Ignition systems for internal combustion engines

Abstract

In an ignition system of an internal combustion engine the provision of a device for fast switching the primary circuit, this device including an infra-red radiation source and an infra-red radiation sensitive element, the radiation path being interrupted in timed relation to the engine revolutions whereby switching current is provided which is amplified for fast switching transistorized elements and applied to the primary winding of the ignition coil. Advance or retard of the ignition system can be achieved in relation to speed and/or load conditions on the engine by altering the line of sight between the radiation source and the radiation sensitive element in relation to a device which interrupts the radiation in timed relation to the engine revolutions.

What I claim and desire to secure by Letters Patent is: 
     
       1. A device for providing rapid switching of the primary circuit of an ignition coil of an internal combustion engine to thereby induce a desired voltage in the secondary circuit .Iadd.of the ignition coil, said device .Iaddend.comprising a photo-transistor sensitive to infra-red radiation which will switch on or conduct when exposed to the radiation and switch off when the radiation is cut off; a gallium arsenide lamp emitting infra-red radiation; an element which is opaque to infra-red radiation positioned between the gallium arsenide lamp and the photo-transistor, said opaque element having as many equi-spaced apertures therein as there are cylinders in the engine; means for moving the opaque element in timed relation to the engine revolutions; .[.an amplifier having first and second transistors connected in cascade to the output of the photo-transistor and arranged to switch in inverse relation to one another so that at any one time a transistor is always conducting; and a power transistor connected to the output of the amplifier to be switched in inverse relation to the second transistor of the amplifier and connected in circuit relationship with the ignition coil such that each time a beam of infra-red radiation is cut off from said photo-transistor, the transistorized amplifier circuit causes.]. .Iadd.and a switching circuit interconnecting the photo-transistor with the ignition coil and including a first transistor connected to the output of the photo-transistor, a second transistor, and a power transistor connected to the primary circuit of the ignition coil, the first, second and power transistors being interconnected in a manner such that adjacent ones switch on and off in inverse relation to one another and such that at least one is conducting at any one time, whereby the switching circuit, in response to each time a beam of infra-red radiation is cut off from the photo-transistor causes .Iaddend.rapid switching of the primary circuit and a resultant production of the desired voltage in .[.said.]. .Iadd.the .Iaddend.secondary circuit. 
     
     
       2. A device for providing rapid switching of the primary circuit of an ignition coil of an internal combustion engine to thereby induce a desired voltage in the secondary circuit .Iadd.of the ignition coil, said device .Iaddend.comprising a radiation sensitive element which will switch on or conduct when exposed to radiation and switch off when the radiation is cut off; a solid state .Iadd.infra-red .Iaddend.radiation source; a cylindrical cup forming part of a rotor enclosing the radiation source; at least one inclined slot in said cup; means for rotating the cup in timed relation to the engine revolutions; means for displacing the radiation sensitive element relative to the slot in the cup and thereby the line of sight between the radiation source and the radiation sensitive element so as to achieve an advance or retard of the ignition timing; .[.a transistorized ignition circuit including an amplifier having at least two transistors connected in cascade to the output of the radiation sensitive element and arranged to switch in inverse relation to one another; and switching means connected to the output of the amplifier means and associated with the ignition coil, said transistorized ignition circuit causing rapid switching of the primary circuit, and the resultant production of the desired voltage in the secondary circuit, responsive.]. .Iadd.and a switch circuit interconnecting the radiation sensitive element with the ignition coil and including a plurality of transistors interconnected in a manner such that adjacent ones switch off and on in inverse relation to each other and such that at least one is conducting at any one time, the first of the transistors being connected to the output of the radiation sensitive element and the last of the transistors being connected to the primary circuit of the ignition coil, whereby the switching circuit, in response .Iaddend.to a slot permitting a beam of radiation to fall onto and to be cut off from the radiation sensitive element.Iadd., causes rapid switching of the primary circuit and the resultant production of the desired voltage in the secondary circuit. .Iaddend. 
     
     
       3. A device according to claim 2.[.,.]. wherein the solid state radiation source comprises a gallium arsenide lamp .[.which emits radiation in the infra-red region of the electromagnetic spectrum.].. 
     
     
       4. A device according to claim 2.[.,.]. wherein said switching .[.means comprises a power transistor.]. .Iadd.circuit includes two n-p-n transistors having commoned emitter electrodes and an n-p-n power transistor having its collector electrode connected to one end of the primary circuit of the ignition coil. .Iaddend. 
     
     
       5. A device for providing rapid switching of the primary circuit of an ignition coil of an internal combustion engine to thereby induce a desired voltage in the secondary circuit .Iadd.of the ignition coil, said device .Iaddend.comprising a radiation sensitive element which will switch on or conduct when exposed to radiation and switch off when the radiation is cut off; a solid state infra-red radiation source; a disc having as many substantially V-shaped slots cut therein in equi-spaced relation around the circumference as there are cylinders in the engine, said disc being positioned between the radiation source and the radiation sensitive element; means for rotating the disc in timed relation to the engine revolutions; means for moving the line of sight between the radiation source and the radiation sensitive element through the slots in the disc so as to achieve an advance or retard of the ignition timing; .[.a transistorized ignition circuit including an amplifier having at least two transistors arranged in cascade and fed from the output of the radiation sensitive element so as to switch rapidly in inverse relation to one another; and a power transistor fed from the output of the amplifier means and feeding the ignition coil, said transistorized ignition circuit causing a switching action to effect.]. .Iadd.and a switching circuit interconnecting the radiation sensitive element with the ignition coil and including a plurality of transistors interconnected in a manner such that adjacent ones switch on and off in inverse relation to each other and such that at least one is conducting at any one time, the first of the transistors being connected to the output of the radiation sensitive element and the last of the transistors being connected to the primary winding of the ignition coil, whereby the switching circuit causes .Iaddend.the sequential magnetic build up and collapse of the field in the primary winding of the ignition coil responsive to a slot permitting a beam of infra-red radiation to fall on and be cut off from the radiation device, said collapse of said field resulting in the production of the desired voltage in the secondary circuit. 
     
