US2355267A

US2355267A - Carburetor

Info

Publication number: US2355267A
Application number: US410251A
Authority: US
Inventors: Henry W Boylan
Original assignee: Detroit Lubricator Co
Current assignee: Detroit Lubricator Co
Priority date: 1941-09-10
Filing date: 1941-09-10
Publication date: 1944-08-08
Anticipated expiration: 1961-08-08

Description

Amig. 8', 1944. v A' H. w. BYLAN 2,355,267

' CARBURETOR l I 4 Filed Seibt. 1-0, 1941 5 Sheets-Sheet 2 INVENTOR I. BM .wl WLM @2M/KM ATTORNEY Aug. 8, 1944. w. BOYLAN 2,355,267.

" CARBURETOR y Filed Sept. 10, 1941 5 Sheets-Sheet 4 IZZ FIG-1 1 INVENTOR Patented Aug.- 8, 1944 atroit Lubricator Company, Detroit,`

I corporation of Michigan Application September 10, 19471', Serial No. 410,251

(Cl. 261 il) 6 Claims.

` This invention relates tonew and useful improvements in carburetors for supplying a miX- ture of air and `fuel .to an internal combustion engine.

An object of the invention is to provide a carburetor which willsupplya proper fuel mixture for all ranges of engine operation.

Another object isV to provide means for temporarily increasing the ratio of fuel to air for rapid acceleration.

Another object is to provide means for increasing the'ratio of fuel to air during high power demands. i.

Another object is to provide a carburetor which is particularly adapted for utilizing an anterior throttle valve.

The invention consists in the improved construction'and combination oiA parts to be more fully described hereinafter, the novelty of which will be particularly pointed out and distinctly claimed. A I ,'y e

In the accompanyingl drawings to be taken as a part of this specification there rare fully and clearly illustrated several preferred embodiments of the invention, in which drawings:

Figure 1 is a top plan view of a duplex downdraft throttle anterior carburetor embodying the invention;

Fig. 2 is a view in sideelevation of the carburetor;

Fig. 3 is a view in section on the line 3 3 of Fig. 1;

Fig. 4jis a partial view in section on the line 4 4 of Fig. 3;

Fig. 5 is a'detail View in section on the line 5 5 ofFig.3;"

Fig; 6 is a detai'lview in section on the line 6 6 of Fig. 1; I

Fig. '7 is a detail view in section on the line 'I 'I of Fig. V4;

Fig, Sis a detail View in section on the ,line` 8 8 of Fig. 2;

Fig. 9 is an enlarged detail View Vof the metering valve in relation to its orifice in idling position;

Fig. 10 is a diagrammatic view of the duplex carburetor of Figs. 1` to 9;

Fig. 10A is a diagrammatic view showing a position of the parts when the throttle valve has .been moved vslightly toward open position.

Fig. 10B is a diagrammatic view showing the position of theparts when the throttle valve has been moved toa still further open position.

Fig. l1 is a view,y in side elevation of a single downdraft anterior throttle carburetor embodying,Y the invention, but having a portion of the fuel conduit in longitudinal section; I

Fig. 12 is a view in elevation looking from right to left of Fig. 11;

Fig. 13 is a view in longitudinal central section Fig. 14 is an enlargeddetailview in -section on the longitudinal center line of the fuel control or economizer means and taken on the line Ill-I4 of Fig. 1l;

Fig. 15 is a detail view in lsection on the line I5 I5 of -Fig. 13 but showing the nozzle an'd baille member in side elevation; y Fig. 16 is a detailtop plan view of the nozzle and bale member; v

Fig. 17 is a detail view of the blank from which the nozzle vand bale memberis formed; and

Fig. 18 is a diagrammatic view of the single carburetor of Figs.` 11-17.'

Referring to the drawings, Figs. 1-10 by chare acters of reference, numeral I designates generally the casing of a` duplex downdraft type carburetor having a lower bodymember 2 on which through the mixing chamber vand taken on the vis mounteda cylindrical air inlet housing 3 hav- Aing a bottom wall 4. The member 2 has a pair of

parallel passageways

5, 6 therethrough separated by a partition wall 1. Each

passageway

5, 6 has a cylindrical air inlet and throttle bore 8 registering with` an opening 9 in the housing bottom wall 4 for supply of air from the common air inlet I0 of housing 3. Each

