US1889081A - Manifolding eight-cylinder engine - Google Patents

Description

Nov. 29, 11932. J. w. SWAN MANIFOLDING EIGHT-CYLINDER ENGINE 3 Sheets-Sheet Filed April 27, 1925 n W MF TJ n o m Q 8 DRUG moemtoz.

Nov. 29, 1932. J. W..SWAN,

MANIFOLDING' EIGHT-CYLINDER ENGINE a Sheets-Sheet 2 Filed April 27, .1925

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NOV. 29, 1932. J w, W 1,889,081

MANIFOLDING' EIGHT-CYLINDER ENGINE Filed April 27Q1925 s Sheets-Sheet s I Y wuemtoz.

Patented Nov. .29, 1932 UNITED STATES PATENT OFFICE JOHN W. SWAN, OF CLEVELAND, OHIO, ASSIGNOR- TO THE SWAN CAR-BURETOR COMPANY, OF CLEVELAND, OHIO, A' CORPORATION OF, OHIO j MANIFOLDING EIGHT-CYLINDER ENGINE v Application filed April 27, 1925. Serial No. 26,197.

This invention relates to a method (and means) of distributing an air and fuel mix' ture to the cylinders of an internal combustion engine.

The invention aims particularly at the uniform distribution of a mixture such as is known in the art as a cold mixture, that is, a mixture under normal atmospheric temperature. However, the use of the invention is not so limited, inasmuch as it is capable of satisfactory performance in connection with mixtures of any temperature.

advantage of cold mixtures arises from the fact that such mixtures contain particles of fuel in liquid state rendering uniformity of air and fuel ratios, as delivered to the cylinders, difficult of accomplishment. This is particulary true of multi-cylinder engines involving say eight or more cylinders. The

desired uniformity in such special types of engines is obtained by the present invention.

Method and means aiding in the attaining of the above stated objects are fundamentally set forth and claimed in my copending application, Serial-No. 744,991, filed November 5, 1924, and in so far as common or divisible subjects matter are concerned, the present application is a continuation of that earlier v application, and the same is true of its parcut application, SerialNo. 501,314, filed September 17, 1921. I

I 'Whereas in my companion application,

Serial No. 7 17,991, the broad phases of the present invention are set forth, together with that specific phase devoted more'parti cularly I to six cylinder engines, and whereas 1n a co pending appl cation, executed of even date herewith, a specific phase of the invention:

devoted more particularly to four cylinder engines, is claimed, the-present embodiment of the invention is primarilyembrace d within a combination of themanifolcl as set forth in my companion application, with an eight or greater number of cylinder engines, and

wherein what I may properly term sub-manifolds are prgvided to suitably connect the main manifold with the various cylinder inlet ports to secure uniform distribution of fuel throughout the various cylinders.

53 An important object of my basic invention A dis-- tional improvements have been conceived by me to enable the best use of the manifold in connection with engines of particular types. in the instance of the four cylinder type the same three branch manifold as used in the six cylinder type of engine of my application, Serial No. 747,991, is shown, the improvement including a novel arrangement of the inlet parts of the four cylinders in relation to the induction cycles of the engine so that the uniform or common type of mani fold couldbe. there practically utilized. The present improvements are of the same general nature, residing as they do, in the combining of the same three-port manifold With auxiliary or sub-manifolds properly asso-' changes of direction required in the course of a fuel charge from the initial distributing point to the cylinder for which said charge is intended.

. With the foregoing understanding, it will be appreciated that the outstanding characteristic of the present invention resides in the provision of a manifold, associated with suitable sub-manifolds to accommodate the number of cylinders, as required, the main manifold and the sub-manifolds being formed and arranged .tosubject the movement of the fuel charges to substantially the same forces and conditions from the beginning to the end of its travel in order that the passage of the fuel in any direction, andvcorrespondingly to any particular cylinder,- will viding at such other points through the manifolds and subananifolds, where changes of direction take place, formations preventing relative enriching or impoverishing of the mixture delivered to any cylinder of a pair as compared to the adjacent cylinder of that air. p A practical and preferred embodiment of the invention is illustrated in the accompanying drawings, forming part hereof, and the details and arrangements of parts will be apparent from an inspection of these drawings in connection with the specific description hereinafter contained.

