Abstract:
A injection conversion body with internal injector compartment for converting a normally carbureted internal combustion engine to a fuel injected engine while concealing the fuel delivery system. The original engine carburetor is removed. The plenum assembly is mated to the original engine intake manifold and a suitable throttle body is mated to the intake apertures which are oriented to permit installation without modification to the vehicle body work or relocation of other engine components. Air drawn through the throttle body is mixed with fuel from fuel injectors inside the plenum as it is directed to and exits the fuel air exhaust opening and enters the engine intake manifold. Interchangeable restriction plates are provided for insertion into the plenum fuel air exhaust opening to tune the fuel/air mixing characteristics to match the needs of the engine with which it is mated. Fuel is delivered to the fuel injectors through an internal, concealed fuel rail and fuel lines.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application derives priority from provisional application 61/000,369 filed on Oct. 25, 2007 which is incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the invention 
         [0003]    The present invention relates to aftermarket customization of automobile or other internal combustion engines in order to increase control, power output and efficiency of the engine while maintaining or improving the aesthetic appearance of the engine mechanics. More particularly, the present invention relates to a system for converting the fuel/air supply system of an internal combustion engine from a carbureted system to a fuel injector system while simultaneously concealing the mechanics of the conversion to maintain a desirable appearance. 
         [0004]    2. Description of the Background 
         [0005]    The aftermarket for performance and specialty auto parts provides consumers with the ability to customize their vehicle to suite their tastes and needs. Cars can be customized to improve performance, aesthetics, efficiency, emissions or other reasons and are often judged in shows and at racing events on these criteria. The increasing cost of fuel is generally of concern to all drivers. One way that manufacturers have improved the power, performance and efficiency of internal combustion engines is by replacing the mechanical carburetor system of mixing fuel and engine intake air with a fuel injection system. Fuel injection systems use electronically controlled fuel injectors to deliver a precisely metered amount of fuel to the engine at controlled intervals and provide significantly better control of the fuel/air mixture thereby increasing both performance and efficiency. 
         [0006]    Although designs vary widely, all carburetors operate on the same design principals. Air is drawn into the engine via an air filter housing and then the carburetor by the pumping action of the pistons. As the air enters the top of the carburetor it passes a venturi or restriction in the throttle bore causing the air to speed up and resulting in a drop in total pressure. This pressure drop pulls fuel from a reservoir or float bowl through a jet and into the throttle bore where it is mixed with the intake air and distributed by the intake manifold and drawn into the cylinders via the cylinder intake ports. 
         [0007]    Fuel injection fuel delivery systems replace the float bowl and jets of the carburetor with electronically controlled injectors. The injectors spray a fine mist of fuel from a high pressure fuel supply into the engine air under the timing and control of an electronic system. The position of the injectors in the system varies. Some systems place the injectors in the throttle body, referred to as single point fuel injection systems or throttle body fuel injection (TBI), while other systems incorporate the injectors into the intake manifold and inject the fuel spray directly into each cylinder intake port. Referred to as multi-port fuel injection, or tuned-port (TPI) fuel injection, these systems have a fuel injector for each cylinder and provide more accurate fuel metering and quicker response and provides greater engine control, but require an intake manifold and engine specifically designed for this purpose. 
         [0008]    Most recently direct injection systems have been developed in which the injector delivers the fuel spray into the cylinder combustion chamber directly. Gasoline direct injection entails injection via a common rail fuel line directly into the combustion chamber of each cylinder, as opposed to conventional fuel injection that happens in the intake tract, or cylinder port. 
         [0009]    Many car enthusiasts are particularly interested in racing and showing vintage vehicles that were originally built before the widespread implementation of fuel injected engines and which are thus powered by carbureted engines. Converting an older carbureted engine to a fuel injected system is challenging due to the need to incorporate the injectors, fuel pressure regulator, fuel supply rails and electronic control components into an engine that was not originally designed to have them, and to do so within a vehicle engine bay that was not designed to accommodate the additional parts. Conversion generally requires disassembly of a substantial portion of the engine including the air intake manifold provided by the original manufacturer. The primary function of the air intake manifold is to evenly distribute the combustion fuel/air mixture to each intake port in the cylinder heads. The intake manifold also serves as a mount for the air filter, carburetor or throttle body, and other components of the engine. Conversion entails removal of each of these components and replacement with a fuel injection system. This work is often beyond the skill or resources of vehicle owners. 
