GB2296937A

GB2296937A - Motor vehicle security system

Info

Publication number: GB2296937A
Application number: GB9600374A
Authority: GB
Inventors: Hans Deischl; Martin Lindmayer
Original assignee: Daimler Benz AG; Mercedes Benz AG
Current assignee: Daimler Benz AG
Priority date: 1995-01-14
Filing date: 1996-01-09
Publication date: 1996-07-17
Anticipated expiration: 2016-01-09
Also published as: FR2729349B1; DE19500999C1; GB2296937B; FR2729349A1; GB9600374D0

Abstract

The security device has one device to protect against unauthorised use. It allows the engine to be started only when the required information is put in. There is a device to protect against unauthorised access, enabling door to be unlocked from outside only when required access information is put in. There is also an auxiliary door security unit (4). The device creates the required internal unlocking information when the required use information is put in, or when the vehicle speed exceeds a set threshold. When the required use information is put in, it interrogates the previous condition of the auxiliary door security device, and switches it to the unlocked state by input of the required internal unlocking information, if the auxiliary device proves to be locked.

Description

Motor vehicle security svstem The invention relates to a motor vehicle security system with a device for protecting against use by third parties and a device for protecting against access by third parties which contains an additional door securing means.

Devices for protecting against use by third parties are known for example in the form of mechanical ignition key/ignition lock combinations in which the authorizing use information is provided by the shape of the ignition key which matches the ignition lock. The actuation of the ignition lock by the matching key permits the vehicle engine to be started and usually also permits steering to be enabled.More modern devices for protecting against use by third parties in the form of so-called immobilizers provide for one or more electrical control units, for example an engine control device, which are necessary for starting an engine and/or a subsequent travel mode to be disabled when the vehicle is parked in order to prevent them being reactivated and not to be enabled until an authorizing user code signal is input, for which purpose the user transmits the code signal to a receiver at the vehicle end by actuating an electronic key. Devices for protecting against access by third parties are known in a variety of forms of door locking devices which only enable the unlocking of a locked door from the outside when an item of authorizing access information is input.Frequently, this authorizing access information is identical with the authorizing use information of the device for protecting against use by third parties, for example the ignition key can serve simultaneously as a key for a mechanical door lock.

A further measure is to provide a so-called additional door securing means, also referred to as "safelock" system for protecting against access by third parties, which additional door securing means prevents a locked door which has previously been protected against unlocking from the outside from being opened from the inside of the vehicle as long as the said means is in a securing state. The inputting of an item of authorizing internal unlocking information changes the additional securing means into its released state in which it then permits the said door opening process. Such an additional securing means is provided for example in the door locking system described in the Offenlegungsschrift DE 33 13 100 Al.The additional securing means here consists of a movable cover which in its securing state is located in a locked position which covers the elements which actuate the locking of the door in the passenger compartment. The cover is moved into this locked position by locking the respective door from the outside, for example by actuating a mechanical key in a closing direction in an associated door lock. Such an additional door securing means prevents an unauthorized person from being able to open the vehicle door when he has forcibly gained access to a corresponding element for actuating locking of the door in the vehicle passenger compartment.

In the patent document DE 38 06 326 C1, a device for locking door locks of a motor vehicle is described, in which device an additional door securing means is formed by a disengageable coupling between an actuation element in the passenger compartment and a door lock, the coupling being capable of being engaged and disengaged by means of servodrives. When the external door locking means is activated, for example by means of a central door locking system, the servo-drive disengages the coupling so that the door locking means cannot be released even if the element which actuates the locking of the door in the vehicle passenger compartment is actuated.

For security systems in which the additional door securing means can be moved into its securing state not only by an action of a user outside the vehicle but also from the vehicle passenger compartment, the problem arises of the undesired locking of persons in the vehicle as a result of inadvertent triggering of that activity which changes the additional door securing means to its securing state. This problem can occur for example in modern motor vehicle security systems in which the device for protecting against access by third parties can be actuated in a remote controlled fashion and the vehicle-end receiver for the authorizing access code signal also reacts to signals which are transmitted from the vehicle passenger compartment by means of a user-end key.If, for example, the user-end key comprises a mechanical steering lock key with infrared button or radiotransmission button for transmitting an item of information for locking the doors with protection against external unlocking and simultaneously changing the additional door securing means into its securing state and the user inadvertently presses the transmission button while handling the key in the steering lock, the additional door securing means can undesirably switch to its securing state in which it is not possible for the user subsequently to open the doors with one of the actuation elements in the vehicle passenger compartment.

The present invention seeks to provide a motor vehicle security system in which there is no risk of the additional door securing means inadvertently being in the securing state while the vehicle is travelling.

According to the present invention there is provided a motor vehicle security system having - a device for protecting against use by third parties, which device enables starting of the engine only when an item of authorizing use information is input and - a further device for protecting against access by third parties, which further device enables unlocking of a locked door from the outside only when an item of authorizing access information is input and has an additional door securing unit which in the securing state disables unlocking, from the inside, of the locked door, protected against unlocking from the outside, and enables the said unlocking in the released state and is switchable from the securing state into the released state by inputting an item of authorizing internal unlocking information, wherein the said motor vehicle security system produces internal unlocking information when the authorizing use information is input and/or the vehicle speed exceeds a prescribed threshold value.

