US2246825A - Carburetor - Google Patents

Description

June 24, 1941. E. A. WlNFn-:LD

CARBURETOR Ffiled April 24, 1939 3 Sheets-Sheet l June 24, 19.41. E A- WgNFgELD '2,246,825

v CARBURETOR Filed April 24, 1939 5 beets-Sheet s @afg- Number 85,693, led June 13, 1936.V

Patented June 24, 1941 UNITED STATES PATENT OFFICE CARBURETOR Edward A. Winfield, Los Angeles, Calif.

Application April 24, 1939, Serial No. 269,665 14 Claims. rol. zei- 34) that afford greater efficiency and completeness of performance under all operating conditions, and that render the carburetor generally adaptable to various types and sizes of engines. The present application is a continuation in part of my earlier application on Carburetor, Serial In one of its major aspects, the invention provides various improvements in carburetors of the type in which the primary metering of fuel occursv in what may be termed an air. diversion passage, through which air is diverted from the main suction passage of the carburetor at the inlet side of the venturi, and is returned together with fuel, into the venturi to be mixed with lthe main air stream owing to the engine. One important object is to provide in conjunction with the air diversion passage an improved body or float chamber construction in accordance with which it is made possible to position the main and accelerating fuel nozzles in com- 7 pact arrangement directly below the diversion passage and, at least as to the main fuel nozzle,

centrally with relation to the oat chamber, so'

that rfuel delivery from the nozzle is not appreciably affected by tilting the carburetor in any direction. This same arrangement permits convenient and compact placement and accommodation of other parts including the idling 'by-pass, accelerating fuel pistony and the various fuel passages, all as will later appear. v

Another important feature is the provision of means whereby the fuel and air mixture formed in the diversion passage "is most effectively directed into the main suction passage to insure completeness and uniformity of distribution in the main air stream. In accomplishing this object I provide at the outlet end of the diversion passage a baille surface, preferably as a part of the fuel metering tube projecting into the venturi, which acts to direct the primary fuel and air mixture in' a path such that it spreads in a cone-shaped pattern toward lthe center of the suction passage' and in the general direction of the air flow. The same baiiie surface may be used to deflect and aid Vin the atomization of the accelerating fuel stream f one yof its typical and illustrative forms.

the suction passage of the carburetor, and at the same time to prevent such reductions yin the Y fuel chamber pressure due to the suction ypassage depressions communicated through the Vent passage, as will interfere with maintenance of the proper effective fuel headand fuel delivery rate from'` the supplyV chamber. From tests of the Variousv methods heretofore proposed, it has been determined that none is capable of maintaining within the fuel chamber the desirably high pressure, i. e., closely approaching atmospheric pressure,`or full v'atmospheric pressure, throughout the range of engine operation, and particularly at high speeds. The invention achieves ideal performance in this regard in that it permits atmospheric or substantially atmospheric pressure to be maintained in the-fuel chamber lat all air velocitiesl and pressure conditions in the suction passage.

A further control is maintained with respect to the fuel chamber pressure to effect fuel economy, principally .Within the range of cruise ing 'speeds under light load and partly open throttle position. The fuel chamber above the liquid level is communicable with the depression existing in the suction passage, by way of an economizer passage'controlled by a valve which in turn is controlled by the manifold or suction passage" pressure at the outlet side of the throttle. Normally the valve is closed, but under predetermined conditions determined by manifold depression and air Velocity in the suction passage,

'the valve opens to place the supply chamber lfuell under reduced pressure and to therefore deadditional objects and details,lwill be most read'- ily understood and explained to better advantage in the following description of the inventionv in In the drawings:

' Fig. 1 is a view showing in verticalv section a typical formof carburetor embodying the invention;

Fig. 2 is a cross section on broken line of Fig; 1;

