Abstract:
A vapor fuel injection system including an air pump having dedicated air cylinders assigned to individual engine cylinders and adapted to produce timed charges of pre-heated air adapted to push timed charges of fuel through a heat exchanger where the timed charges of fuel are converted into metered charges of fuel vapor. The charges of fuel vapor are subsequently pushed into and through fuel vapor delivery nozzles defined in the respective guide bodies of respective intake valve assemblies. After exiting the guide body of said valve assemblies, the timed charges of fuel vapor mix with intake manifold air and then are fed directly into the engine cylinders for combustion.

Description:
FIELD OF THE INVENTION 
   This invention relates generally to a fuel injection system for injection of a vaporizing fuel such as, for example, gasoline or alcohol and, more particularly, to a system which utilizes a multi-cylindered air pump in combination with fuel injectors and heat exchangers for delivering metered and timed charges of fuel vapor into the respective cylinders of an internal combustion engine. 
   BACKGROUND OF THE INVENTION 
   Increasing the efficiency of internal combustion engines has been a continuous endeavor. One of the ways in which efficiency has sought to be increased is through the combustion of vaporized rather than liquid fuels. 
   Although systems have been developed over the years in which combustion is attained using fuel vapors, there remains a need for a fuel vapor delivery system which is simple in structure, efficient and easily adaptable into existing engine systems. The system of the present invention fills these needs. 
   SUMMARY OF THE INVENTION 
   The invention relates to a vapor fuel injection system adapted for delivering timed charges of fuel vapor into an engine including a plurality of cylinders. The system initially comprises a plurality of fuel injectors operatively associated with the plurality of engine cylinders respectively and adapted to emit timed charges of fuel. The system further comprises an air pump including a plurality of air cylinders operatively dedicated to the plurality of fuel injectors and the plurality of engine cylinders respectively and adapted to produce timed charges of air. Still further, the system comprises a plurality of air delivery conduits extending between the air cylinders and fuel injectors respectively, the conduits being sized and adapted to increase the velocity and temperature of the air flowing therethrough. Moreover, a plurality of heat exchange conduits are operatively associated with the plurality of fuel injectors respectively and the timed charges of air are adapted to push the respective timed charges of fuel into and through the heat exchange conduits respectively wherein the timed charges of fuel are converted into timed charges of fuel vapor. 
   Still further, a plurality of vapor delivery nozzles are operatively associated at one end with the plurality of heat exchange conduits respectively and at the other end with the plurality of engine cylinders respectively. Each of the vapor delivery nozzles are preferably, although not necessarily, formed in the bodies of the respective intake valve guides. A control relief valve operatively associated with each of the heat exchange conduits controls the pressure of the timed charges of fuel vapor. Finally, an air intake manifold is operatively associated with the engine cylinders and is adapted to deliver throttled charges of intake air into the engine cylinders respectively. The vapor delivery nozzles and air intake port are positioned and oriented relative to one another in a manner whereby the timed charges of fuel vapor and intake air are mixed together at the point of entry into the respective engine cylinders. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the accompanying drawings which form part of the specification in which like numerals are employed to designate like parts throughout the same: 
       FIG. 1  is a simplified, schematic view of the positive pressure vapor fuel injection system of the present invention; and 
       FIG. 2  is a simplified side view of the multi-cylindered air pump of the positive pressure vapor fuel injection system of the present invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   The invention disclosed herein is, of course, susceptible of embodiment in many different forms. Shown in the drawings and described herein below in detail is a preferred embodiment of the vapor fuel injection system of the present invention. It is to be understood, however, that the present disclosure is an exemplification of the principles of the invention and does not limit the invention to the illustrated embodiment. 
   A positive pressure vapor fuel injection system embodying the principles of the present invention is depicted in a schematic, simplified manner in  FIGS. 1 and 2 . Specifically, it is understood that  FIGS. 1 and 2  depict only a portion of the system of the present invention and, more particularly, the relationship and cooperation between the various elements of the positive pressure vapor fuel injection system of the present invention and only one of the cylinders of, for example, a four cylinder, four-cycle internal combustion engine. Although not shown in any of the FIGURES, it is understood that the various elements of the positive pressure vapor fuel injection system are adapted to be duplicated for each of the other engine cylinders in a similar manner. 
