Abstract:
An attachment for a fuel carburetor possesses a fuel inlet, a needle-and-seat valve disposed in the inlet, and a float attached to the needle-and-seat valve. In one embodiment, the attachment is placed between and is in fluid communication with both the float bowl and the metering block of a typical carburetor. Fuel is pumped into the float bowl and the attachment in parallel from the fuel pump. The float in the attachment rises and falls according to the level of fuel in the interior of the attachment and float bowl, and thus regulates the position of the needle-and-seat valve, which in turn regulates how much fuel is pumped into the attachment and float bowl. The attachment is also provided with a device for injecting a spurt of fuel directly into the metering block to avoid lean fuel conditions when the throttle is initially opened. In an alternative arrangement, the float bowl and attachment are made as one integral unit. In another embodiment, two attachments and an end cap are mounted on the metering block and the float bowl is not used.

Description:
RELATED PATENT APPLICATION 
     This patent application is a continuation-in-part of commonly owned, application Ser. No. 08/527,537, filed on Sep. 13, 1995, now abandoned, entitled &#34;Float Bowl Attachment for Carburetor,&#34; the disclosure of which is incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to fuel carburetors. More particularly, the invention relates to the fuel bowl that supplies fuel to the main body of the carburetor. 
     2. Description of Related Art 
     Float bowls are conventionally used in carburetors. In the typical fuel system of an automobile, a fuel pump pushes fuel into the float bowl via an inlet. Disposed in the inlet is a needle-and-seat valve which is attached to a float. The float rises and falls with the level of the fuel in the float bowl, causing the needle-and-seat valve to either open or close. Vacuum from the venturi of the carburetor pulls fuel out of the float bowl through the metering block to which the float bowl is attached. When the fuel level in the float bowl falls, the float falls and opens the needle-and-seat valve, and fuel is allowed to enter the float bowl. When the fuel level rises, the float rises and closes the needle-and-seat valve, preventing excess or unnecessary fuel from entering the float bowl. 
     Race cars conventionally use various different types of fuel, such as gasoline, kerosene, alcohol, and the like. The use of different fuels may require the use of differently configured carburetors. In one example, a dual-fuel carburetor may use both gasoline and alcohol, with one fuel being supplied to one float bowl of the carburetor and the other fuel being supplied to the other float bowl on the opposite side of the carburetor. Such a carburetor is described in U.S. Pat. No. 4,415,507 to Voliva. The Voliva patent describes a modified Holley 4150-60 carburetor, in which gasoline is pumped into the inlet of a primary float bowl and alcohol is pumped into the inlet of a secondary float bowl. Other dual-fuel systems are described in U.S. Pat. Nos. 4,085,720 to Etoh and 3,807,377 to Hirschler, Jr. et al. In both of these systems, a switching device is provided to switch between two float bowls, each supplied with different fuel. Throttle conditions (e.g., pressure) determine when the switching device will select one fuel over the other. 
     In some cases, it is desirable (e.g., from a cost and/or performance standpoint) to modify an existing fuel system which is designed to run on one type of fuel so that it may run on a different type of fuel. For example, many race cars&#39; fuel systems are initially designed to consume gasoline, and are subsequently provided alcohol. Owing to several factors, such as the augmented power requirements of racing vehicles, the automobile requires approximately twice as much alcohol as gasoline by volume per unit time. 
     A problem arises in how to deliver the lower-volatility alcohol to the venturi of the carburetor. Specifically, roughly twice as much fuel must be delivered through the float bowl in the same amount of time. A known previous method of rectifying this problem is to boost the fuel pressure in the fuel line by using a larger, more powerful fuel pump upstream of the float bowl of the carburetor. By using a fuel pump twice as powerful as the pump originally provided with the automobile, the requisite amount of alcohol can be delivered to the float bowl. 
