IMPROVED ENGINE CARBURETION

Abstract

An emulsion tube for a carburetor is formed with a porous wall surrounding an inner passage, wherein air travels about one side of the wall and fuel travels about the opposite side, with air being supplied through the pores to aerate the fuel (with the aerated fuel then being expelled into a venturi wherein engine intake air is traveling to further mix the fuel with the intake air therein). The emulsion tube can beneficially provide a high degree of fuel/air mixing across the entire range of intake airstream flow rates at which an engine may operate. The porosity of the emulsion tube can also be tailored to provide the desired fuel/air ratio(s) across the engine's operational range of intake airstream flow rates.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a cross-section of a carburetor 10 incorporating a porous emulsion tube 100 which exemplifies the invention, wherein the emulsion tube 100 extends from a fuel supply 18 to a venturi 12, with a section of the emulsion tube 100 between its first opening 110 and second opening 112 being exposed to an air supply 16.

FIG. 2 is a schematic view of a cross-section of another porous emulsion tube 200 exemplifying the invention, wherein the outer diameter of the emulsion tube 200 varies between its first opening 210 and second opening 212 to provide variable resistance to air and/or fuel admittance along its length.

FIG. 3 is a schematic view of a cross-section of another porous emulsion tube 300 exemplifying the invention, wherein the diameter of the inner passage 308 of the emulsion tube 300 varies linearly between its first opening 310 and second opening 312 to provide variable resistance to air and/or fuel admittance along its length.

FIG. 4 is a schematic view of a cross-section of another porous emulsion tube 400 exemplifying the invention, wherein the diameter of the inner passage 408 of the emulsion tube 400 varies nonlinearly between its first opening 410 and second opening 412 to provide variable resistance to air and/or fuel admittance along its length.

FIG. 5 is a schematic view of a cross-section of another porous emulsion tube 500 exemplifying the invention, wherein the porosity of its tubular body 502 varies in pore size and/or density between its first opening 510 and second opening 512 to provide variable resistance to air and/or fuel admittance along its length.

FIG. 6 is a schematic view of a cross-section of another porous emulsion tube 600 exemplifying the invention, wherein the tubular body 602 of the emulsion tube 600 is formed in discrete sections 614, each having a different average pore size and/or density, to provide variable resistance to air and/or fuel admittance along the length of the tubular body 602.

FIG. 7 is a schematic view of a cross-section of another porous emulsion tube 700 exemplifying the invention, wherein the tubular body 702 is formed of a mesh lattice/framework 716 with a porous skin 718 wrapped about the framework 716.

DETAILED DESCRIPTION OF PREFERRED VERSIONS OF THE INVENTION

Expanding on the foregoing discussion, it should be understood that the various versions of the invention discussed above are merely exemplary, and the invention includes other variations as well. As an example, the tubular body of the emulsion tube need not necessarily be formed of metal, and could instead be formed of (for example) ceramic, or potentially even plastic (provided such plastic can withstand engine temperatures and prolonged exposure to fuel). Emulsion tubes made of more than one material, and/or composite structures, are also a possibility, e.g., an emulsion tube having a sintered metal entryway and a plastic section extending into the venturi, or having a ceramic entryway and a metal section extending into the venturi. FIG. 7 illustrates an emulsion tube 700 of this nature wherein a tubular lattice/framework 716 (e.g., one made of metal or plastic) is wrapped with a porous textile skin 718 (e.g., one made of carbon or glass fiber), with the skin 718 being bonded to the framework. Moreover, porosity may be made to vary about the outer skin 718 by varying its weave, and/or by stretching/elongating parts of the textile, so that the pores/spaces between adjoining fibers vary as desired. It should also be understood that the pores need not be present upon initial manufacture of the tubular body of the emulsion tube; for example, they might be formed via laser machining after the tubular body is initially molded, cast, or otherwise formed.

The various foregoing emulsion tubes can incorporate other features as well, e.g., protruding threading or teeth, and/or sockets or other indentations, which allow the emulsion tubes to be firmly installed within (and readily removed from) the carburetor. As an example, some carburetors utilize emulsion tubes having threaded ends which screw into sockets for easy installation of the emulsion tubes. An appropriately designed emulsion tube in accordance with the present invention might be formed to be threaded into such sockets as a replacement for conventional emulsion tubes.

As noted previously, the pores preferably have an average diameter of less than 100 micrometers. By this it should be understood that some pores may have diameters of greater than 100 micrometers and some may have diameters of less than 100 micrometers, but when all diameters are averaged together, they are preferably less than 100 micrometers. Experiments with a sintered bronze tubular body have found that good results arise with pore sizes on the order of about 20 micrometers (on average), but since only limited experimentation has been conducted as of the date that this document was first prepared, this should not be construed as suggesting that other sizes might not work as well. It is believed that pore diameters of less than 50 micrometers (and more specifically at ranges of around 10-40 micrometers) may be particularly useful.

The carburetor 10 in FIG. 1 is merely a simplified exemplary carburetor, and it should be understood that emulsion tubes in accordance with the invention may be used in a wide variety of carburetors having vastly different configurations, including those of the type wherein air is supplied through the inner passage of the emulsion tube to aerate a surrounding body of fluid. The configuration of the emulsion tube may also vary; for example, it need not necessarily extend along a linear path, nor need it have a circular cross-section, though such configurations are preferred since conventional emulsion tubes generally have these features.

