US2656167A

US2656167A - Charge forming device

Info

Publication number: US2656167A
Application number: US142630A
Authority: US
Inventors: Bernard C Phillips
Original assignee: Tillotson Manufacturing Co
Current assignee: Tillotson Manufacturing Co
Priority date: 1950-02-06
Filing date: 1950-02-06
Publication date: 1953-10-20
Anticipated expiration: 1970-10-20

Description

Oct. 20, 1953 B. c. PHILLIPS 2,656,167

CHARGE FoRMING DEVICE Filed Feb. e, 195o BEHNAHD D. FHLLLJPS. -E

Bg A.

Y ttorneg f Oct. 2.0, 1953 B. c. PHILLIPS CHARGE FORMING DEVICE Filed Feb. e, 195o l Win? 2 Sheets-Sheet 2 BERNARD ZHILLIPS.

.5A/Mig.

nventor:

patented ct. 2:0,

v UNITED STATES PATENT FFCE CHARGE FORMING DEVICE BernadC. Phillips, Toledo, hio, assigor to The Tillotson Manufacturingr Company, Toledo, Ohio, a corporation of Ohio Application February 6, 1950, Serial No. 142,630

(Cl. E61-415 A 8 Claims.

This invention relates to charge forming devices for use with internal combustion engines and more especially to a carburetor wherein the major operating components are mounted upon a carburetor body and relates to improvements upon the charge forming deviee disclosed in the application of Edward H, Foster Serial o. 104,225.

An object of the present invention is the provision of a carburetor wherein the fuel reservoir or chamber is made of sheet materialkahd in which the valve mechanism controllingnthewfuel flow to the reservoir and the float mechanism for actuating the Valve are mounted upon the carburetor body independently off the fuel reservoir construction. Y p y Another object of the invention resides in the provision of a carburetor construction `wherein the operative components ofthe carburetor are compactly arranged so as to minimize the space occupied by the. carburetor as well as to reduce the cost of manufact'uring the same. 1 i

Anothe1 objectl of' the invention is the provi- 'sion of a carburetor' wherein the' noat controlled valve' mechanism fory regulating the flow of fuel into thev float bowl or fuel` reservoir is completely independent of the fio-at bowlv construction whereby the latterA may' be removed or assembled without disru'pting the float controlled valve and associated elements. N

Another object.- of the invention is theprovision of4- a carburetorhaving :a float bowlk formed ofi conriparatively` thin sheet material such as brass, copper, aluminum or the like, which issecured` to a` carburetor bodyby'siniple means? which maybe readily manipulated to assembleV or remove the oat bowl with a. minimum of effort and time.

Another object of the invention is the provision of a fuel metering means especially adaptable for incorporation in charge formingdevices bei'ng of a character' in which the ow rate of v fuel through the metering inea/lisis SllbStaIltlally unaffected throughout normal operative temperature ranges of fuel or by changes' viscosity of fuel within th'e'range'of usable' fuels. y

A further phase of4 the invention relates to" the provisioni of aI simple yet effectiveI fuel metering means of' the' fixedl orifice type; the member formed with the ni'eteringk orifice being mounted" in-a manner tofacilitat'e theready interchan'geof members provided with orifices of different s'i'zes" forf securing varyingl riite'sY ot fuel flow'.

Furtheriob'j ects= and`l advantages are within theA scope of this invention such as relate to the'l are rangement, operation andi function of' the' relatedelements of the structure, to various details Vfof construction and v,to combinations of parts, elea ments per se, and to economies of manufacture and numerous other features as will ,be apparent from a consideration` of the specification and drawing of a form of the invention, which may be preferred,- in which: l Fgure l is ra top plan view of a charge forming device or carburetor embodying the, invention;

Figure 211s a vertical longitudinalsectional view taken substantially on the line 2-2 of Figi ure l; c

Figure 3 is a vertical transverse sectional View taken substantially on the line Eef-3 of Figure l; Figure 4 is an enlarged detalview showing a fuel metering means forming apart of the nven tion; c