In the drawings:

Figure 1 is a top plan View of an eight cylinder engine, the latter being shown more or less diagrammatically having'improved manifolding means applied thereto;

Figure '2 is a side view;

Figure 3 is a horizontal sectional view;

Figure 4 is a vertical sectional View;

Figure 5 is a sectional view through the end portion of one of the main manifold branches;

Figure 6 is a vertical sectional View through the uptake and associated parts;

Figure 7 is an elevation looking in a direction from the left of Fig. 6;

Figure 8 is a vertical sectional view similar to Figure 6 showing a slightly modified-form of construction; and

Figure 9is a horizontal sectional view on the line 99 of Figure 8;

Other modifications are shown in Figures 10, 11, 12, and 13, the same in each instance being a top plan view as will be readily understood, the details being the same as in the embodiment illustrated in the first above mentioned views.-

Referring more specifically to the drawings wherein like reference letters refer to the same parts in the several views, A represents a cylinder block or casting in which, in the instance here discussed, eight cylinders are provided, designated conveniently as 1 2, 3, 4, 5, 6, 7, and 8. Cylinders 1 and 2 are provided with siamesed inlet ports 1a: and 20a. The cylinders 3 and 4 are provided with a like siamesed inlet 3aand 4m, and the same system is followed as shown in connection with the pairs of cylinders 5-6 and 78, respectively. Each cylinder is provided with an exhaust, as usual, indicated generally at 9. i

From any suitable carburetor or mixing device a fuel mixture is supplied to the intake portion B of what I will style the main manifold, the intake in this instance being a vertically disposed uptake adapted to be attached to a carburetor by flanges and screws as will be obvious. This uptake, and the same applies to the fuel conduits throughout the main manifold and auxiliary or submanifolds, to be later discussed, is of rectangular or square cross section. although the same may be in instances of other shapes such as round. However, I have found that square or rectangular contouring lends itself most effectively to the uniform distribution of fuel. The uptake terminates in a fuel distributing zone C, the same comprising an approximately square chamber, the walls of which constitute a junction point between manifold branches D, E and F. The top wall of the chamber C is provided with a dome 0 connecting by sharp angles with the top walls'of the main manifold branches D and E and the front and rear walls a and c are recessed and provided with sharp angular corners joining the correspondingly front and rear walls of the branches D and E, so that the distributing chamber is thus at all points of symmetrical formation to favor the branches D, E and F leading from the distributing zone substantially alike, in causing any liquid particles reaching the dome to be delivered back into the uptake B or into the air stream passing through the distributing chamber rather than adhere to and run along any of the walls of the branches D, E and F Which might result in favoring one or more of these branches with liquid fuel as compared to the remaining branches. The branches of the main manifold are substantially of uniform area throughout, save for a slight variation to meet the conditions, for example, the uptake B is slightly larger in cross area than the cross section of the branches D, E and F, and the branch F is slightly larger than the branches D and E because the branch F is in this instance intended to deliver to a sub-manifold whereas the branches D and E lead directlyto cylinder ports. However, the branches D and E are very slightly enlarged towards their delivery ends to compensate for the fiictional resistance that may be offered in the relative- 1y long travel of mixture charges from the distributing zone to the ends of these particular branches. These are details that present advantages, but are not necessary to a practical and satisfactory operation, which can in many instances be attained by the maintenance of a truly uniform area throughout all of the portions of the manifold structure.

The ends' of the manifold branches D and E are provided with recesses e and joined by sharp angular corner with right angular offset leads or terminal portions 0, f of said branches, the inner corners being also at sharp right angles as shown, all of which is pointed out in detail in my companion applications.

