Capacitive discharge solid state ignition system

Claim 2

In an ignition system for an internal combustion engine where firing potential is delivered by a high voltage ignition coil or the like in response to firing commands having a repetition rate dependent upon engine speed, capacitive discharge ignition apparatus comprising: an oscillator operable in response to excitation by a direct current; a step-up transformer having a primary winding coupled with the output of said oscillator, and a secondary winding for providing an alternating current substantially higher in voltage than said direct current; a storage capacitor; rectifier means coupled with said secondary winding and said capacitor for rectifying said alternating current and charging the capacitor with the rectified current when the oscillator is operative; a feedback connection from the output of said rectifier means to said oscillator; means for connecting said capacitor to said coil to establish a path for current flow through the coil upon discharge of the capacitor; control means coupled with said capacitor for discharging the latter and momentarily shorting the output of said rectifier means in response to each of said firing commands, said feedback connection terminating operation of the oscillator in response to said shorting of the rectifier means output during said discharging of the capacitor, whereby to provide positive oscillator turnoff with the occurrence of each firing command and synchronization of the oscillator frequency with the repetition rate of the commands, said oscillator including at least one active electrical device provided with a plurality of terminals and having conductive and nonconductive states assumed alternately during operation of the oscillator, said feedback connection delivering said rectified current to a first of said terminals for conduction through said device to a second of said terminals thereof, whereby said first and second terminals are shorted across said rectifier means output when the latter is shorted by the control means, thereby effecting termination of oscillator operation; and circuit means connecting said second terminal to said capacitor to effect said charging of the latter when said device is in its conductive state.

Claim 3

Apparatus as claimed in claim 1, there being a pair of said devices arranged for push-pull operation and each comprising a transistor having an emitter, a base, and a collector presenting said plurality of terminals, there being a pair of said feedback connections from said rectifier means output to the first terminals of respective devices, said second terminal of each device being the emitter thereof, said emitters being interconnected to provide a common emitter oscillator configuration.

Claim 4

Apparatus as claimed in claim 1, said control means including a silicon controlled rectifier having an anode, a cathode, and a gate, said anode and cathode being serially connected in said path for current flow through the coil, a trigger transformer having a primary winding and a secondary winding, means connected with said primary winding of the trigger transformer for delivering a pulse thereto in response to each firing command, and means coupling said secondary winding of the trigger transformer with said cathode and said gate to trigger the silicon controlled rectifier in response to delivery of said pulse.

Claim 5

Apparatus as claimed in claim 3, said control means further including diode shunting said secondary winding of the trigger transformer and having an anode and a cathode, said anode of the diode being connected with the cathode of the silicon controlled rectifier whereby, when the rectifier conducts, the diode is also placed in conduction to short the secondary winding of the trigger transformer.

Claim 6

Apparatus as claimed in claim 1, said control means including a switching component serially connected in said current path for connection of said coil and said component in series across the output of said rectifier means, said capacitor being connected across the output of said rectifier means, whereby the capacitor and the coil are coupled in a parallel arrangement such that the capacitor is not charged through the coil.

Claim 7

In an ignition system for an internal combustion engine where firing potential is delivered by a high voltage ignition coil or the like in response to firing commands having a repetition rate dependent upon engine speed, capacitive discharge ignition apparatus comprising: an oscillator operable in response to excitation by a direct current; a step-up transformer having a primary winding coupled with the output of said oscillator, and a secondary winding for providing an alternating current substantially higher in voltage than said direct current; a storage capacitor; rectifier means coupled with said secondary winding and said capacitor for rectifying said alternating current and charging the capacitor with the rectified current when the oscillator is operative; a feedback connection from the output of said rectifier means to said oscillator; means for connecting said capacitor to said coil to establish a path for current flow through the coil upon discharge of the capacitor; control means coupled with said capacitor for discharging the latter and momentarily shorting the output of said rectifier means in response to each of said firing commands, said feedback connection terminating operation of the oscillatoR in response to said shorting of the rectifier means output during said discharging of the capacitor, whereby to provide positive oscillator turnoff with the occurrence of each firing command and synchronization of the oscillator frequency with the repetition rate of the commands, said oscillator including at least one transistor device provided with input and output terminals for said rectified current and having conductive and nonconductive states assumed alternately during operation of the oscillator, said feedback connection delivering said rectified current to said input terminal for conduction through said device to said output terminal thereof, whereby said input and output terminals are shorted across said rectifier means output when the latter is shorted by the control means, thereby effecting termination of oscillator operation; and circuit means connecting said output terminal to said capacitor to effect said charging of the latter when said device is in its conductive state.