"Figure 5 is a sectional view similar to Figure 2 illustrating a modified form of construction.. and Figure 6 is a view similar to Figure 5 showing a further form of construction. a Referring to the drawings in detail and first with respect to the form of the invention illus-- trated in Figures l through 4Kinclusive, the carburetor includes abody member I formed with a mixing passage ll having a venturi l2 in communicationwith anv air inlet passage I4 conv nectedv by a tube l5 of an air cleaner (not shown). rIhe mixing passage ll is of smaller diameter than the air inlet i4, the axes of passage Il and` inlet 1 4 being eccentrically arranged, the axis; ofthe mixing passage being nearer the fuel level the receptacle It.V By this arrangement the fuel discharged into the venturi as hereinafter described is lifted but a small distance above the fuel level in the receptacle to the point ofdischarge. f y Y h Asuitable fuel chamber or fuel reservoir ,ll isl provided for the carburetor and includes a bowl-y iilre member or receptacle IB formed ot sheet materialas for lexamplegbrass, copper oryany composition yor alloy which is not subject to the corrosive effects of the fuel. As, will be seen inFiggV ure 2w the carburetor body l0 is formed with anannularly shaped groove 20 adapted toaccom modate therim or edge of the receptacle i8, a' suitable sealing gasket 2 i being' disposed between the rim of` the receptacle andthe walls' ofy the channel 2s; iii` order to" eirect id tig tser between these elements; vlhiletheI receptacle Il? is illustrated as substantially s'eirisplfer al configuration; asthisfshapfaciiitates uis formar tion' of thereceptaciefromsiieet meter itistte understood that receptacle offdiffreiit cdiig'ii;

muonJ may be utilized without departing friirthe spirit of the invention. The carburetor body I is formed with a depending portion 23 which has a hollow interior forming a fuel well 2li. The lower portion of the interior well thereof is threaded to receive a plug 26 which serves to close the lower end of the depending portion 23. The plug 26 is formed with a polygonally shaped head 2 which serves to secure the receptacle I8 in assembled relation with the body iii, an annular sealing gasket 28 being disposed between the head 2l and the receptacle i3 to provide a fluid tight seal. The bolt or plug 26 forms the sole means for securing the receptacle I8 in assembled relation with the carburetor body. The carburetor body ii) is formed with a fuel inlet passage SI which includes a horizontal duct 32 and a vertical passage 33. The Wall oi the duct 32 is threaded as at 3d to accommodate `a coupling with a fuel supply tube 3 in communication with a fuel supply. The vertical passage S3 of the fuel inlet is threaded as at 35 to receive and accommodate a fitting 36 the latter having an interior bore 3l terminating in a valve seat portion 3S. A valve 39 of non-circular crosssection is slidably disposed in the bore i in fitting 36 and has a cone shaped or needle portion All cooperating with valve seat 3S in order to regulate or control the ingress of fuel into the float chamber I7.

The body portion I is formed with depending ears c2 which are bored to receive a pivot pin adapted to support a bracket 44, one arm of' which is secured as by soldering or other suitable means to a float i5 disposed in the float chamber or fuel reservoir I'I. The float member d is preferably fabricated of two annularly shaped cup-like elements il and lil which are joined together as by soldering, brazing or the like at their overlapping central portions to form an hermetically sealed construction. The bracket im is provided with an upwardly extending portion S which is adapted to engage the extremity of the valve member 39 as particularly shown in lfigure 3. The float member :i5 is thus articulately or pivotally connected to the ear por.. tions 42 of the body member Iii and, through the medium of the bracket i4 engaging the valve member 39, controls or regulates the flow of fuel into the float chamber i1 through the inlet 3|'. As the float member 45 is elevated by reason of the fuel rising in the receptacle Il", pressure is exerted in an upward direction through the bracket 119 to move or bias the valve 39 toward closed position, that is, with the needle or tapered portion d engaging the valve seat 3S to interrupt the fiow of fuel into the iioat chamber when the fuel therein reaches a predetermined level.

The mixing passage II is provided with a throttle valve in the forni of a disc 52 which is mounted upon a transversely extending shaft 53 journaled in suitable boss portions ed formed on the carburetor body i. Manipulating means is provide for the throttle valve in the form of an arm 5&5 xedly secured to one extremity of the shaft 5S, a coil spring 5l surrounding a portion of the shaft 53 and being hooked over the arm 56 as shown at 58 in order to resiliently bias the valve 52 toward closed position. The arm 56 may be connected to a suitable operating rod 60 as shown in Figures 1 and 2.

