METHOD OF AND DEVICE FOR PREVENTING UNAUTHORIZED STARTING OF INTERNAL COMBUSTION ENGINE Russian patent published in 1999 - IPC

FIELD: transport engineering; automobile antitheft devices. SUBSTANCE: DC balanced bridge circuit is connected to wire laid from corresponding contact of ignition switch coming from automobile cab and to contact proper. Bridge circuit turns unbalanced when voltage from storage battery is supplied to indicated wire by-passing contact of ignition switch with subsequent supply of alarm signal to bridge unbalance indicator placed in bridge diagonal, bridge unbalance indicator cuts ballast resistor into circuit of ignition coil primary winding or into starter solenoid switch winding circuit to preclude operation of corresponding winding. EFFECT: prevention of possibility of engine starting when ignition key is not available. 6 cl, 1 dwg