Patent ID: 6181026
Filing Date: 2001-01-30
Classification: B60R

Abstract:
An engine immobilizer for an engine in a vehicle, said vehicle having an ignition switch with at least an on position, said engine immobilizer comprising:a transponder coded with a unique security code to be in the possession of an authorized user of the vehicle;a transceiver mounted in said vehicle for interrogating said transponder to obtain said security code;at least one engine-running sensor mounted in said vehicle for detecting whether or not said engine is running; anda controller coupled to said transceiver and said engine running sensor and storing at least one authorized security code, said controller having an armed state during which it disables said engine and having a disarmed state during which it does not disarm said engine;wherein in response to an attempt to start said engine by activating said ignition switch, said controller in said armed state causes said transceiver to interrogate for said unique security code, detects existence of a match between said unique security code and said authorized security code, switches to said disarmed state if a match exists, and remains in said disarmed state while said engine is running; andwherein said controller in said disarmed state monitors said engine-running sensor and switches to said armed state if said engine running sensor indicates that said engine has stopped running even though said ignition switch is not detected to be in said off position.