A suitable valve in the form of a disc-like member 52 is mounted upon a transversely extending shaft 63 which is journaled in suitable boss portions B4 formed integrally with the body portion of the carburetor. One end of the shaft 63 may be bent laterally as at 65 to facilitate the manipulation of the valve 62 in order to control the admission of air to the carburetor through the air inlet passage I4. Frictional resist-ance is provided for the shaft 63 in order that the air valve may be retained in an adjusted position. This means is inclusive of a coil spring 6l which surrounds a portion of the shaft 63 and abuts against a disc or Washer 68 held in place on the shaft by means of a pin 69. The passage II of the carburetor is in communication with an engine manifold the manifold being secured to a fiange portion 'il of the carburetor body by means of suitable bolts l2.

The upper extremity of the depending portion 23 forming the fuel well 24 is threaded as at 'I to receive a fitting 75 which is formed with an interior bore i6 the upper outlet of which forms a main fuel discharge orifice "i8 into the mixing passage i I. The fuel discharge orifice preferably opens in the zone of the choke band Il of the venturi I2, the choke band being the point or zone of greatest restriction to the flow of air through the carburetor. The maximum speed of air passing through the carburetor exists at the choke band i'i and the high air speed through the choke band facilitates the discharge of fuel from the orice I8 into the mixing passage.

In some installations it is desirable to bleed air into the fuel at the time 0f its discharge through the main fuel orice. To this end the carburetor is provided with an air bleed passage or channel which establishes communication between the main air inlet Ill and the fuel well 24. rl`he admission of air to the fuel well through the passage S provides for the admixing with the iquid fuel in the fuel well of a relatively small amount of air so that the fuel discharged through the main jet or orifice 'I8 and the main fuel orice is in the form of an emulsion or admixture, that is, having small bubbles of air in the fuel.

r.'he carburetor is provided With means for introducing fuel to the mixing passage for idling or slow speed engine operation when the throttle valve 52 is in closed or substantially closed position. Extending vertically of the carburetor in the embodiment illustrated as shown in Figure 2 is a relatively small tube S2 which depends below the fuel level in the receptacle l'I and extends upwardly terminating in a bore 84 in the carburetor body. The upper end of tube 32 extends into the hollow interior of a fitting 85 which is formed with openings 86 to facilitate fuel flow into the bore Sd. The bore 84 is in communication with a chamber 81 by means of a duct or passage 88. The chamber 81 is in communication with the mixing passage I I by means of orices or ducts 89 and Sill. As particularly shown in Figure 2, the orifice 89 is in communication with the mixing passage slightly in advance of the throttle valve 52 for engine idling operation while the fuel orifice Si) is in communication with the mixing passage slightly to the rear of the valve 52 when the latter is in closed position, and serves to supply fuel to the mixing passage when the throttle is partially opened and before the main fuel jet is caused to operate. The upper extremity of the chamber 81 is closed by means of a Welsh plug 92 and the upper end 0f the bore 8f3 is closed by means of a threaded plug 93 on fitting 85.

Means are provided for admitting air for admixing with the fuel supplied to the supplemental orices 89 and 90 prior to the ejection of fuel therefrom into the mixing passage I I. A wall of the air inlet passage I4 is provided with av duet 95, the amount of air admitted through the passage .9.5 being .controlled by a valve 9.6 which is threaded as at 91 into a bore in a boss 98 formed on the carburetor body, A lknurled manipulating portion 99 is formed on the valve 96 in order t0 facili# .tate manual control thereof. A spring lim surrounds the threaded portion of the valve member 96 adjacent the manipulating portion S9 and .Serves to provide a frictional component to retain the-valve 96 in adjusted position, A passage 1li1 establishes communication btween the zone ad jacent the valve S16 and the bore 84. In this man-` ner a controlled amount of air may be admitted through the

passages

95 and 101 to the bore 84 which `zone fuel flowing through the openings B6 is admiXed with air in the bore 8.4 a mixture of fuel and air thereafter passing through the passage 88 and .chamber 81 for discharge into the mixing passage 11 through the orices or ducts B9 and 911.

