US2361993A - Carburetor - Google Patents

Description

1944. M. E. Cl -IANDLER 2,

CARBURETOR Filed Aug. 14, 1941 5 Sheets-Sheet 1 Lu-X m W a 4 4. Q

5 Sheets-Sheet 4 n h III.

M. E. CHANDLER CARBURETOR Filed Aug. 14, 1941 Noi 7, 1944.

3 wowwbom MAM/2. 1 Chadd/er.-

Nov. 7, 1944. M. 7E. CHANDLER cmauamoa I Filed Aug. 14, 1941 5 Sheets$heet 5 appear.

Patented Nov. 7, 1944 fUNl'iED s'ra'rss PATENT orncs mom a. Chandler, New Britain, Coma, minimto qhandIer-Evans Corporation, a corporation.

of Delaware Application August 14, m1. Serial so. maria 12 Claims. ((1281-69) My invention relates to carburetors,

It has among its objects to provide improved air flow controlling'mechanism for carburetors, and, more particularly, such an improved mechanism adapted to use in connection with an airplane carburetor. A further object of my inven producing an average metering force distributed over an air passage of substantial area, as dis-- tinguished from obtaining a metering force produced at one or two selected points in the air Fig. 4 is a like enlarged detail section showing the throttle bars of Figure 3 in a diiferentposition;

passage as is usual in prior constructions. Further objects of my invention are, to provide an improved rectangular air meter including connections for measuring air flow therethrough, and to provide an improved cooperating throttle structure controlling the air flow ther'ethrough to the engine. A still further object of my invention is to provide such improved air flow controlling means including such improved throttle means cooperating withthe air meter'and the fuel nozzle or inlet means, whereby it is made possible to effect a more accurate control of the fuel flow controlling means provided in the carburetor. 1 Other objects of myinvention include the provision of an improved air metering and throttling structure whereby while obtaining the above results, it is also made possible to produce an air meter ofthe desired large cross section while at the same time producing a structure which is light and which also permits ready assembly, or disassembly for inspection and repair, .while also being adapted to carry the associated control'mechanisms of the carburetor in convenient locations relative to the air meter. These and other objects and advantages of my imhowever, hereinafter more fully provements will,

- In theaccompanying drawinga l have shown for purposes ,of. illustration one embodiment which ray-invention may assume in practice, In-these drawings,

nism applied to an airplane carburetor;

I Fig. 21s a bottomplan view of.the'same as;seen from the manifold portion thereof a Fig. 5 is an enlarged-section on line 5-4 of Figure 1; Fig.6 is a like section on line 8-4 of Figure 1;

Fig. '1 is a like section on line 1-1 of Figure 1;

Fig. 8 is a like section on line 0-8 of Figure 1;

Fig. 9 is a perspective view of certain of the Venturi bars and oneoi' their associated connecting end plates disposed in spaced relation= to facilitate illustration;

Fig. 10 is a similarview of the same with the opposite connecting end plate;

Fig. ll is an enlarged assembled view of one of the Venturi bars and its associated end plates, a portion of the bar being broken away and the bar and plates being shown in section to facilitate illustration;

Fig. 12 is a 'dic plan view of the assembled Venturi bar and plate unit showing a preferred arrangement of the suction holes in 1 the bars, and

improved Venturimechanism including spaced Venturi bars 8 providing a plurality of improved elongated parallel throat passages and delivering into a rectangular minifold passage I, wherein improved elongated parallel throttles 6 are disposed between a fuel inlet nozzle or bar I and the Venturi throats l and cooperate in an im-" proved manner with one another, the manifold passage I, the improved Venturi mechanism, and

,the throttle bar 1. The main casing I also, cartinuation of application l5, a Referring more; particularly to the Venturi' -l!'ig. 3; is an enlarged transverse section'on line 3-4 of Figure l with parts broken awayto facili of one of the throttle bars:

ries improved fuel flow controlling mechanism, generally indicated at- 8, and responsive to changes in the air flow through the scoop passage 2 tocontrol the fuel fio'w'through a pipe 0, and thereby control the operation of a fuel pressure regulator II in the general manner described and claimed in my eo endmg application, senin No. 474,736, filed February 4, 1943, which is a con- Serial No. 361,239, filed mochanism,.it will be imted that the Venturi bars I. as illustrated, straight and four in number and of animprovedconstruction and connected at their opposite' ends between improvedend plates ii and i2 inan improved manner toform of the compen-Q an improved Venturi bar assembly unit. These end plates II and I2 are herein generally rectangular in shape and received in corresponding openings I3 and I4 in opposite ends of the main casing I. Each bar 3 is of streamlined section and has a hollow longitudinal chamber I5 therein and the plates II and I2 are provided with projecting holding portions or extensions I6 adapted to be received in the opposite ends of these chambers I5. Each of the end plates II and I2 is also provided with a recess portion I? having a corresponding sealing gasket Ila therein and surrounding each of the extensions I6 and adapted to receive the extremity of the bar 3; dowel pins iii in the recesses I'I also connecting each bar to the end plates H and I2 above and below the bar, in such manner as to produce a rigid unitary con struction. As shown, the outer faces of the two outer longitudinal bars 3 engage longitudinally disposed sealing strips I9, shown as tubular and formed of soft rubber and seated in grooves. in the side walls of the scoop passage 2, while the end plates II and I2 also carry rectangular peripheral gaskets 26, in this case also of rubber, engaged by outer casing end plates 2| and 22 to clamp the rectangular Venturi assembly securely in position with its ends in the openings I3 and I4 in the casing I. A plurality of spaced dowels 23 is also provided'at each end of the Venturi assembly and carried by the casing end plates 2I and 22 and extended through suitable apertures 24 in the end plates II and I2, in such manner as to insure correct location. As illustrated, a narrow transverse rib or bridge 25 extends across the bottom of the throats 4 midway between the ends of the Venturi bars 3 and the inner edge of each bar 3 extends into a suitable clearance notch or recess 26 in this rib 25. Further, the two outer Venturi bars 3 are also connected to the mouth of the scoop passage 2 by plate shields 2?, herein suitably connected to the flaring mouth of the scoop passage 2 at their outer ends, as by bolts 28, and having their inner ends received in suit. able longitudinal grooves 29 in the adjacent edges of the outer Venturi bars. These shields 21 thus act to form, two outwardly flaring sides of the scoop passage 2 to direct the air into three inner Venturi passages 4. As shown, also, a series of static scoop tubes 36, herein spaced equally longitudinally along the shields 21, project through each of these shields angularly and these tubes at their inner ends communicatewith longitudinal passages 3| leading to fuel flow control devices as hereinafter described.

The air flowing through scoop passage 2 thus passes through three parallel Venturi passages 4 which extend the full width of the inner bore of the casing between the plates II and, I2. Here,

plate I2 and the end plate 2!, with a passage 33 leading from this chamber 35 to the control devices responsive to the Venturi suction and as hereinafter described.

Cooperating with my improved rectangular Venturi mechanism is also improved throttle mechanism controlling the flow from the Venturi passages 4 to the engine manifold passage 5, and past the fuel inlet nozzle or bar I. Herein, two throttle bars 6 are disposed transversely of the manifold passage 5 parallel to the Venturi bars 3, these throttle bars being Jcurnaled for rotation on their longitudinal axes in the transverse rib or bridge 26 and at the opposite sides of the passage 5. These bars cooperate with one another and with the side and end walls of the rectangular manifold passage 5, in such manner as completely to close the latter passage in the closed position of the throttle 6, while, in their open positions, cooperating with the Venturi bars 3 in further controlling and distributing the flow of air into the manifold 5 and past the inlet nozzle or bar I As shown, each of these bars 6 is of like construction and hollow and of generally elliptical cross section, with a shaft 31 extending longitudinally thereof and having reduced ends 38 journaled in the end plates 2| and 22. Herein each throttle member 6 comprises two longitudinally spaced hollow members 39 suitably fixed to the shaft 31 as by rivets 40. Between these members 39 I herein also show a sleeve 4I surrounding the shaft 31 and in turn surrounded by split bearin members 42 held in position by a snap ring 43; these split members 62 being disposed in an aperture 44 extending through the bar 25 and being positioned in this aperture in such manner as thereby to provide a bearing for each throttle 6 midway between the ends thereof. Herein also it will be noted that these throttles 6 are sealed along the side walls of the manifold chamber 5 when in their fully closed position or approaching this position, the adjacent edge 45 of each throttle then being received in an arcuate seal ing or masking cent wall of the chamber. Moreover, the opposite ends of each throttle 6 also have a sealed connection to the end walls of the passage 6. Each of it will, however, be noted that while various suction aperture arrangements may be provided in the Venturi bars, in the preferred arrangement thereof illustrated, the two outer bars 3 are free from such apertures, while the two inner bars are provided with the arrangement of apertures shown in Figure 12. Each of the inner bars is provided with a series of equally spaced lateral apertures or suction holes 32 on its outer face, and an additional smaller series of apertures 93 on its inner face adjacent each end of the bar. This arrangement is preferred, as it is found to give satisfactory suction effects in various throttle positions. The chambers I5 in these two inner bars 3 also communicate. the extensions or centering bosses I6 with the through apertures 34 in chamber 35 formed by the gasket 20 between the "II the same herein has an end disc 41 abutting the end of each member 39 and each end disc projects beyond the member 39 within an annular cooperating sealing member 43 carried in a suitable recess 49 in the main casting I. 4