passageway

5, 6 is of general'Venturi form below itsbore 8 and has a throat I I with a converging air inlet I2 and a diverging mixing chamber I3 having a mixture outlet I4. .Extending transversely through the partition wall fl andthe air inlet throttle bores 8, there isa throttle shaft I5. Mounted on the throttle shaft vin each .passageway there is a throttle valve-.I6 ofthe balanced butterfly type, which valves are movable simultaneously toward o-pen position and toV closed position Secured to the outlet or under side of each valve I6 and on the leading wing Il thereof there are a plurality of air guide vanes I8 extending transversely to the throttle shaftand having their edges which `face the passageway wall curved as at I9, See Fig. '7, to provideA clearance on opening movement of the valve. The vanes I8 tend to eliminate swirling or turbulent flow of the air entering the converging air inlets I2. VExtending transversely through the wall l, there is a fuel discharge passageway 2li opening into each of the passageways 5. t substantially at but on the mixing chamber side of theirvthroats II, to provide horizontally directed oppositely discharging fuel outlets or orifices ZI, 22 which are `alined with each other and discharge substantially parallel to the aXisof the throttle shaft I5. I The wall of each

passageway

5, 5 has ajrecess23, Fig. 4, opposing its orice 2l, 22. Extending between'each opposed orice and recess and Abridging the passageway there are parallel air `ballleeplates 24 extending vertically at each side ofthe orifice so thatthe discharge from each orifice is longitudinally of 24 terminate in positioning ears 26, 21 which extend respectively into the orices 2I, 22- and `the recesses 23 to hold the plates against displacement. I I

In the air inlet I there is a disk `type choke valve 28 mounted eccentrically on a shaft 29 journaled in the side walls of the housing 3. The valve 28 has an opening 38 therethrough controlled by a poppet type valve plate 3l which is urged to closed position by a coil spring 32. The valve plate 3| is reciprocal on a rod 33 secured to the valve 28, the rod'having a shoulder against which spring 32 abuts. The free end 34 of rod 33 is engageable with the wall of housing 3 to limit the movement of valve 28 beyond full open position. v One end 35 of valve shaft 291 projects from the end of a sleeve 36, Fig. 1, extending from the housing 3. Rigidly secured on the external shaft end 35 there is a lever arm 31. Within the sleeve 36 there is a coil tension spring 38 havingone Vend engaging the lever arm 31 and its other .end anchored to the sleeve 36 so that the spring 38 is operable to move the choke valve 28 to closed position. Journaled on a stub shaft l 39 projecting from the external wall of housing 3 below the shaft there is a choke lever 48, Fig. 2, having a bifurcated upper end providing spaced armsV 4I, 42 engageable with the lever arm 31. The arm .42 in the position shown, is holding valve 28 in open position. `On clockwise movement of lever 40, the arm 4| is engageable with lever arm 31 to move the valve 28 toward closed position against air pressure or to hold it tightly closed. One end of the throttle shaft I5 projects outlets I4 there is a cross slot 48b connecting the mixing chambers I3 for synchronizing the pressures therebetween.

The other end 49 of the throttle shaftV projects through a gear housing 58 and has journaled on its external end'a hand throttle lever 5I engageable with 'a shaft, Figs. 1, 4 and 6, pin 52 to move the throttle valves I6 toward open position. Fixed on the throttle shaftY end 49 within housing 58 there is a gear sector 53 which meshes with a gear sector 54 xed on a shaft 55journaled in a bushing (not shown) fixed in casing I by screw 56.

Supported by the casing member 2 and positioned at one side of the

passageways

5, 6 there is a constant level fuel reservoir having a vliquid receiving chamber 51 with an inlet 58 for connection to a suitable source of fuel supply. The reservoir contains the usual inlet valve 58a` (Fig. l0) and iioat mechanism having a float 59 (Fig. 3) formaintaining a constant liquid level. An air inlet passageway 68 shown in dotted lines in Fig.

. 2 leads from the interior of air inlet housing 3,

' passageway 28.

by the wall 1 there is a tubular housing member 63, Fig. 3, having the mid-portion of its bore providing a fuel passagewayll,

