Electronic ignition spark advance system

Claim 2

An electronic ignition spark advance system comprising in combination with an internal combustion engine and an associated transistor ignition system having an ignition coil primary winding switching transistor, means for producing a series of crankshaft position pulses, each corresponding to one degree of rotation of the crankshaft of said internal combustion engine, means for producing a reference pulse a selected number of degrees before the top dead center position of each piston of said internal combustion engine, a counter circuit having an input terminal and a plurality of output terminals, each corresponding to a binary code bit for counting said crankshaft position pulses and producing upon said output terminals thereof the binary code representation of the number of said crankshaft position pulses counted thereby, an ignition spark advance gate circuit which, when enabled, gates said series of crankshaft position pulses to said input terminal of said counter circuit, means responsive to the binary code representation, upon said output terminalS of said counter circuit, of the number of said crankshaft position pulses counted by said counter circuit equal to said selected number of degrees before the top dead center position of each piston of said internal combustion engine at which each said reference pulse is produced for producing an ignition signal, means responsive to each of said reference pulses for producing a start count signal and to each of said ignition signals for producing a full count signal, first delay circuit means responsive to each of said ignition signals for producing a first engine speed ignition spark advance signal of a preselected duration, second delay circuit means responsive to the end of each of said first engine speed ignition spark advance signals for producing a second engine speed ignition spark advance signal of a predetermined duration, a first count limit circuit means responsive to the binary representation, upon said output terminals of said counter circuit, of a first selected number of crankshaft position pulses counted by said counter circuit for producing a first engine speed ignition spark advance limit signal which terminates said first engine speed ignition spark advance signal if said counter circuit counts said first selected number of crankshaft position pulses prior to the end thereof, a second count limit circuit means responsive to the binary representation, upon said output terminals of said counter circuit, of a second selected greater number of crankshaft position pulses counted by said counter circuit for producing a second engine speed ignition spark advance limit signal which terminates said second engine speed ignition spark advance signal if said counter circuit counts said second selected number of crankshaft position pulses prior to the end thereof, circuit means responsive to the end of said second engine speed ignition spark advance signal for producing an engine vacuum ignition spark advance signal, an enabling gate circuit responsive to said start count signals, said first and second engine speed ignition spark advance signals and said engine vacuum ignition spark advance signals for producing an enabling signal for said ignition spark advance gate circuit and to said full count signals for producing a disenabling signal for said ignition spark advance gate circuit in the absence of said first and second engine speed and engine vacuum ignition spark advance signals, and dwell circuit means responsive to a preselected number of said crankshaft position pulses for initiating the operation of said transistor ignition system to trigger said ignition coil primary winding switching transistor conductive and to each of said ignition signals for initiating the operation of said transistor ignition system to extinguish said ignition coil primary winding switching transistor.

Claim 3

An electronic ignition spark advance system comprising in combination with an internal combustion engine and an associated transistor ignition system having an ignition coil primary winding switching transistor, means for producing a series of crankshaft position pulses, each corresponding to one degree of rotation of the crankshaft of said internal combustion engine, means for producing a reference pulse a selected number of degrees before the top dead center position of each piston of said internal combustion engine, a counter circuit having an input terminal and a plurality of output terminals, each corresponding to a binary code bit for counting said crankshaft position pulses and producing upon said output terminals thereof the binary code representation of the number of said crankshaft position pulses counted thereby, an ignition spark advance NOR gate which, when enabled, gates said series of crankshaft position pulses to said input terminal of said counter circuit, an ignition signal AND gate responsive to the binary code representation, upon said output terminals of said counter circuit, of the number of said crankshaft position pulses counted by said counter circuit eQual to said selected number of degrees before the top dead center position of each piston of said internal combustion engine at which each said reference pulse is produced for producing an ignition signal, means responsive to each of said reference pulses for producing a start count signal and to each of said ignition signals for producing a full count signal, first delay circuit means responsive to each of said ignition signals for producing a first engine speed ignition spark advance signal of a preselected duration, second delay circuit means responsive to the end of each of said first engine speed ignition spark advance signals for producing a second engine speed ignition spark advance signal of a predetermined duration, a first count limit circuit means responsive to the binary representation, upon said output terminals of said counter circuit, of a first selected number of crankshaft position pulses counted by said counter circuit for producing a first engine speed ignition spark advance limit signal which terminates said first engine speed ignition spark advance signal if said counter circuit counts said first selected number of crankshaft position pulses prior to the end thereof, a second count limit circuit means responsive to the binary representation, upon said output terminals of said counter circuit, of a second selected greater number of crankshaft position pulses counted by said counter circuit for producing a second engine speed ignition spark advance limit signal which terminates said second engine speed ignition spark advance signal if said counter circuit counts said second selected number of crankshaft position pulses prior to the end thereof, circuit means responsive to the end of said second engine speed ignition spark advance signal for producing an engine vacuum ignition spark advance signal, an enabling NOR gate responsive to said start count signals, said first and second engine speed ignition spark advance signals and said engine vacuum ignition spark advance signals for producing an enabling signal for said ignition spark advance gate circuit and to said full count signals for producing a disenabling signal for said ignition spark advance gate circuit in the absence of said first and second engine speed and engine vacuum ignition spark advance signals, and dwell circuit means responsive to a preselected number of said crankshaft position pulses for initiating the operation of said transistor ignition system to trigger said ignition coil primary winding switching transistor conductive and to each of said ignition signals for initiating the operation of said transistor ignition system to extinguish said ignition coil primary winding switching transistor.

