US1771531A - Fuel-mixture forming and feeding apparatus for internal-combustion engines - Google Patents

Description

July 29, 1930. w. A. EDWARDS FUEL MIXTURE FORMING AND FEEDING APPARATUS FOR INTERNAL COMBUSTION ENGINES Flled Jan 5, 1924 Patented July 29, 1930 PATENT OFFICE WILLIAM A. EDWARDS, OF CHICAGO, ILLINOIS FUEL-MIXTURE FORMING AND FEEDING APPARATUS ron INTERNAL-COMBUSTION ENGINES. ,7

Application filed January 5, 1924. Serial 18 0. 684,574.

The purpose of this invention is to provide an improved fuel mixture forming and feeding device for internal combustion engines particularly with respect to the com pleteness and fixedness of the mixture and homogenizing of the air and fuel contents It consists in the elements.

of such mixture. and features of construction shown and described as indicated in the claims.

In the drawings Figure 1 is a partly diagrammatic View showing the parts constituting this invention in conventional relation to the engine to be served and the fuel source therefor on an automobile.

Figure 2 is a longitudinal. axial section of the part containing the features which characterize the invention.

Figure 3 is a section at the line 3-3 on Figure 2. s

Figure 4 is a view similar to Figure 2 showing a modification.

Figure 5 is a staggered section at the lines, 5-5, on Figure 6.

Figure 6 is a section at the line, 66, on Figure 1, showing substantially in plan view the fuel mixture connections to the engine intake. In the drawings the engine chassis and fuel tank of an automobile whose engine is equipped with this invention are shown in dotted line with the parts constituting the invention shown in conventional relation to the engine and vehicle. The engine intake manifold is indicated at A. The main fuel tank at B. C represents a constant level chamber corresponding to the usual float bowl of the carburetor from which the liquid fuel content'of the fuel mixture is taken by suction of the engine. The fuel mixture conduit, D, may be understood to have at proper location therein, proximate to the constant level chamber, C, any suitable means indicated at C for atomizlng and mixing the liquid fuel drawn from the cl1a1nber, -C, with the air drawn in at the intake end, d, vof said fuel mixture pipe. These atomizing and mixing devices constitute no part of this invention and are not illustrated in detail. It will be understood that the engine suction .platedthat the proportions and relations of produces air inflow throu h the fuel mixture pipe, D,'and draws the uel mixture on toward the'engine'intake manifold into which it is discharged at E and E. Itis contemthe ducts and discharges by which the liquid fuel and air enter and are caused to be mixed proximate to the level governing chamber, C, as at C will cause the immediately resulting mixture to be richer than suitable for serving the engine otherwise than when idling or operating at low speed or under light load; and the construction shown is designed and adapted to produce an additional admixture of air for adapting the mixture for greatest etficiency in the development of power when serving the engine at high speed under load, as with wide open throttle. For

this purpose the fuel mixture pipe, D, is branched at cl, into an outer pipe member, D2 and an inner pipe member, d, which are reunited at d the combined stream flowing on through the conduit, D, toward the engine said conduit being branched at- (P, said branches. D and D discharge into branches, FE and E respectively, of a final air intake, 1 1, through which additional air is drawn by the suction of theengine past a springclosed valve, F, and through said branches, respectively, into the intake manifold of the engine, said branches being preferably positioned as to their manifold connections at 0 e proximate to the inlet valves of the engine cylinders, respectively, as by each branch serving two cylinders of a four-cylinder enginein the particular construction indicated in the drawings. In the branches, E and Ff, of the final air intake there are provided venturis, e, at the constriction of which the branches, D and D of the antecedent fuel mixture pipe discharge respectively into the final air intake branches, E and E and immediately beyond each venturi there is lo cated in each of said branches, E and E a throttle valve, G. The two throttle valves being mounted on a common stem, G which may be suitably connected for operation to adjust the throttle valves for different running conditions. One purpose and result of this construction is to cause the fuel mixture moving through the antecedent fuel mixture pipe, D, and its branches, D a'hd D to have a sufficiently high velocity to defeat the deposit of any unvaporized liquid which may be carried by the air current. This result is obtained by virtue of the smaller cross section of the fuel path of the antecedent fuel mixture pipe and its branches in comparison with that of the subsequent fuel mixture pipe and its branches, and by virtue of the venturis in the subsequent intake pipe branches through which the antecedent pipes are discharged into said subsequent pipes.

The effect of the rapid flow of the mixture through the smallerpipe ,and the very considerable length of that pipe causes and gives opportunity for the breaking up of the sensible globules of unvaporized liquid which are liable to form after the initial atomizing of liquid which is effected by the atomizing devices located proximate to the constant level chamber or source of liquid fuel, as indicated at C these globules which tend to gather upon the inner surface of the pipe being wiped off by the rapidly flowing current and repeatedly atomized so that there results what may be called homogenization of the air and liquid.