In the foregoing description I have defined the main portion or manifold or my manifolding structure, the same being of a type capable of application to various types of engines. To enable the application being specially considered I herein, I provide the end leads or terminal portions of the branches 1) 'and E with extensions G and H flanged and bolted together as at'g and h and as at g and h, or otherwise secured to the engine in registration with the siamesed ports 1w2ai and the opposite end air of siamesed ports for the cylinders 1 an 2 and 7 and 8, respectively. x

Now, to provide suitable distribution of the fuel from the intermediate or central branch F of the manifold tothe remaining two pairs of inlet ports for the cylinders 3 and 4 and 5 and 6, respectively, Lprovidea sub-manifold of cross section and recessed end formation,

. the same as in the/instance of the main manlfold, flanged and bolted to the branch F as at 9', the sub-manifold having branches J and K at right angles to the branch F and joining therewith through the medium of branch corners indicated at k the same as the sharp meeting corners 12 between the branches D, E and F, and the uptake B. Directly opposite the end of the intermediate or middle branch F, the sub-manifold is provided with a dome L connecting by sharp right angular corners l of the inner walls of the sub-manifold, branches J and K so that the mixture ingredients reaching the dome or recess L which, of course, corresponds to the dome c of the initial or main distributing chamber C, will not be induced to adhere and flow along any Wall of the branches J and Kadjoining the recess L. In this manner a sub or auxiliary distributing zone is provided in which the forces and conditions tending to influence the mixture passing through the chamber in its change of direct'.on at right angles or transversely to'the inlet movement will be the same in opposite directions or to'the branches J and K. As

stated the ends of the branches J and K have .stood that these are also details that recessed portions M and N joined by sharp corners m and n with right angular extensions or terminal leads 0 bolted or secured to the engine, one in registration with the siamesed inlets 3a:4w for the cylinders 3 and 4, and the other with the like inlets to the cylinders 5 and 6. The inner corners of these leads or terminals, that is, where they join the inner walls of the branches J and K are sharp right angles m n, the same as the angular inner corners e and f inthe case of the main manifold. These formationsare such that the movement of the fuel mixture at the ends of the main manifold, and the submanifold, as the case may be, will be subjected to forces and conditions causing a straightening out or right angular movement of the mixture at any turn, and will insure the wet constituents of the mixture reentering the air stream and passing therewith'to the particular cylinder of any siamesed pair at the time in question, rather than permit accumulation and passage to the other cylinder of said pair in subsequent operation thus resultin in relative enriching or impoverish ing of c arges to the cylinders of such pair. The arrangement and operation insures complete delivery of a charge to each cylinder at the time intended and as governed by the induction cycles of the engine whereby uniform distribution is accomplished at ,all times, a matter otherwise difficult in distributing through a common passage leading to siamesed ports where, in the previous art, curvatures and other formations favored some cylinder as compared to another, and brought about disadvantages of uneven distribution, or in other words destroyed the maintenance of uniform ratios of air and fuel constituents. It will be understood that it is the desire to deliver to any particular cylinder a mixture of fuel in the condition that it passes, for example, through the branches 1) and E. The arrangement provided in- ,sures that the said mixture after a change of and exhaust, tha t, as usual, a water cooling chamberor' s stem P is provided, but this need not be urther enlarged upon as such means may be of any form or kind to meet the convenience or particular ends desired in any given case.

While I have shown the end recesses of the main and auxiliary manifolds as of either integral formation, or by means of attached or inserted caps or plugs, it will be undermaybe optionally employed, either in providing the manifold of particular form desired, or in facilitating the initial casting of manifold thereof.

