engine (ignition) is switched off. If a user wants access to the motor vehicle, he first actuates the trigger switch 4 . Since the trigger switch 4 is then queried at intervals, whether an actuation is present, the actuation of the trigger switch 4 is recognized and reported to the control unit 1 .

There then takes place a question-answer dialogue between the control unit 1 and the code signal generator 3 . For this purpose, the control unit 1 sends the request signal to the code signal generator 3 via the transmitting and receiving antenna 2 . The code signal generator 3 then replies with its code signal, which is supplied to the control unit 1 via the transmitting and receiving antenna 2 . In the control unit 1 , the authorization (authentication) of the code signal is checked. For this purpose, the code signal is compared with a target code signal stored in control unit 1 or generated there. If they match, an enable signal is generated for a safety device, whereby the safety device is locked or unlocked.

In order to unlock the doors of the motor vehicle, a button 10 on the code signal generator 3 can also be actuated instead of actuating the trigger switch 4 on the vehicle door. By pressing the button 10 , a code signal is transmitted by infrared or radio to the receiver 6 in the motor vehicle. The receiver 6 passes the code signal on to the control unit 1 , where it is checked for its authorization.

If the authentication was successful, the door locks of the driver's door or all doors as well as other locking points (tank lid, trunk, glove box) are unlocked via the central locking system 8 . At the same time, the functions of a code signal transmitter 3 , which is sensitive in the motor vehicle, can be enabled, which will be discussed in more detail later.

When the user wants to put his vehicle into operation (starting and driving off), he inserts one or more code signal transmitters 3 into the receiving device 7 and actuates an ignition switch. The receiving device 7 can be, for example, the ignition lock. If the code signal generator 3 is arranged on the mechanical ignition key, the ignition key is inserted into the ignition lock and turned. The ignition switch is actuated, whereupon the recording device 7 sends a request signal to the code signal generator 3 , which then responds with its code signal.

The code signal is checked in the control unit 1 for its calculation. In addition, comfort signals can be sent to the control unit 1 with the code signal, through which, for example, the driver's seat, interior and exterior mirrors or the air conditioning system can be set individually for the respective user. For this purpose, corresponding data are stored in the code signal generator 3 for each user and are transmitted in the comfort signals to the motor vehicle.

If the code signal is recognized as authorized, the engine is started and the vehicle can be driven. If the user wants to make a stopover (e.g. to refuel), he first switches the ignition off (engine stop). If the user gets out without wanting to lock, the transmitting and receiving antenna 2 is opened and closed by the driver's door (is detected by the state sensors 5 , in particular door contact switches) by the. Control unit 1 activated. A request signal is sent outside. Due to the metal body, the field generated by the transmitting and receiving antenna 2 does not reach the vehicle interior, or only at a very low level.

If the user leaves the first code signal generator 3 in the receiving device 7 and has a further code signal generator 3 , this additional code signal generator 3 is recognized outside the motor vehicle, since it responds to the request signal with its code signal. As a result, the code signal generator 3 , which is still in the receiving device 7 when the ignition is switched off, can be deactivated in its functions by the control unit 1 , so that it is no longer possible to start the engine with it (transmission of the code signal is prevented).

If no code signal generator 3 is detected outside the vehicle, the code signal generator 3 located in the receiving device 7 continues to be fully operational. When the ignition switch is actuated, the immobilizer 9 is therefore also released, so that the motor vehicle can be put into operation.

When entering the motor vehicle again, this is detected by the state sensors 5 in the door. The control unit 1 then becomes active again and causes the transmitting and receiving antenna 2 to transmit the request signal. If no code signal generator 3 responds with its code signal in the vicinity of the motor vehicle, the code signal generator 3 located in the receiving device 7 remains deactivated. However, if a code signal generator 3 is recognized in the close range, the code signal generator 3 in the vehicle is switched to ready for operation again by the control unit 1 . The vehicle can then be put into operation properly in the receiving device 7 after the code signal from the code signal generator 3 has been emitted.