Figsf

3 and 10, which is of substantially equal diameter to, and intersects the mid-point of the horizontal discharge Below the reservoir liquid level the housing bore is of enlarged diameter as at 65, the enlarged bore intersecting the reservoir chamber 51 and extending therebelow to provide a sump 66 which'is closed and sealed by a plug 61. Positioned concentrically within the enlarged bore 65 there is la tubular member or housing 68 having an annular ange and compression washer 69 fitting against the upper end of the enlarged bore. The upper end of the member 68 extends into the passageway 64 and carries an annular metering valve orice member 18 having a fuel orifice 1I substantially at, but slightly below the plane of the reservoir liquid level. The orice member 18- abuts a downward facing shoulder to positively position the oriiice member with respect to the reservoir liquid level. Within the member 68 there isa longitudinal ow or well chamber 12 having' its upper end formed by the orifice member 18. Opening concentrically through the lower end wall of chamber 12 there is an inlet passageway 13 of reduced diameter. The lower end of passageway 13 opens into a pocket or recess 14 which forms a valve sleeve, the pocket 14 having its top edge champfered and being of slightly less internal diameter than the diameter of passageway 13. Through the side wall of passageway 13 there is a rectangular fuel inlet port 15 having its lower edge defining a portion of the top edge of pocket 14. 'I'he tubular member 68 is held rigidly in position by a disk closure member 16 having labutting engagement with a shoulder on member 68 and screw-threaded into the wall of bore 65 at its communication with reservoir chamber 51. The closure member 1B thus provides in the upper end portion of bore 65 around member 68 a fuelcontaining space, which is divided by an annular partition plate 11 into an upper compartment providing a low speed accelerating well chamber 18 and a lower compartment providing a high speed accelerating well chamber 19. Through the wall of member 68 from the bottom end of chamber 19 into the passageway 13 there are a plurality of ports 88. The chamber 18is in communication with the interior of member 68 by a port 8 I. In the casing member 2 directly above and separated from the chambers 18, 19 by an inclined wall 82 there is' a chamber 83, Figs. 3, 5 and 10, having a vertical partition 84 in the plane of the longitudinal axis of bore 65. The partition 84 extends above thereservoir liquid level and divides the chamber 83 into a low speed acceleratingfuel compartment 85 and a high speed accelerating fuel compartment 86. The compartment 85 communicates with the upper compartment 18 through an aperture 81 in wall 82 so that the

compartments

18 and 85 provide a low speed accelerating well. The compartment 86 communicateslthrough an aperture 88 in wall 82 with the lower compartment 19 to provide a high speed accelerating well. The bottom wall 4 of the inlet housing 3 has a calibrated air bleed inlet 89 therethrough opening into the top end of the chamber 83 so that the high and low speed acceleratingwells are open to atmosphere with controlled maximum air, but subject to a reduced or sub-atmospheric pressure, and a reduced air supply upon movement of choke valve 28 toward closed position.

Extending through the orice 1I there is a passageway 13 and terminates in thepocket 14;

I'hrough the walls of the tube 92 closelyadjacent Y, the valve member 90 there is a cross passage93, which intersects the tube bore 94 to provide out#v let ports therefrom. The flow area of thecom-gg" way 91.

tendsa blade'adjustment member |03 which is journaled in and through a capmember |04 which A U- shaped spring strap |05 extends across the head 'of'` member |03 and has its ends-frictionallylengaging the circumference of capvmember |04 to bined outlets from the cross passage 93 is sliglr'tl'f.

greater than the area of the calibrated bore "94-1,

Figs 3, 9 and 10. Thetube 92 has 7a cylindrical.'4 enlargement or plug 95 intermediate its ends and which extends into, and in spaced relation to the vwalls of, passageway 13 so as to provide a cali;f brated annular inlet orifice to the chamber 12:'` The ow area of this annular orice determinesythe sub-atmospheric pressure in chamber 12 orL on theinlet side of orifice 1I at whichair from' bleed 89 will sweep out the chamber 18 andcham+ ber 12 above aperture 8|, discharging the fuel therefrom through passageway into the mixf' ing chambers I3 of passageways 5 and 0. For

a given size orifice around the plug 95 in the out:

let of passageway 13, the iiow area at the meterf` ing valve orifice 1| will regulate the sub-atmoslf` pheric pressure in the chamber 12, and accorde ingly the size of the outlet orifice from passagef way 13 around plug 95 will determine the extentI 'of opening of the metering valve at which the low speed accelerating well will discharge The free end of tube 92 has a head 96 preferably o f the same diameter as the diameter of plug 95 and which fits the bore of pocket 14 to form therewith a piston or slide valve controlling admission of fuel from inlet port 15 to the tube bore 94. The head 96 has its bottom edge champiered for guiding it into pocket 14 and it extends into pocket 14 at a distance equal to or slightly greata er than the distance which plug 95 extends into passageway 13, this distance being less than the metering pin travel required to move ports 93 above or to the outlet side of orifice 1|. The depth of pocket 14 is such that the valve 90 will be held substantially .005 inch away from longitudinal seating in orifice 1| when head 99 seats against the bottom of pocket 14. The distance from the upper end of port 15 to the upper end or shoulder of head 96 is substantially equal toor slightly less than the distance which plug 95 extends into passageway 13 so that on movement of plug 95 out of passageway 13, the admission of fuel from port 15 to passageway 13 will be controlled by head 96. The reduced external diameter of tube 92 below plug 95 provides, upon movement of plug 95 out of passageway 19 en annular orifice into chamber 12 of sufficient size so that the high speed accelerating well will discharge through ports 80 into chamber 12.