For purposes of illustration and description, jlj v have shown a typical embodiment of the invention in a down-draft carburetor, with the understanding, however, that the showing of vthisparticular type is not to be regarded as limitative on those features of the invention'not specifically claimed in conjunction with a down-,draft carburetor. Referring to the drawings, theV carburetor `in `its .preferred form `comprises asuction passage .lll havingrana'ir .inlet Il anda fuel and .air .mixture .outlet :'l2, fthe flanged end 12a of `which is attached zto the .engine .manifold :I,3 '.'by -bolts 1I4.V The air flow 7toM the engine'is controlled :by suitable -throttle, `typically v"the usual butterfiy valve I5 carried on shaft iliand v operated by .lever arm IJ, :see Fig. 2,.and connected by lever .Ha Sand link :I8 with arm `I,f9.a;integr.al with 'the later described .-accelerating fuel `piston actuating shaft '119. :Choke valve 20 positioned mithin Lthelinletilfl, isgmounted on a shaft 2| offsetfrom theaxiakcenter of the suctionpassage .and operated in theusual manner bya lever 22 attached 'to its outer end. 'Arestriction of vsuitableshape,

preferably inthefform of .a venturi 23,:is'located 1in 'thessuction .passage lill between' the throttle andchoke valve .20, the :venturi :being formed as a separate part and retained within the sucftion .passage 'by vset screw 23a.

'Thefcarburetor-.bodymay 'beimadein'lthree sections 24, 25 Vand 25, secured together byscrewslfl .and 28,.see;l"ig.;3. .-,Section2'4 is a casting shaped Ytofformithe upper portionofa passage 29 through which .a portion of the `air stream taken rin through the inlet all is diverted 'fromthe main suction passage |20. As will `later appear, this vdiverted. air stream is returned'to the main-suc- -ti'on Vpassage :at or directly beyond the ,throat lof the venturi '23, .and during its :coursei of ow, Aserves lin conjunction with certain `of Lthe fuel supply parts of the carburetor, as `the direct or primary fuel metering means. The mouth '29a of the air diversion passage 2.9 is formed by a scoop-shapedbaflie '3'0 projecting ,into the suction passage a distance sufficient Yto cause a substantial fiow of -air to bedeflected'into passage'l29. As illustrated, the mouth of baiiie 30 Yis "disposed in -a .plane substantially .normal to the direction of air .flow 'in Ithesuction ypassage inlet, andthe inclination of the .baflle isin Ithe-general direction 'of the airdiversion passage.

Body :section 25 Ihas a Vvertical bore 3| awhich receives .the venturi'lS, and fcontainsthe fuel supply chamber generallyiindicatedfat 32, see-Fig. '65

3, formedby walls3-2a and 32D spaced 'fromthe sides 'and end of a vvertically .extending Wall .33 lying-.in 'the vertical radial Aplane of rthe suction passage. 'Wall 33 has an upper cayity'134 which forms the lower end of the air diversion passage ated mechanism comprising individual floats 31 \4la vguided within the .bushing and carrying a steel ball Mb, constituting the valve proper, which between engagement with the seat 42a is permitted to rotate on the stem and thereby wear uniformly and evenly. This featiue is of importance in that whereas the usual valves often in a short time develop leakage due to wear resulting from vibratory impacts with their seats,

fthe present valve is found to maintain, by Virtue of its uniform wear, fluid tight engagement with `its seat after long usage.

YWall V33 vcontains 'a main fuel nozzle, .generally indicated at .44, :received within bores .45 and 46, v.the-latteropening atits upper end through ,a reduced diameter bore 4l into the channel-shaped recess ..34 in thetopfof Vwall 33. `Th'e'main fuel nozzle14'4 ycomprises a tubef48, see Fig. 4,threaded at 5'5 into bore 45 andhaving a plurality of air inlet orifices 49, the Vupper diameter ofthe tube being less than the diameter of bore `4l; so .as'to `provide a surrounding air space :50 finto which air is bled from space .5l (by way of .a restricted lv'orifice 5.2. Thereducedfdiameter portion of the ynozzle tube 48 hasarsnug lfit within.bore41,and

the upper discharge fend of the Atube 'projects into bore'54 in the bottom vof the fuel metering Vtube with a small .clearance at 56. bled through orifice -52 is Ataken into l space 15| through its communicationat;53,`see Fig. -1, with The :air

the lower portion `of vthe air diversion Apassage beneath the `inlet end' of the metering tube .35. The ,nozzle tube 48 is engaged Yat its lower lend fbyfa short Vtube 5l threaded .at 58 into vbore 4.5

andhaving a'calibrated, reduced diameter orifice 15S-through which the main'fuel stream is drawn -upwardly into the nozzle bore a. kTube '51 is -replaceable by other tubes of different bore sizes,

when .it is desired to vary the fuel restriction at fthe orifice 5S. Bore 45 and the lower end of Ltube Y51 are in open communication with the fuel supply chamber 32 through openings in opposite sides of the wall |33.