Claim 8

In an ignition system for an internal combustion engine where firing potential is delivered by a high voltage ignition coil or the like in response to firing commands having a repetition rate dependent upon engine speed, capacitive discharge ignition apparatus comprising: an oscillator operable in response to excitation by a direct current; a step-up transformer having a primary winding coupled with the output of said oscillator, and a secondary winding for providing an alternating current substantially higher in voltage than said direct current; a storage capacitor; rectifier means coupled with said secondary winding and said capacitor for rectifying said alternating current and charging the capacitor with the rectified current when the oscillator is operative; a feedback connection from the output of said rectifier means to said oscillator; means for connecting said capacitor to said coil to establish a path for current flow through the coil upon discharge of the capacitor; control means coupled with said capacitor for discharging the latter and momentarily shorting the output of said rectifier means in response to each of said firing commands, said feedback connection terminating operation of the oscillatoR in response to said shorting of the rectifier means output during said discharging of the capacitor, whereby to provide positive oscillator turnoff with the occurrence of each firing command and synchronization of the oscillator frequency with the repetition rate of the commands, said oscillator including at least one transistor device provided with input and output terminals for said rectified current and having conductive and nonconductive states assumed alternately during operation of the oscillator, said feedback connection delivering said rectified current to said input terminal for conduction through said device to said output terminal thereof, whereby said input and output terminals are shorted across said rectifier means output when the latter is shorted by the control means, thereby effecting termination of oscillator operation; and circuit means connecting said output terminal to said capacitor to effect said charging of the latter when said device is in its conductive state.

Claim 9

In an ignition system for an internal combustion engine where firing potential is delivered by a high voltage ignition coil or the like in response to firing commands having a repetition rate dependent upon engine speed, capacitive discharge ignition apparatus comprising: an oscillator operable in response to excitation by a direct current; a step-up transformer having a primary winding coupled with the output of said oscillator, and a secondary winding for providing an alternating current substantially higher in voltage than said direct current; a storage capacitor; rectifier means coupled with said secondary winding and said capacitor for rectifying said alternating current and charging the capacitor with the rectified current when the oscillator is operative; a feedback connection from the output of said rectifier means to said oscillator; means for connecting said capacitor to said coil to establish a path for current flow through the coil upon discharge of the capacitor; and control means coupled with said capacitor for discharging the latter and momentarily shorting the output of said rectifier means in response to each of said firing commands, said feedback connection terminating operation of the oscillator in response to said shorting of the rectifier means output during said discharging of the capacitor, whereby to provide positive oscillator turnoff with the occurrence of each firing command and synchronization of the oscillator frequency with the repetition rate of the commands, said oscillator including at least one active electrical device provided with a plurality of terminals and having conductive and nonconductive states assumed alternately during operation of the oscillator, said feedback connection delivering said rectified current to a first of said terminals for conduction through said device to a second of said terminals thereof, whereby said first and second terminals are shorted across said rectifier means output when the latter is shorted by the control means, thereby effecting termination of oscillator operation.

