Ignition system supplying continuous source of sparks

Claim 2

In an ignition system for supplying a continuous source of spark ignition puLses having substantially constant energy and a substantially constant repetition rate comprising an ignition coil having a primary winding and a secondary winding, a spark plug connected to said secondary winding, a source of direct current electrical energy, a solid state switching device having an output circuit and an input circuit, said output circuit connected in series with said primary winding of said ignition coil, means coupled to said source of electrical energy and to the input circuit of said solid state switching device for periodically switching said solid state switching device between its conducting and nonconducting states, said means including a first RC circuit comprising a series connected resistor and capacitor connected across said source of electrical energy and a second RC network comprising a series connected resistor and capacitor connected across said source of electrical energy, means coupling said first RC circuit and said input circuit of said solid state switching device for switching said solid state switching device to a nonconducting state when current through the primary winding and the voltage on the capacitor of said first RC circuit reaches a predetermined value, and means coupled to said second RC circuit, said input circuit of said solid state switching device and said first RC circuit for permitting current flow into said second RC circuit when said solid state switching device is switched to its nonconducting state, and means coupled to said second RC circuit and the input circuit of said solid state switching device for switching said solid state switching device to a conducting state when the voltage across the capacitor of said second RC circuit reaches a predetermined fraction of the terminal voltage of said source of electrical energy.

Claim 3

An ignition system comprising a spark plug, an ignition coil having a primary and a secondary winding, a source of electrical energy, the terminal voltage of which may vary over wide limits, an electronic circuit means coupled to said source of electrical energy and said primary winding, said electronic circuit means including a solid state switching device having an output circuit and an input circuit, said output circuit of said solid state switching device connected in series with said source of electrical energy and said primary winding, a capacitive means, means coupled to said source of electrical energy and said capacitive means for charging said capacitive means at a predetermined time rate, and means coupled to said capacitive means and said input circuit of said solid state switching device for switching said solid state switching device to a nonconducting state thereby interrupting current flow in primary winding when said capacitive means is charged to a predetermined voltage level corresponding to a predetermined current level in said primary winding, said predetermined voltage level being lower than the lowest terminal voltage of said source of electrical energy whereby the voltage delivered to said spark plug is substantially constant irrespective of wide variations of the terminal voltage of said source of electrical energy, and a second capacitive means, a transistor having a base, an emitter electrode and a collector electrode, one of said electrodes being coupled to said source of electrical energy, means connecting said second capacitor means to the base of said transistor, and across the output circuit of said solid state switching means whereby said second capacitive means is prevented from being charged when said solid state switching device is in a conducting state and said transistor is maintained in a nonconducting state, said transistor being switched to a conducting state by current flow through said base and into said second capacitive means when said solid state switching means is switched to a nonconductive state, first circuit means coupled to one of said electrodes of said transistor and said first capacitive means for discharging said firsT capacitive means when said transistor is in a conducting state, second circuit means coupled to one of said electrodes of said transistor and the input circuit of said solid state switching means, said transistor ceasing conduction when the voltage across said second capacitive means is charged to a voltage level where insufficient current flows through said base of said transistor to maintain conduction whereby said solid state switching means is switched to a conducting state and said first capacitive means commences to change.