The lower end of tube '48 is -annularly lspaced at 61 from the wall of bore 45 to form a chamber into which fuel is delivered from the accelerating fuel piston bore, as Iwill presently appear, 4Aand 'from which the fuel is drawn through rorifices 62 .into the tube bore 45a. Fuel taken into the tube through orifices 59 `andfi2is discharged'lnto the metering tube 35 by virtue of the air =velocity and depression therein, elevation of the fuel `being aided by the air admitted through -orifices491and .direction of wall 33. As a'result, the fuel level :standing above the main fuel nozzle, and the fnormal proper functioning of the: nozzle, will not appreciably be affected by tilting of .the retor in any direction.

Asillustrated in'Fig. 1, the lower Vbody :section 2.6 contains an idling :by-pass. passage through carbuvwhich at closed throttle positions, fuel is drawn into the vsuction passage air stream through orifice 64 located at a suitable point beyond the throttle, the effective size of orifice 64 being'regulated by the usual needle valve 65 and the usual air bleed orifice being provided at 63a@ Bore 63 communicates at its upper rend with a tube 68 threaded into counterbore 61 and spacedalong its upper extent from bore 88 to provide a kfuel passage communicating by wayof bore 69 with the fuel containing recess 6I in the main fuel nozzle bore 45. The upper end of tube v66 fits snugly within the bore of an upwardly projecting boss-1U, and directly below this boss fuel is taken into the tube through orifice 1| by the idlingbore 15 in the wall 331and `carried o-n arod 16 having at its lowerlend` a flange 11. Rod' 16 extends upwardly through the tubular`guide boss 18 formed integrally with the wall 33, the rod being directly guided within bushing 19. `Bore 15 opens'at its upper end into the fuel chamber 32 to provide constantly available fuel above? the piston for delivery to the main fuel nozzle, as will later appear.A During downward movement of thepiston, fuel is discharged from, the

displacement chamber 89' past rcheck valve 8| through `passage 82,V see '7,- into a vertically extending passage 83 from-.which the fuel is discharged into the metering tube 35 through a diagonally extending bore 84. As shown in Fig. 1, bore 84 is Vcontained within a web 85 projecting upwardly from wall 33 at the base of the air diversion passage 29; y As shown in Fig. 6, fuel is taken into the displacement chamberf80 from the supplychamber 32 by way of opening 88, space 81 and passage 88, space 81 containing a disk-type check' valve 89 normally'resting on boss 90 to permit free communication between vthe fuel chamber and passage 88. Upon sudden downward movement of the piston 14, however, disk 89 is forced upwardly to close opening 86, thus checking return` flow fromthe displacement chamber into the supply chamber, requir- 'ing the fuel discharge to occur past the' check valve 8| to the accelerating fuel nozzle B4.

The operating connection between the `throttle I and the piston 14 -comprisesan arm 9| carried on shaft I9 within the diversion passage 2| and engaging the upper end of rod 16.

`Downward movement of the piston rod is"Y resisted by a coil spring 92 centered on the. boss .18 by bushing 19 andfbearing against la ange 93 on the upper end of the rod. The latter isA movable within and relative to the piston`14 sofas to permit lost motion between the parts enabling the piston to have delayedfdownwardmovement upon suddenopeningof the'throttleyand de pression of the rod 16. The downward moving force on the piston is transmitted through coil spring 94 received `within counterbore 95 I and bearing at its upper end against a keeper' ring 91 held in place by.lockgwasher.y f

fan-shaped pattern.