Claim 4

An electronic ignition spark advance system comprising in combination with an internal combustion engine and an associated transistor ignition system having an ignition coil primary winding switching transistor, means for producing a series of crankshaft position pulses, each corresponding to one degree of rotation of the crankshaft of said internal combustion engine, means for producing a reference pulse a selected number of degrees before the top dead center position of each piston of said internal combustion engine, a counter circuit having an input terminal and a plurality of output terminals, each corresponding to a binary code bit for counting said crankshaft position pulses and producing upon said output terminals thereof the binary code representation of the number of said crankshaft position pulses counted thereby, an ignition spark advance NOR gate which, when enabled, gates said series of crankshaft position pulses to said input terminal of said counter circuit, an ignition signal AND gate responsive to the binary code representation, upon said output terminals of said counter circuit, of the number of said crankshaft position pulses counted by said counter circuit eQual to said selected number of degrees before the top dead center position of each piston of said internal combustion engine at which each said reference pulse is produced for producing an ignition signal, means responsive to each of said reference pulses for producing a start count signal and to each of said ignition signals for producing a full count signal, first delay circuit means responsive to each of said ignition signals for producing a first engine speed ignition spark advance signal of a preselected duration, second delay circuit means responsive to the end of each of said first engine speed ignition spark advance signals for producing a second engine speed ignition spark advance signal of a predetermined duration, a first count limit circuit means responsive to the binary representation, upon said output terminals of said counter circuit, of a first selected number of crankshaft position pulses counted by said counter circuit for producing a first engine speed ignition spark advance limit signal which terminates said first engine speed ignition spark advance signal if said counter circuit counts said first selected number of crankshaft position pulses prior to the end thereof, a second count limit circuit means responsive to the binary representation, upon said output terminals of said counter circuit, of a second selected greater number of crankshaft position pulses counted by said counter circuit for producing a second engine speed ignition spark advance limit signal which terminates said second engine speed ignition spark advance signal if said counter circuit counts said second selected number of crankshaft position pulses prior to the end thereof, circuit means responsive to the end of said second engine speed ignition spark advance signal for producing an engine vacuum ignition spark advance signal, an enabling NOR gate responsive to said start count signals, said first and second engine speed ignition spark advance signals and said engine vacuum ignition spark advance signals for producing an enabling signal for said ignition spark advance gate circuit and to said full count signals for producing a disenabling signal for said ignition spark advance gate circuit in the absence of said first and second engine speed and engine vacuum ignition spark advance signals, and dwell circuit means responsive to a preselected number of said crankshaft position pulses for initiating the operation of said transistor ignition system to trigger said ignition coil primary winding switching transistor conductive and to each of said ignition signals for initiating the operation of said transistor ignition system to extinguish said ignition coil primary winding switching transistor.

