Automotive ignition control

Claim 2

An ignition control system for use in an internal combustion engine having at least one means for igniting fuel, said system comprising: a. means for producing a control signal alternating in timed relationship with an engine; b. an energy storing ignition coil possessing a primary and a secondary side, said secondary side being cyclically coupled to said means for igniting in timed relationship with said engine; c. a power output circuit coupled to the primary side of said coil for drawing current through said coil; d. means coupled to said power output circuit and responsive to said control signal for switching said power output circuit off to discharge said coil through said means for igniting; e. means for limiting the maximum current drawn by said power output circuit through said ignition coil; f. means for dissipating energy stored in said coil when said energy fails to discharge through said means for igniting, said means for dissipating comprising at least one diode connected from a reference potential to the primary side of said coil, siad diode coupled so as to conduct current when said primary side is at a selected lower potential than said reference potential; and g. means for turning or maintaining OFF said power output circuit when said means for producing a control signal is either open-circuited or short-circuited.

Claim 3

A system as defined in claim 1 including means for protecting said system from supply voltage transients, said means for protecting comprising a plurality of zener diodes connected in series between a positive voltage supply for said ignition control system and said means coupled to said power output circuit, said diodes operative to switch said power output circuit off in response to a transient voltage spike greater than the breakdown voltage of said plurality of series-connected zener diodes.

Claim 4

means for developing a voltage proportional to the current drawn by aid power output circuit and the primary side of said coil;

Claim 5

means for developing a voltage proportional to the current drawn by aid power output circuit and the primary side of said coil;

Claim 6

a current limiting transistor having a base coupled to said constant current source and an emitter coupled to said means for developing a voltage;

Claim 7

a current limiting transistor having a base coupled to said constant current source and an emitter coupled to said means for developing a voltage;

Claim 8

An ignition control system for use in an internal combustion engine having at least one means for igniting fuel, said system comprising: a. means for producing a control signal alternating in timed relationship with an engine; b. an energy storing ignition coil having a primary and a secondary side, said means for igniting in timed relationship with said engine; c. a power output circuit coupled to the primary side of said coil for drawing current through said coil, said power output circuit comprising a pair of transistors, the collectors of which are coupled to the primary side of said coil and the emitters of which are coupled to ground potential, the emitter of one of said pair also being coupled to the base of the other of said pair; d. means for switching said power output circuit off to discharge said coil through said means for igniting in response to said control signal, said means for switching being coupled to the base of said one of said pair of transistors; e. means for limiting the maximum current drawn by said power output circuit through said ignition coil; and, f. circuit feedback means for varying as a function of engine speed the portion of each cycle during which said power output circuit draws current through said ignition coil.

Claim 9

An ignition control system for use in an internal combustion engine having at least one means for igniting fuel, said system comprising: a. means for producing a control signal alternating in timed relationship with an engine; b. an energy storing ignition coil having a primary and a secondary side, said means for igniting in timed relationship with said engine; c. a power output circuit coupled to the primary side of said coil for drawing current through said coil, said power output circuit comprising a pair of transistors, the collectors of which are coupled to the primary side of said coil and the emitters of which are coupled to ground potential, the emitter of one of said pair also being coupled to the base of the other of said pair; d. means for switching said power output circuit off to discharge said coil through said means for igniting in response to said control signal, said means for switching being coupled to the base of said one of said pair of transistors; e. means for limiting the maximum current drawn by said power output circuit through said ignition coil; and, f. circuit feedback means for varying as a function of engine speed the portion of each cycle during which said power output circuit draws current through said ignition coil.

Claim 10

Structure as in claim 2 including means for preventing a noise spike from changing the state of said power output circuit.

Claim 11

transistor switching means coupled between the collector of said current limiting tranistor and the base terminal of said one of said pair of transistors, wherein variations of the current drawn by said current limiting transistor in response to voltage from said means for developing a voltage effects operation of said transistor switching means to vary the current passing through said power output circuit and said coil until equilibrium is reached as a result of current being drawn by said current limiting transistor substantially equal to the current through said constant current source.

Claim 12

transistor switching means coupled between the collector of said current limiting tranistor and the base terminal of said one of said pair of transistors, wherein variations of the current drawn by said current limiting transistor in response to voltage from said means for developing a voltage effects operation of said transistor switching means to vary the current passing through said power output circuit and said coil until equilibrium is reached as a result of current being drawn by said current limiting transistor substantially equal to the current through said constant current source.

