Fuel injection systems for internal combustion engines

Abstract

A device for generating a voltage pulse for use with a fuel injection system of an internal combustion engine utilizing infra-red radiation source and detector for obtaining a voltage pulse to operate the solenoids of the appropriate fuel injectors in cyclic order, which voltage pulse is timed from shutter means mechanically driven and interposed between the source and detector, the relative angular duration of the voltage pulse determined by the length of unmasking by the shutter, being controlled by the speed of and load on the engine.

What I claim and desire to secure by Letters Patent is: 
     
       1. A device for fast switching the solenoid of a fuel injector system of an internal combustion engine, including 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 at least one aperture therein; 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 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 and connected in circuit relationship with the solenoid such that every time a beam of radiation falls onto and is cut off from the photo-transistor, said transistorized amplifier circuit and power transistor causes the fast switching of the solenoid to inject the desired quantity of fuel into a cylinder of the internal combustion engine in accordance with the period during which the photo-transistor is exposed to infra-red radiation. 
     
     
       2. A device according to claim 1, including a stator member having an annular groove; a cup shaped rotor member constituting the opaque element and rotatable within said annular groove in synchronism with the engine, the photo-transistor and gallium arsenide lamp being mounted on the stator member on opposite sides of the annular groove; at least one open-ended slot provided in the cylindrical wall of the rotor member, said slot having a peripheral width which varies in a linear manner from a small peripheral width at the open end to a greater peripheral width at the closed end; and means for axially displacing the rotor with respect to the stator member in accordance with engine speed, the peripheral width of the radiation window as defined by the slot being used to control the air to fuel ratio injected into the engine. 
     
     
       3. A device according to claim 2, including a diaphragm to which the stator member is mechanically coupled, said diaphragm being open to the atmosphere on one side; and an inlet manifold of the engine, the other side of the diaphragm being in communication with the pressure prevailing in the manifold, so that the diaphragm is subjected to a difference in pressure, whereby the stator member is longitudinally moved in relation to the rotor member according to the load on the engine, the peripheral width of the slot being used to control the air to fuel ratio injected into the engine. 
     
     
       4. A device according to claim 1, including as many fuel injectors as there are cylinders in the engine, every fuel injector being associated with a different cylinder; and as many transistorized circuits as there are fuel injectors, these circuits being arranged in parallel to energize the individual solenoids of the fuel injectors, the injectors being operated in cyclic manner according to the cylinder firing sequence of the engine. 
     
     
       5. A device according to claim 2, including n fuel injectors for an internal combustion engine having m cylinders, the cylinders being arranged in groups, there being at least two cylinders in each group; n gallium arsenide lamps and n photo-transistors, the components of each pair being arranged opposite each other across the annular groove of the stator member, each pair being in equi-spaced relation therearound, so that the injectors operate in a given repeatable sequence. 
     
     
       6. A device according to claim 2, including n fuel injectors for an internal combustion engine having 3n cylinders; n gallium arsenide lamps and n photo-transistors, the components of each pair being opposite each other across the annular groove of the stator member, each pair being arranged so that all the pairs are equi-spaced from their neighbors around the stator, the cylinders being arranged in groups of three such that the injectors operate in a given repeatable sequence. 
     
     
       7. A device according to claim 1, wherein the photo-transistor has its base electrode left unconnected, the emitter electrode of the photo-transistor being connected to the base electrode of the first transistor, the collector electrode of the first transistor being connected to the base electrode of the second transistor, the collector electrode of the second transistor being connected to the base electrode of the power transistor, the emitter electrodes of the transistors being commoned and connected to one side of a battery, the collector electrodes being connected to the other side of the battery each through a resistor, and the base electrodes being connected to the commoned emitter electrodes each through further resistors. 
     