- 4In the broad aspects of the' invention, any suitable means maylbe provided for maintaining a fuel metering restriction inthe air diversion passage 29. Preferably, I use an inserted metering tube`35 of rectangular or square outside cross-sectional shape tting within the cavity 34 in the top of wall 33, and having its discharge end 35a projecting into the suction pas- 'sageA at substantiallythe throat of the Venturi 23; 'I'he tube is set down over boss '18 vat'vthe upper Aend of the idling by-pass tube 66, aspreviously described, and the bottom of the tube at its inlet end is slotted to receive the upwardly projecting web portion which contains the accelerating fuel discharge passage 84. The outlet end 35a is particularly shaped for the purpose of causing the fuel and air mixture being dicharged from 'the tube, to be patterned and directed intor the main suction passage 'in Va course that will insure mostV effective distribution and thorough admixture with the main air stream under all rconditions and throttle positions.

The outlet end of the metering'tube has a carefully designed configuration presenting-an inclined baille or fuel directing surface 35h that causes the mixture'of primary air with fuel 'discharged from the main nozzle to be projected in a cone-shaped pattern, as indicated by Ythe dashed lines, downwardly and centrally within the Venturi bore, and also serves similarly to diffuse and project the `accelerating fuel being dischargedfromvthe nozzle 84 against `the inclined baille surface, in a downwardly spreading In this manner, thefuel is uniformly dispersed in the air stream ata point in advance of the throttle so thatat all positions of the throttle, the portions of the fuel and air mixture taken past its opposite edges will be'uniformly proportioned. The 'downwardly angular or curved baille surface 35h of the meteringtube may be formed by taking initiallya tube having a substantially hemspheric end, and cutting off the end of the tube, assuming its position to be as shown inthe drawings,

at an angle of approximately 30 with respect to the vertical. i As a means for preventing reduction in the 'fuel supply chamber pressure as a result of high rate of fuel withdrawal therefrom, as during high speed open throttle engine operation, I provide a pressure connection with the supply chamber above the liquid level, fromV a pointv in thediversion passage 29 at which it is found possible to obtain a pressure that will prevent any substantial or appreciable reduction'in the supply chamber Ypressure under the conditions stated. Referring to'Fig. 1, I place at the lower end vof the inclined air diversion baille 38, an opening |99 directly in the path olthe diverted air stream, with the plane of the opening disposed substantially normal to the line of air flow along the bottom surface of the baille. The air thus is projected directly-into the opening, as distinguishedfrom being'directed past an opening in a side wall parallel tothe line of air flow, so that a velocity as well as static pressure -is applied -to'the opening. This pressure is communicated `through passage |0| and a transverse bore v|02 into a chamber |03, see FigbS, in open`communication through-bore |04 v'vith the ysupply chamber'32 above the fuel .level therein`.jFrom vmeasurements taken 'of' the/supply' chamber pressure, it has beendetermined that v even during -maximum rates of fuel ywithdrawal.'from `the chamber, :is possible 4to maintain substantially :atmospheric pressure on the' fuel'surfaee, ,and :thereby avoid reduction :below the proper and `.required rate of fuel delivery :to ythe engine.

The invention also provides :an improved ty-pe :of ieconomizer which acts to lean the fuel -mix- .ture :taken to ,the engine when-operating vat part- `opengthrottle and at intermediate cruising speeds when :a `normally rich mixture is not required. The zeconomizer `systein'comprises a vertically extending passage |05, 4see-Figs. 'l vand v10, lead'- `ing from -ansopening |06 that maybe placed at any suitable ylocation beyond the .throttle so as to beV subjected tomanifold pressures. Passage 4105 connects at its open end through an inclined passage |01 wither-chamber |08 c onltaininga disk valve |09 having kslight clearanceafrom-the vchamber bore III) and normally closed against its. yseat gS by acoil spring I-II supported by bushing lI I2. `Passage I0`I leads to an annular ,groove -I'Iiin fthe .-bushing, depression bei-ng communicated to the runder side of `the valve |09 Athrough open.- ings IIII. The Valve |09 controls communication :between ,the upper :interior of the `supply vcharr'iber and a tpassage :I |.6 ,to `which the venturi .or metering tube depression is communicated Vthrough calibrated orifice iin 'the :top .ofthe tube :and the lower end I:0`|a of bore-'|01 below the plug |.II8.

`Indescribing the operation of the carburetor,

fit mayrst `be assumed that the engine is idling, l'with' the throttle V|15 `in substantially `closed position. VThefuel supply to the idling tubeI bore 268 `via-passage '60 iis velevatedV by suction .communiicated 'from :the outlet iside of the throttle to.