The present invention is inclusive of novel means .for metering .or regulating the new of liquid fuel from the fuel reservoir 11 into the fuel Well g4. As shown in Figures 2, 3 and Il a wall of the depending portion 23 is bored and threaded to receive a fitting or bushing 102. The bushing 102 .is provided interiorly with a ledge vHill which positions a plate or cupelile member 195 in position in the fitting 182. The member Lio is pressed into or .otherwise secured in the bore 103 in the fitting. The member 105 is made comparatively thin, a structural feature Which I have found forms an important part in controlling the flow of fuel into the fuel well 251, The cup 135 is Nformed with a metering or passage orifice H36 which establishes communication between the reservoir 1'1 and the well 24. By making the plate or oup It relatively thin in dimension, the .rate of fuel flow through the passage 06 will be substantiallv unaffected by variations in the viscosity gf the fuel over a reasonable range suitable for use internal combustion engines, For example, it is a conventional prsetioe ,in the operation of two cycle engines to introduce a quantity of lubricating oil or lubricant into the liquid fuel in the supply tank for admixture with .the fuel prior to its passage into the carburetor. As lubricating oil used for this purpose usually has a higher viscosity factor than the fuel, the. viscosity of fuel and oil mixture is `higher than the fuel alone. 1rrespective of Whether the fuel passes through the carburetor with or without lubricating .oil being admixed therewith, the liow rate through the metering orifice |06 remains substantially oonstantln order to obtain this result of uniform flow rate through the orifice itt, the blote 'S5 may be made of a thickness up to approximately thirtytfive thousandths o f an inch Without materially affecting the rate of fuel flow through the plate. It has been found that plates -Of a thicker dimension do not function satisfactorily with varying viscosity factors of fuel and lubricant mixture. Through the utilization of a thin plate and .orifice construction of the character illustrated in Figure 4, there is provided a simple yet effective means for establishing a substantially uniform ow rate from the receptnole 11 into the Well irrespective of the viscosity Q the liquid passine therethrough within the .range of usable .fuel mixtures for engines with which the carburetor may be utilized.. `I. .have found bv actual and exhaustive tests that this .desirable result is obs tainable with the above described construction.

Venting means is provided for the chamber 11 in order to prevent .air lock or unequal pressure such. as would interfere with `flov/ into and out the chamber.. As illustrated in Figure 3g a opening 108 is provided to the atmosphere so as to establish .an serialized pressure in the fuel Chamber l1.

The operation of this form of the invention is as follows:

F961, is introduced into the inlet passage 31 .from a fuel supply (not shown), the fuel flowing past the polygonally shaped valve member 33 through the bore 31 into the fuel chamber 11. the fuel lol/el rises in the chamber 11 the float 45 is buoyed upwardly and being pivoted Ql mover .ment around` the axis of the pin 43, the portion 49 of bracket 46 urges the valve member 39 upf Wardly.. When the float has been elevated a preV determined distance in order to establish a defq inite fuel level in thechamber l1, the pressure of erin i9; moves the valve 39 to closed position to interrupt vfuel now into the chamber l1. When the internal combustion engine with which the Carburetor may be used is started, the air or choke valve 6.2 is preferably closed or nearly closed in order to establish a proportionately high vacuum to insure fuel flow into the engine. for starting purposes. After the engine is started, the air valve 62 is moved to full open position as indicated in full lines in Figure .2. During idling operations of the engine, the throttle valve 52 is in closed position as shown in Figure 2 or near closed po sition. During idling operations of the engine under the influence of subatmospherie pressure developed by the engine, fuel is taken upwardly through the tube 82 from the Well 24 where it is mixed with air in the bore 34, the air for mixing With lthe fuel beine taken in through the passages S5 and lill. The fuel and air mixture is then oon,.- veyed through the duct 88 and bore 81 for dis-l charge into the mixing passage Il through the orices 39 and Sil. When the valve is in full closed position as indicated in Figure .2, fuel is taken into the passage through the orifice 89 in advance of the Valve disc 52 to provide an idling mixture for the engine. When .the valve 5.2 .is partially opened and before fuel is delivered into the venturi I2 from the main fuel orifice 18, the orifice l91! delivers additional fuel and air mixture into the mixing passage. The valve disc or throt-Y 121e valve 52 is provided with openings 55 in order to permit the passage of some air through the carburetor for admixing with the fuel and air mixture discharged through the orifice 85 when the throttle valve 52 is in full closed position. the throttle 52 is moved to an open position to ih.- crease the speed of the engine, air passes through the venturi at a much higher rate of speed as the engine speed increases by reason of the decrease in pressure in the mixing passage. This increase air speed through the venturi 12 exerts a, lift.- ,ng force on fuel in the well 2d whereby fuel is extruded from the main fuel orifice 18 into the choke band 1'1 of the venturi. When the main fuel jet '113 comes inte operation, the fuel dis-.- charge from orifices 89 and Si) ceases and the fuel mixture passing into the engine is obtained en.P tirely from the air passing through the venturi of the carburetor which is mixed with fuel from the main jet 18. During high speed operation of the engine, air is bled into the fuel in Iwell 24 through the air bleed channel or duct 80 so that an emulsion or admixture of fuel and air is dis-.,- charged into the venturi through the orice 1g. rl'he metering orifice 136 establishes a uniform new rate of fuel from the chamber 11 into the accede? well 24 so as to establish a predetermined maximum for fuel fiow from the well 24 through the main discharge orifice into the mixing passage.