         [0010]    Vehicle owners have a variety of commercial conversion kits available for purchase. Such kits are patched together from disparate and custom parts and, while generally functional, drastically change the “under-the-hood” and coachwork aesthetics of the vehicle and so are generally unsuitable for display in auto shows and judged competitions. Vintage car owners want their cars to appear true to their era, while being as technologically modern as possible. These homebuilt or kit systems also suffer from an inability to modify air flow and fuel delivery characteristics to match the needs of the particular engine once installed leading to poor engine performance and low efficiency. If a home built system does not perform well it must be removed and redesigned from the ground up, sometimes repeatedly, to match the fuel and air needs of the engine. In many vintage vehicles, conversion to a fuel injector system is altogether impossible given the geometry of various engine bays and other components. 
         [0011]    It would be greatly advantageous to provide a carbureted-to-fuel injection conversion that does not also require replacement of significant engine components such as the intake manifold. It would be further advantageous to provide a carbureted-to-fuel injection conversion having tunable airflow characteristics, that is adaptable to the engine geometry of a variety of vintage vehicles and that conceals the fuel supply and other components of the system to preserve, to a large degree, the aesthetics of the engine. 
       SUMMARY OF THE INVENTION 
       [0012]    Accordingly, it is an object of the present invention to provide a device that enables the user to convert a vehicle&#39;s carbureted internal combustion engine to run on an electronic fuel injection system. 
         [0013]    It is another object of the present invention to provide a device for fuel injection conversion that conceals the fuel system components including the fuel injectors, fuel rails, engine control computer, wiring and other additional components from view so as to allow the vehicle to be entered into judged car competitions. 
         [0014]    It is another object to provide a device for fuel injection conversion that is appropriately configured to allow implementation in the cramped or otherwise closely confined engine compartments of a large number of classic and vintage cars commonly modified for use in the aftermarket performance and show car community. 
         [0015]    It is yet another object of the present invention to provide a device for fuel injection conversion that provides for tunable airflow characteristics to match the needs of the engine. 
         [0016]    According to the present invention, the above-described and other objects are accomplished by providing a carburetor fuel injector plenum for direct engagement with an engine intake manifold and which internally houses the injectors and fuel rail in a concealed manner and which permits the insertion of airflow restrictor plates to tune the fuel/air delivery characteristics of the device. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]    Other objects, features, and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiment and certain modifications thereof when taken together with the accompanying drawings in which: 
           [0018]      FIG. 1  is a side view of a fuel injection conversion body according to the present invention. 
           [0019]      FIG. 2  is a front view of a fuel injection conversion body. 
           [0020]      FIG. 3  is a bottom view of a fuel injection conversion body without the insert in place. 
           [0021]      FIG. 4  is a view of the fuel rail internal to a fuel injection conversion body, from below. 
           [0022]      FIG. 5  is a sectional view of a fuel injection conversion body along cut line  5 - 5  as seen on  FIG. 3 . 
           [0023]      FIG. 6  is an exploded view of a fuel injection conversion body from the front. 
           [0024]      FIG. 7  is an exploded view of a fuel injection conversion body from the side. 
           [0025]      FIG. 8  is a perspective view of an exhaust aperture insert. 
           [0026]      FIG. 9  is a perspective view of an exhaust aperture insert in conjunction with the lower housing. 
           [0027]      FIG. 10  is a perspective view of a fuel injection conversion body mounted on an intake manifold within the engine bay of an automobile. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0028]    The present invention is a fuel injection conversion body  10  for facilitating the conversion of a previously carbureted engine to run on a fuel injected fuel/air mixing system utilizing concealed fuel supply and engine control components to maintain engine compartment and vehicle aesthetics.  FIGS. 1 ,  2  and  3  depict side, front and bottom views of the injection conversion body  10  respectively.  FIG. 10  depicts a three-quarters perspective view of the injection conversion body  10  installed on intake manifold  101  of a suitable engine. With combined reference to  FIGS. 1 ,  2 ,  3  and  10 , a fuel injection conversion body  10  is depicted having an upper housing  20 , lower housing  22 , cover plate  24 , and manifold adapter flange  30 . The upper housing  20  and lower housing  22  collectively define an air intake aperture  26  and internal plenum  11  (described below and seen in  FIG. 5 ) for the metered ducting of intake air to the intake manifold  101  of a previously carbureted internal combustion engine. The lower housing  22  is configured for sealing engagement directly to the intake of an existing engine intake manifold via manifold adapter flange  30  without need to remove or modify the existing intake manifold. 
         [0029]    Attachment of the lower housing  22  to the intake manifold is preferably accomplished by providing a bolt pattern in an integrally formed manifold adapter flange  30  underneath the lower housing  22 , the manifold adapter flange  30  having a bolt pattern corresponding to the existing bolt pattern of the manifold to which it is to be joined. To facilitate greater applicability the manifold adapter flange  30  may be provided with bolt hole patterns corresponding to multiple known engine manifold patterns or with elongate bolt holes capable of matching multiple manifold patterns. Alternately, an adapter plate  102  (see  FIG. 10 ) may be used between the manifold adapter flange  30  and the engine intake manifold. The adapter plate may also be used as a spacer or riser to raise the fuel injection conversion body  10  over the manifold for clearance over other components of the engine. 