     This method possesses several drawbacks. First, the needle-and-seat valve disposed in the inlet of the carburetor&#39;s float bowl is not designed to accommodate double the amount of pressure/flow. For example, most carburetor needle-and-seat valves are designed for 8 psig; however, the larger fuel pump increases fuel line pressure to roughly 16 psig. Consequently, the higher pressure forces the needle-and-seat valve to remain open constantly, and fuel is continuously fed to the float bowl regardless of the fuel level. As a result, fuel bleeds out of the float bowl, and ends up, among other places, in the oil pan. This necessitates changing the oil between each use of the automobile. Moreover, because the needle-and-seat valve never closes, it is impossible to control the amount of fuel being forced through the float bowl, thereby wasting much fuel. Finally, the requisite larger fuel pump is generally an expensive piece of equipment, and may actually be cost-prohibitive in some cases. 
     A problem exists, therefore, in modifying an existing gasoline carburetor for use with a fuel having lower volatility such as alcohol in a manner consistent with the ordinary use of the carburetor, and in a manner that is cost-effective. 
     SUMMARY OF THE INVENTION 
     The above and other problems are solved by the present invention. The invention includes a fuel bowl assembly that allows the carburetor to use different volatility fuels, such as gasoline or alcohol based fuels, without changing the standard operation of the carburetor. Moreover, gasoline carburetors of the type having metering blocks and fuel bowls, can be easily converted for use with alcohol by using a spacer in accordance with the invention. Once the spacer is integrated into the carburetor assembly, the assembly can still be used for gasoline. 
     In one embodiment of the invention, the fuel bowl assembly of the invention includes a spacer interposed between a conventional metering block and conventional fuel bowl. In another embodiment of the invention, the conventional fuel bowl is not used, and a pair of spacers are mounted in series on the metering block and the open end of the outermost spacer is closed by an end plate. However, in either embodiment, the fuel bowl assembly includes, at least, a pair of inlets, a pair of floats and an interior fuel chamber, which is approximately twice the size of the conventional fuel bowl interior fuel chamber. 
     In an embodiment of the invention, the housing of the spacer may include a baffle for controlling fuel turbulence in the interior fuel chamber. Slots may be provided in the baffle to facilitate equalization of the fuel in the interior fuel chamber. 
     In one embodiment, the inventive attachment includes a substantially annular body having an interior volume; the body has a cross-sectional profile conforming to a cross-sectional profile of the float bowl of the carburetor. A fuel passage through the body having an inlet end coupleable to the fuel supply and a discharge end communicating with the interior volume is provided. A valve is disposed in the fuel passage to close the fuel passage selectively. The attachment also includes a float, disposed in the interior volume, operatively coupled to the valve, and mounted to the body for movement between a first, closed position in which the float closes the valve and a second, open position in which the valve is permitted to open the fuel passage. The attachment is sealingly disposed between the float bowl and the metering block and is in fluid communication with the float bowl and the metering block. 
     The attachment also includes an injecting means for injecting a spurt of fuel directly into the carburetor under predetermined conditions, particularly when the throttle is initially opened and the air-fuel ratio would otherwise be lean. The injecting means is disposed for operative engagement by the throttle linkage. The injecting means typically includes an accelerator pump of conventional design. 
     In the above description, the invention includes an attachment or spacer that fits between the float bowl and the metering block. However, in alternate design, a replacement float bowl may be provided. The inventive float bowl includes a body having a peripheral wall, an open end, an opposite, closed end, and an interior volume bounded by the peripheral wall and the open and closed ends. First and second fuel passages are provided through the body. Each of the first and second fuel passages has an inlet end coupleable to the fuel supply and a discharge end communicating with the interior volume. First and second valves are disposed respectively in the first and second fuel passages to close the fuel passages selectively. First and second floats are disposed in the interior volume, respectively operatively coupled to the first and second valves, each of the floats being mounted to the body for movement between a first, closed position in which the float closes the respective valve and a second, open position in which the respective valve is permitted to open the respective fuel passage. As above, the float bowl is preferably provided with an injecting means as described. 