Claim 5

An electronic ignition spark advance system comprising in combination with an internal combustion engine and an associated transistor ignition system having an ignition coil primary winding switching transistor, means for producing a series of crankshaft position pulses, each corresponding to 1* of rotation of the crankshaft of said internal combustion engine, means for producing a reference pulse a selected number of degrees before the top dead center position of each piston of said internal combustion engine, a counter circuit having an input terminal and a plurality of output terminals, each corresponding to a binary code bit for counting said crankshaft position pulses and producing upon said output terminals thereof the binary code representation of the number of said crankshaft position pulses counted thereby, an ignition spark advance NOR gate which, when enabled, gates said series of crankshaft position pulses to said input terminal of said counter circuit, an ignition signal AND gate responsive to the binary code representation, upon said output terminals of said counter circuit, of the number of said crankshaft position pulses counted by said counter circuit equal to said selected number of degrees before the top dead center position of each piston of said internal Combustion engine at which each said reference pulse is produced for producing an ignition signal, a bi-stable multivibrator circuit responsive to each of said reference pulses for producing a start count signal and to each of said ignition signals for producing a full count signal, a first monostable multivibrator circuit responsive to each of said ignition signals for producing a first engine speed ignition spark advance signal of a preselected duration, a second monostable multivibrator circuit responsive to the end of each of said first engine speed ignition spark advance signals for producing a second engine speed ignition spark advance signal of a predetermined duration, a first count limit AND gate responsive to the binary representation, upon said output terminals of said counter circuit, of a first selected number of crankshaft position pulses counted by said counter circuit for producing a first engine speed ignition spark advance limit signal which terminates said first engine speed ignition spark advance signal if said counter circuit counts said first selected number of crankshaft position pulses prior to the end thereof, a second count limit AND gate responsive to the binary representation, upon said output terminals of said counter circuit, of a second selected greater number of crankshaft position pulses counted b said counter circuit for producing a second engine speed ignition spark advance limit signal which terminates said second engine speed ignition spark advance signal if said counter circuit counts said second selected number of crankshaft position pulses prior to the end thereof, circuit means responsive to the end of said second engine speed ignition spark advance signal for producing an engine vacuum ignition spark advance signal, an enabling NOR gate responsive to said start count signals, said first and second engine speed ignition spark advance signals and said engine vacuum ignition spark advance signals for producing an enabling signal for said ignition spark advance gate circuit and to said full count signals for producing a disenabling signal for said ignition spark advance gate circuit in the absence of said first and second engine speed and engine vacuum ignition spark advance signals, and dwell circuit means responsive to a preselected number of said crankshaft position pulses for initiating the operation of said transistor ignition system to trigger said ignition coil primary winding switching transistor conductive and to each of said ignition signals for initiating the operation of said transistor ignition system to extinguish said ignition coil primary winding switching transistor.

Claim 6

An electronic ignition spark advance system comprising in combination with an internal combustion engine and an associated transistor ignition system having an ignition coil primary winding switching transistor, means for producing a series of crankshaft position pulses, each corresponding to 1* of rotation of the crankshaft of said internal combustion engine, means for producing a reference pulse a selected number of degrees before the top dead center position of each piston of said internal combustion engine, a counter circuit having an input terminal and a plurality of output terminals, each corresponding to a binary code bit for counting said crankshaft position pulses and producing upon said output terminals thereof the binary code representation of the number of said crankshaft position pulses counted thereby, an ignition spark advance NOR gate which, when enabled, gates said series of crankshaft position pulses to said input terminal of said counter circuit, an ignition signal AND gate responsive to the binary code representation, upon said output terminals of said counter circuit, of the number of said crankshaft position pulses counted by said counter circuit equal to said selected number of degrees before the top dead center position of each piston of said internal Combustion engine at which each said reference pulse is produced for producing an ignition signal, a bi-stable multivibrator circuit responsive to each of said reference pulses for producing a start count signal and to each of said ignition signals for producing a full count signal, a first monostable multivibrator circuit responsive to each of said ignition signals for producing a first engine speed ignition spark advance signal of a preselected duration, a second monostable multivibrator circuit responsive to the end of each of said first engine speed ignition spark advance signals for producing a second engine speed ignition spark advance signal of a predetermined duration, a first count limit AND gate responsive to the binary representation, upon said output terminals of said counter circuit, of a first selected number of crankshaft position pulses counted by said counter circuit for producing a first engine speed ignition spark advance limit signal which terminates said first engine speed ignition spark advance signal if said counter circuit counts said first selected number of crankshaft position pulses prior to the end thereof, a second count limit AND gate responsive to the binary representation, upon said output terminals of said counter circuit, of a second selected greater number of crankshaft position pulses counted b said counter circuit for producing a second engine speed ignition spark advance limit signal which terminates said second engine speed ignition spark advance signal if said counter circuit counts said second selected number of crankshaft position pulses prior to the end thereof, circuit means responsive to the end of said second engine speed ignition spark advance signal for producing an engine vacuum ignition spark advance signal, an enabling NOR gate responsive to said start count signals, said first and second engine speed ignition spark advance signals and said engine vacuum ignition spark advance signals for producing an enabling signal for said ignition spark advance gate circuit and to said full count signals for producing a disenabling signal for said ignition spark advance gate circuit in the absence of said first and second engine speed and engine vacuum ignition spark advance signals, and dwell circuit means responsive to a preselected number of said crankshaft position pulses for initiating the operation of said transistor ignition system to trigger said ignition coil primary winding switching transistor conductive and to each of said ignition signals for initiating the operation of said transistor ignition system to extinguish said ignition coil primary winding switching transistor.