Claim 13

Structure as in claim 2 including means for minimizing the time that the current through said ignition coil remains at said maximum current level, thereby to minimize power drain and thus control the temperature of said power output circuit.

Claim 14

A system according to claim 3 including means for dissipating energy stored in said coil when said energy fails to discharge through said means for igniting, said means for dissipating comprising at least one diode connected fromm a reference potential to the primary side of said coil, said diode coupled so as to conduct current when said primary side is at a selected lower potential than said reference potential.

Claim 15

A system according to claim 3 wherein said means for limiting comprises: a. a constant current source; b. means for developing a voltage proportional to the current drawn by said power output circuit and the primary side of said coil; c. a current limiting transistor having a base coupled to said constant current source and an emitter coupled to said means for developing a voltage; d. transistor switching means coupled between the collector of said current limiting transistor and the base terminal of said on of said pair of transistors, wherein variations of the current drawn by said current limiting transistor in response to voltage from said means for developing a voltage effects operation of said transistor switching means to vary the current passing through said power output circuit and said coil until equilibrium is reached as a result of current being drawn by said current limiting transistor substantially equal to the current through said constant current source.

Claim 16

A system according to claim 7 wherein said circuit feedback means comprises: a. a first transistor having a collector coupled to a voltage source, an emitter coupled to one side of said means for producing a control signal, and a base terminal, said first transistor being disposed for supplying a reference potential for said means for producing a control signal; b. means for storing a voltage coupled to said means for producing a control signal and the base terminal of said first transistor; and, c. a second transistor having an emitter coupled to ground potential, a collector coupled to said voltage storage means and the base terminal of said first transistor, and a base terminal coupled to said transistor switching means, wherein the voltage reference level of said means for producing a control signal varies in accordance with voltage stored by said voltage storage means such that the reference voltage increases as a function of engine speed and decreases as a function of current drawn by said current limiting transistor.

Claim 17

A system in accordane with claim 3 including means for turning or maintaining OFF said power output circuit when said means for producing a control signal is either open-circuited or short-circuited.

Claim 18

An ignition control system for use in an internal combustion engine having at least one means for igniting fuel, said system comprising: a. means for producing a control signal alternating in timed relationship with an engine; b. an energy storing ignition coil possessing a primary and a secondary side, said secondary side being cyclincally coupled to said means for igniting in timed relationship with said engine; c. a power output circuit coupled to the primary side of said coil for drawing current through said coil; d. means coupled to said power output circuit and responsive to said control signal for switching said power output circuit off to discharge said coil through said means for igniting; and, e. means for limiting the maximum current drawn by said power output circuit through said ignition coil, said means for limiting comprising:

Claim 19

An ignition control system for use in an internal combustion engine having at least one means for igniting fuel, said system comprising: a. means for producing a control signal alternating in timed relationship with an engine; b. an energy storing ignition coil possessing a primary and a secondary side, said secondary side being cyclincally coupled to said means for igniting in timed relationship with said engine; c. a power output circuit coupled to the primary side of said coil for drawing current through said coil; d. means coupled to said power output circuit and responsive to said control signal for switching said power output circuit off to discharge said coil through said means for igniting; and, e. means for limiting the maximum current drawn by said power output circuit through said ignition coil, said means for limiting comprising:

Claim 20

An ignition control system for use in an internal combustion engine having at least one means for igniting fuel, said system comprising: a. a distributor pick-up coil for producing a control signal alternating in timed relationship with an engine; b. an energy storing ignition coil possessing a primary and a secondary side, said secondary side being cyclically coupled to said means for igniting in timed relationship with said engine; c. a power output circuit coupled to the primary side of said coil for drawing current through said coil, said power output circuit comprising a pair of transistors coupled as a compound-transistor; d. circuit means coupled between said distributor pick-up coil and said power output circuit for switching said power output circuit off in response to said control signal to discharge said coil through said means for igniting; e. current sense resistance means coupled between said power output circuit and ground potential for developing a voltage proportional to the current drawn by said power output circuit through said ignition coil; f. a current limiter circuit coupled between said current sense resistance means and said circuit means for limiting the maximum amount of current drawn by said power output circuit through said ignition coil; and, g. a dwell feedback control circuit coupled between said current limiter circuit and said distributor pick-up coil for varying the dwell angle as a function of engine speed during the portion of each cycle that said power output circuit draws current through said ignition coil.