`opens :and lthemain fuel nozzle -is brought into operation. -During idling operation, the rate of air flow through Ithe diversion passage 229 is inrsuiiicient to cause fuel, or at least any' substantial amount `oi fuel, to Tbe discharged 'from the main iuel nozzle 44, but as the'throttle is opened I -to ,aposition of 'say from '10Hto l5" from fully -closed position, the rate of air ilowithrough the :diversion passage, and increased 'suction communicated from the main venturi, produce a suf- 1flcient depression in the metering tube :35 to gradually bring the main 'fuel nozzle into operation. Thereafter, "fuel continues to discharge v'from 'the main fnozzle V.under all normal andhigh speeds of engine operation. vI 'have previously described how, by virtue of pressure communicaition from opening |00 inthe diversion passage to 'the fue] supply chamber, the proper and required rate o-f `fuel discharge vfrom the main nozzle 44,'

'the range of high! accelerating f uel Vnozzle @trovera fperiod of time Vprolonged .--suiciently -to :furnish increased I uel :throughout thefacceleration range. l.Onthe .other hand, when the throttle is gradually opened, the piston may move downward wit-hout .substantial compression of the spring 94, :to -slowly vdisplace the'fuel through passages AIl!! Aand 8B back into the fuel supply y.chamber 3 2. During :comparatively lslow .opening v`movementI fof the throttle, some fuel may discharge past check valve -8|. The .proportion of ifuel discharged past thevalve for a given yrate 'of v:downward piston movement less than that -which will Acause the check :disk f89 :to seat, will depend `upon-the resistanceoiered by `valve .0| toopening against the fpressure -cre :ated under the piston. Upon reaching its lowermost zposition, the rounded end 15a of rod 'IS may, :though not znecessarily, beadapted :toengagea-nd hold the check valve -8I open, thereby `:maintaining Aa supply of rfuel 'to the accelerating nozzle at wide open throttle positions. It will rbeunderstood, of `course, vthat at the end tof lthe piston travel and during `its upward return movement, .disk :89 will-drop away from opening Yllt to restore'the :fuel supply to the Vdisplacement chamber.

Referring now vvto the economizer system, it may Abe 'assumed that the engine is Voperating at part-open vthrottle corresponding 5to normal or cruising speeds and under light load. The mani- H-fold depression communicated `through .port |06 andv passages |105 and |1Il|to-.the 4under jside of ithevalve |109 :during operation at closed throttle, iand partly Vopen .throttle positions within the normal or cruisingspeed range, causes .thevalve to ropenv .against the resistance of spring l'I I'I fan-d to :communicate'ithe Aventuri :or metering tube depression through passages |:|-6,` |'03 .and IM `to dthe 'fuel :supply chamber. Under these lconditions, vvthe yair flows through the venturi-at 'a veloc- -ity suiiioient to' create ya variable tredu'ctionin pressure .on the fuel in :the supply' chamber, 'the amounts .of :depression rbeing governedby the relative .sizes .of :orifice I'Il .and theV larger air lbleed"oriflce1-I102. As will `be understood, under the conditions described,v fthe reduction of pressure onpthe fuel "serves 'to zreduce'"the1am.ount of fuel tbeing discharged torthe suction passage. It -may be further explained :thatthe :economizer isysterriis'fineiective during 'idling operation, since Ythe rate 'offlow .throughtheventuri is insufcient .to create fany material depression that would ybe communicated 'to the Ysupply chamber. Also, during `operation at full open lthrottle posi- Vtion, .the .manifold depression is "insufficient to open 'the valve `|109.

'I'he economizer and accelerating fuel supply systems -may be regarded -as operating in conjunction to provide the :desired leanness "in the `fuel mixture -for-intermediate speed, light Iload operation, 'and for Vgiving :a desirably enriched mixture under highspeed :open throttle ope-ration. Referring againto Fig. 1, as. the piston 'T4 approaches the" *limit of its down movement resulting from opening lof the throttle, the piston uncovers passage |20 and thereby causes excess fuel'to be available to the main fuel :nozzle 4'4 by deliveryfrom the Vchamber above the piston intothe annular'chamber 62| surrounding the nozzle tube. Asv will be apparent, this arrangement provides an extremely simple and yet ac'- cura-tely functioning v'means for supplementing the main nozzle fuel supply Vfor high lspeed operation.

