Electronic magneto ignition for internal combustion engines

Abstract

An electronic magneto ignition for internal combustion engines has a permanent magnet mounted on the engine fly wheel and rotating therewith. A magnetic field coil has a primary winding and a secondary winding in which ignition current and ignition voltage, respectively, are produced during the passage of the permanent magnet. A switching transistor is connected in parallel with the primary winding and in parallel with a diode poled opposite to the emitter-collector path of the transistor. An electronic control circuit blocks the switching transistor at the desired ignition time so that the primary circuit is interrupted and the high voltage for the combustion of the fuel is produced in the secondary winding. In the electronic control circuit, a parallel circuit consisting of a first control coil, which has a resistor in series therewith, and a thyristor is connected from the base to the emitter of the switching transistor. Another resistor is connected from the collector of the switching transistor, as a feedback resistor, to the control electrode of the thyristor. A second control coil has a potentiometer connected in parallel, the potentiometer having a movable tap so that a portion of the voltage applied to the resistor is fed to the control electrode of the thyristor. The first control coil is arranged at an angle from the ignition coil and the second control coil is arranged at an angle from the first control coil, as viewed in the direction of rotation of the fly wheel.