No claim, however, is herein made to the particular construction of the throttle members illustrated or the means for iournaling the same or for effecting sealing at the ends of these throttle members, this being the invention of Paul I P. Bauernschmid and described and claimed in a copendmg application Serial No. 406,789, filed August 14, 1941.

Thus, with an operating lever 60 suitablycon- Y nected to one of the throttle shafts 31 andthe two shafts connected bytoothed sectors ll, it

will be evident that the same may be moved in unison into a completely closed position in which they completely prevent flow through the-passage 6, due to their sealed connections along the side walls and their sealed connection to the end walls of the passage 5. Further, when the same. are

opened and move in the direction of the arrows indicated in Figure 4, it will be evident that their sealed end connections will always be maintained, while in the initial stages of this opening movement their side sealed connections will also be maintained, and that accordingly any air passing portion 46 provided on the adia assuage; 3

through the Venturi passages 4 will first pass between the adjacent longitudinal edges of these throttle means 6, i; e. directly in line-with the 1 fuel bar I. As a result, the entering air is thoroughly mixed with the fuel passing through, the diverging fuel bar outlets la into this stream of incoming air and throughout the whole length of the bar 1, which in turn extends throughout the full width of the manifold passage 5. When the throttles are further opened, it will also be evident that after increasing the space between their adjacent edges, and therefore the flow to the fuel bar 1 throughout the full length of the latter, they will also permit air to flow between the throttles 6 and the side walls of the manifold passage 5, and in their fully open position (illustrated at theright in Figure 3) will be disposed opposite the two outer Venturi passages 4 while the fuel bar-I is opposite the middle Venturi passage, all in'such manner as to effect a uniform mixing of the air and fuel while affording a mini mum obstruction to the air flow.

In my improved oonstructiomthe end plate'll causes a valve 81, normally maintained in open position by a coiled spring 61a, to control the flow from chamber '6 through radial ports 68' into an axial passage 60 in a normally stationary sleeve 10 and .the resultant flow from this axial passage 69 through a lateral port 69a to communicating annular passage means TI and the passage 56 leading to the scoop connecting side of the diaphragm 52. Here attention is also directed to the fact that the sleeve 10 is herein provided with a threaded extension 12 and threaded into a packing gland 13 having the annular passage H therein, while adjusting nuts 14 are provided on the outer end of this threaded extension 12. "Thus. it will be apparent that by reason of the spacing of the diaphragm 52 in its, non-coaxial relation with the valve 61, it is made possible for the ported member I0 to be adjusted longitudinallyjo vary the relation of the ports 68 with respect to the valve 61 with facility whenever desired.

carries an improved arrangement of operating diaphragms and controlling mechanism controlling the fuel flow through the pipe I insuch manner as to control the fuel pressure supplied to the carburetor, as described and claimed in my copending application mentioned above.

In this improved arrangementa diaphragm 52 is clamped between an inclined face 53 and a small cover member 54, both being carried by a casing cover member 55 clamped to the end plate 2|. One side of this'diaphragml! is connected with the chambers l5 inside the Venturi bars 3.

As shown in- Figure 6, a more restricted opening 58 is also provided leading from the passage 36 to the opposite side of the diaphragm 52. Moreover, this diaphragm is normally biased by a spring 59, the tension of which is adjusted by a threadedconnection 58a, in such manner as to cause a button 80 on the opposite side of the diaphragm 52 to press against a smaller cooperating diaphragm 6i and thereby close a port 62 controllingthe connection between the pipe 9 leading from the regulator Ill and a passage 63 delivering intothe manifold chamber '5, all in such manner as thereby to control the pressure acting: on the regulator l0 and thereby control the pressure in the regulator to vary the fuel pressure in accordance with variations in the air flow through the air meter, all as described and claimed in my copending application mentioned.