     In operation, in either design, fuel is pumped into the two (or more) fuel passages from the fuel pump in parallel Both inlets possess floats, which govern the position of their respective valves, typically needle-and seat valves. When the fuel level in the float bowl/attachment drops to a certain level, the floats drop accordingly, and the needle-and-seat valves open, allowing fuel to enter the float bowl/attachment. The vacuum of the venturi then pulls fuel from the float bowl/attachment in a conventional fashion. 
     By use of the present invention, either in the form of an attachment disposed between the original float bowl and metering block or in the form of a replacement float bowl having multiple floats and valves, twice as much fuel (or more) is allowed to enter the system via the two (or more) fuel passages. A more powerful fuel pump is therefore not required. By avoiding using a more powerful fuel pump, the needle-and-seat valves function in the manner in which they were intended: i.e., they allow fuel to enter when it is needed, but to restrict fuel flow when the fuel level is adequate. Thus, fuel flow can be properly controlled, fuel is not wasted, and the oil pan is not contaminated with spillover fuel. Moreover, the expense of using a larger fuel pump can be avoided. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Referring now to the drawings which form a part of this disclosure: 
     FIG. 1 is a top view of a carburetor including spacers in accordance with an embodiment of the invention. 
     FIG. 2 is an exploded perspective view of one side of the carburetor shown in FIG. 1. 
     FIG. 3 is a side view of the spacer in accordance with an embodiment of the invention. 
     FIG. 4 is an exploded view of the components of the spacer shown in FIG. 3. 
     FIG. 5 is a high level top view of a carburetor in accordance with another embodiment of the invention. 
     FIG. 6 is a side view of a spacer housing in accordance with another embodiment of the invention. 
     FIG. 7 is a view the opposing side of the spacer housing of the spacer shown in FIG. 6. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A description of the invention will now be provided with reference to the accompanying drawings. Throughout the drawings, like parts are represented by like reference numerals. 
     The invention relates to a carburetor assembly as shown generally by reference numeral 10 in FIG. 1. Carburetor assembly 10 includes, generally, a carburetor main body 12 in fluid communication, via metering blocks 20a and 20b, with a pair of fuel bowl assemblies 14a and 14b disposed, one each, on opposing sides of carburetor main body 12. Carburetor main body 12 draws fuel from fuel bowl assemblies 14a and 14b at different rates depending upon the volatility of fuel that is being used. For example, a carburetor draws alcohol based fuels, such as methanol, at over two times the rate that gasoline is drawn. 
     By using fuel bowl assemblies 14a and 14b in accordance with the invention, carburetor assembly 10 can accommodate different types of fuel having different volatility, such as gasoline and alcohol, without altering the basic operation of carburetor assembly 10. In particular, carburetor assembly 10 can operate at its normal fuel pressure levels (e.g., 8 psig.) Fuel bowl assemblies 14a and 14b include a pair spacers 16a and 16b used in combination with: a pair of conventional float bowls 18a and 18b as shown in FIG. 1; or, in the alternative, with a second pair of spacers 100a and 100b and pair of end plates 102a and 102b, as shown in FIG. 7. Fuel bowls 14a and 14b have fuel inlets 46a, 46b, 44a, and 44b as will be discussed in detail later. 
     In accordance with the embodiment shown in FIG. 1, carburetor assembly 10 includes the following main components, carburetor main body 12, metering plates 20a and 20b, spacers 16a and 16b, and float bowls 18a and 18b. The components of the carburetor assembly 10 are secured, respectively, on each side of carburetor main body 12 by threaded mounting rods 17, which pass through correspondingly threaded mounting holes in carburetor main body 12, metering blocks 20a and 20b, spacers 16a and 16b, and float bowls 18a and 18b. Disposed between adjacent components of carburetor assembly 10 is a conventional gasket (not shown) of resilient material such as rubber. The gaskets form a liquid tight seal between adjacent components of carburetor assembly 10. 
     Referring now to FIG. 2, a discussion of one-half of carburetor assembly 10 will now be provided. For purposes of this embodiment of the invention, each half of carburetor assembly 10 is substantially a mirror image of the other. Thus, the following describes only one-half of carburetor assembly 10 with the understanding that this discussion is equally applicable to the other side of carburetor assembly 10. Also, it should be noted that the invention is not limited to dual fuel bowl assemblies 14a and 14b, but is equally appropriate for use in a single fuel bowl assembly. 
