Electronic key

0001The invention relates to an electronic key for the contactless Unlocking a motor vehicle, with a receiving unit and a Transmitting unit for transmitting an identification signal upon occurrence an excitation signal.

0002For the contactless unlocking a motor vehicle are increasingly Measurements used electronic keys. Such key responsive to an excitation signal in from the motor vehicle periodically emitted. The key sends Reception of this signal, in turn, an identification signal which is received and verified by the motor vehicle. Once an identification the key was successfully carried out, the unlocked vehicle and released to the owner of the key.

0003Previous experiences have shown that there are definitely methods the key also further distances for sending to cause the identification signal and the identification signal catch. In this way, the identification signal of the key come into possession of unauthorized persons and to open the motor vehicle be misused.

0004Furthermore, is consumed at every discharge of the identification signal energy. This energy is wasted when the key Excitation signals of other motor vehicles misinterpreted and an identification signal sending or when the key continuously for emitting the identification signals is excited, even while the motor vehicle is not used.

0005Object of the present invention is to provide an electronic key provide for a motor vehicle, which is opposed by external excitation Unauthorized is protectable. to the transmission of the identification signal further can be suppressed when not using the key.

0006This object is achieved by the fact that the prevention of the transmission an identification signal, the power supply of the key is interrupted by one arranged on the key switch.

0007Once the user does not need the key, it switches this simply. It is thus an unauthorized impossible by means of a counterfeit excitation signal the key to transmitting its Identification signal to excite. Further, the key is also to other, harmless excitation signals to stop responding and therefore significantly reduce its energy consumption.

0008Thus, the owner of the key on a registered Key from is attentive excitation signal, wherein a first embodiment of Invention provided a signal transmitter on the key, which in appearance the excitation signal emits a warning. For this purpose, on the one hand be provided that the signal transmitter is a buzzer, which in Occurrence of the excitation signal emits a warning tone. On the other hand, also be provided that the signal generator is a lamp, which at Occurrence of the excitation signal lights.

0009Once the warning is issued, the owner of the key can this off and thus prevent unauthorized identification signal can receive.

0010To relieve the user of the key is in a development provided that a movement sensor is embedded in the key, the movements of the key registered. Furthermore, it is provided that the key is automatically disabled when he prescribed for a Time has not been moved.

0011The invention permits numerous embodiments. One of them is in the illustrated drawings with reference to two figures and described below. It shows:<sl><li>Figure 1: safety device of a motor vehicle</li><li>Figure 2: electronic key.</li></sl>

0012Identical parts are provided in the figures with the same reference numerals.

0013In the shown in Figure 1 according to the invention and vehicle access Drive authorization system is a contactless interrogation of a as transmitter 1 formed identification transmitter (remote control key), the Opening and starting a vehicle more comfortable designed. The transmitter 1 can be anywhere on the body (for example in the trouser or jacket ash) are worn and must not intentionally to be served. The remote control key is a start signal transmission device fully automatically without manual user intervention activated. The enable signal is only emitted when the the remote control key wearer at a predetermined distance to Motor vehicle is disposed within the range of the transmitter of Transmission device is.

0014The device has a designed as a safety device 2 transfer means on which in a motor vehicle shown in Figure 1 is permanently installed. The remote control key 1 includes a processing unit 3, which over a long wave receiver 4 and a shortwave transmitter 5 features. From a random 6 numbers are generated from which with the aid of data stored in the computing unit 3 algorithm coding is generated.

0015The security device 2 also includes a computing unit 7, with a longwave transmitter 8 and a shortwave receiver 9 connected is. In addition, the arithmetic unit 7, a control unit represents that with a central 10 and an immobilizer 11 of the motor vehicle is connected to the control thereof. One at a door handle of the motor vehicle disposed sensor 12 provides a signal to the Computing unit 7, when a door handle is operated. These computing unit 7 includes a random number by a random generator 15, which they processed with the aid of an algorithm identical to that in the Processor 3 stored algorithm works.

0016Between the remote control key 1 and the safety device 2 contactless exchanged signals. Receives the computing unit 7 of Safety device 2 a signal from the sensor 12, generates the arithmetic unit 7 a start signal 13 which are transmitted through the long-wave transmitter 8 is (Challenge).

0017This start signal 13 consists of at least two code units, with the first code share a vehicle identifier corresponding fixed code and the second code portion includes a variable identifier, which as real challenge signal is used. but it is also conceivable that both Parts of the start signal 13 are designed as a fixed code or both parts a variable identifier include. It is the advantage of the variable identifier, that, after each transmission by the computing unit 7 of the Controller can be changed in the motor vehicle, which means an additional allows system security.

0018This excitation signal 13 is the long-wave receiver 4 of the Radio key 1 received, after which the processing unit 3 of the radio key 1 is activated and the transmission of an identification signal 14 causes (Response).

0019The shortwave receiver 9 of the safety device 2 receives the Signal 14 and forward it to the computing unit 7 further that the identification signal 14 with a stored in it or by the algorithm compares the generated code. If they match the information are the arithmetic unit 7 either a drive signal to the Central 10 of the vehicle for opening or closing the Vehicle doors and / or or to an immobilizer 11 for activating Deactivation of the drive of the motor vehicle.

0020In order to prevent transmission of the excitation signal is carried out at 13 an unauthorized person an identification signal is generated 14, is between the arithmetic unit 3 and the battery U_B a switch 16 is arranged.

0021According to Figure 2 is to the electronic key 1 buzzer 15 arranged that upon receipt of an excitation signal 13 a Beep emits. By means of a slide switch 16 can be the power supply U_B Key 1 stop as soon as a warning carried out or the key is not needed. The key shown 1 comprises a mechanical key part 17 for actuating the ignition lock or other locks on. However, the invention also comprises Keys that do not require mechanical key part, or those with integrated remote control.