It is desirable, however, to more perfectly insure the homogenization or permanent intermixture of the fuel and air elements so as to render the mixture more nearly equivalent to a fixed gas for purposes of ignition and explosion in the engine, by definitely vaporizing the atomized liquid in this homogenized or partially homogenized mixture, and for that purpose the anterior fuel mixture pipe at some portion, preferably of its horizontal ex- .tent, before discharge of the relatively rich mixture which it conveys into the larger fuel intake pipe where additional air is added to the mixture, is provided with a heating acket connected with a source of heating medium. as the exhaust gases from the engine exhaust manifold. Such heating jacket is shown at K and the construction in detail will be shortly described; but it should first be noticed that gasoline commonly available for serving internal combustion engines contains elements of volatility, some of the elements being so highly volatile that they become fully vaporized in the process of mere mechanical mixture or atomizing which occurs in the mixing devices, of whatevercharacter, provided at the .point of introduction of the liquid element into the fueln'iixture conduit as indicated at-CKz-But other-elements which may be atomized in the atomizingand mixing devices and by-the agitation which occurs in the dispersion eflected-bythe air flow at high velocity through-the antecedent fuel mixture pipe, are nevertheless liable to become recombined into sensible globules of liquid which tend to gatherupon and adhere to the inner surface of the conduit, and are-therefore found at the outer part of the current flowing through the antecedent mixture pipe, D. Since the degree of heat necessary to vaporize these heavier elements of the liquid fuel is greater than that necessary for vaporizing the more volatile elements, it is desirable that said lighter or more volatile elements should not be exposed to this heat, since all addition of heat to the fuel mixture before ignition constitutes a diminution of the kinetic energy which will be developed by the ignition and explosion of the same in the engine cvlindcr. For avoiding such overheating of the more volatile parts of the fuel mixture while heating to proper degree for vaporization the heavy or less volatile parts, I construct means for heating the fuel mixture to vaporize it on its way to the engine, as shown in the drawings as follows:

The portion, D of the fuel mixture pipe, D, which is inclosed in the heating jacket, K, is enough larger in diameter than the preceding and succeeding portion of said fuel mixture pipe to accommodate within it a thin sleeve, D whose inner diameter is substantially that of the preceding and succeeding portions of the fuel mixture pipe and which has exteriorprojections, d, for centering it in the enlarged member, D, of the fuel mixture pipe. to form a thin annular passage, (1 between said sleeve and the inner wall of said member, 1), said annular passage open at its opposite ends into the preceding and succeeding portions respectively of the fuel mixture pipe, D; and said member, D, is connected by reducing pipe couplings, (Z and (1, respectively, to the preceding and succeedin port ons of the fuel mixture pipe, D. The acket, K. encompassing this enlarged section, D of the fuel mixture pipe causes the heavier elements of the liquid fuel which to some extent will have collected upon the inner surface of the fuel mixture pipe, D, and which will be flowing through this narrow annular space, (1, to be especially heated by the exhaust gases flowing through the jacket, so that these heavier elements will be vaporized in their passage through this annular portion of their passage toward the engine. The vapois thus formed and occupving this annular space. serve as a partial insulation of the more volatile elements of the fuel which will be flowing through the center of the sleeve, D and said more volatile elements will be protected from overheating or unnecessary heating from the exhaust gases. The result is, that instead of the entire fuel mixture being heated to a sufficient degree to vaporize the heavier elements, the average and the temperature throughout of the entire mixtnre after the separated parts are recombined in the portion of the fuel mixture conduit beyond the-heating jacket between the same the engine, including the final larger fuel mixture intake, E, will be lower temperaturethan it would be in the absence of the sleeve, the heat applied being limited to the heat units necessary for vaporizing the heavier elements.

In Figure 4, there is shown a modification of the heating means for vaporizing the heavier elements of the fuel, which may be employed with approximately as good results as that already described. In this modified form instead of the sleeve D within the fuel mixture pipe for se arating the heavier elements of the fuel to lie especially heated for vaporization, there is provided a branch or shunt path for the fuel mixture flowing in parallel with the main line pipe, by the pipe, D, D leading off at d, from the main line of the fuel mixture pipe and extending parallel thereto for a limited distance and then reunited with the main ipe at d. This parallel pipe section forming the shunt path preferably is located below the main pipe so that the heavier elements of fuel which will be adherent to or flowing along the interior surface of the fuel mixture pipe, tending as they will to flow to the lower side of that pipe willbe drawn into this shunt path. The shunt pipe is enclosed in a heating jacket, (1 connected with the engine exhaust manifold as in the case of the heating jacket, K. The proximity of the heating jacket, 11 to the main fuel mixture pipe, D, at the portion of the latter which is parallel by the shunt pipe will serve for heating the fuel mixture flowing through said main pipe adequately for vaporization of the more volatile elements which will be there flowing, but will not heat them to any such degree as the heavier elements flowing through the shunt are heated by the exhaust gases flowing through the jacket; and the two elements of the fuel mixture recombined beyond the jacket will be heated only to a very limited extent as compared with the heating which would result from exposing the entire fuel mixture'flow to heating by means'of an enclosing jacket.