Claim 10

In an ignition system for an internal combustion engine where firing potential is delivered by a high voltage ignition coil or the like in response to firing commands having a repetition rate dependent upon engine speed, capacitive discharge ignition apparatus comprising: an oscillator operable in response to excitation by a direct current; a step-up transformer having a primary winding coupled with the output of said oscillator, and a secondary winding for providing an alternating current substantially higher in voltage than said direct current; a storage capacitor; rectifier means coupled with said secondary winding and said capacitor for rectifying said alternating current and charging the capacitor with the rectified current when the oscillator is operative; a feedback connection from the output of said rectifier means to said oscillator; means for connecting said capacitor to said coil to establish a path for current flow through the coil upon discharge of the capacitor; and control means coupled with said capacitor for discharging the latter and momentarily shorting the output of said rectifier means in response to each of said firing commands, said feedback connection terminating operation of the oscillator in response to said shorting of the rectifier means output during said discharging of the capacitor, whereby to provide positive oscillator turnoff with the occurrence of each firing command and synchronization of the oscillator frequency with the repetition rate of the commands, said oscillator including at least one active electrical device provided with a plurality of terminals and having conductive and nonconductive states assumed alternately during operation of the oscillator, said feedback connection delivering said rectified current to a first of said terminals for conduction through said device to a second of said terminals thereof, whereby said first and second terminals are shorted across said rectifier means output when the latter is shorted by the control means, thereby effecting termination of oscillator operation.

Claim 11

In an ignition system for an internal combustion engine where firing potential is delivered by a high voltage ignition coil or the like in response to firing commands having a repetition rate dependent upon engine speed, capacitive discharge ignition apparatus comprising: an oscillator operable in response to excitation by a direct current; a step-up transformer having a primary winding coupled with the output of said oscillator, and a secondary winding for providing an alternating current substantially higher in voltage than said direct current; a storage capacitor; rectifier means coupled with said secondary winding and said capacitor for rectifying said alternating current and charging the capacitor with the rectified current when the oscillator is operative; means for connecting said capacitor to said coil to establish a path for current flow through the coil upon dIscharge of the capacitor; and control means coupled with said capacitor for discharging the latter in response to each of said firing commands, said control means including a silicon controlled rectifier having an anode, a cathode, and a gate, said anode and cathode being serially connected in said path for current flow through the coil, a trigger transformer having a primary winding and a secondary winding, means connected with said primary winding of the trigger transformer for delivering a pulse thereto in response to each firing command, means coupling said secondary winding of the trigger transformer with said cathode and said gate to trigger the silicon controlled rectifier in response to delivery of said pulse, and a diode shunting said secondary winding of the trigger transformer and having an anode and a cathode, said anode of the diode being connected with the cathode of the silicon controlled rectifier whereby, when the rectifier conducts, the diode is also placed in conduction to short the secondary winding of the trigger transformer.

Claim 12

In an ignition system for an internal combustion engine where firing potential is delivered by a high voltage ignition coil or the like in response to firing commands having a repetition rate dependent upon engine speed, capacitive discharge ignition apparatus comprising: an oscillator operable in response to excitation by a direct current; a step-up transformer having a primary winding coupled with the output of said oscillator, and a secondary winding for providing an alternating current substantially higher in voltage than said direct current; a storage capacitor; rectifier means coupled with said secondary winding and said capacitor for rectifying said alternating current and charging the capacitor with the rectified current when the oscillator is operative; means for connecting said capacitor to said coil to establish a path for current flow through the coil upon dIscharge of the capacitor; and control means coupled with said capacitor for discharging the latter in response to each of said firing commands, said control means including a silicon controlled rectifier having an anode, a cathode, and a gate, said anode and cathode being serially connected in said path for current flow through the coil, a trigger transformer having a primary winding and a secondary winding, means connected with said primary winding of the trigger transformer for delivering a pulse thereto in response to each firing command, means coupling said secondary winding of the trigger transformer with said cathode and said gate to trigger the silicon controlled rectifier in response to delivery of said pulse, and a diode shunting said secondary winding of the trigger transformer and having an anode and a cathode, said anode of the diode being connected with the cathode of the silicon controlled rectifier whereby, when the rectifier conducts, the diode is also placed in conduction to short the secondary winding of the trigger transformer.