The previous procedure was described without a lock request at the stopover. If, however, the driver wants to lock his vehicle at the intermediate stop, he actuates the trigger switch 4 near the door handle. The request signal is then sent out. The doors are only locked when a code signal generator 3 sends its code signal back to the control unit 1 outside the vehicle.

If at this point in time a code signal generator 3 in the motor vehicle, e.g. B. is present in the receiving device 7 , this is deactivated so that it can not send out a code signal to release the immobilizer 9 or the Codesi signal is not accepted by the control unit 1 for authentication.

If the driver wants to get back into his vehicle, he actuates the trigger switch 4 , which in turn leads to the question-answer dialog. If the authentication is successful, the vehicle doors are unlocked. If a code signal generator 3 is still arranged in the receiving device 7 or in the vehicle interior, this code signal generator 3 is now activated again so that it can send out the code signal for releasing the immobilizer 9 if this is triggered by actuating the ignition switch.

The code signal generator 3 , which is located in the motor vehicle, can be connected via the control unit 1 , which is connected to the receiving device 7 via a data line 11 (for example a data bus), and the transmitting and receiving unit or by a transmitter in the motor vehicle receive a signal to lock or unlock the code signal generator 3 . As are possible with the transmitting and receiving unit in the receiving device 7, only low-range, the code signal transmitter 3, a signal must be located already in the recording apparatus 7 or in close proximity to her, so he standardized by the transmitting and Empfangsein to lock or unlock can receive its functionality.

The code signal transmitters 3 can be arranged on conventional mechanical keys or on so-called smart cards (chip cards of large chip cards). The receiving device 7 has a corresponding de opening for inserting the code signal generator 3 .

It is advantageous if the code signal generator 3 is arranged on the ignition key. Thus, the ignition lock can be used as a recording device 7 . For the invention, however, it is immaterial how the code signal generator 3 is formed and where the receiving device 7 is arranged in the interior of the motor vehicle.

The ignition switch can be operated by turning the switch the ignition key in the ignition lock. As well a separate ignition switch can be arranged in the vehicle, when actuated, the request signal is generated.

The code signal generator 3 can be supplied with energy via the receiving device 7 . For this purpose, the code signal generator 3 can have its own rechargeable energy store, which is then charged with energy when the code signal generator 3 is arranged in the receiving device 7 . The code signal generator 3 can also be supplied with energy with a battery, which must then be replaced when the energy supply is running low. This can be detected by voltage monitoring via the recording device 7 and be signaled to the user by a display.

The receiving device 7 can have a lock, not shown, by which removal of the code signal generator 3 from the receiving device 7 is prevented when the ignition is switched on. In the case of the ignition lock (cylinder lock), this is conventionally already implemented, since the ignition key is not to be removed in the "ACC", "START" or "ON" position. In the "OFF" position, the ignition key is inserted into the ignition lock and can only be removed again in this position.

A status sensor 5 can also be arranged in the driver's seat, which detects whether the driver's seat is occupied or not. If the seat is not occupied, it can be provided that a code signal generator 3 located in the receiving device 7 or another code signal generator 3 which is located in the interior of the motor vehicle is blocked in its function. The lock is only released again when the user gets into the vehicle with a code signal generator 3 and occupies the driver's seat.

If there is a person in the motor vehicle who actuates the locking mechanism on a door, a blocked code signal generator 3 in the receiving device 7 can be released again if a code signal generator 3 is located in the vicinity of the motor vehicle and its code signal is correct to the control unit 1 sends.

Likewise, a start attempt with a blocked code signal transmitter 3 in the receiving device 7 can lead to the release of this code signal transmitter 3 if at the same time a further code signal transmitter 3 is detected in the vicinity of the motor vehicle.

The functionality of the code signal generator 3 can be the same, ie that with each code signal generator 3 both the central locking system 8 can be actuated and the immobilizer 9 can be released. With each code signal, 3 comfort functions (window / sunroof / convertible top opening or closing, lights / air conditioning / heating switching on or off) can also be remotely controlled in the motor vehicle.