In the first alternative the security system produces the authorizing internal unlocking information, with which the additional door securing unit can be moved into the releasing state, after starting of the engine has been enabled by the device for protecting against use by third parties, in response to an authorizing item of use information. Even if the user has unintentionally changed the additional door securing unit into the securing state when starting a journey, the production of the authorizing internal unlocking information which is coupled to the enabling of the starting of the engine has the effect that the additional door securing unit can, if appropriate, be moved directly back into the released state and it remains there for the rest of the travel operation.Undesired locking of persons in the vehicle owing to a triggering of the additional door securing means caused by an unintentional action of the user in the vehicle passenger compartment is thus prevented. In the second alternative which may be provided in addition to or instead of the first, the exceeding of a prescribed threshold value, which preferably lies near to zero, by the vehicle speed brings about the release of the additional door securing means.

With simultaneous realization of both alternatives redundancy is provided which has the effect that the additional door securing means can be moved into its released state even in the event of a failure of the production or inputting of the authorizing internal unlocking information which is coupled to the enabling of the starting of the engine if the instantaneous vehicle speed lies above the prescribed threshold value.

A development of the invention provides for the state of the additional door securing unit to be interrogated before the internal unlocking information is produced or input into the additional door securing unit so that the internal unlocking information only has to be input into the additional securing unit if the latter has hitherto been in the securing state.

A further development of the invention realizes a motor vehicle security system which advantageously combines a use-code-protected immobilizer function with the cancelling of undesired triggering of the additional door securing means. The high degree of protection of the use authorization coding which is known for immobilizers is transferred to the disabling of the additional door securing means since the operation of the engine control device and thus starting of the engine is not enabled until the authorizing use code signal is input, which is in turn a precondition for the disabling of the additional door securing means at any rate when the vehicle is stationary.

Consequently, in this development the additional door securing means cannot be disabled solely by unauthorized short-circuiting of the ignition. In an advantageous refinement of this measure, a powerless steering lock in the form of an electronic ignition starter switch with transponder forms the input device for the authorizing use information, as a result of which a motor vehicle security system is realized which utilises a modern use authorization identification in addition to the monitoring of the additional door securing function.

A preferred embodiment of the invention is illustrated in the drawing and is described below.

The single figure shows a schematic block diagram of a motor vehicle security system with a device for protecting against use by third parties and a device for protecting against access by third parties which contains an additional door securing means.

The motor vehicle security system shown in block diagram form contains a device for protecting against use by third parties in the form of a conventional immobilizer with an electronic ignition starter switch 1 as a powerless steering lock with coupled transponder. The user must identify himself at the ignition starter switch 1 by inputting a use code. If an item of authorizing use code information is input into the ignition starter switch 1 the latter transmits a use enabling signal by means of a transponder via a signal transmission line 3, protected against tampering, to a central engine control device 2 whose previously blocked operational capability is subsequently enabled, the engine control device 2 having been previously placed in the functionally disabled state whenever the vehicle is parked or, if appropriate, in response to an externally supplied request signal.Of course, when required further control devices arranged in the vehicle can be included in the immobilizer in the same way as the engine control device 2.

Furthermore, the vehicle security system contains, in a manner not shown in greater detail, a device for protecting against access by third parties in the form of a door locking system which is of conventional nature and therefore does not need to be described in greater detail here. It contains, inter alia, a central locking system and on each door in each case an external manually operated actuating element, an internal manually operated actuating element and an internal securing knob. Using the external manually operated actuating element the door can be opened from the outside if it is unlocked but not if it is locked.

The internal securing knob moves downwards if the vehicle is locked from the outside and upwards if it is unlocked from the outside. In order to lock or unlock the door from the outside an electronic door lock is provided which can be actuated correspondingly by an electronic key which contains the authorizing access information. In this context, the same user-end key element serves both as electronic key for transmitting the authorizing access information via a radio or infrared transmission link and as an element which communicates with the electronic ignition starter switch 1 in order to input the authorizing use code.By pressing the internal securing knob the vehicle can be locked from the inside in such a way that the door can only be unlocked, and subsequently opened, by means of the internal manually operated actuating element but not by means of the external manually operated actuating element.

An additional door securing means 4 is coupled as a function block to the internal manually operated actuating means of the door. Said additional door securing means 4 has the effect that the door cannot be unlocked and opened by actuating the internal manually operated actuating element if it has been locked from the outside by the device for locking the door, i.e. by actuating the electronic key and transmitting the authorizing access information to the vehicle-end receiver. This prevents an unauthorized person from opening the door and being able to enter the vehicle easily when he has already gained access to the internal manually operated actuating element, for example by smashing - in a side window.The additional door securing means 4 is switched over as authorizing internal unlocking information or internal locking information between the securing and the released state in each case by inputting the authorizing access code which brings about the locking of the door, which secures against unlocking from the outside, or permits unlocking from the outside again. The motor vehicle security system additionally contains, as a further security measure, a break-in theft warning system 5 which is also indicated in the figure as a function block and is of conventional design, further details of which do not need to be given here.

