Breakerless flywheel magneto ignition system

Abstract

This invention provides an improved magneto system which is reliable and stable irrespective of environmental conditions, wear and the like, and has no contacts, breakers or other moving parts in addition to the rotor itself. The conduction in the magneto winding means is initiated and terminated by a solid state device and preferably a solid state threshold device which is responsive to impulses of electrical energy to change its state between one of conduction and nonconduction whereby magneto operation can be controlled by relatively short duration trigger impulses. The trigger impulses may automatically produce a spark advance for increased magneto speeds.

What is claimed is: .[.1. In a magneto system including stator means, rotor means cyclically movable relative to said stator means and a magnetoelectric assembly including armature means on said rotor means and magnetically coupled first and second winding means on said stator means, said armature means inducing voltages in said first and second winding means as said rotor means moves relative to said stator means, the improvement comprising a solid state threshold device having conductive terminals connected across said first winding means and trigger coil means mounted on said stator means and providing a timed bipolar cyclic electrical signal in response to movement of said rotor means, said trigger coil means being electrically connected to said threshold device to render said threshold device conductive at an initial time in the cycle of movement when said signal is of one polarity and substantially nonconductive at a predetermined later time during said cycle of said rotor when said polarity is reversed, said solid state threshold device having characteristics such that it remains nonconductive until said trigger coil means renders it conductive in a subsequent cycle, a high voltage impulse being generated in said second winding means in response to said timed electrical signal..]. .[.2. The magneto system of claim 1 including a trigger coil assembly mounted on said stator means, a source of magnetic flux mounted on said rotor means, magnetic pole pieces mounted on said rotor in association with said flux source, said pole pieces cooperating with said magneto coil assembly to generate a voltage therein, and second pole pieces mounted in said rotor in association with said flux source, said second pole pieces cooperating with said trigger coil assembly to generate a voltage therein, and circuit means operatively interconnecting said coil assemblies..]. .[.3. The magneto system of claim 1 wherein said trigger coil means provides timed electrical signals having a gradually increasing magnitude directly related to the rate of movement of said rotor means, conduction between said conductive terminals being terminated at earlier times in said cycle for increased rates of rotor movement..]. .[.4. The magneto system of claim 1 wherein said trigger coil means comprises a first trigger coil and a second trigger coil, each providing a bipolar cyclic signal to said threshold device, said threshold device being rendered nonconductive at low rates of rotor movement in response to the combined energy of said coils, the signal of one of said coils terminating conduction through said threshold device at an advanced time in said cycle for increased rates of rotor movement..]. .[.5. The magneto system of claim 4 wherein the effective ratio of inductance to resistance in said first coil is substantially different from the effective ratio of inductance to resistance in said second coil..]. .[.6. The magneto system of claim 5 including means for altering the effective ratio of inductive reactance to resistance of one of said coils, the relationship of the time at which the threshold device is rendered nonconductive to the rate of rotor movement being controllable thereby..]. .[.7. The magneto system of claim 1 wherein said trigger coil means includes a first coil connected to said threshold device to initiate conduction therein at said initial time, a second coil and an energy storage circuit energized therefrom, and a third coil connected to said energy storage circuit to apply said energy storage circuit to said 
     
        threshold device at said later time..]. 8. In a magneto system including stator means, rotor means cyclically movable relative to said stator means and a magnetoelectric assembly including two poled armature means and a flux source on said rotor means, an E-shaped magnetic core having first, center and last legs and secured to said stator means, said core cooperating with said armature means to provide low reluctance flux paths first between said first and center legs and subsequently between said center and last legs as said rotor moves through its cycle, and first and second winding means coupled to said center leg to produce in each of said winding means a first voltage, a second voltage of reversed polarity and a third voltage of the same polarity as said first voltage as said rotor moves through said cycle, the improvement comprising a solid state threshold device having conductive terminals connected across said first winding and poled for conduction in response to said second voltage and trigger coil means mounted on said stator means and providing a timed cyclic bipolar electrical signal in response to movement of said rotor means, said trigger coil means being electrically connected to said threshold device to render said threshold device conductive at an initial time in the cycle of movement when said signal is of a first polarity and substantially nonconductive at a predetermined later time during said cycle of said rotor when said polarity is reversed, said solid state threshold device having characteristics such that it remains nonconductive until said trigger coil means renders it conductive in a subsequent cycle, a high voltage impulse being generated in said second winding in response to said timed electrical signal.[...]. .Iadd.rendering said solid state 
     
     
        threshold device nonconductive. .Iaddend. 9. The magneto system of claim 8 wherein said trigger coil means comprises a first trigger coil and a second trigger coil, each providing a bipolar cyclic signal to said threshold device, said threshold device being rendered nonconductive at low rates of rotor movement in response to the combined energy of said coils, the signal of one of said coils predominating in terminating conduction through said threshold device for increased rates of rotor 
     
     
        movement. 10. The magneto system of claim 9 wherein the effective ratio of inductance to resistance in said first coil is substantially different from the effective ratio of inductance to resistance in said second coil. 
     