The end plate 2| and cover 55 carry an improved arrangement of aneroid mechanism operating to vary the controlling pressure and the fuel pressure in accordance with changes in altitude and temperature of the air stream. As illustrated, this mechanism includes a sealed Sylphon-type bellows 64 having a tube 65 extending into the 'air stream through the middle Venturi passage 4 and responsive to changes in temperature in the air stream, while the bellows 64 is responsive to changes in pressure due to changes in altitude and is disposed in a chamber 66 which communicates with the longitudinal passages II and the static tubes 30. Thus, this bellows 84 upon any changes in scoop pressure,

and/or changes in temperature of the tube 6i,

Attention is here also directed to the fact that the cross bar or rib25 makes it possible for an accelerating pump to be conveniently carried therein at a central point in the air stream passing through the air' meter. As shown, an accelerating pump plunger 15 is movable longi- 'tudinally in a sleeve 16 extending longitudinally of the rib 26 at a point between the throttle l andthe Venturi bars 3 and movable transversely of both of the latter. Herein, this plunger has a diaphragm 11 connected to the outer end thereof and disposed in a chamber 18 in a cap 18a, while a coiled spring HI normally biases the plunger to seat' upon and close a port ill connected to communicating passages 8|, 8!, 83 which, in turn, communicate with a chamber 84 receiving fuel from the pressure side of the regulator I0 through a passage 85, while ports 86, when the plunger 15 is open, deliver fuel from the port into the manifold passagei on opposite sides of the rib 25., Further, it will be observed that manifold pressure is supplied through a passage 81 to one side of the diaphragm 11 and is also supplied through a restricted passage 88 to the other, or spring pressed, side of that diaphragm. Thus, when the throttles 6 are opened quickly, it 'will be apparent that the rise in pressure in the manifold 5 will be communicated through the passage II to the adjacent side of the diaphragm 11 in such manner as to cause the plunger 15 to move to the left (Fig. 3) and immediately open port ill to increase the fuel supply momentarily. When, however, suilicient time has elapsed, the how through the restricted opening 88 will be sumcient to reestablish a balanced pressure on opposite sides ofthe diaphragm TI and thereby again close the port 80. Should, however, the throttles I be opened slowly, this port II will ordinarily not be opened.

It will also be noted that this improved construction permits an improved compensating valve mechanism to becarried on the end plate 22. .This mechanism includes a diaphragm it having one side thereof connected through a bleed 90 and passagell to the static scoop tubes 30, while the other side of this diaphragm is connected to the fuel supply from the regulator ll through a connection 82. Herein, this diaphragm carries a compensating valve 88 having spaced seats 94 and 95 on a valve seat member 96 at opposite ends of the valve, while the valve 83 is provided with an axial passage 81 communicating throughradial ports 91a with the struction and the new ends", it is made possible fuel connection 92 and through a port 98 and an annular passage 99 which, in turn, communicatethrough a slot 99a and chamber 9% with a passage I leading to one end I. In this construction, the diaphragm W is as usual biased to a position closing the valve 93, by a spring l0! acting against an abutment Hi2 adjustable by a threaded pin W3. Attention is also directed to the fact that the valve 93 is provided with triangular guiding portions lll l at its opposite ends and with external annular passages l05 for also permitting an external flow around and along the valve.

It will be noted that the cross bar or rib 25 is of considerable depth, providing a septum extending transversely of the main air passage provided within the carburetor body, the same being a relatively narrow member and having those edges which in Fig. 3 are uppermost and lowermost, respectively, curved, as shown in Figs. 1 and 2, for stream-lining. At its upper part (Fig. 3) this septum has the clearance-notches in which considerable portions of the bodies of the Venturi bars are received, and in the body of the septum below these notches is the chamber in which the accelerating pump is received,

said pump being arranged to supply fuel to the outlet ports 86 a short distance below the pump, which ports slant downwardly proximate lateral faces of the septum, these ports being in line with the elongated passage between the two inner Venturi bars, and these ports being above (Fig. 3) and in linewith and a short distance from' the line where the throttle bars in their closed position meet each other. The middle bearings for the throttle bars are also provided the fuel bar '5 extends through it at a point somewhat above (Fig. 3) the lower margin of the septum. The septum, furthermore asshown in Fig. 3, serves to provide within it a portion of the passage 81 previously referred to, which is intended to be subject to manifold pressures.