1 Above the fuel discharge passageway 2. the bore of` housing member 63, Fig. 3, is of slightly `enlarged diameter to provide a guideway 91. The

metering valve stem 9| extends upward into the .guideway 91 and has an end head or flange 98 which lits within a sheet metal coupling member 99 which lits loosely in the guideway 91. Engaging the stem end 98 is the flanged end of an adjustment member |00 which extends through and hold thethreaded member :|00 in its adjusted position in sleeve member |0| thereby hol-ling the metering valveiniixed positionY relative to the rack |02. Aileaf spring |05 engages the end of adjustment member |03 to hold it tightly against cap lmember |04 thereby sealing the aperture therethrough and additionally opposing rotation of theadjustment membery |03. A helical coil spring |01- surrounds the valvestem 9|` and is `held under compression between a shoulder at the inner end .of `the guideway and the base of a cup-like follower member |08 which reciprocally fits-the guideway 91 and has its base or upper end wall engagingthe coupling., member 99 and acting'to move the metering valve out of orice 1|. The rack |02 meshes with a pinion |09 fixed onthe end `of shaft 55 so that the metering valve is mechanically `interconnected with the throttle valves I6. The loose coupling formed by the coupling member 99 between the adjustment member |00 and stem 9|- permits thetube 92 to `aline'with passageway13 and pocket 14.

When'. the carburetor is constructed to supply fuel mixture toa Ford-V8 eng-ine, for example and solely for illustration of the relation of certain important dimensions tojeach other, the followingtable and metering valve construction isset forth: i Inches diameter Passageway throats .870 Metering valve stemg9| '.171 Metering orifice 1| .156

Metering valve 90 is tapered at 21,41"` included angle to provide (Fig. 9) a diameter at a of i156 substantially .154" from its minimum diameter, and such that on the longitudinal valve center line:

Taper b ofA 2%" included angle, extends .030"

Taper c of 7 included angle, extends .030" Taper d of 16 included angle, extends .047 and Taper e of `40 included angle, extends .047"

yMetering valve diameter .150 at a is, at minimum idling speed position, substantially -.015 longitudinally out of or away from diameter .156" of @rinse 1|.

Pocket 14 .125." diam..080" long The operation of the carburetor of Figs. 1 to 10 is as follows:` Whenit is desired to start the engine, the choke lever '40 will be rotated inv a clockwise direction facing Fig. 2 .to an extent depending upon engine temperatura'that is, in hot Y Weather or when the engine has been running and it is desired to restart the same there may be no movement required of lever 40.- However, in cold Weather and with a cold engine the choke lever 48 will be rotated so that arm 42 will permit spring 38 to move the choke valve to or toward-closed position. This movement of lever 40 will act through link 48 and lever 46 to rotate the throttle kicker cam 45 to automatically move the throttle valves I6 slightly toward open position. This movement of the throttle valves will act through

gear sectors

53, 54 to rotate pinion |89 thereby movingV the metering valve 90 to a high idle speed position. Asithe engine is now "turned-over sufficiently rapidly for lfiring, the sub-atmospheric pressure created in

passageways

5, 6 will draw fuel through the fuel inlet conduit, that is, from the float chamber through port 15, inlet passageway 13, flow chamber 12 and pas;

sages

64 and 28, to discharge from outlets 2|, 22 into the passageway mixing chambers V|'3. If the speed of the engine cranking is sufficient there Will also be a suliicient differentialof reverse air pressure on the fuel wells from the fuel reservoir so that fuel will be discharged upwardly from the wells through air bleed inlet or orifice 89 into the air inlet I anterior to the throttle valves I6. This supplemental starting fuel from the wells will mix with minimum-air passing the choke valve 28 and be supplied therewith'to the mixing chambers I3. As soon as the engine res and is running under its own power the increased sub-atmospheric pressure or pressure reduction in

passageways

5, 6 will move the choke valve 28 toward open position against the force of spring -38 thereby automatically supplying sufficient air for cold engine idling operation. Opening movement of choke valve 28 will increase the air pressure on air bleed orice 89 so' that fuel will no longer feed therethrough into the air inlet I0. However, the choke valve 28 from an almost closed position to about from full open position will reduce the air flowto and vthe air pres- 'sure on the wells through orifice 89. As a result, the quantity of fuel supplied to passageway 28 will be increased, thereby assuring the supply through the cold manifold to the engine of a proper air-fuel mixture for full range engine operation. The richness of the fuel mixture of course decreasing as the choke valve moves or is moved toward open position as a result of air Vflow into the fuel conduit through orifice 89. In

v:extremely cold Weather starting when choke lever arm 4| engages the arm 31 to lock choke valve 28 in closed position, the idling speed operation of the ,engine will open -poppet valve 3| yto supply sufficient air for continued idling speed operation. When the engine has warmed up, the choke lever 40 Will be returned to the position shown in Fig. 2 and the a'rm42 will be holding the choke valve in full open position as in Fig.3.