Claim 7

An electronic ignition spark advance system comprising in combination with an internal combustion engine and an associated transistor ignition system having an ignition coil primary winding switching transistor, a crankshaft position sensor for producing a series of crankshaft position pulses, each corresponding to 1* of rotation of the crankshaft of said internal combustion engine, a reference pulse generator for producing a reference pulse a selected number of degrees before the top dead center position of each piston of said internal combustion engine, a counter circuit having an input terminal and a plurality of output terminals, each corresponding to a binary code bit, for counting said crankshaft position pulses and producing upon said output terminals thereof the binary code representation of the number of said crankshaft position pulses counted thereby, an ignition spark advance NOR gate having input terminals and an output terminal for gating said series of crankshaft position pulses to said input terminal of said counter circuit, an ignition signal AND gate having input terminals and an output terminal for producing an ignition signal, means for connecting said output terminals of said counter circuit upon which appear the binary code representation of the number of said crankshaft position pulses counted by said counter Circuit equal to said selected number of degrees before the top dead center position of each piston of said internal combustion engine at which each said reference pulse is produced to respective input terminals of said ignition signal AND gate, a bi-stable multivibrator circuit having two input terminals and an output terminal for producing a start count signal in response to said reference signals and a full count signal in response to said ignition signals, means for applying said reference signals and said ignition signals to respective input terminals of said bi-stable multivibrator circuit, a first monostable multivibrator circuit having an input, an output and a reset terminal responsive to each of said ignition signals for producing a first engine speed ignition spark advance signal of a preselected duration, means for applying said ignition signals to said input terminal of said first monostable multivibrator circuit, a second monostable multivibrator circuit having an input, an output and a reset terminal responsive to the end of each of said first engine speed ignition spark advance signals for producing a second engine speed ignition spark advance signal of a predetermined duration, means for differentiating the trailing edge of each of said first engine speed ignition spark advance signals, means for applying said differentiated trailing edge of each said first engine speed ignition spark advance signals to said input terminal of said second monostable multivibrator circuit, a first count limit AND gate having input terminals and an output terminal for producing a first engine speed ignition spark advance limit signal, means for connecting said output terminals of said counter circuit upon which appear the binary representation of a first selected number of crankshaft position pulses counter by said counter circuit to respective said input terminals of said first count limit AND gate, means for applying said first engine speed ignition spark advance limit signal to said reset terminal of said first monostable multivibrator circuit, a second count limit AND gate having input terminals and an output terminal for producing a second engine speed ignition spark advance limit signal, means for connecting said output terminals of said counter circuit upon which appear the binary representation of a second selected greater number of crankshaft position pulses counted by said counter circuit to respective said input terminals of said second count limit AND gate, means for applying said second engine speed ignition spark advance limit signal to said reset terminal of said second monostable multivibrator circuit, means for differentiating the trailing edge of said second engine speed ignition spark advance signals, engine vacuum sensitive circuit means having an input and an output terminal for producing an engine vacuum ignition spark advance signal, means for applying said differentiated trailing edge of said second engine speed ignition spark advance limit signal to said input terminal of said engine vacuum sensitive circuit means, an enabling NOR gate having input terminals and an output terminal for producing an enabling signal for said ignition spark advance NOR gate, means for applying both said start count and said full count signals, both said first and second engine speed ignition spark advance signals and said engine vacuum ignition spark advance signal to respective input terminals of said enabling NOR gate, means for applying said crankshaft position pulses and said enabling signal to respective input terminals of said ignition spark advance NOR gate, dwell circuit having two input circuit means responsive to a preselected number of said crankshaft position pulses for initiating the operation of said transistor ignition system to trigger said ignition coil primary winding conductive and to each of said ignition signals for initiating the operation of said transistor ignition system to extinguish said ignition coil primary winding switching transistoR, and means for applying said crankshaft position pulses and said ignition signals to respective said input terminals of said dwell circuit means.