   Referring to  FIGS. 1 and 2 , positive pressure vapor fuel injection system  10  initially comprises a multi-cylinder swash plate type air pump  11  which is adapted to be timed to engine  12  alternatively using either gear  24  ( FIG. 2 ) or a toothed endless timing belt  16  (FIG.  1 ). As shown in  FIG. 1 , one end of the belt  16  is adapted to surround the shaft  18  of flywheel  20  while the other end of the timing belt  16  is adapted to surround a shaft  22  which is operatively associated with air pump  11 . As shown in  FIG. 2 , timing belt  16  may be appropriately substituted with gear  24  which, although not shown, is adapted to cooperate with the shaft  18  of engine flywheel  20 . In the embodiment of  FIG. 1 , engine shaft  18  is preferably half the diameter of air pump shaft  22  so that air pump  11  operates and rotates at half the speed of engine shaft  18 . Similarly, in the embodiment of  FIG. 2  where gear  24  is operatively associated with pump  11 , the diameter of gear  24  is preferably twice the diameter of engine shaft  18  to effect the same half speed relationship between the engine  12  and pump  11 . Thus, the system of the present invention is adapted to complete one full positive pressure vapor fuel injection cycle for each full revolution of gear  24  while one complete power stroke cycle of the engine  12  is effected for two revolutions of crank shaft  18 . 
   Although not shown or described in any great detail, it is understood that the timing belt  16  (in the embodiment of  FIG. 1 ) and the gear  24  (in the embodiment of  FIG. 2 ) are both adapted to impart a rotary motion to air pump shaft  22  which, in turn, is adapted to impart a back and forth motion to a swash plate  26  operatively associated therewith. Air pump pistons  28  and  30  extend from the respective opposite ends of the plate  26 . Pistons  28  and  30 , in turn, are adapted for back and forth longitudinal linear movement within the interior longitudinal cavities of respective upper and lower air pump piston cylinders  32  and  34  in response to the back and forth movement of plate  26  within the interior of pump  11 . 
   In accordance with the invention, and although  FIG. 2  depicts only two of the pistons  28  and  30  and two of the piston cylinders  32  and  34 , it is understood that the pump  11  is adapted to incorporate between one to two piston cylinders per engine cylinder. Thus, in the embodiment where the system  11  is adapted for use in connection with a four cylinder engine, there could be anywhere between four to eight piston and associated cylinders located within the interior of pump  11 . Stated another way, the system and components of the present invention would be duplicated four fold for a four cylinder engine. 
   An oil supply conduit  36  ( FIG. 1 ) is adapted to extend between pump  11  and engine  12 . Alternatively, and although not shown, it is understood that the air pump  11  could incorporate its own oil pump. 
   In accordance with the present invention, air compressed by piston  30  is directed into and through a first conduit  35  operably coupled to one end  37  of the cylinder  32  while air compressed by the piston  28  is directed through a second conduit  39  operably coupled to one end  41  of the cylinder  34 . Conduits  35  and  39  are thereafter joined together at junction  43  and the combined stream of air flowing through conduits  35  and  39  is transferred into conduit  42 . 
   Although not shown or described in any detail, it is understood that air compressed by pistons  45  and  47  would be directed to conduits (not shown) which would be operatively coupled to the opposite ends  49  and  51  of cylinders  32  and  34  respectively. These two conduits, in turn, would be operatively coupled to another conduit similar to conduit  42  which would, in turn, be operatively associated with another air/fuel mixing chamber and heat exchanger similar in structure and relationship to air/fuel mixing chamber  52  and heat exchanger  44 . It is further understood that pump  11  would need to incorporate four additional air pump cylinders where the system of the present invention is used with a four cylinder engine. Alternatively, another pump of the type shown in  FIGS. 1 and 2  could simply be added to the system. 
   Air pump  11  additionally incorporates valves  38  and  40  which are operatively associated with air pump conduits  35  and  39  respectively and adapted for controlling, and where necessary relieving, the pressure of the output air generated by the pump  11 . Although not shown, it is understood that pump  11  is also adapted to incorporate check valves and inlet filter pipes of the type known to those of ordinary skill in the art. 