     
       8. A device according to claim 7, wherein a resistor is connected in series and a zener diode is connected in parallel with the gallium arsenide lamp. .Iadd. 9. An opto-electronic device for fast switching the solenoid of a fuel injector system of an internal combustion engine including 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 lamp; an element positioned between the solid state lamp and the photo-transistor and having one portion which is opaque to the radiation and another portion through which the radiation can pass; means for moving the element in timed relation to the engine revolutions; and a switching circuit interconnecting the solenoid and the photo-transistor including a plurality of transistors interconnected in a manner so that the output of one is connected to the input of the next and so as to switch on and off in inverse relation to one another, the first of the transistors being connected to the output of the photo-transistor and the last of the transistors being connected to the solenoid whereby the transistors, in response to switching of the photo-transistor, switch between on and off conditions and cause alternate energization and de-energization of the solenoid to thereby inject the desired quantity of fuel into a cylinder of the internal combustion engine. .Iaddend. .Iadd. 10. A device according to claim 9 including a stator member having an annular groove; a cup shaped rotor member constituting the element and rotatable within said annular groove in synchronism with the engine, the photo-transistor and solid state infra-red lamp being mounted on the stator member on opposite sides of the annular groove; at least one open-ended slot in the cylindrical wall of the rotor defining a radiation window through which radiation from the infra-red lamp can pass, the slot having a peripheral width which varies in a linear manner from a small peripheral width at the open end to a greater peripheral width at the closed end; and means for axially displacing the rotor with respect to the stator member in response to engine speed whereby the peripheral width of the radiation window controls the air to fuel ratio injected into the engine. .Iaddend. .Iadd. 11. A device according to claim 10 wherein said means for axially displacing the rotor includes a diaphragm mechanically coupled to the stator, one side of the diaphragm connected in communication with the atmosphere and the other side of the diaphragm connected in communication with the pressure prevailing in an inlet manifold of the engine whereby the stator member, in response to the pressure differential existing across the diaphragm indicative of the load on the engine, is moved longitudinally relative to the rotor member. .Iaddend..Iadd. 12. A device according to claim 9 including an individual injector for each cylinder in the engine; a switching circuit associated with each fuel injector and arranged to energize the respective fuel injector solenoid whereby the fuel injectors are operated in a cyclic manner according to the cylinder firing sequence of the engine. .Iaddend..Iadd. 13. A device according to claim 10 including n fuel injectors for an internal combustion engine having m cylinders arranged in groups, each group having at least two cylinders; n solid state infra-red lamps; and n photo-transistors, each pair of lamps and photo-transistors oppositely disposed across the annular groove of the stator member and circumferentially spaced relative to each other pair at equal intervals around the stator, the cylinders being arranged in groups, such that the injectors operate in a given repeatable sequence. .Iaddend. .Iadd. 14. A device according to claim 10 including n fuel injectors for an internal combustion engine having 3n cylinders arranged in groups of three; n gallium arsenide solid state infra-red lamps; and n photo-transistors, each pair of lamps and photo-transistors oppositely disposed across the annular groove of the stator member and circumferentially spaced relative to each other pair at equal intervals around the stator, the cylinders being arranged in groups of three, such that the injectors operate in a given repeatable sequence. .Iaddend..Iadd. 15. A device according to claim 9 wherein the switching circuit includes three transistors, the base electrode of the photo-transistor is unconnected, the emitter electrode of the photo-transistor is connected to the base electrode of the first transistor, the collector electrode of the first transistor is connected to the base electrode of the second transistor, the collector electrode of the second transistor is connected to the base electrode of the third transistor, the emitter electrodes of the three transistors are commoned and connected to one side of a battery, each of the collector electrodes of the first and second transistors is connected to the other side of the battery through a resistor, and each of the base electrodes of the three transistors is connected to the commoned emitter electrodes through a further resistor. .Iaddend. .Iadd. 16. A device according to claim 15 including a resistor connected in series and a zener diode connected in parallel with the gallium arsenide solid state infra-red lamp. .Iaddend..Iadd. 17. A device according to claim 9 wherein said solid state infra-red lamp is a gallium arsenide lamp. .Iaddend..Iadd. 18. A device according to claim 9 wherein said solid state infra-red lamp is a β-lamp. .Iaddend. .Iadd. 19. An opto-electronic device for fast switching the solenoid of a fuel injector system of an internal combustion engine, including a photo-transistor sensitive to infra-red radiation which will conduct when exposed to infra-red radiation and revert to its non-conductive state when the infra-red radiation is cut off; a gallium arsenide lamp which will emit radiation in the infra-red region of the electro-magnetic spectrum when energized; an element made of a material opaque to the infra-red radiation emitted by the lamp positioned between the lamp and the photo-transistor being said element having at least one aperture through which infra-red radiation can pass; means for rotating said element in timed relation to the engine revolutions; and a switching circuit interconnecting the solenoid and the photo-transistor including a plurality of transistors interconnected in a manner so that the output of one is connected to the input of the next and so as to switch on and off in inverse relationship to one another, the first of the transistors is connected to the output of the photo-transistor and the last of the transistors is connected to the solenoid, whereby the transistors, in response to switching of the photo-transistor, switch between on and off conditions causing de-energization of the solenoid during the time period infra-radiation is cut off from the photo-transistor and causing energization of the solenoid during the time period the photo-transistor is exposed to infra-red radiation to thereby inject the desired quantity of fuel into a cylinder of the internal combustion engine. .Iaddend. .Iadd. 20. A device according to claim 19 wherein the switching circuit includes three transistors having commoned emitter electrodes and the last of the transistors is a power transistor. .Iaddend.