While so far as distribution is concerned, it is by no means essential to the practical and successful operation of my system of mani- -folding, I have found that it is useful at times to apply suflicient heat to the walls of the intake for the fuel mixture to'overcome any tendency of the mixture to adhere to-said walls. To that end the uptake B is illustrated as in part formed integral through an exhaust manifold Q (Fig. 6), the upperportlon of.the uptake being formed integrally with the branches D and E of the main manifold and bolted as at q to the exhaust manifold. The exhaust manifold, is, in the form of Fig. 6, formed integral throughout, as clearly illustrated in Figure 2, and while such exhaust manifold and its particular relation to the uptake is a part of my invention, the

same will not be claimed herein in view of the fact that it more properly constitutes subject matter for a divisional application. The same facts are true with respect to the form of manifold illustrated in Figure 8 where the central portion R of the exhaust manifold is formed integrally with the lower portion of the fuel uptake, but is separate from the opposite leads of the exhaust manifold represent'ed at S, the parts being bolted together as at r with a suitable packing s interposed between the abutting faces.

I have refrained from speaking of the inter-position of packing between all faces where joints are provided throughout my manifold structure and where the same is joined to associated structure, it being obvi-' ous that-such packing may be resorted'to wherever found expedient to create the desired scaling effect, and, of course, the entire manifold may be cast integral.

Although the same need not always be the case to obtain useful application of my manifolding of engines, I have found that best results are available where no two successive flows of fuel take place through the same main or auxiliary branches of the manifold structure. With this in mind it might be stated that, assuming the firing order of the engine to be 1-8258674, the desired result of the successive change in direction of flow results from the combination of an engineof that firing order with the arrangement of main and auxiliary or submanifolds hereinabove illustrated and described. There are no two successive flows of fuel through the same main or auxiliary .outlet branch.

The-mixture from the carburetor will move in rectilinear lines through the distributing zones where it takes a right turn, and after it leaves sa d io ues and'in passing through the outlet branches the mixture will not pass by any similar port, in similar rectilin ar lines through the branches, and take right angle turns into the extensions leading to the cylinders as demanded by the induction cycles of the enginesi Although the results may not be as good, yet I have illustrated in Figure 10 an arrangement where my distributing zone with the end recesses of the branches, and with the right angle turns are employed, the right angle turns each leading toa pair of inlet ports of an engine of the eight cylinder type. Of course advantages inherent in my arrangement previously set forth will be absent from this form. but substantial portions of the invention will be utilized. It is to be here understood that in connection with this disclosure at Figure 10, as well as in connection with the disclosure of the remaining figures,

namely: Figures 11 to 13, inclusivefthe details as to configuration, formation, and relation of the distributing zone to the uptake six cylinder type of engine.

is preserved as in the case of the embodiments previously set forth in detail in this specification, although it is to be again noted that where rectilinear shapes. are alluded to, the said shapes may be varied in instances to round, hexagon, octagon or otherwise. With this understanding, it will be. seen that in Figure 11 the manifold is provided with four outlets T for a six cylinder'engine, two of the outlets each supplying a pair of cylinders, represented at 23 and et-5, respectively, and the other two outlets each supplying a single cylinder, designated 1 and 6, respectively. Here the main manifold is represented at U and the uptake thereinto at u, the outlets to the auxiliary or sub-manifolds being indicated at '0 enteringthe sides of the auxiliary manifolds V. v

Substantially the same arrangement is illustrated in Figure 12, where, however, the four outlets '1, are each connected With a pair of cylinders of an eight cylinder type I of engine.

In Figure 13, three out-lets, W, are provided on what might be here styled as the auxiliary manifold, the same, following the idea herein from time to time expressed, namely: that they are at right angles to the longitudinal axis of the body of the auxiliary manifold shown at 10. Each of the outlets connects with a pair of cylinders, for example,,of a The auxiliary manifold, in this instance, has two equally spaced inlet openings Y constituting inlets from a main manifold Z, said openings Y being at the side of the auxiliary manifold and equi-distant between the outermost and intermediate outlets Q. Centrally thereof the main manifold Z has the distributin chamber vertically aligned with the vertical up take from the carburetor or other source of supply, as represented at 2.

The foregoing are intended to illustrate some additional embodiments of the present invention wherein good results may be obtained, although, as stated, they may be found ellicient in one respect or another as compared to the preferred embodiment of the invention herein first particularly set forth and as will'be specifically claimed herein.

