Diebstahlschutzeinrichtung als Immobilisationseinrichtung an einem Kraftfahrzeug

摘要

The invention relates to an anti-theft device as an immobiliser on a motor vehicle, having an ignition lock consisting of a mechanical lock component (2) and an electric lock component (3) which is connected thereto and having at least one component (14) whose operation can be blocked in order to immobilise the vehicle. According to the invention a circuit (10) is provided as a monitoring circuit from which a conductor loop (11) leads from the electrical lock component (3) to the region of the mechanical lock component (2). An electronic evaluation device which detects unacceptable electrical changes in the circuit (10) and then blocks a component (14), preferably an engine control unit, in order to bring about immobilisation is connected to the circuit (10). If force is applied to the ignition lock (1), the conductor loop (11) is disconnected and the same kind of blocking is brought about. In advantageous developments, a resistance measurement (resistor 12) in the monitoring circuit (10) is additionally proposed, as is the monitoring of the simultaneous occurrence of switching processes by the ignition switch and a clocked evaluation, also in conjunction with a bit sequence.