Capacitor discharge type contactless ignition system for internal combustion engines

Claim 1

A capacitor discharge type contactless ignition system for an internal combustion engine comprising; a first capacitor charging coil mounted in a magneto generator driven by an engine and for generating a first alternating current in accordance with the rotation of said magneto generator; a second capacitor charging coil mounted in said magneto generator and for generating a second alternating current in accordance with the rotation of said magneto generator whose phase is retarded by a certain angle from that of said first alternating current, whereby when the engine rotates in an undesired direction the second positive half wave of said second alternating current being generated prior to the first positive half wave or said first alternating current and the latter certain part of said second positive half wave overlapping the former certain part of said first positive half wave; a capacitor means forming a capacitor charging circuit connected in series with said first and second capacitor charging coils and including rectifying means for rectifying said first and second alternating current and applying the rectified current to said capacitor; means forming a capacitor discharging circuit including said capacitor, a semi-conductor switching element having a control gate and a primary winding of an ignition coil having a primary and secondary winding; a spark plug connected with said secondary winding of said ignition coil; and a pulse generator connected with said control gate and for generating an ignition pulse in Synchronism with the rotation of said magneto generator during the rotation of the engine in a desired direction, whereby the charge stored in said capacitor is discharged through said capacitor discharging circuit, to thereby induce a high voltage at said secondary winding to produce an ignition spark at said spark plug; said pulse generator generating a reverse protecting pulse during the rotation of the engine in an undesired direction in order to make said semi-conductor switching element conductive for each period while said second positive half wave is generated, whereby said second positive half wave is shortcircuited around said capacitor and said first positive half wave is sequentially short-circuited through said semiconductor switching element due to the overlap of said first and second positive half wave, thus preventing said spark plug from producing an ignition spark which may otherwise keep the rotation of the engine in the undesired direction.