     Carburetor main body 12 is of a generally conventional construction and operates in accordance with conventional practice to mix fuel vapor and air before combustion. Carburetor main body 12 is shown as a four barrel carburetor, but may be a two barrel carburetor. As discussed above, with the invention the basic operation of carburetor assembly 10 is unchanged. However, when using alcohol, an alcohol type carburetor main body must be used rather than a gasoline type carburetor. The only difference between these types of carburetor main bodies is that in the alcohol carburetor main body the fuel passages (not shown) are 2.3-2.5 times larger in diameter than the fuel passages in the gasoline carburetor main body. This is to accommodate the greater required flow rate of alcohol over the flow rate of gasoline. 
     Carburetor main body 12 includes a housing 28 with a mounting surface 22 formed on an exterior side of housing 28. Mounting surface 22 is a substantially planar rectangular shaped surface with a central opening for providing access to a fuel vapor inlet 24. 
     Metering block 20b is of a conventional construction and controls the passage of fuel from the fuel bowl assembly 14b into carburetor main body 12 in accordance with conventional practice to form fuel vapor for carburetor main body 12. Metering block 20b mixes air with the fuel from the interior fuel chamber of fuel bowl assembly 14b in accordance with conventional practice. Metering block has two opposing sides 9 and 11. Side 11 of metering block 20b is disposed on mounting surface 22. Fuel vapor produced by metering block 20b is supplied to carburetor main body 12 in accordance with conventional practice, for example, via inlet 24. Fuel bowl assembly 14b is mounted on side 9 of metering block 20b. 
     Fuel bowl assembly 14b stores fuel in its interior fuel chamber and replenishes the fuel as needed by way of fuel inlets 46b and 44b. The control of fuel through inlets 46b and 44b will be discussed below. Carburetor main body 12 draws fuel, via metering block 20b, from fuel bowl assembly 14b. In the present invention, fuel bowl assembly 14b defines the interior fuel chamber. The interior fuel chamber includes a first portion defined by spacer 16b, which is substantially the same size as a second portion of the interior fuel chamber. The second portion is defined by conventional float bowl 18b. Accordingly, the use of spacer 16b approximately doubles the size of the interior fuel chamber, as compared to when conventional float bowl 18b is used alone. Conventionally, the float bowl 18b would have been attached directly to metering block 20b. 
     Spacer 16b is interposed between side 9 of metering block 20b and float bowl 18b. Float bowl 18b is of a conventional type having a fuel inlet 44b with one end in fluid communication with a conventional fuel pump (not shown) and another end in fluid communication with the interior fuel chamber. Float bowl 18b has a housing that has an annular four sided wall 43, a closed end 41 and an open end 42. Again, in the present invention, the housing of float bowl 18b defines the second portion of the interior fuel chamber, which is about one half of the interior fuel chamber. The flow of fuel from the fuel pump through fuel inlet 44b and into float bowl 18b is controlled by a conventional check valve regulated by a float (not shown) inside float bowl 18b. The buoyancy of the float allows the float to float partially submersed in the fuel in the interior fuel chamber. The float rises and falls along with the level of the fuel, thereby controlling the passage of fuel through fuel inlet 44b into the interior fuel chamber. The fuel level in the interior chamber must be maintained at a particular level for proper performance. The fuel level in the interior fuel chamber should be level with the opening of the main discharge nozzle (not shown) of carburetor main body 12. The fuel, generally, fills approximately three-quarters of the interior fuel chamber. A slight drop in the fuel level is adequate to cause the float to allow the entry of the fuel into the interior fuel chamber. 
     Spacer 16b has a housing 28 that is substantially a rectangular box-shaped configuration and defines the second portion of the interior fuel chamber. Spacer 16b is shaped to correspond to the conventional substantially rectangular shaped metering plate 20b and float bowl 18b. Accordingly, any shape corresponding to the shape of metering block 20b and/or float bowl 18b can be used. Spacer 16b is preferably made from machined metal and more preferably from anodized aluminum. However, any type of material that can be used so long as the material is capable of use in an environment with automotive fuel such as gasoline, kerosene, alcohol or the like. 