     
         1. The magneto system of claim 10 including means for altering the effective ratio of inductance to resistance of one of said coils, the relationship of said high voltage impulse to rate of rotor movement being 
     
     
        controllable thereby. 12. The magneto system of claim 8 wherein said trigger coil means includes a first coil connected to said threshold device to initiate conduction therein at said initial time, a second coil and an energy storage circuit energized therefrom, and a third coil connected to said energy storage circuit to apply said energy storage circuit to said threshold device at said later time. .[.13. In a magneto system including a magnetoelectric assembly having winding means and flux means, said winding means and flux means being cyclically movable relative to one another in a flux linking relationship, the improvement comprising a solid state threshold device having conductive terminals connected across said winding means and a control terminal, and means activated by said cyclic movement and electrically connected to the control terminal of said threshold device to render said threshold device conductive at an initial time in the cycle of movement and substantially nonconductive at a later predetermined time during said cycle, said solid state threshold device having characteristics such that it remains nonconductive until said means activated by said cyclic movement renders it conductive in a subsequent cycle, a high voltage impulse being generated in said winding means in response to the rendering of said threshold device nonconductive..]. .[.14. In a magneto system including a magnetoelectric assembly having magnetically coupled first and second winding means and flux means, said winding means and flux means being cyclically movable relative to one another in a flux linking relationship, the improvement comprising a solid state threshold device having conductive terminals connected across said first winding means and a control terminal and control means activated by said cyclic movement and electrically connected to said control terminal to render said threshold device conductive at an initial time in the cycle of movement and substantially nonconductive at a later predetermined time during said cycle, said solid state threshold device having characteristics such that it remains nonconductive until said means activated by said cyclic movement renders it conductive in a subsequent cycle, a high voltage impulse being generated in said second winding means in response to the rendering of said threshold device nonconductive..]. .[.15. The magneto system of claim 14 wherein said threshold device has an anode connected to one terminal of said first winding means and a cathode connected to the other terminal of said first winding means, and wherein diode means is connected across said first winding with its cathode connected to said one terminal and its anode connected to said other terminal..]. .Iadd. 16. In a magneto system including stator means, rotor means cyclically movable relative to said stator means and a magnetoelectric assembly including armature means on said rotor means and magnetically coupled first and second winding means on said stator means, said armature means inducing voltages in said first and second winding means as said rotor moves relative to said stator means, the improvement comprising a solid-state threshold device having conductive terminals connected across said first winding means and a trigger coil means mounted on said stator means and providing a timed bipolar cyclical electrical signal in response to movement of said rotor means, said trigger coil means being electrically connected to said threshold device to render said threshold device conductive at an initial time in the cycle of movement when said signal is of one polarity and substantially nonconductive at a predetermined later time during said cycle of said rotor when said polarity is reversed, said solid state threshold device having characteristics such that it remains nonconductive until said trigger coil means renders it conductive in a subsequent cycle, a high-voltage impulse being generated in said second winding means in response to said timed electrical signal rendering said solid-state threshold device nonconductive, said trigger coil means including a first trigger coil and a second trigger coil, each providing a bipolar signal to said threshold device, said threshold device being rendered nonconductive at low rates of rotor movement in response to the combined energy of said coils, the signal of one of said coils terminating conduction through said threshold device at an advanced time in said cycle for increased rates of rotor movement. .Iaddend..Iadd. 17. The magneto system of claim 16 wherein the effective ratio of inductance to resistance in said first coil is substantially different from the effective ratio of inductance to resistance in said second coil. .Iaddend..Iadd. 18. The magneto system of claim 17 including means for altering the effective ratio of inductive reactance to resistance of one of said coils, the relationship of the time at which the threshold device is rendered nonconductive to the rate of rotor movement being controllable thereby. .Iaddend..Iadd. 19. The magneto system of claim 16 wherein said trigger coil means includes a first coil connected to said threshold device to initiate conduction therein at said initial time, a second coil and an energy storage circuit energized therefrom, and a third coil connected to said energy storage circuit to apply said energy storage circuit to said threshold device at said later time. .Iaddend.