US Patent 7496431 Rolling away protection after engine switch off and security device

In order to satisfy the key interlock regulation in a system for keyless starting of a motor vehicle by an ID transducer carried by the vehicle user and a control element (2) for starting and stopping the engine, a mechanism is provided such that the engine can only be stopped when the gear position “P” for Park is engaged but the engine can be stopped at a vehicle speed (v) equal to or greater than a preset threshold speed (v-threshold) without the gear position “P” for Park being engaged, so that the driver can turn off the engine in emergencies even while driving.