     Housing 28 is essentially six sided. An annular four sided wall has solid walls 30, 32, 34 and 36. Walls 30 and 34 are disposed parallel to each other and substantially perpendicular to walls 32 and 36, while walls 32 and 36 are disposed parallel to each other and substantially perpendicular to walls 30 and 34. Two opposing major sides 38 and 40 include openings 39 and 41 (shown in FIG. 3). Sides 38 and 40 are disposed substantially parallel to each other and substantially perpendicular to wall sections 30, 32, 34 and 36. Side 40 of spacer 16b is disposed adjacent metering block 20b and side 38 of spacer 16b is disposed adjacent open end 42 of float bowl 18b. 
     Fuel inlet 44b is positioned on an opposite side of fuel bowl assembly 14b than fuel inlet 46b. This arrangement is preferred because it is believed to reduce turbulence in the interior fuel chamber. However, fuel inlet 44b may be positioned on same side as fuel inlet 46b; varying the disposition of the fuel inlets 44b and 46b is within the scope of the invention. 
     Referring now to FIG. 3, the components of spacer 16b will be discussed. In FIG. 3, spacer 16b is viewed from side 40. Spacer 16b is shown with an annular thin gasket 41, of the type discussed earlier, positioned on side 40 and having a substantial open central portion. As shown, side 40 includes a slight annular recess having a depth substantially equal to the thickness of gasket 41 for purposes of receiving and positioning gasket 41 on side 40. Spacer 16b includes fuel inlet 46b to supply fuel to the interior fuel chamber. By including fuel inlet 46b in addition to fuel inlet 44b, fuel can be supplied to the interior fuel chamber at an increased rate. This will insure that enough fuel can be provided to accommodate increased fuel demands when an alcohol based fuel is used. Fuel inlet 46b has a first end disposed outside housing 28 of spacer 16b, including a nozzle 48 for connecting fuel inlet 46b with a conventional fuel pump (not shown) via a conventional fuel line (not shown). Fuel inlet 46b has a second end opening into the first portion of the interior fuel chamber inside housing 28 of spacer 16b. A valve 50 is disposed at the second end opening of fuel inlet 46b inside housing 28 to regulate the flow of fuel through fuel inlet 46b into the interior fuel chamber. The operation of valve 50 is controlled by float assembly 52. Float assembly 52 is disposed inside spacer 16a to monitor the fuel level in the interior fuel chamber. Valve 50 and float assembly 52 are provided in addition to and operate along with the valve and float in float bowl 18b. 
     Even though spacer 16b is added, the same predetermined fuel level is maintained in the interior chamber. That is, the fuel level should remain level with the opening of the main discharge nozzle of carburetor main body 12, as in the conventional fuel bowl 18b. However, because the interior fuel chamber has an increased volume, the amount of fuel that can be stored in the interior chamber is increased. Float assembly 52, in cooperation with the float in float bowl 18b, enables the accurate and precise control of the fuel level in this enlarged volume of the interior fuel chamber. If only the conventional float in float bowl 18b were to control the fuel level across this enlarged interior fuel chamber, performance will likely be sacrificed. Accurate control of the fuel level is necessary to insure peak performance. If the fuel level in the interior fuel chamber is too low, not enough fuel will be supplied to carburetor main body 12 and the engine will stall when the vehicle makes turns. If the fuel level in the interior fuel chamber is too high, too much fuel will be supplied to carburetor main body 12. By utilizing spacer 16a in accordance with the invention, the amount of fuel that can be stored in the interior fuel chamber is essentially doubled without compromising performance. 