Claim 21

An ignition control system for use in an internal combustion engine having at least one means for igniting fuel, said system comprising: a. a distributor pick-up coil for producing a control signal alternating in timed relationship with an engine; b. an energy storing ignition coil possessing a primary and a secondary side, said secondary side being cyclically coupled to said means for igniting in timed relationship with said engine; c. a power output circuit coupled to the primary side of said coil for drawing current through said coil, said power output circuit comprising a pair of transistors coupled as a compound-transistor; d. circuit means coupled between said distributor pick-up coil and said power output circuit for switching said power output circuit off in response to said control signal to discharge said coil through said means for igniting; e. current sense resistance means coupled between said power output circuit and ground potential for developing a voltage proportional to the current drawn by said power output circuit through said ignition coil; f. a current limiter circuit coupled between said current sense resistance means and said circuit means for limiting the maximum amount of current drawn by said power output circuit through said ignition coil; and, g. a dwell feedback control circuit coupled between said current limiter circuit and said distributor pick-up coil for varying the dwell angle as a function of engine speed during the portion of each cycle that said power output circuit draws current through said ignition coil.

Claim 22

An ignition control system for use in an internal combustion engine having at least one means for igniting fuel, said system comprising: a. a distributor pick-up coil for producing a control signal alternating in timed relationship with an engine; b. an energy storing ignition coil possessing a primary and a secondary side, said secondary side being cyclically coupled to said means for igniting in timed relationship with said engine; c. a power output circuit coupled to the primary side of said coil for drawing current through said coil, said power output circuit comprising a pair of transistors coupled as a compound-transistor; d. circuit means coupled between said distributor pick-up coil and said power output circuit for switching said power output circuit off in response to said control signal to discharge said coil through said means for igniting; e. current sense resistance means coupled between said power output circuit and ground potential for developing a voltage proportional to the current drawn by said power output circuit through said ignition coil; f. a current limiter circuit coupled between said current sense resistance means and said circuit means for limiting the maximum amount of current drawn by said power output circuit through said ignition coil; g. a dwell feedback control circuit coupled between said current limiter circuit and said distributor pick-up coil for varying the dwell angle as a function of engine speed during the portion of each cycle that said power output circuit draws current through said ignition coil; h. means for dissipating energy stored in said ignition coil when said energy fails to discharge through said means for igniting, said means for dissipating comprising at least one diode connected from a reference potential to the primary side of said ignition coil, said diode coupled so as to conduct current when said primary side is at a selected lower potential than said reference potential; and, i. means for protecting said system from supply voltage transients, said means for protecting comprising a plurality of zener diodes connected in series between a positive voltage supply for said system and said circuit means, said diodes operative to switch said power output circuit off in response to a transient voltage spike greater than the breakdown voltage of said plurality of series-connected zener diodes.

Claim 23

An ignition control system for use in an internal combustion engine having at least one means for igniting fuel, said system comprising: a. a distributor pick-up coil for producing a control signal alternating in timed relationship with an engine; b. an energy storing ignition coil possessing a primary and a secondary side, said secondary side being cyclically coupled to said means for igniting in timed relationship with said engine; c. a power output circuit coupled to the primary side of said coil for drawing current through said coil, said power output circuit comprising a pair of transistors coupled as a compound-transistor; d. circuit means coupled between said distributor pick-up coil and said power output circuit for switching said power output circuit off in response to said control signal to discharge said coil through said means for igniting; e. current sense resistance means coupled between said power output circuit and ground potential for developing a voltage proportional to the current drawn by said power output circuit through said ignition coil; f. a current limiter circuit coupled between said current sense resistance means and said circuit means for limiting the maximum amount of current drawn by said power output circuit through said ignition coil; g. a dwell feedback control circuit coupled between said current limiter circuit and said distributor pick-up coil for varying the dwell angle as a function of engine speed during the portion of each cycle that said power output circuit draws current through said ignition coil; h. means for dissipating energy stored in said ignition coil when said energy fails to discharge through said means for igniting, said means for dissipating comprising at least one diode connected from a reference potential to the primary side of said ignition coil, said diode coupled so as to conduct current when said primary side is at a selected lower potential than said reference potential; and, i. means for protecting said system from supply voltage transients, said means for protecting comprising a plurality of zener diodes connected in series between a positive voltage supply for said system and said circuit means, said diodes operative to switch said power output circuit off in response to a transient voltage spike greater than the breakdown voltage of said plurality of series-connected zener diodes.