A further important advantage in 'the Epresent '21a-ideas" 5 ing with passages in section being retained, 101

and to remove and replace the venturi 23 with another venturi having a port diameter corresponding to or having proper relationship with, the port size ofthe replacing lower carburetor sectio 26. to all various size engines and manifold connections, can be made from a stock of sections 26 and venturis 23 of the different sizes,..withoutk necessitating any changes inthe main carburetor assembly, other than perhaps minoriadjust-120` ments.

I claim: i 1 1. In a vcarburetor including a fuel supply', chamber, a vertically extending suction passage! containing a throttle .and `having .an air inlet125 and an outlet; the combination comprising, means forming an air diversion passage vextending downwardly above the level of fuel in the supply chamber and `through which a substantial portion of the suction passage air stream 30 is diverted therefrom and then returned to the suction passage at anV elevation above the bottom of the supply chamber without passing through said supply chamber, a vertically disposed wall extending from the side of the suction passage wall within said chamber-and directly below the diversion passage, float means inthe supply chamber at opposite sides of said Wall, and means for feedingfuel from the supply chamber upwardly through a passage in said wall into the air stream in said diversion passage.

2. In a carburetor including -a fuel supply chamber, a vertically extending suction passage containing a throttle` and having an air inlet and an outlet; the combination comprising, means forming an air diversion passage extending downwardly above the level ofl fuel in the supply chamber and through which a substantial portion of the suction passage air stream is diverted therefrom and then returnedto the suctionV pasl sage at an elevation -above the bottom of the" said supply chamber without passingfthrough said supply chamber, Va vertically disposed wall extending from the side of -the suction passage Wall within said chamber Aand directly 4belowjthe 55 diversion passage, float means in the supply chamber at opposite sides of said-wallfand;meansfor feeding fuel from the supply chamber -upwardly through a passage in said-wall into the air stream in said diversion passage, the last mentionedvpas'-` j60 sage'being positioned centrally with relation :to-r the supply chamber so that the l'delivery ofv fuel-j through the passage is not substantially aivectedI by tilting of the supply chamber in any direction.

3. In a carburetor including a fuel supply chamber, a vertically extending suction passage a containing athrottle and Ahaving an -aireinletiandran outlet; the combination comprising; means forming an air diversion passage extending-down-` wardly above the level of fuel in the supplychamber and through which a:k substantial portion of*VVV the suction passage air stream is diverted therel from and then returned` to the suctionpassage i* at afl-.elevation above the' bottomof the supplyl chamber without. passing through said supply'75-'stream in' said diversion passage-and means forV Thus, adaptation of` the carburetor-15 chamber, a -vertically disposed wall extending from the side of the suction passage wall within said chamber and. directly below the diversion passage, oat means in the supply chamber at opposite sides ofl said wall, means forming a restriction in said'diversion passage above said wall, means for feeding fuel from the supply chamber through a passage in said wall into the air stream at said restriction', andmeansfor bleeding air from the diversion passage into the fuelstream inthe last mentioned passage before the fuel enterssaid restriction in the diversion passage.

4.' In" a carburetor including `a fuel supply chamber, a vertically .extending suction passage containing a throttle and having an air inlet .and an outlet the combination comprising, a venturi in said passage, means forming an air diversion passageV extending downwardly above vthe vlevel of fuelin the supply chamberv and vthrough which a substantial portion Lof the suction passage air stream is diverted therefrom' andthen returned to the suction passage at the throat of said venturi and'at anelevation above thev bottom of the supply chamber without passing Vthrough said supply chamber, a vertically "disposed 'Wall extending from., the side of the suction passage wall within said Ychamber and directly below the diversion passage, float means in the supply chamber at opposite sides of said wall, Aand means for feeding fuel from the'supply chamberthrough a passage in said wall upwardly into the air stream in said diversion passage ata rategin accordance with the rate` of air flow therethrough.` j Y 3 5. In 'a carburetor including a fuel supply chamber, a vertically extending suction'passage containing, athrottle and having an air inlet and an outlet; the combination comprising-a venturi in said passage, -Vmeans forming an air diversion passage extending; downwardly above the level ofA fuel in the supply chamber, and through which a substantial portion `of the suctionA passage air stream is diverted therefrom and then returned to the suction passage at the throatrof said venturi and at an ,elevation above the bottom of the fuel supply chamber without passing through said supply chamber,v a vertically disposed wall extending from thesideof the suction passage wall Within said chamber `and directly below the diversion passage, -oat means in the supply chamber at opposite sides of said wall, means forming a restriction in said diversion passage directly above saidrwall, and'means comprising a fuel displacement plunger within a bore in said wall for dischargingfuel from the supply chamber through a passage in said wall intol the air stream in the v diversion passage at said restriction.