If the throttle valves |6are moved from idlin speed position toward open position to increase 'the air flow through the passageways 5, 5to the -sponding to say 10 milesper' hour level road car speed,lFig. 10A, the metering valve 90'Wil1have moved sufiiciently Vout-of its orifice' 1| so that the sub-'atmosphericpressurein the flow cham@ its cross passage 93.

ber 12 will cause the well chamber 18 and the flow chamber 12 above'aperture 8| to empty into the fuel conduit, the supplemental fuel from the Well being followed by air from the bleed orifice 89 which is metered at the calibrated aperture 8| so that uponemptying of the low speed accelerating well an emulsion of fuel and air will be fed through the chamber 12 to the metering valve orifice 1|. are opened still further, Fig. 10B, and sufficiently to draw the plug out of inlet passageway 13 which will occur at about 45 miles per hour level road car speed, the well comprising chambers 19 and 86 will discharge its fuel through ports 88 into the fuel conduit and this supplemental fuel will be followed by air from bleed orifice 89 which is metered by calibrated ports 88. Simultaneous with the discharge of Well chamber 19, the tube head or valve 96 will have moved out of pocket 14 thereby opening the economizer tube bore 94 directly to inlet port 15 from the fuel reservoir so that supplemental fuel will be continuously discharged from-cross passageway 93 directly into the fuel conduit.

The 'accelerating wells serve to provide the `necessary over rich mixture for quick acceleration either from idling or from part open throttle position. When the throttle valves I6 are quickly opened but not suii'cient to draw the plug 95 out of inlet passageway 13, the sub-atmospheric pressure in flow chamber 12 acting on the low speed accelerating well decreases and Well chamber 18 will discharge the necessary quantity of solid liquid fuel into the fuel conduit to assure the discharge of the necessary enriched mixture from outlet I4. Continued operation of the engine at part open throttle will not empty the well chamber 19 of the high speed accelerating well, but if the throttle valves are quickly opened from part throttle sufiiciently to withdraw the plug 95 from inlet passageway 13 then there will be a substantially instantaneous discharge of solid liquid fuel into the fuel conduit from the high speed accelerating well chambers 19 and 86 to provide the necessary enriched mixture to the engine for high speed acceleration. As noted above, the economizer passage 94 will be opened when the well chamber 19 discharges and therefore supplemental fuel will continue to be discharged through passage 94 at this throttle valve position and for all further open positions of the throttle valves. Should the throttle valves be .quickly opened for rapid acceleration from idling vposition to an open throttle position corresponding to a level road car speed of 45 miles per hour or more, then there will be a substantially instantaneo-us discharge of solid liquid fuel from both of the accelerating wells into the fuel conduit and this supplemental discharge which suddenly increases the ratio of fuel to air will be supplemented instantaneously by the continuous discharge through tube bore or passage 94 and 'Ihe chamber 86, however, will not completely empty until the engine has attained a speed corresponding to a car speed of about 8 or 9 miles .per hour. It will be noted that upon movement of plug 96 to open the economizer bore 94, the mixing chambers I3 will be supplied from two fuel supply means or jets, each feeding into the fuel discharge cross passage 20, one of these jets being the bore of economizer tube 94 and the other being the annular passage- Way through tubular member 68 around the tube 92.

In Figs. 11-18 inclusive, there is shown a single When the throttle valves I6v garage# t'ype carburetor which operates v'substantially-iri the manner above described for the duplex carburetor but which `has certain structuralfch'anges and additional features. Thissingle carburetor has a one-piece body l| I having amain vertical passageway I I I therethrough witha top air -inlet I I2 and a bottom mixture outlet I |3. rIlhe upper portion of body ||0 forms a cylindrical-air'inlet housing ||4 which contains an eccentric disc type choke valve or platel |5 mounted on a shaft I I6 journaled in the housing side walls. Through the valve ||5 there is an air opening I |1` controlled lby a4 spring-pressed plate `type poppet valve I I8 such asis shown `in Fig. 3.4 One end of shaft ||6 extends throughthe housingwallland has a lever ||9 rigidly fixed thereon. Pivotedon a bracket-carried stud verticallyliabove shaft I |6 there is Aa choke'lever |2I'which extends` below the shaft 6 and has atension coil spring |22 connecting it to a-transverse arm |23 on lever |.|9.` The arm |23 extends rfreely through a slot or aperture .|24 in lever |2|` and isheld against one end |25'of the slot by! the spring `|22 so that valve ||5 is heldin wide open vertical position. A pull and pushrod `may belconn'ected to thelever post |26 to move theA lever |2I. As the lever |2| is rotated clockwiseor toward the left, facing Fig. 11, the spring |22 willpull thefchoke valve to closed position. When the choke valve has been. closed, the continued movement of le ver |2| will move slot end |25 away from arm |23 and increasingly load the valve 5. The other slot end |21 is engageable-with arm |23 to positively hold the valve ||5` in closed lposition or tolimit its openingV movement' by air pressure.

