US1684055A - Carburetor - Google Patents

Description

Sept. 11, 1928. l 1,684,055

R. F. ENslGN CARBURETOR Filed Nov. 5o, 1925 5 sheets-sheet 1 Sept. 1l, 1928.

R. F. ENslGN cARBuREToR mm; mm S Sept. ll, 1928. 1,684,055

R. F. ENslGN aantal sept.y 11, 192s.

y .UNITED STATES- ROY ENSIGN, OF SOUTH PASADENA, CALIFORNIA, vASSIGNOR TO SIGN CARBURETOR T j, OFFICE.

COMPANY, OF LOS ANGELES, CALIFORNIA, CORPORATION vOF CALIFORNIA..

camsumnron.

Application led November 30, 1923. Serial No. 677,649.

This discovery and invention involves novel principles in the production of a constant liquid to air ratio This invention comprises a Venturi type carburetor having the inherent characteristic of producing a constant 'fuel to air ratio throughout the entire range of operation of the carburetor, and l have thereby'dispensed withthe so-called compensating devices such as air bleeds, air valves and auxiliary jets which have heretofore been deemed necessary to accomplish such production.

|llhis discovery and invention is directed toward simplifying the construction and vim- )rovine the o eration of formercarburetors b and to the introduction of novel accelerating means, novel economizing means, and novel means for combining a balancing system with a starting system.

` An object of this invention is to thin the mixture of fuel and air at moderate or normal loads without involving a like change at higher loads, and ll use the depression between the throttle and thel engine intake to 'accom-` plish this.

rlhe depression beyond the throttle changes. according to engine load; a high depression indicates a low oad and alow depression a high load and l make use Vof this changing depression to operate a piston which controls a valve, the opening of which permits the application of the depression existing in the carburetor below the throttlato the airA above the fuel in the fuel supply chamber, V4thus derezsing the How of fuel orifice through the Some of the objects of this invention are as follows:

To provide novel means whereby separate restrictions of the venturi are used to regulate the atomizing and proportioning of fuel to air;

'fo provide novel Ameans whereby a carburetor will provide a constant mirrture proportion during entire range of operation;

To provide novel and better means for furnishing ample fuel for accelerating purposes.

fan object of the invention is to maire provision for increasing the flow of fuel through l the fuel orice durin acceleration, according to the degree of acce ration.

Another object is to provide a Venturi type carburetor in which the mixing of fuel and air or atomizing` of the fuel by air does not interfere with the proportioning of the fuel to the air passing through the carburetor. y

Another object is to provide novel means for changing from normal mixture to a lean- 'er mixture according to the degree of load on the engine. v

Heretofore, the majority of carburetors have been provided with a small fuel orice through which the liquid may flow from the float bowl; and owing to the natural tendency to increase the amount of fuel in proportion to the air whenever the velocity 4through the carburetor increases, such carburetors do not maintain, over a Wide range of pressures, a uniform or constant proportion.,

l have made provision to correct such tendency and'af'ford a larger range of How than heretofore from the constant level chamber to the depressionchamber from which the fuel to flow through the fuel orifice; and to bring l about the proportioning of the fuel to the air by the depression of the air only at the large throat of the venturi, I admit no fuel from the supply chamber to such large throat, and l impose such depression upon the fuel orifice by action of the air stream through an extra large air passage.

In order to thoroughl min the fuel and air, I provide a venturi smaller than the Iproportioning point which creates a greater depression and thus maintains a flow of fuel from the fuel orifice, and air from the proportioning point to the mixing venturi.

l have located the throttle beyond the mining venturi in order to avoid wide differences in pressure between the mixing venturi and the proportioning point.

@ther objects of the invention are simplic-v lll@ invention may appear from the accempanying drawings, the subjoined detail' description and the appended claims.

This invention may be carried out by various means and the accompanying drawings illustrate such -means and the form of appar-a1A tus l at present deem preferablel for carrying ingremoved.

Fig. 6 is an enlarged fragmentalv sectional detail on line :r4-m", Fig. 2, showing the joint formed with packing.

Fig. 7 is a horizontal section of the venturi taken on line wf, Figs. 4 and 8.

lig. 8 is a vertical sectional view on line Figs. 2, 9 and 10.