To facilitate and render more certain the drawing of the heavier parts of the fuel through the shunt pipe, D, there is interposed in' the main pipe, D, a Venturi sleeve, D which has an exterior rabbet at d, at its entrance end forming av shoulder which tends to arrest the li uid globules of the heavier parts of -the fue which tend to collect on the inner surface of the pipe, said rabbet form ing also a circumferentiallyextending channel which operates to cause the heavier fuel parts thus arrested to flow around to the lower side of the pipe, D; and the shunt pipe, D. is connected at this rabbet for receiving the liquid thus collected and directed to it.

The high pressure resulting from the abrupt shoulder of the venturi, D, at the rabbet, (1, causes the fluid which is diverted into the entrance to the passage, d, at the rab et, d,

and heated and presumably vaporized in its discharge through d", to be drawn back into the stream at the venturi, D. And for roducing a sufiiciently stron suction to in uce proper flow through the s unt pipe, there is located in the main pipe another Venturi sleeve, D", at a position such that the shunt lpipe makes its return into the main pipe just eyond the constriction of said venturi.

I claim 1. In a fuel mixture forming and feeding apparatus, a conduit connected for suction with the engine intake, having air and liquid fuel connections for roducing a fuel mixture flowing toward t e engine, said conduit at a part of its extent between the point of entrance into it of the li uid elements and the engine being parted into two elements affording courses extending in parallel for a limited distance and then reunited, one of said courses leading off from the outer zone of the antecedent portion of the conduit for Y taking the portion of the fuel mixture flowing at said outer zone, means for heating the element which constitutes said outer course, and means for admitting auxiliary air at a point subsequent to the reunion of the courses and antecedent to the engine intake.

2. In the construction defined in claim 1,

foregoing, the two courses in parallel being formed by means of a sleeve extending in and spaced from the inner wall of the conduit and forming an annular course outside of a central course; both said courses opening at their opposite ends in respectively antecedent and subsequent centers of the conduit; and heating means consisting of a acket connected with the source of heating medium encompassing the conduit at the portion thereof in which said sleeve is located.

3. In a fuel mixture forming and feeding apparatus, a conduit connected for suction from the engine intake having air and liquid fuel connections for producing a fuel mixture flowing toward the engine, said conduit at a part of its extent between the point of entrance into it of the liquid element of the fuel mixture and the engine, comprising an 4. In a 'fuel mixture forming and feeding apparatus, a conduit connected for suction from the engine intake having air and liquid fuel connections for producing a fuel mixture flowing toward the engine, said conduit at a part 05 its ex ent between the point of entrance into it of the liquid element of the fuel mixture and the engine comprising two courses extending in parallel for a substantial distance, said courses both leading at 5 substantially the same point from an antecedent part of the conduit, one of said courses being encompassed by the other at said point at which they both lead from said antecedent part, and heating means consisting of a acket connected with a source of heating medium encompassing the course having said encompassing annular entrance portion.

5. In a-fuel mixture forming and feeding apparatus, a conduit connected for suction from the engine intake having air and liquid fuel connections for producing a fuel mixture flowing toward the engine, said conduit at apart of its extent between the point of entrance into it of the liquid element of the fuel mixture and the engine comprising two courses extending in parallel for a substantial distance, said courses both leading at substantially the same point from an antecedent-part of the conduit, one of said courses being encompassed by the other at said point at which they both lead from said antecedent part, and heatin means constituting a jacket connected wit a source of heating medium encompassing the courses, having m said encompassing annular entrance portion,

said two courses being united after a substantial extent of the jacketed courses, and means for admitting an additional air supply at a point subsequent to the conjunction of the two courses and anterior to the discharge of the mixture at the engine intake.

6. A process for producing a fuel mixture for an internal combustion engine which comprises the following steps: first, producing by engine suction a current of combined air and atomized liquid fuel by atomizing the latter at the point at which it becomes an element in said current; second, separating the less volatile from the more volatile parts of the atomized fuel element through a portion only of the path of flow of current from the point of such separation to the engine; third, heating the less volatile portion while separated from the more volatile for vaporizin the same, in excess of any heating appli to the more volatile part, and, fourth, admitting additional air for cooling and rendering leaner the vaporized mixture at a point anterior to its delivery into the engine.

5 "In testimony whereof, I have hereunto set my hand this 5th day'of December, 1923. s r 'WILLIAM -A. EDWARDS.

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