chamber, a ,vertically extending suction passage containinga r,throttle and having an air inlet and Y an outlet; .the combination comprising, means forming an air diversion `passage extending downwardly above `the levely ofy fuel in the Asupply chamber and through which a substantial portion of the suction passage airstream is diverted therefrom and then returnedto the suction passage at an elevation above the bottom of the fuel supply chamber lwithout passing ,through said supply chamber; aV vertically disposed Wall extending from theside ofthe suction passage wall within said-chamber and directly below the diversionpassage, float means; in the supply chamber at opposite sidesiof said wall, means for feeding fuel from the supply chamberthrough avfuel passage in said ,wall leading upwardly into the air bleeding air from the diversionV passage into saidV fuel passage.

7'. In a carburetor including a 4fuel, supply chamber, a vertically extending suction passage containing a throttle and having van air inlet and an outlet; the combination comprising, means forming an air diversion passage extending downwardly above the level of fuel in the supply chamber and through Whichy aV substantial portion of the suction passage' air stream is diverted therefrom and then returnedto th suction passage at an elevation above the bottom of the fuel,

8. In a carburetor including a fuel supply.

chamber, a vertically extending suction. passage containing a throttle having an air inlet and an outlet, and a venturi between said throttle and the inlet; the combination comprising, means forming an air diversion passageextending down- Wardly above the level of fuelin the supply chamber and outside the fuel supply chamber. and through which a substantial:` portionV of the, suction passage air stream is diverted from a. point between said venturi and said` inletl and then returned to the suction passage at" the throat.. of the venturi at an elevation above the bottom of the fuel supply chamber, a verticallyY disposed wall extending from the side of thesuctionrpas.- sage Wall Within saidV chamber and directly below the diversion passage, a float meansin the supply chamber at opposite sides of said Wall, a. hom-. zontally extending tube mounted on the top of said Wall and forming arestriction in said diversion passage, said tube having anoutlet endpresenting an inclined baille surfaceA Within' the 1nterior of said venturi, and means for feeding fuel. from the supply chamber through a passagem-` said Wall directly into the metering tube.

9. In a carburetor including a fuel supply chamber, a suction passage containing: al. throttle and having an air inlet andan out1et;.the.com` bination comprising a venturi in said passage, means forming an air diversion passage through which a portion of the suction passage airfstream is diverted therefrom and? then returned tof-the suction passage at the venturi throat without passing through the supply chamber, a1 tube 1nv the outlet of said diversion-passage, means for feeding fuel from the supply chamber intosaidl tube, the discharge end of theztube projecting intothe venturi and having a-bale surface inclined in the direction of. airflow through. the suction passage to deflectthe fuel: and air m1-x,

ture centrally and longitudinally` therein, andi means independent of. said fuel feeding means.-

fordischarging accelerating fuely longitudinally; Within said tube against saidubaiilesurface. l 10. In a carburetor includingA a closed. fuel supply chamber, a suction. passage. containing: a.

venturi, a throttle and having` aninlet and outlet; the combinationcomprising. means fori delivering.4

fuel from.. the supply.` ychamber tothe venturi;4 .Y 5..

means: forming.r an. economizerfpassag'e for come LTT municating venturi created depression'. to. the 'sup-- said valveV element against,l theV seat,. and means.

forming a passage communicating. the suction passage pressure at. the outlet. side offtheV throttle to said'y chamber-.to unseat said element against thel resistance of. the spring during normal operations` of. the carburetor at part-openu throttle` positions. e