         [0030]    As seen in  FIGS. 3 and 5 , a plenum exhaust aperture  28  is provided through the bottom of the lower housing  22  and through the adapter flange  30  for fluid engagement of the internal plenum  11  with the engine intake manifold. The exhaust aperture  28  may be a single opening corresponding in size with the manifold intake. Improved performance is experienced by restricting the exhaust aperture area thereby altering air velocity, flow volume, pressure and fuel/air mixing on an injector pulse event. Restriction of the exhaust aperture area is preferable accomplished by providing one of a plurality of interchangeable exhaust aperture inserts  29  (see  FIGS. 8 and 9 ) that may be removed or replaced depending on the needs of the engine (as further described below). 
         [0031]    With reference to  FIG. 5 , restriction plate  29  is provided to alter the flow characteristics of air as it passes from the injection conversion body  10  to the engine intake manifold via the exhaust aperture  28 . It is contemplated that a variety of restriction plates  29  will be available for use with an injection conversion body  10  according to the present invention so that the installer can tailor the fuel air mixture entering the engine to the requirements of that engine. In the depicted embodiment the restriction plate  29  is formed to seal off the exhaust aperture  28  save for 4 flared cylindrical exhaust ports  31  ( FIG. 8 ) in alignment with the 4 injectors of the present invention. Restriction of the airflow in this manner increases the velocity of the air through the ports  31 . Coupled with the axial orientation and alignment of the injectors/exhaust aperture  28 , this velocity increase promotes better fuel/air mixing within the intake manifold. Poor fuel/air mixing can result in a richer fuel/air mix in the center cylinders and a lean mixture in the end cylinders reducing potential torque and engine smoothness. Uniform fuel/air mixing produced by the present invention eliminates this problem, particularly at part throttle. 
         [0032]    Restriction plate  29  may also be designed with a single central exhaust port, an alternate number of ports corresponding to an alternate number of fuel injectors, conical ports, ports having a non round profile and vaned ports. Most importantly, and most commonly, the diameter of the exhaust ports in the restriction plates depicted will be altered to match the air need of engine across its operating range. In an alternate embodiment, the diameter of exhaust ports  31  may be further reduced by individual cylindrical inserts to permit fine tuning without removing or replacing he entire restriction plate  29 . 
         [0033]    With reference to  FIG. 5 , air is drawn into the plenum  11  via one or more intake apertures  26  through a suitable throttle body  100  (see  FIG. 10 ) such that intake air is drawn into the plenum  11  under the control of the throttle valve (obscured within throttle body  100 ). Intake apertures  26  are, in the preferred embodiment, formed in the front wall of the fuel injection conversion body  10  which defines the plenum  11 , and may be partially defined by the front section of the lower housing  22  and partially by the front section of the upper housing  20 , as seen in  FIG. 6 . The primary axis X ( FIG. 5 ) of the intake apertures  26  in this configuration is in the horizontal plane and is generally parallel to the engine crankshaft in a longitudinally mounted engine (and consequently perpendicular to the crankshaft in a transversely mounted engine). The intake apertures  26  are, in the depicted embodiment defined within the upper and lower housings  20 ,  22 . 
         [0034]    The number, size and shape of apertures  26  are selected to correspond to or cooperate with the number and shape of barrels or bores in the selected throttle body  100 . The throttle body  100  may be attached by machine screws. A gasket may be employed to seal the connection between the throttle body  100  and the fuel injection conversion body  10 . To accommodate the engine bay characteristics of certain vehicle/engine combinations, the intake apertures  26  may be successfully positioned on the side wall of the plenum with only minimal, if any, decrease in performance. 
         [0035]    The primary axis Y of the exhaust aperture  28  in the depicted embodiment (see  FIG. 5 ) is vertical. Thus the angle “a” between the primary axis of the intake aperture  26  and the primary axis of the fuel/air exhaust aperture  28  is 90 degrees, with air entering the engine intake manifold perpendicular to the engine crank shaft. In an alternate embodiment of the invention the primary axis of the exhaust aperture may be in the vertical longitudinal plane but at an angle “a” greater than 90 degrees (obtuse) to the primary axis of the intake aperture. The obtuse angle offset configuration between air intake apertures  26  and fuel/air exhaust aperture  28  permits installation of the plenum assembly  10  without the need for a hood bulge or other modification to the vehicle body work in many instances, as would be required to permit installation of a purely linear system. As angle a is increased, axis X is retained in the horizontal plane such that the intake apertures in the depicted embodiment are shifted forward and down in relation to the intake manifold, so as not to interfere with the existing coachwork, and the air plenum  11  must be extended along axis Y. The effective area of the exhaust aperture  28  is reduced as is the area within the fuel system bay (described below) in which to mount and align the fuel injectors. In practice as angle “a” approaches 140 degrees the flow restriction and geometry detrimentally effect performance. 