Below the housing ||4, there is a cylindrical air inlet and throttlebore |28 within which there is an anterior balanced buttery-type throttle valve |29 mounted on a throttle shaft/|30 `extending transverse to shaft I |6 and journaled-i-n thewalls of `body H0. 1 Oneend of shaft`|30 projects externally'and has rigidlylxed thereona throttle lever |3|. The other `endof shaft |30 extends intov a hollowliboss |32,.se`e2Fig. -l4; and

In the .passageway III, Fig`s`.13, 15and 18, "below the throttle valve |29, there isla/tube |38 o'f Venturi form having "a throat vv|39;" Opening throughthe body |=|0 Sandi tuber|38,wthere isa horizontal, fuel discharge" |40=Jfsubstantially `at the throat |39 and fparallelrto `thrttle'shaft |30; Bridging the inlet end ofthe tube .|38 and the throttle bore |28` there-is anozzle and .bafe mem# ber- |4| having4 a. pair of parallel baiiieuplates |42; |43 extending parallelto `and directly below the throttle shaft |30 and embracingv the. discharge opening |40. The .plate |42\is.cutto.trthe inlet end of passageway and seat on theconverging end of tube |38. .The .plate `|ll2fextends upward substantially to the shaft |30so as toblockair ow .diagonallyA acrossl thevpassageway below the leadingV `edge of..valve |291sandi-=diagonally 'across the outlet of l passageway.' .I 405;. Theimem.- ber |4|1isof generally U-fshapeclwform having its base. yportion .|441cut to conform .with .the .outlet of :passageway 1| 40 7"and vthaving? a lip?` 1| 45: extending downward f and outward from passageway' |40. Extending-betweerplates `|'42-,1 |43 there is.- acap portionf |46 which is: bent outward' and-.downward to forn `theroof ortop Walllof the nozzle. Atoneside:of.the body. |0 there .is a constant level-.fuel reservoir'. |41, Fig.. l1, Ahaving an Lair inlet passageway 41@ openingl upward through the-.fbody' ||0 'into thefairinlet ||2 4above valve ||5 'so that-theiloat chamber is open to' atmosphere above` the liquid 1. level.` f .The chamber. .I 41 has affuel inlet |48.and. therusualoat operated inlet valve` |48`a (Fig. 18.).. Between-the reservoir and the `passageway1||.|,.:the. wall of body 0 has an inclinedabore"therethroughl'with a fuel passageway |49, Figsl` 14.1` and18,. which'intersectsthe horizontalrfuel passageway |40.l Below passageway|49,lthe boreis enlarged. as at |50., to` receive a tubular. memberor housing I 5| .which -ts` the bore |50.; Fttingvinthe lupper end :of member il 5| and lin the; lower end. ofy passageway |49, there is a metering orice member.v |52 "having" a metering lvalve orioe or port 53.5. The `tubular member \|.5'| and orice 'member |52- are heldin position against `the I downward *facing-1 end wall ori shoulderof `bore |50 :byla'screw plug l| 54 which closes the lowerend'of the. bore. The orifice |53 is v.positioned substantially at; butv slightly below the. plane of the reservoirfuel` llevel. designated Theforice .member |52 forms the upper end of `a fuel flow andV wellwchamber '|55 `into the `lower end of which a concentricv 'fu'el '2 inlet passageway |56 opens. Atfits -bottomendi the passageway .I 561terr`ninat'eslin a cylindrical pocket or recess |51'. having. itsbore diameter `reduced slightly :.relativet'o the bore of passagewayv |56. A "fuel-ductorr passage |58` leads from the reser voir |41 into the bore |50.and opens intopassage; way ;|56 slightlyiabovepocket |51th'rough .an aperture |59. (Fig. '11).` lAtthe side of the-` bore |50^,.the body .l0-has a cylindrical fuel-chamber |60 which is divided internally' byF-a cylindrical partitionorftubulanmember |6I into am annular surrounding-fuel welllchamber-IISZ for lowI 'speed acceleration, and f into a-central fuel Swell chamv .ber |6134 `for highlspeedacceleratiorij. 'fI'hef-parti'` tion 1|.6| :is held in` lo'ositionbya` plug :|64 which closes. andseals the. top .of chamber |60. The plug |64hasatubular extensio`n|65fwhich re'- ceilves i and lpositions 'theuppe'r end 4of partition |61` and hasa;..fsurrounding flange |66 fitting the boreoffchamber f 60:1 The annular air cham`` loer` or:mani'fold".|61 between flange |66"and\1the head of .plugl 64=is Ain vcommunicationwith `chamber |63 -byair inlet'ports'|68 in extension |65 and is` ingcommunioation with` chamber |62 by air inlet.Y ports |69 in, flange 166.. `Air i'sv suppliedi'to 'air chamber. |611 .by'a duct `or conduit |10.` which extends'upwardthroughthe wall of .body |.I0 and hasi a.calibrated,inlet1|;1| .(vlig; 11) openingfinto 4the ain-inletgllZl betweenichokenvalved I5 and throttle valve |29. From the bottom end offac.- celerating4 chamber; |62, a. -ductz-` |12 l leads into bore |50-and opens through a calibrated port or orifice |'|3` into` the well chamber 5.5.` 1 From the bottomlehnd ofaccelerating. chamber .|63 a duct or C QnduitJ 14 leads into borezl Eiland opens into an annular .orl .circumferential groove. |15 from the'.l:ottom end of -valve |8| "and extending lconcentrically. therefrom, there is an economlizer tubeV or ,tubularmember |82" vwhich extends through passageway |56 and into pocket |51; The `tube |82 has Vacalibrated bore |83 forming a high speed fuel; ductwhichopens ,through a calibrated outletfcross passage |84 substantially at, valve .|8| andl into chamber, |55, Intermediate its ends, the tube |82 has a circumferential enlargement |85 providing a plug with'a downf,