     
       6. A device according to claim 5.[.,.]. wherein the radiation source and the radiation sensitve element are each mounted at the end of a member the ends of which are movable in relation to the disc to cut the line of sight between .[.said.]. .Iadd.the radiation source and the radiation sensitive .Iaddend..[.elements.]. .Iadd.element.Iaddend., one end of the member being moved in response to engine speed and the other in response to load. 
     
     
       7. A device according to claim 5.[.,.]. wherein the radiation source and radiation sensitive element are each mounted at the end of an elongate member, .Iadd.and said device further includes .Iaddend.means for displacing each end of said elongate .Iadd.member .Iaddend.including a diaphragm mounted in a chamber respectively connected to the venturi of a carburetor and the vacuum spark port of the carburetor so as to be sensitive to the partial vacua, the ends of said member being pivotally connected to respective diaphragms whereby the ends of said member are respectively moved in response to engine speed and load to thereby vary the timing at which the radiation sensitive element is cut off from the radiation source and hence the timing of the spark in relation to crank position. 
     
     
       8. A device for providing rapid switching of the primary circuit of an ignition coil of an internal combustion engine to thereby induce a desired voltage in the secondary circuit .Iadd.of the ignition coil, said device .Iaddend.comprising a photo-transistor sensitive to infra-red radiation which will switch on or conduct when exposed to the radiation and switch off when the radiation is cut off; a solid state infra-red radiation source; an element which is opaque to infra-red radiation positioned between the infra-red radiation source and the photo-transistor, said opaque element having as many equi-spaced apertures therein as there are cylinders in the engine; means for moving the opaque element in timed relation to the engine revolutions; means for moving the line of sight between the infra-red radiation source and the photo-transistor through the apertures in the element so as to achieve an advance or retard of the ignition timing; .[.a transistorized ignition circuit including an amplifier having at least two transistors connected in cascade to the output of the photo-transistor and arranged to switch in inverse relation to one another; and a power transistor connected to the output of the amplifier and connected in circuit relationship with the ignition coil such that each time a beam of infra-red radiation is cut off from said photo-transistor, the transistorized amplifier circuit causes.]. .Iadd.and a switching circuit interconnecting the photo-transistor with the ignition coil and including a first transistor connected to the output of the photo-transistor, a second transistor, and a power transistor connected to the primary circuit of the ignition coil, the first, second and power transistors being interconnected in a manner such that adjacent ones switch on and off in inverse relation to one another and such that at least one is conducting at any one time, whereby the switching circuit, in response a beam of infra-red radiation being cut off from the photo-transistor, causes .Iaddend.rapid switching of the primary circuit and a resultant production of the desired voltage in .[.said.]. .Iadd.the .Iaddend.secondary circuit. 
     
     
       9. A device according to claim 8.[.,.]. wherein the photo-transistor has its base electrode left unconnected.Iadd., .Iaddend..[.and wherein.]. the .[.amplifier comprises two.]. .Iadd.first and second .Iaddend.transistors .Iadd.are .Iaddend.of like type, the emitter electrode of the photo-transistor .[.being.]. .Iadd.is .Iaddend.connected to the base electrode of the first transistor, the collector electrode of the first transistor .[.being.]. .Iadd.is .Iaddend.connected to the base electrode of the second transistor, the collector electrode of the second transistor .[.being.]. .Iadd.is .Iaddend.connected to the base electrode of the power transistor, the emitter electrodes of the .Iadd.first, second and power .Iaddend.transistors .[.being.]. .Iadd.are .Iaddend.commoned and connected to one side of a battery, .Iadd.each of .Iaddend.the collector electrodes .[.being.]. .Iadd.of the first, second and power transistors is .Iaddend.connected to the other side of the battery .[.each.]. through a resistor, and .Iadd.each of .Iaddend.the base electrodes .[.being.]. .Iadd.of the first, second and power transistors is .Iaddend.connected to the commoned emitter electrodes .[.each.]. through .Iadd.a .Iaddend.further .[.resistors.]. .Iadd.resistor.Iaddend.. .Iadd. 10. An opto-electronic ignition system for an internal combustion engine including an ignition coil having primary and secondary windings, said system including an infra-red radiation source; a photo-transistor which will switch on or conduct when exposed to infra-red radiation from the source and switch off when the radiation is cut off; an element opaque to infra-red radiation positioned between the radiation source and the photo-transistor and having as many equi-spaced apertures therein as there are cylinders in the engine; means for moving the opaque element in timed relation to the engine revolutions; a first transistor connected to the output from the photo-transistor so as to conduct when said photo-transistor conducts; a second transistor connected to the output of the first transistor so as to switch in inverse relation to the first transistor; and a third transistor connected to the output of the second transistor so as to switch in inverse relation to the second transistor and having an output connected to the primary winding of the ignition coil, whereby, every time radiation is cut off from the photo-transistor, the third transistor is rendered non-conductive to cause a collapse of the magnetic field associated with the primary winding and the resultant induced voltage in the secondary winding produces an ignition spark. .Iaddend.