Abstract An ignition apparatus for an internal combustion engine realizes a stable ignition control by ensuring an adequate capacitor charge voltage even in a high-speed engine operation. The apparatus comprises a trigger circuit (50) which includes a pulse generator (30) for sustaining a trigger signal for a predetermined period required for a capacitor (8) to discharge, and a switch (40) for applying a voltage to a gate of a thyristor 12 by opening a short-circuit between gate and cathode thereof. The gate-cathode path of the thyristor is short-circuited upon charging of the capacitor and after discharging thereof, to thereby set a hold current for the thyristor at a high level so that after lapse of a predetermined time and a turn-off time from the beginning of the discharge of the capacitor, the DC-DC converter (2) is restarted to secure an adequate capacitor charge voltage (d).
An ignition apparatus for an internal combustion engine, comprising: a DC-DC converter connected to a power supply source; a capacitor charged with a boosted voltage supplied from said DC-DC converter; an ignition coil having a primary winding connected to said capacitor and a secondary winding connected to a spark plug; a thyristor inserted in a discharge path of said capacitor, said discharge path including the primary winding of said ignition coil; and a trigger circuit for generating a trigger signal for turning on said thyristor in synchronism with an ignition timing signal generated at an ignition timing demanded for operation of said internal combustion engine; wherein said trigger circuit includes: pulse generating means for sustaining said trigger signal for a predetermined time required for said capacitor to discharge; switching means for applying a voltage to a gate electrode of said thyristor for opening a short circuit formed between said gate electrode and a cathode electrode of said thyristor for said predetermined time.
Claim 2
Dependent Claim
162 words
An ignition apparatus for an internal combustion engine, comprising: a DC-DC converter connected to a power supply source; a capacitor charged with a boosted voltage supplied from said DC-DC converter; an ignition coil having a primary winding connected to said capacitor and a secondary winding connected to a spark plug; a thyristor inserted in a discharge path of said capacitor, said discharge path including the primary winding of said ignition coil; and a trigger circuit for generating a trigger signal for turning on said thyristor in synchronism with an ignition timing signal generated at an ignition timing demanded for operation of said internal combustion engine; wherein said trigger circuit includes: pulse generating means for sustaining said trigger signal for a predetermined time required for said capacitor to discharge; switching means for applying a voltage to a gate electrode of said thyristor for opening a short circuit formed between said gate electrode and a cathode electrode of said thyristor for said predetermined time.
Claim 3
Dependent Claim
68 words
An ignition apparatus according to claim 1, wherein said pulse generating means includes an input terminal to which said ignition timing signal is applied, an emitter-grounded transistor having a base connected to said input terminal and a collector connected to a capacitor, while said switching means includes an emitter-grounded transistor having a base connected to said capacitor and a collector connected to said gate electrode of said thyristor.