The rubber sealing strips of the fuel bar within this septum, and furthermore,.

is, which abut the pressure thereof supplied to the engine cylinders and while also markedly increasing the metering force for actuation of the various control devices. Attention is further directed to the fact that, due to the provision of the improved sealed Venturi unit and sealed throttle bars, it is made possible to eliminate air leaks past either the Venturi bars or the throttle bars,

(Fig. 3) t0 the the Venturi bars being sealed at all times, and the throttle bars being sealed at their ends at all times and along their sides in their fully closed position or positions approaching and leaving the same, while atthe same time, under these conditions of small air flow, directing the air in such manner as to form an effective mixture with the fuel emerging from the apertures in the fuel inlet bar. vAttention is also directed to the improved Venturi unit structure provided, and to the facility with which the same may be produced and assembled or removed in the carburetor, with this unit longitudinally insertable or withdrawable through the end apertures in the main casing. These and other advantages of my improvements will, however, be apparent to those skilled in the art.

While I have herein specifically described one embodiment which my invention may assume in practice, it will be understood that this form of the same is shown for purposes of illustration, and that the construction may be modified and embodied in various other forms without departing from its spirit or the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent is:

l. A carburetor comprising a body or casing having a through opening or passage of generally rectangular cross section extending from a face having an enlarged inlet or scoop to an opposite face at,which a manifold connection is made, the carburetor being provided within said against the sides of the outermost Venturi bars,

serve to an extent to support the bars in a cushioned manner and to reduce vibration and permit expansion and contraction under temperature changes. The rubber gasket 20 also support the Venturi bars in a cushioned manner and reduce vibration and obviate close tolerances, this being in addition to their function of providing effective seals at the ends of the bars against leakage of fluid. The plates 2! and 22 clamp the plates ii and I2 against the ends of the Venturi bars in a resilient manner.

the plates and bars being provided with means whereby they interengage or interlock, for which purpose one element has preferably a locating boss or; projection fitting a corresponding recess in the it is made possible to- The plates H and I2 serve to tie the Venturi bars together in a definite spaced relation,

passage with bars providing a plurality of narrow substantially rectangular Venturi passages and being provided beyond the discharge of the Venturi passages with a pair of throttle bars adapted to be turned to a closed position and to various open positionsand adapted when in an open position to provide between them a restricted passage, and the carburetor also having in its main passage in a region close to and somewhat beyond said restricted passage in the direction of air flow a fuel bar extending lengthwise of said restricted passage, shield plates arranged to provide a flaring scoop portion adjacent the entrance of the main passage having inner edges in proximity to the air-receiving ends of the marginal Venturi bars and having outer edge portions attached to the body wall, and a relatively deep septum crossing the main passage transverselyof the Venturi bars adjacent the discharge sides of said bars, said septum having clearance notches receiving substantial portions of the respective Venturi bars, said septum carrying intermediate bearings for said throttle bars and providing an intermediate support for said fuel bar, and said septum further providing within it in a location forwardly of the throttle bars a chamber and an auxiliary fuelpumpwithin the chamber, said pump havs septum, and the septum having auxiliary fuel discharge ports at its side faces in locations forwardly of the throttle bar axes and between said axes. I

2. A carburetor comprising a body or casing a discharge intermediate the ends of the.

2,861,998 having a through opening or passage of generally rectangular cross section extmding from a face having an enlarged inlet or scoop to an opposite face, the carburetor being provided withlnsaid passage with means providing a plurality of narrow substantially rectangular Venturi pas-.