   As briefly discussed above, pistons  28  and  30  are configured to compress air for engine cylinder  50  provided engine  12  is adapted to fire the standard one cylinder at a time. Other internal combustion engine designs such as, for example, opposed cylinder designs which are adapted to fire two cylinders at a time could, of course, incorporate an appropriately modified embodiment of the air pump  11 . 
   In accordance with the present invention, pump  11  is sized in a manner corresponding and proportional to the internal volume capacity of air supply conduit  42  and the associated system hardware such as, for example, heat exchanger  44 , control relief valve  46 , and intake valve guide injection nozzles  48  so as to allow and effectuate a complete and efficient exchange or transfer of air into system  10  following each of the strokes of pistons  28  and  30  of pump  11 . It is further understood that the internal volume capacity of conduit  42  is such that a restricted passage is defined which, as result of friction, advantageously raises the temperature of the air traveling therethrough. 
   Although not shown or discussed in any detail, it is also understood that pump  11  is adapted to be appropriately timed in a manner consistent to allow a full charge of compressed air to be properly injected into engine cylinder  50  during the intake stroke of the engine cycle. 
   Restricted volume air supply conduit  42  is adapted to extend between the outlet of air pump  11  and the inlet of an air/fuel mixing chamber  52  operatively associated with heat exchanger  44 . In the embodiment of the system  10  depicted in  FIG. 1 , heat exchanger  44  comprises a length of steel or the like tubing  56  extending out of the outlet side of mixing chamber  52  and wrapped around the exterior surface of engine exhaust pipe  58 . 
   System  10  also encompasses and incorporates the use of a fuel delivery system  61  comprising initially of a fuel injector  60  including a fuel injector port  62  adapted to extend and protrude into the interior of the air/fuel mixing chamber  52 . Although the invention envisions the use of a fuel injector of the common port injection automotive style, it is understood that the invention encompasses and envisions the use of all other suitable fuel injectors known in the art. 
   A conduit  64  connects the fuel injector  60  to a fuel tank  66 . A fuel pump  68  is disposed along conduit  64  between fuel tank  66  and fuel injector  60 . An engine control module (ECM)  70 , together with its associated hardware, throttle valve assembly and sensors, is adapted to control the operation of fuel injector  60  and fuel pump  68 . 
   In accordance with the present invention, air pump  11  pumps air which is carried and delivered into the fuel mixing chamber  52  via conduit  42 . In the chamber  52 , the air mixes with the liquid fuel charge emitted from the fuel injector  60  and subsequently pushes the fuel through the tortuous heat exchange conduit or tubing  56  where the air/fuel mixture is heated to a temperature in excess of 400 degrees (the temperature required to permanently vaporize fuel) and subsequently progressively and increasingly converted into a vapor. In accordance with the present invention, the pre-heating of the air as a result of the travel thereof through conduit  42  assures complete vaporization of the air/fuel mixture in heat exchange conduit  56 . 
   In accordance with the present invention, the timing of the fuel charges can be started early so as to allow increased vaporization time in the heat exchanger. The timing of the fuel charges is also adapted to coincide and correspond with the air pump&#39;s draw of additional air at the start of a new positive pressure vapor fuel injection cycle. Moreover, it is understood that each of the dedicated pistons of air pump  11  are adapted to deliver a timed and metered burst of pre-heated air on an individual basis to each of the fuel injectors respectively and, in turn, the pump  11  is adapted to deliver said set charges of fuel emitted from said respective fuel injectors in a timed relationship through respective heat exchangers and then through respective individual vapor delivery nozzles  48 . The presence of pre-heated air also shortens the time necessary for the effective operation of the heat exchanger following the start of the engine. 
   Relief valve  46  is operatively associated with and connected to the outlet end of the heat exchange conduit  56 . In accordance with the invention, relief valve  46  is adapted to be set at a relief pressure allowing the respective fuel injection charges to be timed approximately to the respective opening of the engine intake valve  74 . From relief valve  46 , the air/fuel vapor mixture travels through conduit  76 , through the interior of the cylinder head cavity  77 , and then into and through the engine intake valve guide body  78  of fuel intake valve  74 . 