     Accordingly, float assembly 52 is provided in spacer 16a, in addition to the float assembly provided in float bowl 18b, to assure that a precise and accurate fuel level is maintained in the interior fuel chamber. Valve 50, as shown, is a conventional needle and seat valve. Float assembly 52 includes a float 54 connected to a float lever 56. A portion of valve 50 contacts float lever 56 so as to be correspondingly controlled thereby. Float lever 56 has an end rotatably mounted on pin 58, which is disposed on an interior surface of side 38 such that float 54 may rise and fall along with the level of fuel in the interior of the fuel chamber. As float 54 rises and falls, float lever 56, in turn, controls the needle and seat valve 50, which, in turn, opens and closes fuel inlet 46b, thereby controlling the flow of fuel from the fuel pump into the interior fuel chamber. In the present invention, float assembly 52 is constructed to have a same buoyancy as the buoyancy of the conventional float in float bowl 18b so that float 54 in spacer 16b rises and falls at the same rate and at the same level as the float in float bowl 18b. Float lever 56 is free to rotate around pin 58, however, a biasing spring 57, as shown, may be provided on the bottom portion of float lever 56. 
     Spacer 16b may be provided with a conventional accelerator pump 60, such that fuel can be squirted into carburetor main body 12 via metering block 20b whenever desirable. As shown, accelerator pump 60 is disposed in a housing 62 on side 34 of spacer 16b. Accelerator pump 60 is in fluid communication with the interior fuel chamber via small bores (not shown); and metering block 20b via channel 68. Cam arm 64, which pivots on pin 66 is cammingly engaged with a throttle (not shown). When the throttle is initially pressed, cam arm 64 is moved in the direction of arrow A around pin 66, thereby forcing fuel that has accumulated in accelerator pump 60 to be squirted into metering block 20b via channel 60. Although accelerator pump 60 is shown disposed on spacer 16b, it is within the scope of invention, as an alternative, to dispose accelerator pump 60 on float bowl 18b. 
     An exploded view of the components of spacer 16b discussed above is provided in FIG. 4. The components of spacer 16b can be made from any of the conventional materials used in the components of float bowl 18b. 
     Referring now to FIG. 5, a carburetor assembly in accordance with an alternate embodiment of the invention is shown generally at reference numeral 98. Carburetor assembly 98 is similar to carburetor assembly 10 discussed above, however, float bowls 18a and 18b have been replaced by spacers 100a and 100b and end plates 102a and 102b. 
     Spacers 100a and 100b include fuel inlets 120a and 120b to supply fuel to the interior fuel chambers, respectively. Spacers 100a and 100b are substantially the same as spacers 16a and 16b as discussed above, thus explanation will not be provided again. However, spacers 100a and 100b may include a housing 130 configured differently from housing 28 as discussed below. Nonetheless, spaces 100a and 100b include opposing sides 118a, and 118b; and 110a and 110b, respectively, each of which has an opening. Accordingly, end plates 102a and 102b are provided to close the openings in sides 110a and 110b, respectively. Ends plates 102a and 102b may have a recess formed on sides 103a and 103b to enlarge the interior fuel chamber slightly. For purposes of illustration, gaskets 104a, 104b, 106a, 106b, 108a, and 108b are shown positioned between the components of carburetor assembly 98 as mention in the embodiment shown in FIG. 1. 
     As shown, carburetor assembly 98 includes fuel inlets 46a, 46b, 120a and 120b. On the left side of carburetor main body 12, fuel inlets 120a and 46a are disposed on opposite sides; and on the right side of carburetor main body 12 fuel inlets 46b and 120b are shown opposing each other. However, the disposition of fuel inlets 46a, 46b, 120a and 120b may be varied in accordance with the invention. 
     Spacers 100a and 100b may include housing 28 of spacers 16a and 16b discussed above, or in the alternative, spacers 100a and 100b may comprise the alternate housing configuration, housing 130, as shown in FIGS. 6 and 7. Similarly, if desirable, spacers 16a and 16b may include housing 130. Thus, spacers 16a, 16b, 100a and 100b may include any combination of housings 28 and 130. 
