Fuel vapor injector and igniter system for internal combustion engines

Abstract

A combined fuel vapor injector and igniter system for internal combustion engines and method of operating the engine therewith in which liquid fuel enters an injector-igniter device, is vaporized using the engine's heat of combustion, and exits in vapor form into the engine combustion chamber where it mixes with air or an air-fuel mixture which has entered through an intake valve, or port, and the resulting air-fuel mixture is ignited. The system assures reliable ignition, so that engines may be run at leaner than stoichiometric air-fuel ratios to take advantage of increased fuel economy, and reduced emissions of the oxides of nitrogen hydrocarbons and carbon monoxide. Power output equalization is attained between cylinders.

What is claimed is: 
     
       1. In combination with an internal combustion engine having a combustion chamber and means to selectively supply air or an air-fuel mixture thereto, a combined fuel vapor injector an igniter comprising an insulating body, an electrically conductive member securing said body to said chamber and including a first electrode extending into said chamber, a heat .Iadd.and .Iaddend.electrically conductive vaporizing tube extending through said insulating body and into said chamber serving as a second electrode and terminating in an end adjacent said first electrode to provide a spark gap therebetween, a fuel vapor exit orifice at said end of said tube, a liquid fuel inlet orifice adjacent the other end of said tube, means to supply liquid fuel to said tube through said inlet orifice, a check valve interposed between said inlet orifice and said fuel supply means, said check valve opening only in response to a predetermined drop in pressure in said chamber to allow fuel to enter said inlet orifice, said vaporizing tube having been heated by the combustion in said chamber and in said tube, and means to provide a spark across said spark gap at and during the time fuel in vapor form exits into said chamber from said exit orifice to admix with the air or an air-fuel mixture in said chamber supplied thereto and produce a readily ignitable mixture of fuel vapor and air at said spark gap, said electrically conductive member including an open-ended shield surrounding said fuel vapor exit orifice of said tube to confine the exiting fuel vapor and increase the ratio of fuel to air in said shield. 
     
     
       2. The combination of claim 1 and means to vary the size of said fuel inlet orifice. 
     
     
       3. The combination of claim 2 wherein said means to vary said fuel inlet orifice is a needle valve secured to said insulating body and extending variably across said inlet orifice. 
     
     
       4. The combination of claim 2 wherein said means to vary said fuel inlet orifice are discs adapted selectively to seat on said other end of said vaporizing tube having openings of varying sizes communicative with said tube. 
     
     
       5. The combination of claim 1 wherein said first electrode is a venturi shield surrounding said fuel vapor exit orifice, said shield including circumferentially spaced ports to draw air therethrough and increase the admixture of fuel vapor and air into said shield which serves as the spark gap area. 
     
     
       6. The combination of claim 1 wherein said first electrode is a shield which acts to control the heat range in the injector tube and confine the exiting fuel vapor therein to increase the ratio of fuel vapor to air in said shield which serves as the spark gap area. 
     
     
       7. The combination of claim 1 and means to control the heat retentive capacity of said tube to vary the rate of fuel vaporization therein. 
     
     
       8. The combination of claim 7 wherein said means to control the heat retentive capacity of said tube includes a heat conductive insert in said tube increasing the internal surface thereof and providing a tortuous path for the flow of fuel therethrough from the inlet to the exit orifice. 
     
     
       9. The combination of claim 1 wherein the internal combustion engine is a four-cycle engine having a piston reciprocal in the chamber, intake and exhaust valves, the air or fuel-air mixture being supplied through said intake valve, said check valve opening in response to a drop in pressure in the chamber to allow fuel to enter said fuel evaporating tube through said inlet orifice during the intake stroke of said engine while the air or fuel-air mixture are drawn selectively into said chamber at said time, said check valve closing when the pressure in said cylinder rises to a value above that of the fuel supply to said inlet orifice, fuel vapor entering said spark gap area from said exit orifice to admix with air thereat and produce a readily ignitable mixture of fuel vapor and air at and during the time said spark is produced. 
     
     
       10. The combination of claim 1 wherein the internal combustion engine is a two-cycle engine having a piston reciprocal in the chamber and air intake and exhaust ports, said check valve opening in response to a drop in pressure in the chamber to allow fuel to enter said inlet orifice of said fuel vaporizing tube when the piston drops to uncover said air and exhaust ports, said check valve closing as said piston moves up and increases pressure in said chamber during the compression stroke, fuel vapor entering said spark gap area from said exit orifice to admix with air thereat and produce an ignitible mixture of fuel vapor and air at and during the time the spark is produced. 
     