A modified form of fuel metering means for establishing a predetermined maximum flow of fuel from the chamber Il to the fuel well is illustrated in Figure 5. In this form of construction the depending portion 23 of the carburetor body l is interiorly threaded as at to receive the threaded portion of a fitting I I i. The fitting I I I is formed with an interior bore il? in which is disposed a needle valve H4, the extremity of the valve ||4 cooperating with a restricted opening in the fitting |i| for regulating the flow of fuel to the passage or duct H5. The bore ||2 is in communication with the fuel reservoir or chamber I'I through the medium of a transverseh7 extending passage IIB formed in the fitting The needle valve ||4 is formed with an enlarged portion III which is threaded into a. threaded portion I i8 in the fitting I I I, the portion Il being provided with a manipulating handle or pin ||3 as shown in Figure 5. Thus the position of the valve I I4 may be regulated by rotation of the valve through manual operation of the pin H9, the position of the valve i ifi in the orifice I I5 determining the metering or rate of fuel fiow into the Well 24.

A stufng gland |20 is provided surrounding the portion II'I of the valve construction and cooperates with a threaded cup |Ei so as to prevent leakage of fuel to the exterior of the receptacle i8 along the valve member li?. The fitting II! serves a dual purpose, it encloses and supports the needle valve II4 and also secures the receptacle I8 in position. As shown a gasket |23 is disposed between a ledge portion |24 of the fitting li! so that when the tting I I i is threaded into the depending portion 23 of the carburetor body, the gasket |23 is brought into sealing engagement with the receptacle I3 to hold the latter into sealing contact with the gasket 2| in the channel 2d of the carburetor body I3. By this means the metering of fuel may be accomplished by manipulating the needle valve H4, the fitting supporting the valve also functioning as a means for securing the receptacle I3 to the carburetor body. The operation and functioning of the carburetor illustrated in Figure 5 is the same as that hereinefore described in connection with the form of the invention illustrated in Figures l through 3 inclusive.