mine the idling jfuel flow by a key member |9| which fits slidably in a slot |92 in the end of adjustment member |81. i rotatably fits in an annular plug |93 which closes the upper end of the metering pin bore. A spring clip |94 :holds the key member |9| against unintended rotation which wouldchange the setting of the metering valve. .f n E A .The operation'of this single carburetor will be clear from the foregoing description and the description ofV operation ofv theiduplex" carburetor of Figs.; 1-10. The annular orifice areav provided in passageway |56 by plug |85 determines the open position of metering valve |8| and the Asub-atmospheric pressure on the'finlet side of orice |53 in chamber |55 at which the low speed accelerating well, comprising annular chamber |62 and the portion'of chamber |55 above orice |13, will dump its'fuel intoLthe fuel conduit.` AThe extent VOfopeningl or the open position of the metering valve |8| at'which 4plug' ervoir fuel leveland Vat a point between the point of discharge of said first-named well and said metering valve, means determining the open positionof said lmetering valve at which said second well will supply air to saidV conduit, means determining the openposition of said metering valve fat which said first-named Well will supply air to `said conduit, and means operable to supply fuel to said conduit adjacent said metering valve upon supply of air to said conduit from said firstnamed well.

2.A carburetor comprising a casing having a passageway therethrough with an air inlet and 'a-mixture outlet, a constant level fuel reservoir,

afuel conduit leading from said reservoir and discharging into said passageway, a metering valve controlling .fuel now through said conduit, an atmospheric fuel well for supplying fuel and air to said conduit on the inlet side of said metering valve and below the reservoir fuel level, a second atmospheric fuel well for successively supplying fuel and air to said conduit below the reservoir fuel level and at a point between the point of discharge of said first-named Well and said metering valve, means determining the open position of said metering valve at which said second well will supply air to said conduit, means operable by said metering valve and determining the open position of said metering valve at which said first-named well will supply air to said conduit, and means controlled by said metering valve and operable to supply fuel to said conduit adjacent said metering valve upon supply of air to i said conduit from said first-named well.