     
       11. The combination of claim 1 wherein the internal combustion engine is a rotary engine having a stator forming the combustion chamber, a rotor of substantially triangular cross-section mounted for eccentric rotation therein, a fuel-air inlet port and an exhaust port, said combined fuel vapor injector and igniter being secured to said stator, said check valve opening during the compression phase of engine operation to allow fuel to enter said inlet orifice of said tube, said check valve closing before the end of the compression phase, fuel vapor entering the spark gap area from said exit orifice to admix with the air thereat and produce an ignitible mixture of fuel vapor and air at and during the time the spark is produced. 
     
     
       12. The combination of claim 1 and a flame quenching zone in said fuel vaporizing tube. 
     
     
       13. The combination of claim 12 and means to vary the location of the flame quenching zone along the length of said tube. 
     
     
       14. The combination of claim 13 wherein said means to vary the location of the flame quenching zone includes at least one restriction acting to narrow the bore of said tube selectively at at least one predetermined location along the length thereof. 
     
     
       15. In combination with an internal combustion engine having multiple combustion chambers and means to selectively supply air or an air-fuel mixture thereto, a combined fuel vapor injector and igniter for each combustion chamber comprising an insulating body, an electrically conductive member securing said body to said chamber and including a first electrode extending into said chamber, a heat and electrically conductive vaporizing tube extending through said insulating body and into said chamber serving as a second electrode and terminating in an end adjacent said first electrode to provide a spark gap therebetween, a fuel vapor exit orifice at said end of said tube, a liquid fuel inlet orifice adjacent the other end of said tube, means to supply liquid fuel to said tube through said inlet orifice, means to vary the supply of liquid fuel to said tube, a check valve interposed between said inlet orifice and said fuel supply means, said check valve opening only in response to a predetermined drop in pressure in said chamber to allow fuel to enter said inlet orifice, said vaporizing tube having been heated by the combustion in said chamber and in said tube and means to provide a spark across said spark gap at and during the time fuel in vapor form exits into said chamber from said exit orifice to admix with the air or an air-fuel mixture in said chamber supplied thereto and produce a readily ignitable mixture of fuel vapor and air at said spark gap, said means to vary the supply of liquid fuel to each tube acting to equalize the power output from each chamber, said electrically conductive member including an open-ended shield surrounding said fuel vapor exit orifice of said tube to confine the exiting fuel vapor and increase the ratio of fuel to air in said shield. 
     
     
       16. In combination with an internal combustion engine having multiple combustion chambers and means to selectively supply air or an air-fuel mixture thereto, a combined fuel vapor injector and igniter for each chamber comprising an insulating body an electrically conductive member securing said body to said chamber and including a first electrode extending into said chamber, a heat and electrically conductive tube extending through said insulating body and into said chamber serving as a second electrode and terminating in an end adjacent said first electrode to provide a spark gap therebetween, a fuel vapor exit orifice at said end of said tube, a fuel inlet orifice adjacent the other end of said tube, means to supply only fuel to said tube through said inlet orifice, means to vary the supply of fuel to said tube, a check valve interposed between said inlet orifice and said fuel supply means, said check valve opening only in response to a predetermined drop in pressure in said chamber to allow fuel to enter said inlet orifice, said tube having been heated by the combustion in said chamber and in said tube and expanding the fuel therein, and means to provide a spark across said spark gap at and during the time fuel in vapor form exits into said chamber from said exit orifice to admix with air or an air-fuel mixture supplied thereto and produce a readily ignitible mixture of fuel vapor and air at said spark gap, said means to vary the supply fuel to each tube acting to equalize the power output from each chamber, said electrically conductive member including an open-ended shield surrounding said fuel vapor exit orifice of said tube to confine the exiting fuel vapor and increase the ratio of fuel to air in said shield. 
     
     
       17. In combination with an internal combustion engine having a combustion chamber and means to selectively supply air or an air-fuel mixture thereto, a combined fuel vapor injector and igniter comprising an insulating body, an electrically conductive member securing said body to said chamber and including a first electrode extending into said chamber, a heat and electrically conductive tube extending through said insulating body and into said chamber serving as a second electrode and terminating in an end adjacent said first electrode to provide a spark gap therebetween, a fuel vapor exit orifice at said end of said tube, a fuel inlet orifice adjacent the other end of said tube, means to supply only fuel to said tube through said inlet orifice, a check valve interposed between said inlet orifice and said fuel supply means, said check valve opening only in response to a predetermined drop in pressure in said chamber to allow fuel to enter said inlet orifice, said tube having been heated by the combustion in said chamber and in said tube and expanding the fuel therein, and means to provide a spark across said spark gap at and during the time fuel in vapor form exits into said chamber from said exit orifice to admix with air or an air-fuel mixture in said chamber supplied thereto and produce a readily ignitible mixture of fuel vapor and air at said spark gap, said electrically conductive member including an open-ended shield surrounding said fuel vapor exit orifice of said tube to confine the exiting fuel vapor and increase the ratio of fuel to air in said shield. 
     