Claim 8

An electronic ignition spark advance system comprising in combination with an internal combustion engine and an associated transistor ignition system having an ignition coil primary winding switching transistor, a crankshaft position sensor for producing a series of crankshaft position pulses, each corresponding to 1* of rotation of the crankshaft of said internal combustion engine, a reference pulse generator for producing a reference pulse a selected number of degrees before the top dead center position of each piston of said internal combustion engine, a counter circuit having an input terminal and a plurality of output terminals, each corresponding to a binary code bit, for counting said crankshaft position pulses and producing upon said output terminals thereof the binary code representation of the number of said crankshaft position pulses counted thereby, an ignition spark advance NOR gate having input terminals and an output terminal for gating said series of crankshaft position pulses to said input terminal of said counter circuit, an ignition signal AND gate having input terminals and an output terminal for producing an ignition signal, means for connecting said output terminals of said counter circuit upon which appear the binary code representation of the number of said crankshaft position pulses counted by said counter Circuit equal to said selected number of degrees before the top dead center position of each piston of said internal combustion engine at which each said reference pulse is produced to respective input terminals of said ignition signal AND gate, a bi-stable multivibrator circuit having two input terminals and an output terminal for producing a start count signal in response to said reference signals and a full count signal in response to said ignition signals, means for applying said reference signals and said ignition signals to respective input terminals of said bi-stable multivibrator circuit, a first monostable multivibrator circuit having an input, an output and a reset terminal responsive to each of said ignition signals for producing a first engine speed ignition spark advance signal of a preselected duration, means for applying said ignition signals to said input terminal of said first monostable multivibrator circuit, a second monostable multivibrator circuit having an input, an output and a reset terminal responsive to the end of each of said first engine speed ignition spark advance signals for producing a second engine speed ignition spark advance signal of a predetermined duration, means for differentiating the trailing edge of each of said first engine speed ignition spark advance signals, means for applying said differentiated trailing edge of each said first engine speed ignition spark advance signals to said input terminal of said second monostable multivibrator circuit, a first count limit AND gate having input terminals and an output terminal for producing a first engine speed ignition spark advance limit signal, means for connecting said output terminals of said counter circuit upon which appear the binary representation of a first selected number of crankshaft position pulses counter by said counter circuit to respective said input terminals of said first count limit AND gate, means for applying said first engine speed ignition spark advance limit signal to said reset terminal of said first monostable multivibrator circuit, a second count limit AND gate having input terminals and an output terminal for producing a second engine speed ignition spark advance limit signal, means for connecting said output terminals of said counter circuit upon which appear the binary representation of a second selected greater number of crankshaft position pulses counted by said counter circuit to respective said input terminals of said second count limit AND gate, means for applying said second engine speed ignition spark advance limit signal to said reset terminal of said second monostable multivibrator circuit, means for differentiating the trailing edge of said second engine speed ignition spark advance signals, engine vacuum sensitive circuit means having an input and an output terminal for producing an engine vacuum ignition spark advance signal, means for applying said differentiated trailing edge of said second engine speed ignition spark advance limit signal to said input terminal of said engine vacuum sensitive circuit means, an enabling NOR gate having input terminals and an output terminal for producing an enabling signal for said ignition spark advance NOR gate, means for applying both said start count and said full count signals, both said first and second engine speed ignition spark advance signals and said engine vacuum ignition spark advance signal to respective input terminals of said enabling NOR gate, means for applying said crankshaft position pulses and said enabling signal to respective input terminals of said ignition spark advance NOR gate, dwell circuit having two input circuit means responsive to a preselected number of said crankshaft position pulses for initiating the operation of said transistor ignition system to trigger said ignition coil primary winding conductive and to each of said ignition signals for initiating the operation of said transistor ignition system to extinguish said ignition coil primary winding switching transistoR, and means for applying said crankshaft position pulses and said ignition signals to respective said input terminals of said dwell circuit means.