Claim 4

An ignition system comprising a spark plug, an ignition coil having a primary and a secondary winding, a source of electrical energy, the terminal voltage of which may vary over wide limits, an electronic circuit means coupled to said source of electrical energy and said primary winding, said electronic circuit means including a solid state switching device having an output circuit and an input circuit, said output circuit of said solid state switching device connected in series with said source of electrical energy and said primary winding, a capacitive means, means coupled to said source of electrical energy and said capacitive means for charging said capacitive means at a predetermined time rate, and means coupled to said capacitive means and said input circuit of said solid state switching device for switching said solid state switching device to a nonconducting state thereby interrupting current flow in primary winding when said capacitive means is charged to a predetermined voltage level corresponding to a predetermined current level in said primary winding, said predetermined voltage level being lower than the lowest terminal voltage of said source of electrical energy whereby the voltage delivered to said spark plug is substantially constant irrespective of wide variations of the terminal voltage of said source of electrical energy, and a second capacitive means, a transistor having a base, an emitter electrode and a collector electrode, one of said electrodes being coupled to said source of electrical energy, means connecting said second capacitor means to the base of said transistor, and across the output circuit of said solid state switching means whereby said second capacitive means is prevented from being charged when said solid state switching device is in a conducting state and said transistor is maintained in a nonconducting state, said transistor being switched to a conducting state by current flow through said base and into said second capacitive means when said solid state switching means is switched to a nonconductive state, first circuit means coupled to one of said electrodes of said transistor and said first capacitive means for discharging said firsT capacitive means when said transistor is in a conducting state, second circuit means coupled to one of said electrodes of said transistor and the input circuit of said solid state switching means, said transistor ceasing conduction when the voltage across said second capacitive means is charged to a voltage level where insufficient current flows through said base of said transistor to maintain conduction whereby said solid state switching means is switched to a conducting state and said first capacitive means commences to change.

Claim 5

The combination of claim 2 in which the time constants of said first capacitive means and said second capacitive means are selected to maintain the time period between successive switchings of said solid state switching means a conductive state essentially constant over wide variations in the terminal voltage of said source of electrical energy.

Claim 6

The combination of claim 3 in which said first circuit means includes a solid state switching means, said solid state switching means having an output circuit connected across said first capacitive means and a control electrode connected to one of the electrodes of said transistor.

Claim 7

The combination of claim 4 in which said second circuit means comprises a solid state switching network having an input circuit connected to said one of said electrodes of said transistor and an output circuit connected to the input circuit of said solid state switching device.

Claim 8

An ignition system comprising a spark plug, a source of direct current electrical energy, an inductor connected in series with said source of direct current electrical energy and adapted to be charged to a predetermined current level for providing a predetermined energy charge to the spark plug, a capacitor connected to said source of electrical energy, means coupled to said capacitor for limiting the voltage across said capacitor to a predetermined voltage level lower than the voltage of said source of direct current electrical energy, means coupled to said capacitor and said source of electrical energy for causing said capacitor to charge to said predetermined voltage level at the same time the current through said inductor reaches the predetermined level, and means coupled to said inductor, said capacitor and said means coupled to said capacitor for limiting the voltage across said capacitor, for interrupting current through said inductor when the predetermined voltage across said capacitor is reached, and means coupled to said source of electrical energy, said capacitor, and said last mentioned means for discharging said capacitor and for restoring current through said inductor at a time interval after the current through the inductor has been interrupted, said last mentioned means including means for causing said time interval to vary as a function of the terminal voltage of said source of electrical energy.

Claim 9

An ignition system comprising a spark plug, a source of direct current electrical energy, an inductor connected in series with said source of direct current electrical energy and adapted to be charged to a predetermined current level for providing a predetermined energy charge to the spark plug, a capacitor connected to said source of electrical energy, means coupled to said capacitor for limiting the voltage across said capacitor to a predetermined voltage level lower than the voltage of said source of direct current electrical energy, means coupled to said capacitor and said source of electrical energy for causing said capacitor to charge to said predetermined voltage level at the same time the current through said inductor reaches the predetermined level, and means coupled to said inductor, said capacitor and said means coupled to said capacitor for limiting the voltage across said capacitor, for interrupting current through said inductor when the predetermined voltage across said capacitor is reached, and means coupled to said source of electrical energy, said capacitor, and said last mentioned means for discharging said capacitor and for restoring current through said inductor at a time interval after the current through the inductor has been interrupted, said last mentioned means including means for causing said time interval to vary as a function of the terminal voltage of said source of electrical energy.

Claim 10

In an ignition system, a spark plug, an ignition coil having a primary and a secondary winding, a source of direct current electrical energy, means coupling said secondary winding of said ignition coil to said sparkplug, and circuit means coupled to said source of direct current electrical energy and to said primary winding of said ignition coil for applying a series of voltage pulses having a substantially constant repetition rate and substantially constant electrical energy to said primary winding over wide ranges of the terminal voltage of said source of electrical energy, said circuit means including a solid state switching device having an output circuit and an input circuit, said output circuit connected in series with said source of electrical energy and said primary winding of said ignition coil, a voltage responsive means coupled to the input circuit of said solid state switching device for switching said solid state switching device to a nonconducting state when the voltage on said voltage responsive means is at a predetermined value, and current responsive means coupled to the input circuit of said Solid state switching device for switching said solid state switching device to a conducting state when the current through said current responsive device is at a predetermagnitude.