The key member |9| i 3. A carburetor comprising a casing having a passageway therethrough with an air inlet and a mixture outlet, a constant level fuel reservoir, a throttle valve, a main fuel conduit having a said passageway, a metering valve operable by Y Y said throttle valve and controlling ow through |85 moves out of its orifice or passageway|56 determines the dumping of the high speed ac-'11` celerating well formed =by.central. chamber. |6325@- a fuel conduit.leadingfronr'saidreservoirf'and discharging into saidpassag'eway, a metering valve controlling VVfuel flow through said conduit, 1an atmospheric fuel well for supplying fuel `and air to. said conduit' on the inlet side of said'meter- :ing valve and below the reservoir fuel-level, a 'secondatmospheric fuel` WellI for successively supplying fuel and airito said conduit below-the 'res- 15 saidport, low speed accelerating means to supply a quantity of fuel followed by air to said conduit at an open position of said metering valve, high speed accelerating means to supply a quantity of fuel followed by air to said conduit ,at a further open position of said metering valve, and means movable with said metering valve and operable to supply fa metered quantity of supplemental fuel to said conduit for all open positions of said metering valve vbeyond a predetermined open position, said movable means being initially positioned to discharge fuel into said conduitl anterior toV said metering rport and on movement of said metering valve being positioned to .discharge into said conduit posterior to said metering port.

,4,;A.carburetor Vcomprising a casing having a mix-ing chamber with an air inlet and a mix-1 tureoutlet, a throttle valve for said mixing chamber, a constantl level fuel reservoir, a fuel conduit leading from said reservoir to said mixing chamber; and1having a flow chamber with. an outlet vo riiice;andY anV inlet passage, a metering valve cooperable with said orifice, a tube having an openend and extending from said valve through said, flow Chamberland said passage, a pocket openingintosaid passage and receiving the end lof said' tube, -a head on said tube slidably fitting saidpocket, a circumferential plug on said tube and posltionedwithinsald passage to restrict ow tol said wichamber, opening movement of said meteringV .valveacting to move said plug out of said-"passage: and vsimultaneously `to .move said head. out'of .said pocket and intcposition to restrict ow through said passage, said tube having an outlet adjacent said valve and positioned on the outlet side of said orifice upon movement of said head out of said pocket so that said tube will discharge fuel into said conduit beyond said valve, an air bled fuel well discharging into said ilow chamber, said plug cooperating with the wall of said inlet passage to determine the open position of said metering valve at which said well will discharge, an air bled fuel well discharging into said inlet passage, said plug on movement out of said inlet passage establishing ow from said second-named well, and means operatively connecting said metering valve to said throttle valve.

5. An anterior throttle carburetor comprising a casing having a mixing chamber with an air inlet and a mixture outlet, an anterior throttle valve for said mixing chamber, a constant level fuel reservoir, a fuel passage having an enlarged bore at its lower end communicating with said reservoir, a tubular member in said bore and having an internal elongated chamber and an external shoulder seating against the end wall of said bore, said tubular member having at its upper end a metering orifice substantially in the plane of the reservoir fuel level, said fuel passage having a transverse passage portion leading from above said orifice and having a fuel outlet opening into said mixing chamber on the outlet side of said throttle valve, a guideway alined with said tubular member and extending from said fuel passage, a metering valve extending into said orifice and having a stem extending into said guideway, a sleeve member reciprocally tting said guideway and having an external rack, gear means interconnecting said rack and said throttle valve, said sleeve member being adjustably screw-threaded on said stem to determine the position of said metering valve relative to said throttle valve, said tubular member having a pocket at its lower end and an inlet passage extending from said pocket to said elongated chamber, a tube on said metering valve and extending into said pocket, a head on said tube and fitting said pocket to cut off fuel admission to said tube, a circumferential enlargement on said tube within said inlet passage and restricting iiow to said elongated chamber, said tube having an aperture closely adjacent said metering valve for discharge of fuel from said tube, an air bled well discharging into said elongated chamber, an air bled well discharging into said inlet passage, said tube aperture, said head and said enlargement being so related to said metering valve that in the full open position of said metering valve, said enlargement will be out of said inlet passage, said head will be out of said pocket and said tube aperture will be positioned on the outlet side of said orifice, means on said throttle valve to guide air flow to said mixing chamber, and baflie means in said mixing chamber deilecting air ilow away from said fuel outlet.

6. An anterior throttle carburetor comprising a casing having a passageway therethrough having an air inlet and a mixture outlet and a converging-diverging portion forming a throat, a butterfly throttle valve in said air inlet and controlling the volume of mixture discharged through said outlet, said casing having a fuel outlet orice adjacent and on the outlet side of said throat and discharging parallel to the axis of said valve, a vane on said throttle valve and in a plane transverse to the plane of discharge from said orifice, said vane being positioned on the mixture outlet and leading side of said throttle valve, a baffle plate positioned at each side of said orifice and extending across said passageway parallel to the plane of discharge from said orifice, a ange bridging the space between said plates and shielding the air inlet side of said orice, means on said plates extending into said orifice to locate said plates, and means to supply fuel to said orifice.

HENRY W. BOYLAN.