Eltra Corporation

Gerald M Owen

William J Roberts

An electronic ignition system having an automatic shutdown feature is disclosed. In a first embodiment of the invention, should an output terminal of an integrated circuit (10, 10a) remain in a high voltage condition for a prolonged period of time, a capacitor (C100) which is charged from a constant voltage and alternately discharged through a terminal (105) of the integrated circuit, is allowed to charge, and gradually reaches the threshold voltage of a transistor (Q200) which is connected to shunting transistor (Q1), which diverts current from transistor (Q2) in series with an ignition coil primary winding (76, 76a) and gradually deenergizes the ignition system. In a second embodiment, a capacitor (C200) is charged from a constant voltage, and alternately discharged by being shorted by an inverting transistor (Q300) connected to a terminal (205) of an integrated circuit (200, 200a), which provides a signal which is the compliment of an output terminal. Thus, an ignition system according to the invention remains energized for a short period of time following the accidental or intentional stopping of an engine, and then is gradually deenergized, without producing a spark which may cause the engine to unexpectedly start.

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Hartselle, AL, United States of America

Gerald M Owen