   Particularly, and as shown in  FIG. 1 , a fuel vapor delivery collar  79  is adapted to surround the outer circumferential surface  88  of the intake valve guide body or sleeve  78  at a location thereon generally adjacent a mid-point thereof below the spring  83  associated therewith. In accordance with the present invention, collar  79  defines a first bore  85  (shown in phantom) extending radially inwardly into the body thereof from the outer radial surface thereof. Conduit  76  is adapted to extend into the collar  79  and, more particularly, is adapted to extend into vapor flow communication with the bore  85  thereon. 
   Collar  79  additionally includes a circumferential groove  87  defining a vapor fuel transfer passage extending inwardly into the body thereof from the inner circumferential surface  89  thereof which surrounds and abuts the outer peripheral surface  88  of the valve guide body  78 . In turn, guide body  78  defines a plurality of longitudinal vapor fuel passages or bores  93  (shown in phantom) extending between the groove  87  in collar  79  and terminating in the distal radial end face of valve guide body  78  wherein said vapor fuel passages  93  define said plurality of vapor delivery nozzles  48 . Passages  93  span around the circumference of guide body  78  in spaced apart and parallel relationship and in vapor flow communication with circumferential groove  87  defined in collar  79 . 
   In accordance with the present invention, conduit  76  is in vapor flow communication with bore  85  in collar  79  which, in turn, is in vapor flow communication with fuel vapor groove or passage  87  which, in turn, is in vapor flow communication with, and is adapted to transfer the vaporized air/fuel mixture into, the plurality of vapor fuel passages  93  defined in the valve guide body  78 . 
   An intake air manifold  82 , which is normally associated with the cylinder head intake port of engine  12 , is operatively associated with engine intake valve assembly  80  and adapted to introduce air into the engine cylinder  50  in response to the timed opening of intake valve  74 . Moreover, and in accordance with the present invention, injection of the vaporized air/fuel mixture introduced through the guide body  78  of intake valve assembly  80  is adapted to occur in response to the opening of the control relief valve  46  which, in turn, is adapted to occur during the opening of intake valve  74 . Still further in accordance with the present invention, the resultant high velocity/high pressure flow or injection of the air/fuel mixture through the intake valve guide body  78  is adapted to induce an increased flow of intake air through intake valve opening  86  and into the engine cylinder cavity  84 . 
   Moreover, and as shown in  FIG. 1 , the intake port  81  of air manifold  82  is located and positioned relative to the engine intake valve  74  in a manner whereby air is drawn into the engine at a point below the nozzles  48  and the vaporized air/fuel mixture traveling through the valve guide body or sleeve  78  and nozzles  48  and is mixed with the intake air at a point adjacent and directly above the cylinder valve opening  86 . Stated another way, the intake air is fed into the space defined between the distal end of the guide  78  where the air mixes with the air/fuel mixture being delivered through nozzles  48  and then directly therefrom through opening  86 . In accordance with the present invention, mixing the intake air and fuel vapor at the opening  86  increases the volumetric efficiency of the engine by minimizing the distortion of the intake air which normally occurs when the fuel and intake air are mixed at a point upstream of the valve opening  86  while simultaneously advantageously avoiding a raise in the temperature of the intake air, i.e., an event which is normally adverse and detrimental to engine power output. 
   Moreover, in accordance with the present invention, the introduction and injection of the air/vapor fuel mixture with the intake manifold air at a point adjacent the outlet end of the intake port rather than at a point upstream of the manifold outlet offers the dual advantages of causing an increase in the flow rate of said intake air while simultaneously keeping the intake manifold air temperature low. The combination intake air/fuel vapor mixture is then introduced into cylinder  50  through valve opening  86 , subsequently compressed therein, ignited and then combusted. The positive pressure vapor fuel injection and combustion process described above is adapted to complete one full cycle for each power stroke (i.e., intake, compression, power, exhaust) of the engine cylinder cycle. 
   It will be readily apparent from the foregoing detailed description of the invention and from the illustrations thereof that numerous variations and modifications may be effected without departing from the true spirit and scope of the novel concepts or principles of this invention.