     
       18. A method of operating an internal combustion engine comprised of providing a tubular heat and electrically conductive member having one end opening into the combustion chamber and serving as an electrode and thereby exposing the same to the heat generated in said combustion chamber .[.providing a confining zone around said one end of said tubular member,.]. disposing another electrode in said chamber adjacent said one end of said tubular electrode to provide a spark gap therebetween, feeding liquid fuel to the tubular electrode adjacent its other end at a temperature less tnan that generated in the chamber, allowing the liquid fuel to flow into said tubular electrode only in response to a predetermined drop in pressure in said chamber feeding selectively an air or air-fuel mixture into said chamber when the liquid fuel is entering the tubular electrode and until the pressure in the chamber exceeds that of the liquid fuel feed into the tubular electrode to close it off, retaining the fuel in the tubular electrode for a time sufficient to allow the heat retained in the tubular electrode to cause the fuel therein to expand and exit as a vapor into the confining zone and producing a spark between the electrodes at and during the time the fuel vapor is exiting into the chamber to ignite the fuel vapor admixture with air in the chamber at that time to produce the power stroke. 
     
     
       19. The method of claim 18 and altering the internal volume of the tubular electrode to alter the heat retention thereof and hence the time required to allow the liquid fuel therein to change to a vapor state. 
     
     
       20. The method of claim 18 and altering the mass of the tubular electrode to alter the heat retention thereof and hence the time required to allow the liquid fuel therein to change to a vapor state. 
     
     
       21. The method of claim 18 and altering the heat conductive surface in the tubular electrode to control the time required to vaporize the fuel therein. 
     
     
       22. The method of claim 18 and varying the rate of flow of the fuel in the tubular electrode to control the quantity of fuel to exit as a vapor into the spark gap. 
     
     
       23. The method of claim 17 wherein a lean air-fuel mixture is fed into the combustion chamber which exceeds a ratio of 15:1 by weight of air to fuel excluding the fuel fed into the tubular electrode. 
     
     
       24. The method of claim 18 wherein the internal combustion engine is a four-cycle engine and wherein fuel is fed to the tubular electrode and the air or air-fuel mixture to the chamber during the intake stroke, the feed of fuel to the tubular electrode is stopped at the end of the intake stroke or beginning of the compression stroke and the fuel in the tubular electrode exits as a vapor into the chamber during the compression stroke. 
     
     
       25. The method of claim 24 wherein the pressure of the fuel feed to the tubular electrode is about 5-10 psi. 
     
     
       26. The method of claim 25 wherein the pressure of the fuel feed to the tubular electrode is about 150-200 psi. 
     
     
       27. A method of operating an internal combustion engine comprised of providing a tubular heat and electrically conductive member having one end opening into the combustion chamber and serving as an electrode and thereby exposing the same to the heat generated in said combustion chamber, disposing another electrode in said chamber adjacent said one end of said tubular electrode to provide a spark gap therebetween, feeding liquid fuel to the tubular electrode adjacent its other end at a temperature less than that generated in the chamber, allowing the liquid fuel to flow into said tubular electrode only when the pressure in the combustion chamber is below that of the pressure of the liquid fuel, feeding selectively an air or air-fuel mixture into said chamber when the liquid fuel is entering the tubular electrode and until the pressure in the chamber exceeds that of the liquid fuel feed into the tubular electrode to close it off, retaining the fuel in the tubular electrode for a time sufficient to allow the heat retained in the tubular electrode to cause the fuel therein to expand and exit as a vapor into the chamber and producing a spark between the electrodes at and during the time the fuel vapor is exiting into the chamber to ignite the fuel vapor admixture with air in the chamber at that time to produce the power stroke, and providing .Iadd.at least one .Iaddend.restricting .[.areas.]. .Iadd.area .Iaddend.in the tubular electrode at .Iadd.a .Iaddend.selected .[.points.]. .Iadd.point .Iaddend.along its length to provide .Iadd.a .Iaddend.quench .[.zones.]. .Iadd.zone .Iaddend.and thereby control the heat sufficient to allow the fuel to exit as a vapor into the combustion chamber. 
     
     
       28. The method of claim 18 wherein the internal combustion engine is a two-cycle engine and wherein the fuel is fed into the tubular electrode after the air and exhaust ports of the engine are open, the feed of fuel to the tubular electrode is stopped during the compression stroke of the piston and the fuel exits as a vapor into the combustion chamber at that time. 
     