sages and being provided beyond the discharge of the Venturi passages with a pair of throttle bars adapted to be turned to a closed position and to various open positions and adapted when in an open position to provide between them a restricted passage, and the carburetor also having in its main passage in a region close to and somewhat beyond said restricted passage in the direction of air fiow a fuel bar directed longitudinally of said restricted passage, said Venturi bar being formed as separate individual members, plates extending across said members at the respective ends of the latter for tying them together set in apertures formed in the carburetor body at opposite sides of the body, separate plates attached to the body exteriorly and cooperating with said first-named plates in holding the Venturibars firmly in position lira, detachable manner, sealing'strips interposed between the side faces of the marginal Venturi bars and the adjacent wallsoi the body, and shield plates arranged to provide a fiaring scoopportion adjacent the entfance of the main passage having inner edges in proximity to the air-receiving ends of the marginal Venturi bar and having outer edge portions attached to the body walls. 3. A carburetor comprising a body or casing having a through opening or passage of generallyrectangular crosssection extending-- from a face having an enlarged inlet or scoop to an opposite face, the carburetor being provided within said passage adjacent the base of the scoop with a plurality of straight bars in the same plane, said bars being four in number and providing a middle or median Venturi passage and side Venturi passages, the carburetor being provided beyond the discharge of the Venturi passages with a pair of throttle bars turning on axes substantially in line with the respective side Venturi passages and adapted to be moved to a closed position and to various open positions and adaptedon first opening to provide a restricted passage at the median portion only of the main passage and on full opening to provide outer passages as well as a median passage, and the carburetor also having in its main passage in a region close to and somewhat beyond said median restricted passage in the direction of air flow, a fuel bar directed longitudinally of said passage.

4. A carburetor comprising a body or casing having a through opening or passage of generally rectangular cross section extending from a face having an enlarged inlet or scoop to an opposite face, the carburetor being provided'wiiih'in said passage adjacent the base of the scoop with a plurality ofstraight bars in the same plane, said bars being four in number and providing a middle or median Venturi passage and side -Venturi passages,-the caburetor being provided beyond the discharge of the Venturi passages with a pair of throttle bars turning on axes substantially in line with the respective side Venturi passages and adapted to be moved to a closed position and to various open positions and adapted on first opening to provide a restricted passage at the median portion only of the main passage and on full opening to provide outer passages as well as a median passage, and the carburetor also having in its main passage in a region close to and somewhat beyond said median restricted passage in the direction of air flow, a fuel bar directed longitudinally of said passage, and a relatively deep septum crossing the main passage transversely of the Venturi bars adjacent the discharge sides of said bars, said septum carrying intermediate bearings for said throttle bars and providing an intermediate support for said fuel bar.

5. A carburetor comprising a body or casing having a through opening or passage of generally rectangular cross section extending from a face having an enlarged inlet or scoop to an oppositeface, the carburetor being provided within said passage adjacent the base of the scoop with a plurality of straight bars in the same plane, said bars being four in number and providing a. middle or median Venturi passage and side Venturi passages, the carburetor being provided beyond the discharge of the Venturi passages with a pair of throttle bars turning on axes substantially in line with the respective side Venturi passages and adapted to be moved to a closed position and to various open positions and adapted on first opening to provide a restricted passage at the median portion'only of the main passage and on full median passage, and the carburetor also having in itsmainpassage in a region close to and somewhat beyond said median restricted passage in the direction of air flow, a fuel bar directed longitudinally of said passage, and aseptum crossing the main passage transversely of the Venturi bars in the space between the Venturi bars and the throttle bars and provided with an interior chamber and an auxiliary fuel pump in said chamber, said pump discharging forwardly of the throttle bar axes in a location between said axes.

6. A carburetor comprising a body or casing having a through opening or passage of generally rectangular cross section extending from a face having an enlarged inlet or scoop to an opposite face, the carburetor being provided within said passage adjacent the base of the scoop with a plurality of straight bars inthe same plane, said bars being four in number and providing a middle or median Venturi passage and side Venturi passages, the carburetor being provided beyond the discharge of the Venturi passages with a pair of throttle bars turning on axes substantially in line with the respective side Venturi passages and adapted to be moved to a closed position and to various open positions and adapted on first opening to provide a restricted passage at the I median portion only of the main passage and on 0 full opening to provide outer passages as well as a median passage, and the carburetor also having in its main passage in a region close to and somewhat beyond said median restricted passage in the direction of air flow, a fuel bar directed longitudinallyof said passage, and a septum crossing the main passage transversely of the enturi bars in the space between the Venturi bars andthe throttle bars and provided with an interior chamber and an auxiliary fuel pump in said chamber, said pump discharging forwardly of the throttle bar axes in a location between said axes, said septum carrying intermediate bearings for said throttle bars and providing an intermediate support for said fuel bar.