I claim:

1. The combination with an eight cylinder engine having-ports leading to pairs of inlet valves; of a manifold structure through which fuel is distributed from a source of supply, comprising a distributing chamber, an intake pipeleading into said chamber, three outlet conduits leading from said chamher, two of said conduits being each connected with one of the inlet ports in said engine, a distributing chamber at the end of the other of said outlet conduits, and two outlet conduits each leading fromsaidlast mentioned chamber to an inlet port in said engine, said chambers I being interiorly formed and arranged to uniformly influence the mixture passing therethrough into the conduits leading therefrom.

2. The combination with a multi-cylinder engine having suitable inlet ports, of means for manifolding the same comprising a main manifoldand a sub-manifold both formed throughout with sharp inside corners to present right angles at every turn to cause a fuel mixture introduced into the manifold to follow rectilineal paths to and from said turns throughout the main and sub-manifolds to the point of ultimate discharge to any port.

3; The combination with an eight cylinder engine provided with suitable inlet ports, of means for manifolding the same including an intake, a main manifold and a sub-manifold operatively associated with each other and with the inletports to insure that no successive charges of the fuel mixture pass through the same portion of the manifold branches the intake and main manifold hav-Q ing constant open communication therebetween.

4. The combination with an eight cylinder engine, of a manifolding means comprising an intake, a main manifold having suitable branches, and a sub-manifold having suitp able branches, leading to the ports of said cylinders, the main and sub-manifold being operatively associated, the main manifold at the juncture of its branches and the intake having constant open communication therebetween and having a distributing zone of symmetrical formation to uniformly distribute the fuel laterally to said branches and to the sub-manifold, and the sub-manifold having a distributing zone of symmetrical formation to similarly uniformly distribute the fuel mixtures laterally to the branches of the sub-manifold.

5. The combination with an eight cylinder engine, of a manifolding means comprising a plurality of manifolds operatively related to,

deliver to the ports of said'cylinders, each of said manifolds at its point of reception of fuel mixture being symmetrically formed to uniformly distribute the fuel mixture Where engine, of a manifoldng means comprising a main manifold and a sub-manifoldoperative- 1y associated leading to the-ports of said cylinders, each manifold comprising branches having offset leads adapted to register with cylinder ports, and each manifold branch adjacent said ofiset portions being sharply related to said ofi'set portions and provided with recesses beyond the juncture therebe tween to compensate for the chan e of direction of the fuel mixture by subjecting the mixture to forces tending to restore the mixture after the turn to the conditions thereof prior to reaching the turn.

8. The combination with engine, of' manifolding means comprising a main' manifold and a sub-manifold each having a distributing zone of symmetrical formation to uniformly distribute the fuel mixi ture laterally from said zones to manifold branches leading fromsaid zones, the several manifolds being operatively associated one to receive the fuel mixture from the other, and the several manifolds being provided with turns to register with cylinder ports, the turns being formed by right angles and arranged to-cause the mixture to travel a rectilineal path throughout and to influence the mixture so as to favor no one inlet of an adjacent pairrelative to'the other inlet of that air.

9. The method of distributing fuel mixtures to a multi-cylinder engine of eight or more cylinders having a given cycle of induction comprising the moving of the fuel mixture from a source of supply to a distributing .zone, subjecting the mixture at said zone to forces tending to uniformly distribute the mixture therefrom in three or more directions, conducting the mixture in two of said directions to cylinder ports, conducting the mixture in another direction to a distributing zone and there subjecting the same to forces tending to'uniformly distribute the same in several directions leading to other cylinder ports.

10. Manifolding means comprising a main manifold of rectangular cross section throughout, a sub-manifold of similar cross section throughout operatively associated therewith and offset portions for the several branches of the main and sub-manifold, the manifolds throughout being formed to present right angular" turns wherever the fuel mixture must change its direction in passing through the manifolds to cylinder ports.