Figure 6 illustrates a further form of the invention in which the carburetor body IIJ" is provided with a depending central portion 23". The depending portion 23" is provided with a central bore |30 in which is disposed the fitting l5, the latter being provided with an interior -bore |3| the upper exit of which forms the main fuel extruding jet or orifice into the venturi I2". The lower portion of the walls of bore |33 are threaded to receive a threaded portion |32 integrally formed on the fitting l5". The portion |32 of the fitting is formed with a restricted opening |33 into which extends the tapered extremity |34 of a needle valve |35. The diameter of opening |33 is such as to cooperate with the tapered portion |34 of the metering valve or needle so as to regulate the flow of fuel from the float chamber Il into the well or bore I3I. The space |33 immediately beneath the portion |32 is in communication with the fuel supply chamber I'I by means of a passage or duct I3?. The metering needle or valve |35 is made of hollow or tubular configuration having openings |39 in the side Walls thereof so as to permit the passage of fuel from the fuel well |3| to the interior of the tubular needle valve |35. r:Che upper end of the valve extends into a fitting |46 which is disposed in a bore 84", a passage |4| being in communication with the interior of the tube |35 and the bore 34". The bore 84 provides a mixing zone in which air is mixed with fuel passing upwardly through the valve tube |35 to supply a fuel and air mixture to the orifices 89" and 96" for idling or slow speed engine operation. The fitting |43 is fixedly connected to the tube |35 and is adapted to be manipulated by a handle |43 in order to regulate the position of the needle with respect to the metering orifice or bore |33 in portion |32. By this means rotation of the needle |35 and fitting |653 adjusts the position of the tapered portion |34 thereof in the orifice |33 to meter or control the flow of fuel from the chamber |'I through passage |31, space |33, orifice |33 and into the well |3|. When the engine is idling, fuel from the Well i3! iiows through the openings |33 to the interior of tube |35, thence upwardly through passage |4| into the zone or space 84 where the fuel is mixed with air from the passages 95 and Nil" for subsequent discharge into the mixing passage i!" through the orifices 89" and 90". An air channel or duct 3B is provided for bleeding air into the bore |33 and through transverse openings |65 formed in the walls of the fitting l5 into the well |3I. In this manner a small amount of air is mixed with the fuel prior to its ejection from the main fuel orifice into the venturi I2. In this form of construction receptacle I3 is held in piace with respect to the body portion I5 of the carburetor by means of a bolt Id? threaded into the interior of the depending portion 23". A gasket |48 is disposed between the head of the bolt I4? and the receptacle I8 in order to make a fluid tight seal and prevent leakage of fuel from chamber Il.

In all forms of the invention, the tube for conveying fuel from the fuel well to the idling discharge ports extends through the main fuel jet and is disposed eccentrically therein, the tube being nearer to the air inlet so that fuel is discharged into the mixing passage from the main jet at the right side of the tube as viewed in Figures 2, 5 and 6.

It should be further noted that in all forms of the invention the float 45 is pivotally connected and supported from the body portion of the carburetor. By this means the receptacle I8 can be quickly and easily removed from the carburetor body for purposes of cleaning or inspection without dismantling or disassembling any of the other elements of the construction. In the form shown in Figure l removing the bolt 2 releases the receptacle from engagement with the body lil without disrupting any of the other elements of the carburetor. In the form shown in Figure 5 the fitting may be removed by rotating the same in a direction to disengage the threads with the threaded interior of the depending portion 23 thus permitting removal of the receptacle I8. In the form shown in Figure 6 removing the bolt |47 permits the receptacle I3 to be disengaged from the body portion I0 of the carburetor. Through the arrangement of the present invention I have been able to provide an inexpensive receptacle assembly for a carburetor providing a fuel supply chamber or float bowl which may be easily manufactured and which is capable :inf 1quick assembly Without the use of special oo s.

9 It is to be understood that the valve 96 for regulating the amount of air for the idling mixture may, if desired, be disposed in a horizontal position i. e. in alignment with the axis of the channel or passage |01. This arrangement of control may be desirable when the carburetor is used with marine engines, and especially those of the so called outboard type embodying panel mounting for the carburetor and engine controls.

It is apparent that, Within the scope of the invention, modifications and different arrangements may be made other than is herein disclosed, and the present disclosure is illustrative merely, the invention comprehending all variations thereof.

What I claim is:

1. In a charge forming device, in combination, a substantially horizontal body member, a receptacle secured to said body member forming a fuel chamber, a mixture outlet formed in said body member, a venturi formed in said body member axially aligned with the-mixture outlet, an air inlet in line with said venturi and mixture outlet and formed in said body member, said body member having a portion depending into the receptacle formed with a fuel Well beneath said venturi, said fuel well having an opening into said venturi, a secondary fuel-air mixture discharge orice in a wall of said mixture outlet above said venturi, a secondary air inlet in a wall of said air inlet above said venturi and arranged to admit air for admixing with fuel prior to its discharge from said secondary orifice, a mixing chamber formed in said body member and located above said venturi, two passageways one of which connects said mixing chamber with said secondary air inlet and the other of which connects said mixing chamber with said secondary mixture orifice, said passageways being substantially parallel to said air inlet and mixture outlet, a fuel line connecting said well with said mixing chamber, means for metering fuel flow from said fuel chamber to said fuel Well, and means formed in said body for admitting air into the well for admixing with the fuel prior to the discharge thereof into the venturi.