     In housing 130, sides 118a and 118b of spacers 110a and 110b include a side 132 with opening 113 as shown in FIG. 7. Open side 132 is substantially the same as open side 40 of housing 28. In the embodiment shown in FIG. 5, sides 110a and 110b of spacers 100a and 100b preferably have include side 132. As shown in FIG. 6, side 130 includes a baffle 110 defining an opening 111, which is smaller than opening 39 in side 38 of housing 28. In the embodiment shown in FIG. 5, sides 118a and 118b would preferably have side 130. Baffle 110 serves to control turbulence and fluid flow in the interior fuel chamber. Preferably, baffle 110 is substantially centrally disposed to most effectively control fuel turbulence in the interior fuel chamber. Baffle 110 may include slots 112 passing through baffle 110 and disposed in close proximity to a bottom wall 115 of housing 130. Slots 112, as shown, are oval shaped. Slots 112 are provided to allow the fuel in the two portions of the interior fuel chamber to equalize. Moreover, if the fuel falls below the height of baffle 110, slots 112 will still allow the fuel level to equalize across the entire interior fuel chamber. 
     In the one embodiment (FIG. 1), the spacers may be retrofitted into a conventional gasoline carburetor assembly by mounting spacers, one each, between the metering blocks and float bowls. Then, the modified carburetor assembly can be used with either gasoline or alcohol. Again, as discussed above, the only modification to the structure is with the main carburetor body. The main carburetor body must have either gasoline fuel passages or alcohol fuel passages. Thus, when converting a gasoline carburetor assembly to alcohol, the fuel passages in the carburetor main body must be enlarged. In the other embodiment, the conventional fuel bowls may be entirely removed and replaced with fuel assemblies 14a and 14b, which are then mounted on the metering plates. It is within the scope of the invention to either have the spacers retrofitted or originally manufactured in the carburetor assembly in accordance with the invention. 
     Carburetor assembly 10 operates in the following manner. A vacuum produced in the venturi of carburetor main body 12 pulls fuel out of fuel bowl assemblies 14a and 14b. Thus, the fuel level drops in the interior fuel chamber of fuel bowl assemblies 14a and 14b. This drop in fuel level causes both floats in the interior chamber to drop along with the fuel level. Each float preferably drops at substantially the same rate and at substantially the same level as the other float. When the floats drop, the float levers and the needles in needle-and-seat valves also drop causing the valves to open allowing fuel from the fuel pump to enter the interior fuel chamber via the two fuel inlets. The addition of fuel into the interior fuel chamber causes the fuel level in the interior fuel chamber to rise, thereby raising the level of the floats and closing the needle-and-seat valves when the fuel returns to the desired level. 
     In accordance with the present invention, an additional flow path for fuel is added into the interior fuel chamber, additional interior volume in the fuel bowl assembly is provided, and an additional float assembly is provided in the interior fuel chamber, thereby increasing the amount of fuel that can be delivered to the carburetor as needed, without changing the fuel level in the interior fuel chamber, without sacrificing the accurate and precise control of the fuel level in the interior chamber, and without changing the basic operation of the carburetor assembly. Unlike a previously known method, which requires a more powerful fuel pump to force fuel into the float bowl, the present invention operates at normal fuel pressure levels (e.g., 8 psig). Because the fuel is under normal pressure, the needle-and-seat valves close properly and reliably when the fuel inside the float bowl reaches the desired level. As a result, fuel does not bleed from the float bowl into the oil pan and elsewhere; fuel is not wasted, and the oil need only be changed according to a normal maintenance schedule. Moreover, an expensive fuel pump need not be added to the fuel system of the automobile; the original fuel pump is still used in the present invention. 
     The present invention is not limited in scope to what is described above. For example, the fuel assemblies of the invention can be used with alcohol, kerosene, or gasoline alone or in combination. The fuel assemblies, especially, spacers 16a, 16b, 100a or 100b, may include additional fuel inlets. Moreover, any quantity of spacers may be provided on the carburetor assembly to accomplish the teachings of the invention. The spacers need not be separately formed and may be contiguous housings so long as the portions of the interior fuel chamber remain in fluid communication. 
     While the invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention.