US2363153A - Auxiliary carburetor - Google Patents

Description

Nov. 21, 1944. R, SHIPM AN AUXILIARY CARBURETOR Filed Dec. 20, 1940 s Sheets-Sheet 1 Nov. 21, 1944. R. SIHIPMAN 2,363,153

AUXILIARY CARBURETOR Filed Dec. 20, 1940 3 Sheets-Sheet 2 2'9 20 1'9 WM gww Nov. 21, 1944.

a SHIPMAN AUXILIARY CARBURETOR Filed Dec. 20, 1940 3 Sheets-Sheet 3 a) F) 5 r0 m g/2% IOWA VII/Z Patented Nov. 21,1944

UNITED STATES PATENT OFFICE AUXILIARY CARB URETOR Ralph S hipman, Sunbury, Pa.; Raldo E. Shipman and I. Kenneth Shipman, executors of said Ralph Shipman, deceased, assignors, by mesne assignments, to themselves, as joint tenants Application December 20, 1940, Serial No. 371,042

'3 Claims. (01. 261 -41) This inventionrelates to carburetors for internal combustion engines, and more particularly to an auxiliary carburetor designed to be used in conjunction with the usual or main carburetor.

iliary carburetor has air passages which are relatively small, as compared with those of the main carburetor, and in which the auxiliary carburetor is brought into action first, as,

the pedal is depressed, whereby, atlow engine speeds, air is drawn through saidauxiliary carburetor at high velocity, and eftlcient atomization thus obtained i A further object of the invention is tofprovide main and auxiliary carburetors of the character above described, and of the spray nozzle,

constant level type, both having jets fed from the same float chamber.

A still further object is to provide an auxiliary,

carburetor in the nature of an attachment which can be readily applied to existing engines,

and to this end the invention contemplates An object of the invention is' to provide an internal combustion engine (with a main and,

auxiliary carburetor itself and the means by whichit is caused to cooperate with the main or conventional carburetor, the invention consists in the construction, arrangement and combination of parts hereinafter described and claimed, and illustrated, by way of example, in

the accompanying drawings, forming part of this specification,and in which: i i

Fig. l is a side elevation showing my improved auxiliary carburetor in position between the main carburetor and intake manifold;

the accelerator Fig. 2 is a pl'an view of the, upper part of the auxiliary carburetor, showing the means for connecting the same to the float chamber of the main carburetor; I i Fig. 3 isa planview of the lower portion of the auxiliary carburetohshowing the adapter.

Fig. 4 is a longitudinal section substantially on the line 4--4 of Fig. 1, looking in the direction ofthearrowyy p 1 Fig.5 is a fragmentary longitudinal section substantially onthe line 5-5 of Fig. 2, looking in the directionof the arrowsbut on a greatly enlarged scale; and i Figs. 6 and 7 are fragmentary side elevations of the lower portion of the assembly shown in Fig. 1, illustrating the throttle valves in diife'rent positions, parts in Fig. 6 being broken away, and partsbeing shownin section.

Referringfto' the drawings in detaiL A designates what I shall call the main carburetor, this equipping the auxiliary carburetor with an adapter constructed to be interposed between the main carburetor and the intake manifold, and serving to connect the auxiliary carburetor with such manifold.

As is wellknown, it is an inherent characteristic of carburetors of the spray nozzle and Venturi type that, asthe engine speed increases, the rate atwhich fuel is drawn in increases faster than therate at which air is drawn in, with the result that the mixture tends to become too rich. Various means have heretofore been proposed to overcome this, among such means being what is known as an air-bled fuel jet. Still another object of the present invention, therefore, is to producea more efficient compensating carburetor of the air-bled type, and to thisend I provide improved means whereby the amount ofairadmittejd to the jet tubeprogrwsively increases with engine speed until the amount needed by the jet is reached. 7

With the above and other objects in view, and to improve generally on the details both of the being shown in light mes ing. 1 for thesake of clearness, and comprising the usual conven tional or any suitable standard type of carbu-' retor. As illustrated, it comprises a tubular body havingan intake opening atthe upper end I, and containing the usual mixing chamber and spray nozzle or fuel jet fed from a suitable float chamber 2, to which fuel is supplied through the pipe 3. i

4 designates the choke yalvelever and this is suitably connected with a,lever 5 pivoted at its lower end and carrying an adjustable throttle stop screw 6. i i k m The throttle valve, itselfis indicated in dotted lines at I2, and this is carried by a shaft ll journalled in thecarburetor body. Secured to i this shaft is a set Ofifliihk armsl, 8 and 9, the arm Tcooperating with thestop screw Gyto limit the idlingposition of thethrottle; valve, and the arm 8: having means; attached-thereto by which the throttle may be operated; Piyotally con nectedto the arrn Bis a link. lll connected; at

its upper end with, the usual accelerator pump. At its lower end, the carburetor A is formed with a bolting flange A adapted to mate with and be secured toa similar flange D at the end of the usual intake manifold D.

While I have shown and described the main carburetor A as comprising certain details of construction, it will, of course, be understood that, so far as the present invention is concerned, the exact details of this carburetor are immaterial.

My improved auxiliary carburetor is designated in its entirety by the reference character B and comprises a tubular body and a laterally extending delivery conduit terminating in an fadapter C. As shown in Fig. 1, this adapter is constructed to be interposed between the flanges A and D, as will be hereinafter more fully described.

Adapted to engage the usual ball at the end of the actuating arm 8 is a socket member l3- carried by a rod l4 having a head [5 at the opposite end and freely slidable through a pin I l journalled in a boss H carried by an arm l8, secured to a shaft l9 journalled in the body of the auxiliary carburetor. A helical spring 56 surrounds the rod I4 and is-interposed between the socket member l3 and pin", for a purpose hereinafter described. v I

Carried by the shaft 19 is a throttle valve 22 controlling the flow of the fuel mixture from the auxiliary carburetor. Carried by the arm I8 is a ball connection 23, to which is pivotally secured the end of an operating rod 24, by means of which the throttles are actuated, as hereinafter described, suchrod being usually connected with the accelerator pedal. 1 Referring to Figs. 1, 3 and 4, it will be seen that theiauxiliary carburetor B has an air intake at its upper open end 2|, and adelivery conduit 25 at its'lower end. This conduit extends laterally at substantial right angles to the body of the carburetor, and terminates in theadapter. C. It will be understood that this adapter has a periphery conforming with the shape of the flanges A and D, and that it is hollow, having an upper wall 26 and lower wall 2,1, provided with flat outer faces. The central part of the adapter is cut away as at 28- to form an opening of substantially the same shape as the end of the manifold D, and the adapter is also provided with a plurality of peripheral holes: 29' so placed as to register with the bolt holes in the mating flanges A 'and D. While,asshown in Fig. 3, the adapter is of somewhat elliptical shape, it may, in many cases, be circular, and the adapter may thus properly be described as annular, this term being intended to include both circular and non-circular configurations.

Thus the adapter C, constituting the end of the laterally extending delivery conduit 25, and having opposed flat faces as described, may readily be interposed between the flanges A and D, as shown in Fig. 1, and the several parts of the assembly rigidly secured together as by means of bolts 30 passing through the aligned bolt holes.

It will thus be seen that by the construction above described, I have provided an auxiliary carburetor in the nature of an attachment which may be readily applied to an existing internal combustion engine, and having an "adapter which may be interposed between the bolting flanges of the usual carburetor and intake manifold. In actual practice, it will, of course, be necessary to make up the auxiliary carburetors with adapters of different shapes and sizes to fit different models of engines. However, having provided the auxiliary carburetorwith an adapter of the proper shape to fit a particular model of car, it will be seen that the auxiliary carburetor can be readily applied to any car of that model, by disconnecting the existing carburetor from the intake manifold, and interposing the draft type.

Referring to the construction of the auxiliary carburetor itself, it will be seen, by reference to Figs. 1 and 4, that it comprises a lower section 20, preferably formed integral with the conduit 25, and an upper section 33 detachably secured thereto as by meansof a set screw 32-. The upper section 33 is formed integral with or brazed to a venturi-shapedmember 3|, having a flange fitting within the section 20,'against which flange the set screw 32 bears. Other details of construction may, of course, be employed without departing from the spirit of the invention.

Supported centrally within the tubular upper section 33 of the carburetor is a venturi- 34, of theusual or any desired shape, adapted to receive the incoming air at its upper funnel-shaped end. Projecting into the throat of this venturi is the end of a jet tube 35, constituting aspray nozzle.

In orderto break up and morethoroughl'y vaporize and heavier particles of fuel passing downwardly from the fuel jet, I preferably place in the lower end of the venturi 34 a" conical baffle 36, formed of wire netting orother foramin'ous material, as shown in Fig. 4. It will be noted that this baffle projects down into the throat of the venturi 3!, 'so that not only does the primary air coming down through the venturi3'4 and carrying the fuel particles impinge against it, but also the secondary air coming in around the venturi 3'4 sweeps over it as the air passes down through the venturi 3!. Thus the fuel is" eifectively vaporized.

As illustrated in the drawings, a casting- 31 surrounds the upper portion of the tubular section 33' and is formed at one side with a hollow boss 38 constituting a fuel well 39' ('see Fig. 4).

From the well 39-, a port 411' communicates with the jet tube 35.

Seated against the top of thebos's 331s the head 4| of a specially constructed screw member having a shank 42 extending, down through the well 39. Thismember is provided at its lower end with screw threadslengagingl with similar threads in a. cup-shaped fitting. An annular spacer or sleeve M is shown as interposed between'the boss 33 andfitting 43,. and-it will 'be seen that when the head. is turned, the

parts 13 and MIwill be'drawn firmly against each other and-against thelower surface ofthe boss 38,, thus forming a liquid tight assembly.

By reference to Figs. 1 and 2, itwill be seen that a tube 35 taps the cup-shaped fitting 43 and carries at its other end a-n annular fitting 46, adapted tobe clamped by means ofascrew H- to an opening inthe bottomo'fthe floa-t chamber 2. Thus the auxiliary, carburetor-is supplied with fuel fromthe existing float chamber. 2-, through" the tube 4-5. In other words; both the main and auxiliary "carburetors: are .fed from the same float chamber, and the fuel jets are substantially at the same level. w

Referring again to ,Fig. 4, it will be seen that the shank.42,is smaller than the interiorof the sleeve 44, so that an annular passage is formed between them, andextending downwardly from this annular passage through the threaded lower end of theshank 42 is a port 48 establishing com- .removablemetering plug 49, having a restricted passag therethrough. It will be understood that a plug having a passage of any desired size to suit, the particular conditions may be employed. The operation of my improved apparatus as so far described will now be briefly explained.

With the parts in the position shown in Fig. 1,,the throttle 22 of theauxiliary carburetor is substantially, closed, and the spring l6 compressed, thus holding the throttle l2 of the main carburetorin the closedor idlingposition indicated. In other words, at this. time the auxiliary carburetor i imperative and the fuel required for the engine when idling, isprovidedby the main carburetor, as usual. u

, When it is desired to operate the engine at working speed, the driver depresses the accelerator pedal and thus exerts a pull on the rod 24.

Fig. 6-illustrates the, position of the parts when the engine is operating at comparatively low speeds, requiring only a part of the capacity of the auxiliary carburetor. In this figure, it will be seen that the throttle 22 of the auxiliary carburetor is about /3 open, while the throttle [2;

of the main carburetor is-still maintained in idling position by the, spring l6. .ThusQunder these circumstances, practically all, of the fuel for running the engine is derived from the aux ing fullopen position. Thus at high engine speeds, both carburetors are workingand both deliver fuel mixture into the intake manifold at substantially the same point. Thus, if there shouldbe an inequality between the character of the mixtures delivered by the two carburetors into the manifold, these two fuel mixtures havean opportunity to blend intoa uniform mixture in the manifold before reaching the intake valves. i

Referring again to Figs. 6 and 7, it will be noted that the throttle 22 of the auxiliary carburetor occupies somewhat different angular positions in the two figures, Fig. 6 showing it asit begins to move to open position. When the op.- erating rod 24 is moved slightly further to the left than shown in Fig. 6, the throttle 22 will reach substantially full open position, while the throttle [2 still remains in idling position, and

iliary-carburetor; It;will be noted by reference to Figs. 1 and 3 that the cross sectional area of the air passages of the auxiliary carburetor are relatively small as compared with those of the main carburetor, so that, even at low engine speeds, the air flows through the mixing chamber of the auxiliary carburetor at relatively high velocity. This produces efficient atomization of the fuel from the spray nozzle, because a larger proportion of the total volume of air passes close thereto. Owing to the relative sizes of the air passages in the two carburetors, it will be understood that even at low engine speeds the velocity of air through the auxiliary carburetor, which is the only one then supplying any substantial amount of fuel, is of the same order as the velocity of air would normallybe through the main nectin the two throttle mechanisms, has moved the throttle l2 of the main carburetorto substantially full open position, while the throttle 22 of the auxiliary carburetor is also approachit is'only after the capacity of the auxiliary carburetor is reached and the operating rod is moved beyond this point that the main throttle l2 begins toopen. Finally, when the accelerator pedal is fullydepressed, both throttles are wide open, as shown in Fig. '7. i

As is well known, it is an inherent characteristic of carburetors of the venturi and fuel jet type that, as; the velocity of air increases,

the amount offuel sprayed increases at a greati buretor at high engine speeds, the fuel mixture which would be produced by this carburetor, as

above described, would be far too rich andits efficiency greatly lowered. In order to remedy this defect, I provide a novel compensating arrangement illustrated in detail in Fig. 5.

By reference to Figs. 1 and 2, it will be seen that formed integral with the casting 31 .on either side of the boss 38 are vertically disposed cylindrical bosses and 5|, and that at the sides of these bosses are other and smaller parallel bosses 52 and 53.

Referring to Fig. 5, it will be seen, that longitudinal bores 54 are formed in the bosses 52 58 with the fuel well 39.

as follows.

velocity of air through the venturi 34 is only.

and 53, and horizontal bores 55 extend from the bores 54 into the bosses 50 and 51. These bosses 50 and 5| are bored toform valve chambers 5'1 and 58, and each of these valve chambers communicates at its bottom through a port 56 with the bores 55.

In the chambers 57 and 58 are weighted valves 59 and 69, each having a conical point BI received in a tapered seat at the upper ends of the ports 56, the weight on one of the valves, as

for example the valve 60, being substantially greater than the weight on the Valve 59. The upper ends of the chambers 5'! and 58 are closed by plugs 62, through which are threaded stop screws63 adapted to .engage the, upper ends of the valve members 59 and 60, and limit their movement.

Ports S4 connect the valve chambers 5'! and The upper ends of the air passages 54 are closed bymeans of screw plugs 55 having restricted openings 66 therethrough, for the purpose of limiting the amount of, air which can enter.

The operation of this part of the invention is At low engine speeds, when the moderate, fuel is sucked up through the tube 35 to the jet in the usual manner, the Weighted valves 59 and. BO remaining on their seats. As, however, the engine speed, and hence the velocity oi air through the venturi increases to a certain.

point, a stronger suction is generated in the tube 35 and in the fuel well 39. Since, however, the amount of fuel that can flow to this well is limited by the restricted opening 49 in the metering plug, a partial vacuum is created in the well 39 and this, operating through the port 64, eventually becomes sufficient to lift the lighter valve 59 from its seat. When this happens, air is drawn in through the passages 56 and 55, and port 56, into the valve chamber ti, and this air passes through the port 64 and mixes with the liquid fuel as it enters the port 40 and: jet tube 35, thus diluting the fuel and limiting the amount which is actually delivering from the jet. -.As the engine speed and suction still further increase, the partial. vacuum generated finally becomes strong enough to also lift the heavier valve 60 from its: seat and additional air then enters the valve chamber 58 and flows through the port (i4 into the fuel well 39, thus further diluting the fuel supplied to the jet, and further reducing the actual amount delivered.

In this Way, I amv enabled to compensate for the tendency of the mixture to: become unduly rich at higher engine speeds and to produce a rnbcture which is substantially uniform, for all practical purposes, within the usual speed ranges.

While I have indicated the use of only two weighted valves, it will, of. course, be understood that a greater number can be employed if de sired, and While I have described the valves as weighted, it is apparentthat they can, instead,

if. desired, be operated by springs of progressively increasing strengths. It Will also be understood that it is necessary, for the best results, to have the proper relation between the restrictedopening in the metering plug ii) and the restricted openings 66 in the air plugs 65, and for this reason these plugs are made removable and interchangeable so that plugs having openings .of theproper size may be selected.

What I claim is:

1 The combinationwith an internal combustien engine having an intake manifold formed with a bolting flange at its end, of'main and auxiliary carburetors of the constant level type, each formed as anindependent uni-t, separable from-the other and eachhaving a, separate mixing chamber and fuel jet, asingle, common float chamber with which the fuel jets of both carburetor's communicate, means for supplying fuel to said float chamber, said carburetors having superposed portions both connected to the bolting flange of said manifold, a separate throttle valve for controlling" the flow of fuel mixture from each carburetor to said manifold, and means for opening said throttle valve sucees siv'ely,

2. An attachment for internal combustion engines having an. intake manifold provided with a bolting flange, and the usual carburetor adapt ed to be connected thereto and having a throttle valve and a float chamber, said attachment comprising an auxiliary carburetor having a fuel jet and throttle valve and also having a laterally extending delivery conduit constructed to fit upon. and be secured to said bolting flange and interposed between said manifold and usual c'arburetor; said attachment also comprising means for connecting the fuel jet of said auxiliary carburetor' to the said float chamber, and means connecting the throttle valve of said auxiliary carburetor, to that of the usual carburetor wi iereby' both said valves may be operatedby the usual control device.

3, In a carburetor, the combination with a venturi and jet conduit,- oi a fuel well with which said jet conduit communicates a float RALPH- sH-IeMArt

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