Claim 9

An electronic ignition spark advance system comprising in combination with an internal combustion engine and an associated transistor ignition system having an ignition coil primary winding switching transistor, a crankshaft position sensor having output circuit means for producing a series of crankshaft position pulses, each corresponding to 1* of rotation of the crankshaft of said internal combustion engine, a reference pulse generator having output circuit means for producing a reference pulse a selected number of degrees before the top dead center position of each piston of said internal combustion engine, a counter circuit having an input terminal, a plurality of output terminals, each corresponding to a binary code bit, and a reset terminal for counting said crankshaft position pulses and producing upon said output terminals thereof the binary code representation of the number of said crankshaft position pulses counted thereby, an ignition spark advance NOR gate having input terminals and an output terminal for gating said series of crankshaft position pulses to said input terminal of said counter circuit, an ignition signal AND gate having input terminals and an output terminal for producing an ignition signal, means for connecting the said output terminals of said counter circuit upon which appear the binary code representation of the number of said crankshaft position pulses counted by said counter circuit equal to said selected number of degrees before the top dead center position of each piston of said internal combustion engine at which each said reference pulse is produced to respective input terminals of said ignition signal AND gate, a bi-stable multivibrator circuit having two input terminals and an output terminal, for producing a start count signal in response to said reference signals and a full count signal in response to said ignition signals, means for connecting said output circuit means of said reference pulse generator to one of said input terminals of said bi-stable multivibrator circuit, means for connecting said output terminal of said ignition signal AND gate to the other said input terminal of said bi-stable multivibrator circuit and to said reset terminal of said counter circuit, a first monostable multivibrator circuit having an input, an output and a reset terminal responsive to each of said ignition signals for producing a first engine speed ignition spark advance signal of a preselected duration, means for connecting said output terminal of said ignition signal AND gate to said input terminal of said first monostable multivibrator circuit, a second monostable multivibrator circuit having an input, an output and a reset terminal responsive to the end of each of said first engine speed ignition spark advance signals for producing a second engine speed ignition spark advance signal of a predetermined duration, means including a differentiator circuit for connecting said output terminal of said first monostable multivibrator circuit to said input terminal of said second monostable multivibrator circuit, a first count limit AND gate having input terminals and an output terminal for producing a first engine speed ignition spark advance limit signal, means for connecting said output terminals of said counter circuit upon which appear the binary representation of a first selected number of crankshaft position pulses counted by said counter circuit to respective said input terminals of said first count limit AND gate, means for connecting said output terminal of said first count limit AND gate to said reset terminal of said first monostable multivibrator circuit, a second count limit AND gate having input terminals and an output terminal for producing a second engine speed ignition spark advance limit signal, means for connecting said output terminals of said counter circuit uPon which appear the binary representation of a second selected greater number of crankshaft position pulses counted by said counter circuit to respective said input terminals of said second count limit AND gate, means for connecting said output terminal of said second count limit AND gate to said reset terminal of said second monostable multivibrator circuit, engine vacuum sensitive circuit means having an input and an output terminal for producing an engine vacuum ignition spark advance signal, means including a differentiator circuit for connecting said output terminal of said second monostable multivibrator circuit to said input terminal of said engine vacuum sensitive circuit means, an enabling NOR gate, having input terminals and an output terminal for producing an enabling signal for said ignition spark advance NOR gate, means for connecting said output terminal of said bi-stable multivibrator circuit, said output terminals of both said first and second multivibrator circuits and said output terminal of said engine vacuum sensitive circuitry to respective said input terminals of said enabling NOR gate, means for connecting said output circuit means of said crankshaft position sensor and said output terminal of said enabling NOR gate to respective input terminals of said ignition spark advance NOR gate, and dwell circuit having two input circuit means responsive to a preselected number of said crankshaft position pulses applied to one said input circuit means for initiating the operation of said transistor ignition system to trigger said ignition coil primary winding switching transistor conductive and to each of said ignition signals applied to the other one of said input circuit means for initiating the operation of said transistor ignition system to extinguish said ignition coil primary winding switching transistor.

