Solid state ignition circuitry

Abstract

Solid state ignition circuitry for transmitting impulse voltages, produced by .[.a.]. magneto .Iadd.means .Iaddend.associated with an internal combustion engine, to a transformer, which, in turn, generates a high voltage impulse to produce sparks in the spark plugs of the engine. The circuitry includes two silicon controlled rectifiers adapted to control the discharge of a capacitor through the transformer. The capacitor charges during one part of a given time period, e.g., the positive half cycle of alternating current produced by the magneto, and the silicon controlled rectifiers are adapted to discharge the capacitor during the other part of such time period, e.g., the negative half cycle of such current. The particular instant at which the capacitor discharges can be varied by .Iadd.adjustable .Iaddend.means .Iadd.for applying controlled input voltages to the control electrodes of .[.of a potentiometer, which is associated with.]. the silicon controlled rectifiers. Thus, the timing of the ignition sparks generated in the spark plugs can .[.thus.]. be set by adjusting the .[.potentiometer.]. .Iadd.time at which the capacitor discharges..Iaddend.

What we claim is: 
     
       1. Circuitry for controlling the transmission of impulse voltages produced by a magneto on an internal combustion engine to a transformer which, in turn, generates a high voltage impulse to produce sparks in the spark plugs of the engine, said circuitry comprising, an input conductor .Iadd.means .Iaddend.adapted to receive impulse voltages from a magneto;   a first circuit connected to said input conductor .[.compris.]. .Iadd.means comprising .Iaddend.in series a first diode rectifier, a first capacitor and an output conductor, the latter being adapted to be connected to the transformer;   a second circuit connected between said first circuit and ground comprising, a first silicon controlled rectifier having an anode, cathode and a control electrode, with the cathode thereof connected to ground and the anode thereof connected to said first circuit between said first rectifier diode and said first capacitor;   a third circuit comprising, a second diode rectifier and a second silicon controlled rectifier connected in series between said input conductor and ground with the cathode and anode of said second diode rectifier being connected to the input conductor and the cathode of the second silicon controlled rectifier respectively, and the anode of said second silicon controlled rectifier being connected to ground, said second silicon controlled rectifier having a potentiometer shunting the anode and cathode thereof with the variable contact arm of said potentiometer being connected to the control electrode of said second silicon controlled rectifier, said third circuit also including a second capacitor and a resistor connected in series between the cathode of said second silicon controlled rectifier and ground, with the control electrode of said first silicon controlled rectifier being connected to said third circuit at a point therein intermediate between said second capacitor and said resistor.   
     
     
       2. Circuitry as claimed in claim 1 wherein said second silicon controlled rectifier is shunted by a series connection comprising a resistor, a potentiometer and another resistor. 
     
     
       3. Circuitry as claimed in claim 1 wherein a resistor shunts said second capacitor and resistor of said third circuit. 
     
     
       4. Circuitry as claimed in claim 1 in combination with an internal combustion engine having a magneto, transformer, and at least one spark plug. 
     
     
       5. Circuitry as claimed in claim 4 wherein a normally open switch is connected between a point intermediate between said first diode and said first capacitor and ground for stopping the engine. 
     
     
       6. Circuitry as claimed in claim 1 in combination with an internal combustion engine having a magneto, a transformer and from one to four cylinders with a spark plug for each cylinder. 
     
     
       7. The combination as claimed in claim 6 wherein the internal combustion engine has one cylinder. 
     
     
       8. The combination .[.is.]. .Iadd.as .Iaddend.claimed in claim 6 wherein the internal combustion engine has two cylinders. 
     
     
       9. The combination as claimed in claim 1 wherein the internal combustion engine has three cylinders. .Iadd. 10. Circuitry for controlling the transmission of impulse voltages produced by magneto means on an internal combustion engine to a transformer which, in turn, generates a high voltage impulse to produce sparks in the spark plugs of the engine, said circuitry comprising, input conductor means adapted to receive impulse voltages from a magneto;   a first circuit connected to said input conductor means comprising in series a first diode rectifier, a first capacitor and an output conductor, the latter being adapted to be connected to the transformer;   a second circuit connected between said first circuit and ground comprising, a first silicon controlled rectifier having an anode, cathode and a control electrode, with the cathode thereof connected to ground and the anode thereof connected to said first circuit between said first rectifier diode and said first capacitor;   a third circuit comprising, a second diode rectifier and a second silicon controlled rectifier connected in series between said input conductor means and ground with the cathode and anode of said second diode rectifier being connected to the input conductor means and the cathode of the second silicon controlled rectifier respectively, and the anode of said second silicon controlled rectifier being connected to ground, said third circuit also including a second capacitor and a resistor connected in series between the cathode of said second silicon controlled rectifier and ground, with the control electrode of said first silicon controlled rectifier being connected to said third circuit at a point therein intermediate between said second capacitor and said resistor; and   means in conjunction with said magneto means for applying controlled input voltages to the control electrode of said second silicon controlled rectifier. .Iaddend.