The mechanics of the code signal generators 3 do not have to be identical. It is important that the same locking units can be controlled with the code signal. The code signal transmitter 3 can thus be arranged on a mechanical key (on the key handle), on a chip card or in a functionally equivalent housing. The code signal generator 3 should be made small so that it can easily be carried by the user in each pocket.

The code signal generator 3 can also be different in their functionality. It can be code signal generator 3 ben, which can remain permanently in the motor vehicle. These code signal generator 3 are referred to below as an inner key. The user carries other code signal transmitters 3 with him. This code signal generator 3 are referred to below as an external key. Several anti-theft keys and several external keys can be assigned to the anti-theft system.

The inner key is hen hen for the receiving device 7 and can remain permanently in it. The inner key is used to issue the basic driving authorization (release the immobilizer 9 and, if necessary, unlock the steering wheel lock).

The inner key can also include functions for remote control of the central locking system 8 and for remote control of comfort functions. The inner key can also be used for coding radio, radio telephone, etc. In this case, corresponding locking / release functions are only given if the inner key is in the device 7 and has given an authorized code signal. Only then can the radio be switched on, for example.

The external key is primarily used for access authorization, ie remote control of the central locking system 8 . The remaining functions of the external key can be designed to be limited in terms of time or quantity (e.g. limited number of remote control operations, limited number of start-ups, locking of the trunk release, locking of the glove compartment, etc.). It can also be provided that these functions are only limited if there is no internal key in the motor vehicle.

If the central locking system 8 is locked by means of an external key, the control unit 1 blocks all functions of the internal key. This can be designed so that the blocking takes place only when the inner key is in the receiving device 7 .

The functions of the inner key can only be done after an ei a certain amount of time, a number of kilometers driven locked or a limited number of engine starts will.

It can also be provided that only certain functions of the inner key are locked so that, for example, only an engine start (releasing the immobilizer 9 ) with the inner key and locking the doors via the central locking system 8 is possible. The vehicle can thus be handed in with the external key in a workshop for repair or in a hotel for parking the vehicle. If the inner key then remains in the motor vehicle, the outer key can be fully functional. However, if the inner key is not in the motor vehicle, certain functions are blocked. For example, the trunk and the glove box could not be unlocked with the external key. With the insertion of the inner key in the receiving device 7 , the full functionality is restored.

If the central locking system 8 is unlocked by means of an external key or another internal key, the control unit 1 releases the functions of the internal key again. When the functions of the inner key are released, it does not necessarily have to be in the receptacle 7 .

If the central locking system 8 is unlocked via an internal locking switch (locking button inside the door) when the internal key is locked, the control unit 1 can query whether an external key is in the vicinity of the motor vehicle. If an outer key is recognized as authorized at close range, the inner key is released.

If a start attempt is made with a locked internal key tern, you can also query whether a External key is located in the vicinity of the motor vehicle. If there is an external key there, the In Key released. The commissioning can then ord according to the instructions.

If no external key is recognized as authorized, it can Alarm directly on the motor vehicle (horn or lights switched on and off intermittently). It a "silent" alarm can also be triggered, in which a Alarm signal via a transmitter to the external key or to is sent to a remote headquarters.

In the anti-theft system according to the invention, none Antenna needed that their signals sen inside the vehicle det and receives from there. Simple and small types are sufficient tennen on the outside of the vehicle. An exact limit between the interior and exterior of the motor vehicle stuff is not necessary.

Also, the code signal generator 3 , which has released the immobilizer 9 , cannot be removed from the motor vehicle without this being noticed and the motor vehicle being secured accordingly. The anti-theft system is easy to use because a code signal generator 3 can remain in the vehicle without the security being restricted. The user therefore does not have to pull out his code signal generator 3 every time before he wants to put his motor vehicle into operation.

The range of the signals that are sent from the transmitting and receiving antenna 2 on the outside of the motor vehicle and from the transmitting and receiving unit in the receiving device 7 depends on the design of the respective antennas and their control. If coils are used as antennas, the signals are transmitted inductively. The transmitting and receiving antenna 2 should have a range of approximately 1 to 2 m.

