DE19513341A1 - Motor vehicle anti-theft security device circuit arrangement - Google Patents

Abstract

The security system for the vehicle uses the security code in the radio to release the immobilising control. If the vehicle door is opened, with the engine running, the security system wipes out the radio code, with a time delay, causing the immobilising system to operate. To continue to use the vehicle, after a door has been opened, the user must re-enter the radio code before the time delayed locking process. The immobiliser shuts off the ignition, blocks the starter motor and immobilises the radio. The security system is in addition to other security systems.

Description

The invention relates to a circuit arrangement for theft protection of motor vehicles testify with interruption of the ignition, fuel supply and starter and car radio secured by code.

Methods and arrangements are known which use an electronic immobilizer prevent the theft of motor vehicles.

These electronic immobilizers are independent components in the vehicle built-in.

If the vehicle is put into operation without authorization, e.g. B. by bypassing the ignition system, an existing immobilizer disables important components of the vehicle. This happens at least by interrupting the ignition, the fuel supply and the Starter.

Extended systems include other components of the vehicle.

The immobilizer is activated by the owner using a coded key, one Code card or other suitable input device activated or deactivated.

All vehicles will increasingly be equipped with an electronic immobilizer, which prevents casual theft.

When such immobilizers are mass-produced, however, their mode of operation can be changed cannot be kept secret.

As a result, there is the possibility of making duplicates of the input devices (coded keys) at the manufacturer, in the workshop, when the vehicle changes ownership, after theft of the input devices, for example, in an apartment or restaurant, violent Requesting the keys etc.

Furthermore, violent access to the vehicle while driving, e.g. B. at Stop at traffic lights or when leaving the garage and much more.

Organized crime has adapted to this and practices this method even for vehicles in the higher price range.

In this regard, conventional immobilizers are worthless.

The invention has for its object to provide an anti-theft device, even then prevents theft if the owner has deactivated the immobilizer,  or the aforementioned possibilities of theft exist, for example at traffic-related stopping.

At the same time, the technical effort should be compared to conventional immobilizers be reduced.

According to the invention the object is achieved in that the immobilizer in conjunction with the door contacts of the car doors as an interruption mechanism and a code entry is realized on the existing car radio in such a way that when opening a vehicle door by means of the circuit according to the invention with the ignition switched on on the car radio entered coding, which deactivates the immobilizer, deleted and thus the Immobilizer is activated, the locking effect of the immobilizer by means of circuit according to the invention is delayed in time.

Exemplary embodiments of the invention are shown schematically on the basis of the figures will.

Fig. 1 shows the block diagram of the invention using a commercially available car radio with code lock.

Fig. 2 shows an embodiment of the inventive solution.

In Fig. 1 a logic assembly 1, the ignition voltage 2, and the switching state of the car door contacts 3 respectively. It is now assumed that the car doors are closed and the ignition is switched on.

Now logic module 1 queries whether the intended number code has been entered on the car radio.

If this is not the case, the conventional circuit breaker circuit 5 is activated by the logic module 1 , as a result of which the ignition, fuel supply and starter are preferably switched off.

The vehicle cannot be started.

Only after entering the internal code on the car radio 4 does the logic module 1 switch through and release the interruption mechanism 5 .

The vehicle can now start its journey.

Under normal circumstances there is no reason to close one of the car doors while driving to open.  

Will now when the vehicle stops due to traffic, e.g. B. at traffic light stop (with the ignition switched on) a car door is opened, the switching state present on the door contacts is registered and the logic module 1 and switches the interruption mechanism 5 on .

The vehicle is taken out of service. At the same time, the logic module 1 deletes the code input on the car radio.

You can only continue driving after re-entering the code on the car radio. The interruption takes place with an adjustable time delay Δt. This enables the thief to drive away for a predetermined period of time before the consumers connected downstream of the interruption mechanism 5 are switched off. This also ensures the criminal offense.

Fig. 2 shows an embodiment of the circuit according to the invention. The basic module is a NAND circuit 1 , which ensures the logical switching functions.

As soon as a car radio with code lock is disconnected from the vehicle's electrical system, it is electronically blocked and worthless for a thief.

The control voltage 6 is tapped at a suitable point in the car radio.

If the code is entered correctly, approx. 12 V DC voltage is provided and used by circuit 1 for evaluation.

When one of the car doors 3 is opened, the car radio is briefly disconnected from the vehicle electrical system via R2 / S2. The control voltage 6 now goes against 0 V DC voltage, the code is deleted.

The vehicle is secured.

The advantages of this solution are a much higher theft security and reduction of insurance fraud.

The technical effort is already present in the vehicle by including it Assemblies (number code car radio) reduced so that separate input devices do not are necessary.

The components required to solve the invention are advantageous already integrated in the car radio and designed the same so that the number code from User can be freely chosen that the code entry is possible and the hidden Deletion of the number code chosen for the theft protection, not the others Car radio functions impaired.

Claims (2)

1. Circuit arrangement for theft protection of motor vehicles with interruption circuits for, for example, ignition, fuel supply and starter and number code-secured car radio, characterized in that the ignition voltage and the door contact voltage are supplied to a logic module which checks the number code programmed in the car radio when the ignition and door contact circuit is closed and at Deviation from this by the logic module by means of an interrupter circuit, the power supply for the ignition, fuel supply and starter is switched off and, when the door contact circuit is interrupted, the ignition circuit is simultaneously interrupted. 2. Circuit arrangement according to claim 1, characterized in that the Interrupt circuit switches with a time delay.