7. A carburetor comprising a body or casing having a through opening or passage ofigenerally rectangular cross section extending from a face having an enlarged inlet or scoop to an opposite face, the carburetor being provided within said passage with four removable straight bars provide a flaring scoop portion adjacent the 'entrance of the main rectangular passage having inner edges leading to the inner edges in proximity to the forward edges of the marginal Venturi bars and having outer edge portions attached to the body walls, the carburetor being provided beyond the discharge of the Venturi passages and within the rectangular main passage with a pair of throttle bars adapted to be turned to a closed position and to various open positions and adapted when in an open position to provide between them a restricted passage, and the carburetor also having in its main passage in a region close to and somewhat beyond said restricted passage in the direction of air flow a fuel bar directed lengthwise of said passage.

8. A carburetor comprising a body or casing having a through opening or passage of generally rectangular cross section extending from a face having an enlarged inlet or scoop to an opposite face, the carburetor being provided within said passage with means providing a plurality of narrow substantially rectangular Venpassage, the Venturi passage means aforesaid including separate individual straight Venturi bars extending across the passage, plates extending across said Venturi bars at the respective ends and tying them together in a definite spacing, said plates being set in apertures formed in the body at opposite sides of the body, and separate plates attached to the carburetor body exteriorly and cooperating with said first-named plates in holding the Venturi bars firmly in position in a detachable manner, said throttle bars having end bearings supported in said lastnamed plates and said fuel bar being extended into and supported within one of said lastnamed plates and being in communication with a fuel supply passage in said plate.

turi passages and being provided beyond the discharge of the Venturi passages with a pair of throttle bars adapted to be turned to a closed position and to various open positions and adapted when in an open position to provide between them a restricted passage, and the carburetor also having in its main passage in a region close to and somewhat beyond said restricted passage in the direction of'air flow a in the body at opposite sides of the body, and

separate plates attached to the carburetor body 10. A carburetor comprising a body or casing having a main passage through it of generally rectangular cross section, the carburetor being provided within said passage with means providing a plurality of narrow substantially rectangular Venturi passages and being provided beyond. the discharge of the Venturi passages with a pair of throttle bars adapted to be turned to a closed position and to various open positions and adapted when in an open position to provide between them, a restricted passage, and the carburetor also having in the main passage in a, region close to and somewhat beyond said restricted passage in the direction of air flow a fuel bar longitudinally disposed with respect to said passage, the Venturi passage means aforesaid comprising a plurality of straight parallel Venturi bars together with end members tying said bars together in a definite spacing to provide a removable frame disposed in the passage and extended at its ends into apertures at opposite sides of the body, and plate members ap-- thereinto and the other of said members being in a-location spaced from the entrance comprismg a plurality of straight bars extending across the passage and defining between them a pluexteriorly and cooperating with said first-named plates in holding the Venturi bars firmly in position in a detachable manner, said throttle bars having end bearings supported in said lastnamed plates.

9. A carburetor comprising a body or casing having a through opening or passage of generally rectangular cross section extending froma face having an enlarged inlet or scoop to position and to various open positions and adapted when in an open position to provige between them a restricted passage, and the carburetor also having in its main passage in a rality of rectangular Venturi passages, said Venturi passages comprising a middle passage and two side passages, fuel inlet means comprising a fuel bar arranged in the main passage on the delivery side of said Venturi means and in line with the middle Venturi passage, spaced throttle bars in the main passage between the Venturi means and the fuel inlet means turning on axes in approximate alinement with the side Venturi passages, said throttle bars having edges adapted to meet each other in a line substantially in line with the middle Venturi passage and to be turned to various open positions so as to create a restricted passage substantially in line with the middle Venturi passage, and means in connection with opposite walls of the casing providing masking means for said throttle bars such that region close to and somewhat beyond said restricted passage in the direction of air flow a v only in the restricted passage between them while on further opening air passes said bars at their outer sides also.

12. In a fuel supply system for an internal 2,861,998 combustion engine, four walls forming an air passage of substantially rectangular cross-section, Venturi means in said passage for producing two unequal pressure whose diflerence is a measure of the quantity of air flowing thru said passage, said. Venturi means comprising a plurality of parallel bars in the same plane, said bars being four in number and providing a central Venturi passage and two side Venturi passages, a pair of substantially rectangular throttle bars in said passage downstream from said Venturimean's, said bars turning on axes substantially in line with the respective side Venturi passages and adapted to be moved to a closed position and to various open positions, means for controlling the relationship between angular ther opening outer passages are provided'in ad-' dition to said central passage, means for supplying i'uel to said engine, and mean responsive to said difference of air pressures for controlling said fuel supplying means.

MILTON E. CHANDLER.

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