11. The method of distributing a fuel mixture to eight cylinder engines having a given induction cycle comprising the moving of the mixture to distributing zones adapted to uniformly influence the mixture in its travel in all directions, and conducting the fuel. mixture towards some of the cylinder ports in a direct path and to another disan eight cylinder,

tributing zone from which fuel mixture will be similarly uniformly distributed towards other cylinder ports, the movement of the fuel mixture being in consonance with the induction cycle of the engine so that the movement of the mixture will not be suc-v cessively duplicated through any single path portion comprising a main duct and a secondary duct common to said pair of ports, the inside juncture between the main and secondary ducts being substantially a right angle and the outside juncture being a sharply related recessed portion, the arrangement being adapted to act upon the passing fuel mixture to insure uniform delivery thereof to the pair of cylinders from the common secondary duct.

a portion to deliver fuel to said ports, said portion comprising a main duct and a secondary duct common to said pair of ports, said main and secondary ducts being of angular cross section, the inside juncture between the main and secondary ducts being substantially a right angle and the outside juncture being a sharply related recessed portion, the arrangement being adapted to act upon the passing fuel mixture to insure uniformdelivery thereof to the pair of cylinders from the common secondary duct.

14. A manifold having a portion comprising a duct level throughout its length and closed save for an inlet and two outlets, a straight or substantially straight supply duct adapted to connect with the inlet at an intermediate portion of the main duct and being at right angles or substantially at right angles thereto, theinterior of the connection of the supply duct with the inlet being at substantially right angles throughe' out the connection, and two secondary ducts, one at each end of the first mentioned duct,

said secondary ducts being at right angles or substantially right angles to the first mentioned duct, a distributing Zone being formed at the junction of the said first mentioned duct and supply duct','the secondary ducts being parallel or substantially parallel to each other and perpendicular or substantially perpendicular to the first mentioned duct and on the interior making right angle connections therewith.

15. A manifold of the character described comprising a main duct having three outlet branches at right angles thereto and substantially level with the main duct, the main duct and outlet branches being rectangular in cross section, a centrally arranged vertically disposed feed pipe connected to the main duct, the juncture therebetween being a sharp angle.

16. A manifold of the character described comprising a mainduct having three out e branches at right angles there-to andsubstantially level with the main duct, the main in cross section, a centrally arranged vertically disposed feed pipe connected to the main duct, the juncture therebetween being a sharp angle, the main duct having a dome formed therein opposite the inlet to the main duct and having sharp [right angle marginal edges.

17. A manifold of the character described comprising a main duct having three outlet branches at right angles thereto and substantially level with the main duct, the main duct and. outlet branches being rectangular in cross section, a centrally arranged vertically disposed feed pipe connected to the j a main duct, the juncture therebetween being 13. The combination with a pair of ad]a-' cent cylinder ports, of a manifold having a sharp angle, the opposite ends of the main duct beyond the adjacent outlet branches being recessed and sharply joined to the outlet branches.

18. A manifold of the character described comprising a main duct having three outlet branches at right angles thereto and substantially level with the main duct, the main duct and outlet branches being rectangular in cross section, a centrally arranged vertically disposed feed pipe connected to the ma n duct, the juncture therebetween being a sharp angle, the main duct having a dome formed therein oppositethe inlet to the mam duct and having sharp right angle marginal edges, 4

the opposite ends of the main duct beyond" the adjacent outlet branches being recessed and sharply joined to the outlet branches.

19. A manifold comprising a main duct having end branches the inner junctures of which form approximately right angles, an

intermediate inlet to the manifold and a recessed or dome portion in the manifold opposite the inlet bordered by a sharp right angle union with the adjacent wall of the manifold. v v

20. A manifold comprising a main duct having end branches the inner junctures of which form approximately right angles, an

intermediate inlet to the manifold and a recessed or domeportion in the mamfoldopposite the inlet bordered by a sharp right angle union with the adjacent wall of the manifold, the manifold and branches being square in cross section.

