Capactive discharge ignition circuit

Claim 2

A capacitive discharge ignition circuit for an internal combustion engine comprising: a magneto operably connected to the engine and having at least one winding; a spark plug transformer having primary and secondary windings; a storage capacitor connected to said magneto winding for being charged with the output voltage of said magneto during the first half cycle thereof; a thyristor connected to said storage capacitor for forming a discharge circuit for said storage capacitor together with said primary winding: resistance means connected to the gate of said thyristor across which the voltage appears during the second half cycle, the voltage across said resistance means being applied to the gate of said thyristor, a diode for forming a closed circuit together with said thyristor and said resistance means so as to remove the voltage from said gate once said thyristor is fired; and further comprising a diode connected between said magneto winding and a reference potential so that it conducts thereby inhibiting the output of said magneto winding from being applied to said resistance means during the first half cycle.

Claim 3

A circuit as claimed in claim 1, wherein said resistance means includes a thermistor.

Claim 4

A circuit as claimed in claim 1, wherein said magneto has a main winding and a further winding connected in series with said main winding, the number of turns of said further winding being larger than that of said main winding.

Claim 5

A capacitive discharge ignition circuit for an internal combustion engine comprising: a magneto operably connected to the engine, said magneto having a main winding, a further winding connected in series with said main winding, the number of turns of said further winding being larger than that of said main winding, and means for short-circuiting said further winding during the second half cycle of said magneto voltage; a spark plug transformer having primary and secondary windings; a storage capacitor connected to said magneto winding for being charged with the output voltage of said magneto; a thyristor connected to said storage capacitor for forming a discharge circuit for said storage capacitor together with said primary winding; the size of said storage capacitor and the windings of said magneto being set so as to limit charging of said storage capacitor to the first half cycle of the voltage produced across said winding; resistance means connected to the gate of said thyristor across which the voltage appears during the second half cycle, the voltage across said resistance means being applied to the gate of said thyristor, and further comprising a diode for forming a closed circuit together with said thyristor and said resistance means so as to remove the voltage from said gate once said thyristor is fired.

Claim 6

A capacitive discharge ignition circuit for an internal combustion engine comprising: a magneto operably connected to the engine, said magneto having a main winding, a further winding connected in series with said main winding, the number of turns of said further winding being larger than that of said main winding, and means for short-circuiting said further winding during the second half cycle of said magneto voltage; a spark plug transformer having primary and secondary windings; a storage capacitor connected to said magneto winding for being charged with the output voltage of said magneto; a thyristor connected to said storage capacitor for forming a discharge circuit for said storage capacitor together with said primary winding; the size of said storage capacitor and the windings of said magneto being set so as to limit charging of said storage capacitor to the first half cycle of the voltage produced across said winding; resistance means connected to the gate of said thyristor across which the voltage appears during the second half cycle, the voltage across said resistance means being applied to the gate of said thyristor, and further comprising a diode for forming a closed circuit together with said thyristor and said resistance means so as to remove the voltage from said gate once said thyristor is fired.

Claim 7

A circuit as claimed in claim 4, wherein said short-circuiting means is a diode which is connected in parallel with said further winding.

Claim 8

A circuit as claimed in claim 4, further comprising means for permitting only the voltage produced across said main winding during the second half cycle to be applied directly to said resistance means.

Claim 9

A circuit as claimed in claim 4, further comprising means for permitting only the voltage produced across said main winding during the second half cycle to be applied to said resistance means through said short-circuited further winding.

Claim 10

A circuit as claimed in claim 1, wherein said diode is coupled in series between the anode and gate of said thyristor.

Claim 11

A circuit as claimed in claim 3, further comprising means for permitting only the voltage produced across said main winding during the second half cycle to be applied directly to said resistance means.

Claim 12

A circuit as claimed in claim 4, further comprising: means for permitting the current flowing to said resistance means to flow through said main winding but not through said further winding during said second half cycle.

Claim 13

A circuit as claimed in claim 10, wherein said means for permitting current to flow is a diode with its anode connected to ground potential and its cathode connected between said main and further windings.

Claim 14

A circuit as claimed in claim 3, further comprising: means for permitting the current flowing to said resistance means to flow through said main winding but not through said further winding during said second half cycle.

Claim 15

A circuit as claimed in claim 12, wherein said means for permitting current to flow is a diode with its anode connected to ground potential and its cathode connected between said main and further windings.

Claim 16

A circuit as claimed in claim 4, further comprising: means for permitting current to flow through said winding and said short-circuited further winding during said second half cycle so that the current is retarded by the reactance of said further winding but only the voltage produced across said main winding is applied to said resistance means.

Claim 17

A circuit as claimed in claim 14, wherein said means for permitting the current in said resistance means to flow comprises a diode with its anode connected to ground potential and its cathode connected to the end of said further winding not connected to said main winding.