This then also corresponds to the close range around the motor vehicle, within which a code signal generator 3 can be recognized as authorized. The range and the close range depends on the location of the transmitting and receiving antenna 2 . Usually, the close-up area extends approximately hemisphere-shaped around the driver and front passenger door or around the outside mirror.

One is sufficient for the transmitter and receiver unit in the vehicle Range of a few centimeters. The IR or radio signals however have a range of z. T. over 100 m.

The code signals are usually binary coded signals that are encrypted according to a predetermined mathematical calculation. A so-called alternating code is advantageously used to generate the code signal. Each time it is transmitted, a code signal that is different from the predecessor is transmitted. If the code signal should be intercepted without authorization, the playback of the recorded code signal does not result in the central locking system 8 being actuated or the immobilizer 9 being released .

The anti-theft system becomes even more secure if the code signal is generated using a crypto-algorithm. A random number is sent out as a request signal. A code signal is calculated in the code signal generator 3 as well as in the control unit 1 with the aid of a secret crypto key and the random number. If the received code signal and the code signal generated in the control unit 1 match, then the authentication is successful and the received code signal was authorized.

The term immobilizer means all electronic interventions in electronic units of the motor vehicle, by means of which starting and driving away of the motor vehicle is only possible with an authorized code signal. For example, the engine control unit, the ignition control unit, the transmission control unit, etc. can be integrated individually or together in the immobilizer 9 . These control units are only released when the code signal is calculated. Commissioning is not possible without the approval of these control units.

Claims (9)

1. Theft protection system for a motor vehicle with

• 1. - a plurality of code signal transmitters ( 3 ), each of which sends code signals through which one or more security devices ( 8 , 9 ) are locked or unlocked when successful receipt in a control unit ( 1 ) has taken place through the received code signals ,
• 2. - A code signal generator ( 3 ) located in the motor vehicle is at least partially blocked in its functions if after locking one or more security devices ( 8 ) or after locking one or more safety devices ( 8 ) and a further condition with another code signal generator this is recognized as authorized in the vicinity of the motor vehicle, and a code signal transmitter ( 3 ) located in the motor vehicle is released if, after unlocking one or more security devices ( 8 ) with another code signal transmitter, this is recognized as authorized in the vicinity of the motor vehicle.

2. Theft protection system according to claim 1, characterized in that a code signal generator ( 8 ) on a conventional mechanical key or on a credit card-sized card is arranged te. 3. Theft protection system according to one of the preceding claims, characterized in that the control unit ( 1 ) is electrically connected to a transmitting and receiving antenna ( 2 ), the range of which can be received with sufficient strength up to the code signals immediate environment around the motor vehicle is limited and that the control unit ( 1 ) is connected to a receiver ( 6 ) for infrared or radio signals. 4. Theft protection system according to one of the preceding claims, characterized in that a receiving device ( 7 ) for the code signal generator ( 3 ) is provided in the interior of the motor vehicle, into which the code signal generator ( 3 ) is inserted to put the motor vehicle into operation. 5. Theft protection system according to one of the preceding claims, characterized in that the code signal generator ( 3 ) has a key ( 10 ), after its actuation a Codesi signal is sent out wirelessly. 6. Theft protection system according to claims 1 to 4, characterized in that a trigger switch ( 4 ) is arranged in the region of the door handle, through which a request signal is generated by the control unit ( 1 ), the vehicle from the motor vehicle to the code signal generator ( 3 ) is sent, which then generates the code signal and sends it back wirelessly. 7. Theft protection system according to claims 1 and 2, characterized in that an ignition switch is arranged in the region of the steering wheel or the dashboard, through which a request signal is generated, which is sent to the code signal generator ( 3 ), which then returns the code signal wirelessly det. 8. Theft protection system according to one of the preceding claims, characterized in that a central locking system ( 8 ), an electronic immobilizer system ( 9 ), a radio telephone or a car radio are used as security devices, which are respectively released or blocked by the code signal. 9. Theft protection system according to one of the preceding An sayings, characterized in that the further condition  an expiration of a period of time, a number of kilos driven meters or a number of startups.