Claim 11

In an ignition system, a spark plug, an ignition coil having a primary and a secondary winding, a source of direct current electrical energy, means coupling said secondary winding of said ignition coil to said sparkplug, and circuit means coupled to said source of direct current electrical energy and to said primary winding of said ignition coil for applying a series of voltage pulses having a substantially constant repetition rate and substantially constant electrical energy to said primary winding over wide ranges of the terminal voltage of said source of electrical energy, said circuit means including a solid state switching device having an output circuit and an input circuit, said output circuit connected in series with said source of electrical energy and said primary winding of said ignition coil, a voltage responsive means coupled to the input circuit of said solid state switching device for switching said solid state switching device to a nonconducting state when the voltage on said voltage responsive means is at a predetermined value, and current responsive means coupled to the input circuit of said Solid state switching device for switching said solid state switching device to a conducting state when the current through said current responsive device is at a predetermagnitude.

Claim 12

In an ignition system, a sparkplug, an ignition coil having a primary and a secondary winding, a source of direct current electrical energy, means coupling said secondary winding of said ignition coil to said spark plug, and an oscillator coupled to said source of direct current electrical energy and to said primary winding of said ignition coil for applying a series of substantially rectangular voltage pulses having a substantially constant repetition rate and substantially constant electrical energy to said primary winding over wide ranges of the terminal voltage of said source of electrical energy, said oscillator comprising a solid state switching device having first and second output electrodes and a control electrode, said first and second output electrodes being connected in series with said source of electrical energy and said primary winding of said ignition coil, a first capacitor, means coupling said source of electrical energy and said first capacitor for charging said first capacitor from said source of electrical energy, circuit means coupled to said source of electrical energy, to one terminal of said first capacitor and to said control electrode of said solid state switching device for maintaining said solid state switching device in a conducting state as said first capacitor charges to a predetermined voltage level and for switching said solid state switching device to a nonconducting state when said first capacitor charges to said predetermined voltage level, a second capacitor having a first terminal and a second terminal connected across said first and second output electrodes of said solid state switching device, and current responsive means coupled to said source of electrical energy and said second capacitor for charging said second capacitor therethrough, said current responsive means switching said solid state switching device to a conducting state when current therethrough declines to a predetermined level as said second capacitor charges to a predetermined voltage level.

Claim 13

In an ignition system, a sparkplug, an ignition coil having a primary and a secondary winding, a source of direct current electrical energy, means coupling said secondary winding of said ignition coil to said spark plug, and an oscillator coupled to said source of direct current electrical energy and to said primary winding of said ignition coil for applying a series of substantially rectangular voltage pulses having a substantially constant repetition rate and substantially constant electrical energy to said primary winding over wide ranges of the terminal voltage of said source of electrical energy, said oscillator comprising a solid state switching device having first and second output electrodes and a control electrode, said first and second output electrodes being connected in series with said source of electrical energy and said primary winding of said ignition coil, a first capacitor, means coupling said source of electrical energy and said first capacitor for charging said first capacitor from said source of electrical energy, circuit means coupled to said source of electrical energy, to one terminal of said first capacitor and to said control electrode of said solid state switching device for maintaining said solid state switching device in a conducting state as said first capacitor charges to a predetermined voltage level and for switching said solid state switching device to a nonconducting state when said first capacitor charges to said predetermined voltage level, a second capacitor having a first terminal and a second terminal connected across said first and second output electrodes of said solid state switching device, and current responsive means coupled to said source of electrical energy and said second capacitor for charging said second capacitor therethrough, said current responsive means switching said solid state switching device to a conducting state when current therethrough declines to a predetermined level as said second capacitor charges to a predetermined voltage level.