         [0036]    With combined reference to  FIGS. 4 ,  5 ,  6  and  7 , fuel injection conversion body  10  is further comprised of an cover plate  24 , together with upper housing  22  defining fuel system bay  42  ( FIG. 5 ) for housing and concealing the fuel injectors and fuel rail  46 . Fuel bay  42  is wholly contained within the fuel injection conversion body  10  but is sealed off from air plenum  11  by the floor  43  of the upper housing. Floor  43  is machined or otherwise provided with mounting bungs  40  for the seating conventional Bosch style or similar fuel injectors inserted from above. Bungs  40  are generally circular in form and stepped in profile to sealingly seat the injectors and are further provided with a central aperture  60  through the floor  43  dividing the fuel bay  42  and the air plenum  11  such that fuel from the injector spray tip is delivered to the air stream in the plenum  11  but no air is permitted to pass between the plenum  11  and fuel bay  42 . The longitudinal axis of the injectors is substantially parallel to the longitudinal axis Y of the exhaust aperture  28  and thus, in the depicted embodiment, vertical. Where the primary axis of the exhaust aperture is non-vertical, as described above, the primary axis of the fuel injectors is altered to match such that the spray tip of the injectors generally targets the exhaust aperture directly along the primary axis. The housing elements of the injection conversion body  10  are altered accordingly. 
         [0037]      FIG. 4  is a view of the fuel rail  46  which is internal to the injection conversion body  10 . The fuel rail  46  is positioned above the fuel injectors within the fuel bay  42  such that each injector inlet nozzle is seated into a bore  48  in the fuel rail with an O-ring or the like. The fuel rail  46  is secured to upper housing  20  by machines screws to retain the injectors in their bungs  40  yet permit removal and service of the injectors (see  FIG. 5 , injectors omitted). 
         [0038]    The fuel rail  46  is formed as a circuitous tubular manifold defining a looping conduit that extends to and through the rear of the upper housing  24  of the injection conversion body  10  where pressurized fuel supply and return lines are provided to and from a fuel pump, fuel pressure regulator and fuel storage tank. High pressure fuel (40-60 psi) is provided to the injectors via two internal parallel fuel supply passages  50  machined into the fuel rail  46 . The two internal parallel fuel supply passages  50  are tapped by bores  48 , each bore  48  in the fuel rail connecting to one of the two internal parallel fuel supply passages  50  to provide fuel to the injectors. A fuel return passage  52  connects the fuel supply and returns unused fuel to be re-circulated. An air temperature sensor may be mounted beneath the fuel rail with a mounting plug  44  ( FIG. 3 ) and sealed aperture through floor  43  into the air plenum to sample the incoming air. When the housing members  20 ,  22 ,  24  are assembled as depicted in  FIGS. 6 and 7  the cover plate  24  on the top of the plenum assembly  10  conceals the fuel injectors and fuel rail  46  in the injector compartment from view, as observed in  FIG. 10 , providing a desirable aesthetic appearance and concealing the fact that the engine has been converted to a fuel injection system temperature. 
         [0039]    In operation, air drawn is into the fuel injector plenum  11  on a horizontal axis via the intake apertures  26  by the low pressure vacuum created in the intake manifold during operation of the engine. The air is diverted downward toward the intake manifold by the confines of the injection conversion body  10  as it passes through the plenum  11  and exits the fuel/air exhaust opening  28 . As the air exits the plenum  11  through restriction plate  29  it is thoroughly mixed with fuel spray from an injector pulse event, the vertically mounted injectors directing their spray directly into the high velocity airstream passing through the restriction plate  19  and into the intake manifold without contacting the plenum sidewalls or any other obstruction. 
         [0040]    An engine control module may be installed within the fuel bay  42  of the injection conversion body  10 . Relatively cooler intake air continuously drawn into the air plenum helps to keep components in the fuel plenum cool through conduction by the conversion body  10  which may be manufactured by machining from suitable metals such as aluminum, brass or steel. The plenum assembly may also be manufactured in components or as a single unit by injection molding from plastic materials of suitable strength and chemical or solvent resistance such as Delrin™, however with loss of much of the conductive cooling. 
         [0041]    Having now fully set forth the preferred embodiments and certain modifications of the concept underlying the present invention, various other embodiments as well as certain variations and modifications thereto may obviously occur to those skilled in the art upon becoming familiar with the underlying concept. It is to be understood, therefore, that the invention may be practiced otherwise than as specifically set forth herein.