     
       29. The method of claim 18 wherein the internal combustion engine is a rotary engine having a rotor of substantially triangular cross-section rotating in a stator having air-fuel inlet and exhaust gas outlet ports, and wherein the fuel is fed into the tubular electrode during the compression phase, the fuel feed to the tubular electrode stopping before the end of compression phase and existing as a vapor into the stator towards the end of the compression phase. 
     
     
       30. A method of operating an internal combustion engine comprised of providing a heat conductive tube having an exit end extending and opening into the combustion chamber, and having a first, larger inside diameter extending inwardly a predetermined distance from said exit end and a second, smaller inside diameter thereafter, .Iadd.providing a confining zone around said exit end, .Iaddend.feeding only liquid fuel into the inlet end of said tube adjacent its other end at a temperature less than that generated in the chamber, allowing the liquid fuel to flow into the tube only, and until the pressure in the chamber exceeds that of the liquid fuel feed into the tube to close it off, retaining the fuel in the tube for a time sufficient to permit the heat stored in the tube which was acquired from the heat of combustion in the combustion chamber and in the tube to be transferred to the liquid fuel to change less than all of said fuel to a vapor state and thereby expand in the tube and exit therefrom only as a vapor into the confining zone in the chamber containing air or air-fuel mixture and igniting the fuel vapor-air mixture adjacent the exit end of the tube to produce power. 
     
     
       31. A method of operating an internal combustion engine comprised of providing a heat conductive tube having an exit end extending and opening into the combustion chamber, providing a confining zone around said exit end, feeding only fuel into the inlet end of said tube adjacent its other end at a temperature less than that generated in the chamber allowing the fuel to flow into the tube only, and until the pressure in the chamber exceeds that of the fuel feed into the tube to close it off, retaining the fuel in the tube for a time sufficient to permit the heat stored in the tube which was acquired from the heat of combustion in the combustion chamber and in the tube to be transferred to the fuel to expand it in the tube and force it as a vapor into the confining zone in the combustion chamber selectively containing air or air-fuel mixture and igniting the fuel vapor-air mixture adjacent the exit end of the tube to produce power. 
     
     
       32. The method of claim 31 and providing a confining zone circumferentially about the exit end of the tube, a portion of said confining zone opening to the combustion chamber. 
     
     
       33. A method of operating an internal combustion engine having multiple combustion chambers comprised of providing a heat conductive tube for each chamber having an exit end extending and opening into the combustion chamber, feeding only fuel into the inlet end of said tube adjacent its other end at a temperature less than that generated in the chamber, allowing the fuel to flow into the tube only, and until the pressure in the chamber exceeds that of the fuel feed into the tube to close it off, retaining the fuel in the tube for a time sufficient to permit the heat stored in the tube which was acquired from the heat of combustion in the combustion chamber and in the tube to be transferred to the fuel to expand it in the tube and force it as a vapor into the confining zone in the combustion chamber selectively containing air or air-fuel mixture, igniting the fuel vapor-air mixture adjacent the exit end of the tube to produce power and varying the quantity of fuel supplied to each tube to equalize the power output of each chamber. 
     
     
       34. In a method of operating an internal combustion engine, the steps of providing an elongated electrically conductive fuel vapor injecting zone having an exit end opening into the combustion zone of the engine, confining the exit end with a portion thereof opening into the combustion zone feeding liquid fuel into the injecting zone only in response to a drop in pressure in the combustion zone, selectively feeding air or an air-fuel mixture into the combustion zone when the fuel is entering the injecting zone until the pressure in the combustion zone rises sufficiently to close off the fuel feed, allowing the heat of combustion of the combustion zone and the heat of combustion in the injecting zone to heat the injecting zone for a time sufficient to cause the fuel to vaporize and to expand and thereby be injected into the confining zone as a vapor and producing a spark from the exit end of the injecting zone to another electrode at and during the time the fuel is exiting as a vapor into the combustion zone to ignite the fuel vapor admixture with the air or air-fuel mixture at that time to produce the power stroke of the engine. 
     
     
       35. In a method of operating an internal combustion engine, the steps of providing an elongated electrically conductive fuel vapor injecting zone having an exit end opening into the combustion zone of the engine, feeding only fuel into the injecting zone only in response to a drop in pressure in the combustion zone, confining the exit end with a portion thereof opening into the combustion zone selectively feeding air or an air-fuel mixture into the combustion zone when the fuel is entering the injecting zone until the pressure in the combustion zone rises sufficiently to close off the fuel feed, allowing the heat of combustion of the combustion zone and the heat of combustion of the injecting zone to heat the injecting zone for a time sufficient to expand the fuel therein and cause it to be injected into the confining zone to another electrode as a vapor, and producing a spark from the exit end of the injecting zone at and during the time the fuel is exiting as a vapor into the combustion zone to ignite the fuel vapor admixture with the air or air-fuel mixture at that time to produce the power stroke of the engine.