2. In a charge forming device, in combination, a substantially horizontal body member, a receptacle formed of sheet metal secured to said body member forming a fuel chamber, a mixture outlet formed in said body member, a venturi formed in said body member axially aligned with the mixture outlet, an air inlet in line with said venturi, and mixture outlet and formed in said body member, the axis of the venturi and mixture outlet being nearer the fuel level in said fuel chamber than the axis of the air inlet, said body member having a portion depending into the receptacle formed With a fuel well beneath said venturi, said fuel well having an opening into said venturi, a iitting in said opening projecting slightly into said venturi and having a main orice for discharging fuel from said Well into said venturi, a secondary fuel-air mixture discharge orifice in a wall of said mixture outlet above said venturi, a secondary air inlet in a wall of said air inlet above said venturi and arranged to admit air for admixing with fuel prior to its discharge from said secondary orice, a mixing chamber formed in said body member and located above said venturi, two parallel passageways one of which connects said mixing chamber with said 10 secondary air inlet and the other of which connects said mixing chamber with said secondary mixture orifice, said passageways being substantially parallel to said air inlet and mixture outlet, a fuel line connecting said well with said mixing chamber and passing through said tting, said main orice, and said venturi, means for metering fuel flow from said fuel chamber to said fuel well, and means formed in said body for admitting air into the Well for admixing with the fuel prior to the discharge thereof into the venturi.

3. In a charge forming device according to claim 2 and having removable means passing through an opening in the receptacle and engageable with the body member for securing the receptacle to the body member.

4. In a charge forming device according to claim 1 and having a fitting connected to said depending portion of said body member and having a passage therein for admitting fuel from the fuel chamber for discharge into the venturi, an adjustable valve in said passage having la por- Ytien accessible exterorly of the receptacle for manipulating said valve, said fitting being formed to secure said receptacle to said body member.

5. In a charge forming device according to claim 1 and having said fuel metering means including a relatively thin member having a port therein for predetermining the fuel flow from the fuel chamber into the fuel well.

6. In a charge forming device according to claim 1 and having said fuel metering means including -a fitting removably disposed in said fuel well, said fitting having a passage formed therein, a relatively thin metaI plate extending across said passage, and a fuel metering port formed in said plate for establishing communication between said fuel chamber and said Well.

7, In a charge forming device according to claim 1 :and having said fuel metering means including a bushing removably disposed in said fuel well, a plate carried by said bushing, the thickness of said plate not exceeding thirty-five thousandths of 4an inch, and a fuel passage formed in said plate for establishing communication between said fuel chamber and said Well.

8. In a charge forming device according to claim l and having a fitting connected to said depending portion of said body member and having a passage therein for admitting fuel from the fuel chamber for discharge into the venturi, an adjustable valve in said passage operated from above said venturi and being accessible exteriorly of said body member for manipulating said valve.

BERNARDy C. PHIlll PS.

References Cted in the le of this patent UNITED STATES PATENTS Number Name Date 1,121,630 Holley Dec. 22, 1914 1,299,454 Gardner Apr. 8, 1919 1,453,490 Bessom May 1, 1923 1,505,565 Johnson Aug. 19, 1924 1,523,095 Zarracina Jan. 13, 1925 1,632,279 Eckles June 14, 1927 1,733,730 Haling Oct. 29, 1929 1,741,401 Bryan Dec. 3l, 1929 1,742,376 Beard Jan. 7, 1930 1,758,954 Linn May 20, 1930 1,323,017 Wolf-ard Sept. 15, 1931 2,038,206 Chandler Apr. 21, 1936 2,093,011 Grosz Sept. 14, 1937