11. In a carburetor including a closed fuel supply chamber, a suction passage containingaventuri a throttle: and. having an inletA and an outlet; thel combination. comprising meansd for delivering .,yfuel; from the supplly chamber to' the; venturi,-

means4 forming anv economizer: passage. for communicating venturiv created. depression.' to: the supply chamber above the fuelA leveltherein., and.-

valive means actuated in; accordance withfthecsuc- .tionV passage pressure at. the outlet; side of. the

throttle, for controlling thea communicationof depressiontothe supplyy chamber through. said economizer passage;L said: valvefm'eans comprising a..wall` formi-ng: aV cylindrictchamber, a,.disc valve ,movable therein-,. a lval-ve seat spaced from. the.

wall of said. chamber to, form. an annular space communicating; withsaid` economizer passage, said space being Communicable-through apassagein the valvesea-t Witlrsaidsupply chamber, a spring4 iurging saidvalvez disc against the seat andimeans forming a passage communicating; the: suction passage pressure at the outlet sideof the throttle to said chamber and uniformlyI against thesurface of the disc adjacent. said. spring, to. unseat said. disc against the resistance of. the spring during normal operations of-` the carburetor at partopen` throttle positions.`

12.v In 'a carburetor includingv a closed fuel supply chamber, a4 suction passage containing' a "venturi, a throttle `and having an inlet and an4 outlet; the combination comprising; means for delivering fuel from the supply chamber to the venturi created depressionfto the supply chamber abovethe .fuel level'therein, andr valve means actuatedA in accordance withl the suction` passage pressure. at the outlet sideof the throttle, for

controlling thecommunication. of depression to the-supply. chamber. through saideconomizer passaga, said. valvemeans, comprising` a Wall forming a valvel chambenv a valve element movable ,e therein, a valveseat spaced from the Wall. of said chamber to formaspace communicating with said economizerV passage, said.` space being communicable througha. passage the valve seat with said supplyA chamben. aplug closing one end of said chamber,aspringA contained withinga-.bore in `said plug..andurging.; said .valve element againstv the-seat, and` meansgforming; a-passage communi.-

eating-Whe suction passage pressure at, the 1 outlet. side: of1 thel throttle;v through. aeport` in'. theA side r or said; pluginto said bore. and valve: chamber., whereby said lvalve element: isf unseatedl against theresistance ofithespring; during normal opera-A l tionsio the.: carburetor atizparteopenathrottle `p'c-r l.

Sitibns...

13. In a carburetor including a fuel supply chamber, a vertically extending suction passage containing a throttle and having an air inlet and an outlet; the combination comprising, means forming an air diversion passage extending downwardly above the level of fuel in the supply chamber and through which a substantial portion of the suction passage air stream is diverted therefrom and then returned to the suction passage at an elevation above the bottom of the supply chamber without passing through said supply chamber, a vertically disposed wall extending from the side o-f the suction passage wall within said chamber and directly below the diversion passage, float means in the supply chamber at opposite sides of said wall, means for feeding fuel from the sup-ply chamber upwardly through a passage in said wall into the air stream in said diversion passage, means forming an economizer passage for communicating depression from said diversion passage to the supply chamber above the fuel level therein, and valve means actuated in accordance with the suction passage pressure at the outlet side of the throttle during normal operations at part-open throttle positions, for controlling the communication of depression to the supply chamber through said economizer passage.

14. In a carburetor including a fuel supply chamber, a. vertically extending suction passage containing a throttle and having an air inlet and outlets; the combination comprising, means forming an air diversion passage extending downwardly above the level of fuel in the supply chamber and through which a substantial portion of the suction passage air stream is diverted therefrom and then returned to the suction passage at an elevation above the bottom of the supply chamber without passing through said supply chamber, a vertically .disposed wall extending from the side of the suction passage wall within said cham-ber and directly below the diversion passage, float means in the supply chamber `at opposite sides of said Wall, means for feeding fuel from the supply chamber upwardly through a passage in said wall into the air stream in said diversion passage, and means for communicating pressure to the supply chamber above the fuel level therein through an opening located directly in the path of the diverted air stream and positioned so that the plane of the opening interse'cts the line of the diverted air flow and the air therefore flows against said opening to y

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