In the motor vehicle security system which is designed in such a way there is provision for the use enabling signal which is well protected against tampering and which is only transmitted to the engine control device 2 after an authorizing use code is input at the electronic ignition starter switch 1 to branch off to the additional door securing unit 4 and the break-in theft warning system 5 via a branch line 6 and to use it as internal unlocking information, with which the additional door securing means 4 can be moved into the released state, and for disabling the break-in theft warning system 5.' The effect of this is that whenever the engine management function of the engine control device 2 is enabled the additional door securing means 4 can be released if it has previously been moved into the securing state inadvertently.The latter can take place unintentionally, for example as a result of the transmission button being pressed inadvertently when the infrared key or radio key in the ignition starter switch steering lock 1 is being used, as a result of which the door locking system which is protected against unlocking from the outside is activated and at the same time the additional door securing means 4 is changed into the securing state.

The release of the additional door securing means which is permitted with the enabling of the starting of the engine prevents the user from being unintentionally "locked in" in the vehicle as a result of the inadvertent pressing of the door locking transmission button. This is because after the resetting of the additional door securing means 4 into the released state he can subsequently open the door from the inside using the internal manually operated actuating element as usual. In order to avoid unnecessary driving of the additional door securing means 4 by the use enabling signal output by the ignition starter switch 1 there is provision for the state of the additional door securing means 4 initially to be interrogated when the use enabling signal is transmitted and for driving by the use enabling signal only to be carried out if the additional door securing means 4 is actually in the securing state as a result of undesired actuation of the door locking transmission button.

In order to keep the additional door securing means 4 in the released state during a journey even in the event of a failure of the driving of the additional door securing unit 4 by the use enabling signal, there is provision, as a redundant measure, for the additional door securing means 4 to be switched to its released state at any rate if it is recognized by the system that the vehicle is travelling at a speed which is higher than a prescribed, preferably very low threshold value, for which purpose the output signal of a speedometer is interrogated by the system. Of course, this measure can also be used alone for releasing the additional door securing means, i.e. without the release coupled to the enabling of the starting of the engine.

The coupling of the additional door securing means to the high degree of protection against tampering of the use authorization coding of the immobilizer permits it to be released by starting of the engine with a high degree of protection against tampering. In contrast, coupling of the additional door securing means to the ignition line provides less security since the additional door securing means could then be moved to the released state simply by shortcircuiting the ignition line.

Claims

1. A motor vehicle security system having - a device for protecting against use by third parties, which device enables starting of the engine only when an item of authorizing use information is input and - a further device for protecting against access by third parties, which further device enables unlocking of a locked door from the outside only when an item of authorizing access information is input and has an additional door securing unit which in the securing state disables unlocking, from the inside, of the locked door, protected against unlocking from the outside, and enables the said unlocking in the released state and is switchable from the securing state into the released state by inputting an item of authorizing internal unlocking information, wherein the said motor vehicle security system produces internal unlocking information when the authorizing use information is input and/or the vehicle speed exceeds a prescribed threshold value.

2. A motor vehicle security system according to Claim 1, further including means adapted to interrogate the state of the additional door securing means hitherto in response to the inputting of the authorizing use information and to switch over the said additional door securing means into the releasing state by inputting the authorizing internal unlocking information if the said additional door securing means was previously in the securing state.

3. A motor vehicle security system according to Claim 1 or 2, wherein, in response to the inputting of the authorizing use information a use authorization signal is produced by means of which the previously disabled operation of an engine control device is enabled and which simultaneously serves as authorizing internal unlocking information for releasing the additional door securing unit.

4. A motor vehicle security system according to Claim 3, wherein an electronic ignition starter switch with a transponder as device for inputting the authorizing use information and for emitting the use authorization signal to the engine control device and the additional door securing unit.

5. A motor vehicle security system, substantially as described herein with reference to and as illustrated in the accompanying drawing.

Amendments to the claims have been filed as follows 1. A motor vehicle security system having - a device for protecting against use by third parties, which device enables starting of the engine only when an item of authorizing use information is input and - a further device for protecting against access by third parties, which further device enables unlocking of a locked door from the outside, only when an item of authorizing access information is input and has an additional door securing unit which in the securing state disables unlocking, from the inside, of the locked door, protected against unlocking from the outside, and in the released state enables the said unlocking, and is switchable from the securing state into the released state by inputting an item of authorizing internal unlocking information, wherein the said motor vehicle security system produces internal unlocking information, only when the authorizing use information is input and/or the vehicle speed exceeds a prescribed threshold value.

3. A motor vehicle security system according to Claim 1 or 2, wherein, in response to the inputting of the authcrizing use information a use authorization signal is produced by means of which the previously disabled operation of an engine control device is enabled and which simultaneously serves as authorizing internal unlocking information for releasing the additional door securing unit.

4. A motor vehicle security system according to Claim 3, wherein the device for inputting the authorizing use information and for emitting the use authorization signal to the engine control device and the additional door securing unit comprises an electronic ignition starter switch with a transponder.