Engine ignition method and engine ignition device

An engine ignition device that applies a high voltage to an ignition plug attached to a cylinder of an engine to produce spark discharges in the ignition plug, the engine ignition device comprising:

• a magneto generator that is provided with a magneto rotor having a three-pole magnetic field formed at an outer circumference of a flywheel attached to a crank shaft of the engine and a stator having an armature core with a magnetic pole part opposed to the poles of the magnetic field of the magneto rotor and having a plurality of coils served as magneto coils which are wound around the armature core, the plurality of coils including an exciter coil and a primary coil of an ignition coil and a secondary coil of the ignition coil, the magneto generator sequentially outputting, from the magneto coils, a first half-wave voltage, a second half-wave voltage of a different polarity from the first half-wave voltage, and a third half-wave voltage of the same polarity as the first half-wave voltage during one rotation of the crank shaft;
• an ignition capacitor that is provided on a primary side of the ignition coil;
• a charging switch that is provided so as to be turned on when the second half-wave voltage is induced in the exciter coil and to form a circuit that charges the ignition capacitor with the second half-wave voltage;
• an ignition switch that is provided so as to be turned on when an ignition signal is provided and to form a discharging circuit that discharges, through the primary coil, electric charge accumulated in the ignition capacitor;
• and
• a microcomputer that is programmed so as to perform
• a processing for detecting an ignition timing of the engine,
• a processing for supplying an ignition signal to the ignition switch to place the ignition switch to be turned on in order to produce a first spark discharge in the ignition plug when the ignition timing is detected,
• a processing for controlling the ignition switch and the charging switch so as to give rise to a state in which both the ignition switch and the charging switch are in an open state thereby preventing current from flowing to the primary coil while insulation across a discharge gap of the ignition plug is in broken down state due to the first spark discharge, wherein
• the engine ignition device being configured so that a second spark discharge is produced in the ignition plug due to a voltage induced in the secondary coil of the ignition coil accompanied with a change in magnetic flux that is inputted to the armature core from the magneto rotor while the insulation across the discharge gap of the ignition plug is in the broken down state due to the first spark discharge.