21. A manifold comprising a 'main duct having end branches the inner junctures of which form approximately right angles, an intermediate inlet to the. manifold and a recessed or dome portion in the manifold opposite the inlet borderedby a sharp right angle union with the ad acent wall of the manifold; the manifold and branches being square in cross section. and the ends of the manifold being recessed and providing a sharp angle connection with the adjacent portion of the outlet branches.

22. A manifold comprising two elongated substantially straight manifold portions in parallel relation and occupying a horizontal plane, one portion being substantially shorter ,than the other, lateral outlet portions for connection with cylinders, the outlet portions being parallel to each other and at r1 ght angles to the elongated portions, and vertical fuel inlet means at right angles to said elongated portions, the manifold being interiorly formed to present subtantially right angles at every turn throughout the travel of the mixture therethrough.

23. A manifold comprising two elongated substantially straight manifold portions in parallel relation andoceupying a horizontal plane, one portion being substantially shorter than the other, lateral outlet portions for connection with cylinders, the outlet portions being parallel to each other and at right angles to the elongated portions, and vertical fuel inlet means at right angles to said elongated portions, the manifold being interiorly formed to present substantially right angles at every turn throughout the travel of the mixture therethrough, the shorter straight manifold portion being located between and having its end walls facing but spaced from the outlet portions of the longer straight portion, the outlet portions of the shorter straight portion communicating therewith through openings in the face thereof.

24. A manifold comprising two elongated substantially straight manifold portions in parallel relation and occupying a horizontal plane, one portion being substantially shorter than the other, lateral outlet portions for conncction with cylinders, the outlet portions being parallel to each other and at right angles to the elongated portions, and vertical fuel inletnieans at right angles to said elongated portions, the manifold being interiorly formed to present substantially ri ht angles at every turn throughout the travel of the mixture thercthrough, the shorter straight portion being centrally disposed adjacent to one end of the longer straight portion and communicating with the latter through the face thereof, the inner end of said shorter straight portion terminating at a point substantially removed from the opposite outlet end of the longer straight portion, and the ,outlet portions from the shorter straight portion communicating with the opposite ends thereof through the face of the same.

25'. A manifold comprising three elongated substantially straight manifold portions,

two of the portions being substantially shorter than the third portion but in parallel relation therewith, the two shorter portions being in alignment, and all of the portions occupying a horizontal plane, lateral outlet portions for connection with cyllnders, the outlet portions being parallel to each other and at right angles to the elongated portions,

and vertical fuel inlet means at right angles to said elongated portions, the manifold being interiorly formed to present substantially right angles at every turn throughout the travel of the mixture therethrough, the shorter straight portions being centrally disposed one adjacent to each end of the longer straight portion and communicating with the latter through the face thereof, and the outlet portions from the shorter straight portions communicating with the opposite ends thereof through the face of the same.

26. A manifold comprising two elongated substantially straight manifold portions in parallel relation and occupying a hofizontal plane, one portion being substantially shorter than the other, lateral outlet portions for 1 connection with cylinders, the outlet portions being parallel to each other and at right angles to the elongated portions, and vertical fuel inlet means at right angles to said elongated portions, the manifold being interiorly formed to present substantially right angles at every turn throughout the travel of the mixture therethrough, the outlet portions communicating through the end and central face portions of the longer straight portion, and the shorter straight portion communieating with the longer straight portion through the adjacent faces thereof at points between the end and intermediate outlet portions from the longer straight portion.

27. The combination with a multi-cylinder engine having suitable inlet ports, of means for manifolding the same comprising a main manifold, a sub-manifold and manifold branches leadingfrom said main manifold and said sub-manifold to said inlet ports, said main manifold and said sub-manifold being formed throughout with sharp inside turns to present right angles at every turn to cause a fuel mixture introduced into the manifold to follow rectilineal paths to and from said turns throughout the main and sub-manifold and into any of said branches.

In testimony whereof I hereunto aflix my

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