In addition, while the invention was previously described as being preferred for use in small SI engines, the invention is not limited to such uses. As an evident example, the invention is readily usable in large SI engines, though the current trend is away from the use of carburetion (and toward fuel injection) in such engines. The invention may also be used for carburetion in non-SI engines and other engines/motors. For example, many gas turbine engines have carburetion systems wherein emulsion tubes—which, in the gas turbine context, are more often referred to as atomizers, injectors, or injection nozzles—provide fuel to a supply of air leading to the combustion chamber/passage, and the invention is suitable for use in these types of carburetors as well.

The invention is not intended to be limited to the preferred versions of the invention described above, but rather is intended to be limited only by the claims set out below. Thus, the invention encompasses all different versions that fall literally or equivalently within the scope of these claims.

Claims

1. A carburetor for an engine including an emulsion tube with an elongated tubular body, the tubular body having an outer surface, an opposing inner surface surrounding an inner passage, and opposing first and second openings between which the inner passage extends, wherein at least a portion of the tubular body is porous, with a. multiple pores extending between the inner surface and outer surface, andb. the pores having an average diameter of less than about 100 micrometers.

2. The carburetor of claim 1 wherein the thickness of the tubular body, as measured between its inner and outer surfaces, is greater at the second opening than at the first opening.

3. The carburetor of claim 2 wherein the outer surface decreases in diameter between the first opening and the second opening.

4. The carburetor of claim 1 wherein the average diameters of the pores decrease over the tubular body as it extends from its first opening to its second opening.

5. The carburetor of claim 1 wherein the tubular body is formed of two or more axially aligned tubes situated in abutment.

6. The carburetor of claim 5 wherein at least two of the tubes have pores of different average diameter, with one of the tubes having an average pore diameter at least 3 micrometers greater than the average pore diameter of an adjacent tube.

7. The carburetor of claim 1 wherein the pores have an average diameter of less than 50 micrometers.

8. The carburetor of claim 1 wherein the pores have diameters between 10-40 micrometers.

9. The carburetor of claim 1 wherein the tubular body is at least partially formed of sintered metal.

10. The carburetor of claim 1 further including: a. a fuel supply situated at one of the first and second openings, andb. an air supply about at least a portion of the outer surface, wherein the air supply is at an air pressure such that air is urged from the outer surface into the inner passage.

11. The carburetor of claim 1 further including a fuel supply and a venturi having a narrowed throat, wherein the inner passage of the tubular body extends between the venturi and the fuel supply with the first opening receiving fuel from the fuel supply and the second opening supplying fuel to the venturi.

12. The carburetor of claim 10 wherein: a. the second opening of the tubular body opens onto the narrowed throat of the venturi, andb. the carburetor further includes a high-pressure air passage leading between: (1) an area of the tubular body between its first and second openings, and(2) a high-pressure area situated upstream or downstream from the narrowed throat of the venturi.

13. A carburetor for an engine including an emulsion tube with an elongated tubular body, the tubular body having an outer surface, an opposing inner surface surrounding an inner passage, and opposing first and second openings between which the inner passage extends, wherein at least a portion of the tubular body is formed of sintered material having pores extending between the inner surface and outer surface, with the pores having an average diameter of less than 0.5 mm.

14. The carburetor of claim 12 wherein the outer surface of the tubular body has lesser diameter at the first opening than at the second opening.

15. The carburetor of claim 12 wherein the average diameters of the pores vary in relation to their distance from the first opening.

16. The carburetor of claim 12 wherein the tubular body is formed in two or more tubular sections, wherein at least one of the tubular sections has an average pore diameter which is at least 3 micrometers greater than the average pore diameter of an adjacent tubular section.

17. The carburetor of claim 12 wherein the pores have an average diameter of less than 100 micrometers.

18. The carburetor of claim 12 further comprising: a. a fuel supply supplying fuel to the emulsion tube, andb. an air supply supplying air between the inner surface and the outer surface of the tubular body of the emulsion tube.

19. The carburetor of claim 12 further including a fuel supply and a venturi having a narrowed throat, wherein the first opening of the tubular body is in fluid communication with the fuel supply and the second opening of the tubular body is in fluid communication with the venturi.

20. A carburetor for an engine including: a. a venturi having a narrowed throat,b. a fuel supply,b. an air supply,c. a sintered metal emulsion tube with an elongated tubular body, the tubular body having an outer surface and an opposing inner surface surrounding an inner passage, wherein: (1) the inner passage extends between a first opening in fluid communication with the fuel supply and a second opening in fluid communication with the venturi,(2) pores extend through the tubular body from the outer surface to the inner surface to open upon the inner passage, and(3) the air supply is situated about at least a portion of the outer surface, and is at a pressure sufficient to urge air through the outer surface and into the inner passage.

21. The carburetor of claim 18 wherein the pores in the tubular body have an average diameter of less than 0.5 mm.

22. The carburetor of claim 18 wherein the pores in the tubular body have an average diameter of less than about 100 micrometers.