Claim 10

An electronic ignition spark advance system comprising in combination with an internal combustion engine and an associated transistor ignition system having an ignition coil primary winding switching transistor, a crankshaft position sensor having output circuit means for producing a series of crankshaft position pulses, each corresponding to 1* of rotation of the crankshaft of said internal combustion engine, a reference pulse generator having output circuit means for producing a reference pulse a selected number of degrees before the top dead center position of each piston of said internal combustion engine, a counter circuit having an input terminal, a plurality of output terminals, each corresponding to a binary code bit, and a reset terminal for counting said crankshaft position pulses and producing upon said output terminals thereof the binary code representation of the number of said crankshaft position pulses counted thereby, an ignition spark advance NOR gate having input terminals and an output terminal for gating said series of crankshaft position pulses to said input terminal of said counter circuit, an ignition signal AND gate having input terminals and an output terminal for producing an ignition signal, means for connecting the said output terminals of said counter circuit upon which appear the binary code representation of the number of said crankshaft position pulses counted by said counter circuit equal to said selected number of degrees before the top dead center position of each piston of said internal combustion engine at which each said reference pulse is produced to respective input terminals of said ignition signal AND gate, a bi-stable multivibrator circuit having two input terminals and an output terminal, for producing a start count signal in response to said reference signals and a full count signal in response to said ignition signals, means for connecting said output circuit means of said reference pulse generator to one of said input terminals of said bi-stable multivibrator circuit, means for connecting said output terminal of said ignition signal AND gate to the other said input terminal of said bi-stable multivibrator circuit and to said reset terminal of said counter circuit, a first monostable multivibrator circuit having an input, an output and a reset terminal responsive to each of said ignition signals for producing a first engine speed ignition spark advance signal of a preselected duration, means for connecting said output terminal of said ignition signal AND gate to said input terminal of said first monostable multivibrator circuit, a second monostable multivibrator circuit having an input, an output and a reset terminal responsive to the end of each of said first engine speed ignition spark advance signals for producing a second engine speed ignition spark advance signal of a predetermined duration, means including a differentiator circuit for connecting said output terminal of said first monostable multivibrator circuit to said input terminal of said second monostable multivibrator circuit, a first count limit AND gate having input terminals and an output terminal for producing a first engine speed ignition spark advance limit signal, means for connecting said output terminals of said counter circuit upon which appear the binary representation of a first selected number of crankshaft position pulses counted by said counter circuit to respective said input terminals of said first count limit AND gate, means for connecting said output terminal of said first count limit AND gate to said reset terminal of said first monostable multivibrator circuit, a second count limit AND gate having input terminals and an output terminal for producing a second engine speed ignition spark advance limit signal, means for connecting said output terminals of said counter circuit uPon which appear the binary representation of a second selected greater number of crankshaft position pulses counted by said counter circuit to respective said input terminals of said second count limit AND gate, means for connecting said output terminal of said second count limit AND gate to said reset terminal of said second monostable multivibrator circuit, engine vacuum sensitive circuit means having an input and an output terminal for producing an engine vacuum ignition spark advance signal, means including a differentiator circuit for connecting said output terminal of said second monostable multivibrator circuit to said input terminal of said engine vacuum sensitive circuit means, an enabling NOR gate, having input terminals and an output terminal for producing an enabling signal for said ignition spark advance NOR gate, means for connecting said output terminal of said bi-stable multivibrator circuit, said output terminals of both said first and second multivibrator circuits and said output terminal of said engine vacuum sensitive circuitry to respective said input terminals of said enabling NOR gate, means for connecting said output circuit means of said crankshaft position sensor and said output terminal of said enabling NOR gate to respective input terminals of said ignition spark advance NOR gate, and dwell circuit having two input circuit means responsive to a preselected number of said crankshaft position pulses applied to one said input circuit means for initiating the operation of said transistor ignition system to trigger said ignition coil primary winding switching transistor conductive and to each of said ignition signals applied to the other one of said input circuit means for initiating the operation of said transistor ignition system to extinguish said ignition coil primary winding switching transistor.