Fig. 9 is a 'horizontal section on line we, Figs. 1, 4, 5 and 8. j

Fig. 10 is a broken horizontal section on line 031, liigsl, 4, 5 and 8.

'lhe carburetor shell comprises upper and lower sections A, B which are fastened together by a liquid and air tight joint and enclose a Venturi structure C and associated parts.-.

rlhe upper portion A is asingle casting comprising a throttle barrel 6, bored out as at to receive an inserted Venturi tube, and flange, as at 8, for connection to an engine intake, and an extension which forms the upper part of a constant level chamber l and a. depression chamber 3. The partition separating these chambers has a horizontal portion 2, in which is a threaded opening for the sleeve 26,v hereinafter described more fully. The lower portion 4 of the depression chamber is hereinafter called a fuel well.

The lower section' B is conveniently made to includes thel air intake b, a diaphragm chamber o, and a Venturi seat and is conl nected to the upper section A by means of screws e.

The Venturi structure@ is adapted to snugly lit into the bore 7 iii the piece A belowr the throttle barrel 6 and is secured thereinby a screw 8, The structure C is shown as containing the mixing Venturi throat 11 or the point of 'maximum air velocity through the carburetor and at which point the fuel is introduced into the main air stream below the upper expanding mouth portion f of the venventuri at a point, as 9, of greater area than the throat 11, said ports ale shown as slots which extend approximately entirely around the venturi at the point 9 and open into a passage 12 between the venturi and the bore 7 of the carburetor body.

Said slots are separated by the connections v 13 which prevent Separation of the structure. The depression chamber 3 connects with the upper end of the passage l2, to permit the depressioneffective at the orifices 1() to be also effective in the chamber 3. The lower end 14 of throat 9 flares and forms a stream line approach to the proportioning point 9.

rll'ie constant level fuel chamber 1 is supplied with fuel through the usual fuel supply connections 15 and the fuel insaid chamber is maintained at a .so-called constant level 16 by the usual ioat 17 and valve 18.

The fuel delivery passage that delivers fuel Afrom the supply Achamber-1 to the main air stream thru the Venturi structure for all except very low speeds, comprises the fuel controlling orifice 19, the overflow fuel passage 20, the vertical adjustable ports 21the fuel well 4, passage 5 and nozzle 24. The passage 5 opens thru a wall of the section A to the bore 22 `in the boss 23 that projects from the reduced portion of the Venturi structure. rlhe nozzle 24 fits in the bore 22 and communicates with. the main air stream and passage 5.

fllhe part-26 is screwed into the threaded portion 2 and contains the fuel controlling` orifice 19 and the bore 2 into which fits the part 20 of the adjusting screw 27.

The fuel controlling erice. 19 is below the constant level 16 is normally submerged in the fuel in the supply chamber and admits fuel to the passage 20 from. which such fuel is drawn through the vertically adjustable port 21 into the fuel well 4 from which it is drawn through the passage 5 and is discharged from the nozzle 24 into the venturi at the mixing throat 1l.

rlhe overflow fuel passage 20 is mounted for vertical adjustment in said part 26, and extends vertically from, and is arranged axially to, the fuel controlling orifice 19. rllie ports 21 are usually adjusted so that the bottom edge of said ports, will be a predetermined distance from the constant fuel level 16. lThe passage 5 is preferably extended by a tube 28 andopens at one end into the suction well 4 below the level of the adjustable port 21 and near the bottom of said well 4, and is preferably provided with ports 28. The space above the fuel inthe fuel supply chamber is connected to the air passage in the air intake by means of an equalizer tube 29, one end of which is open toward the inflowing air at the proportioning.Venturi throat 9 and the other end of said tube 29 is secured in a bore 3() formed in the Venturi structure C and opens into a passage 3l that communicates with a passage 3l and port K which opens into the fuel supply chamber. 'lheidling bypass 32 is connected at its lower end through a passage 38 with` an an` nular chamber 39 formed between the nozzle seat 22 and the delivery end of the nozzle 24, which is reduced to form said annular chamber; the object being'to pick up at the end of the nozzle, any fuel which may flow into the venturi when there is not suicient velocity ot air to carry such fuel to the throttle; the depression at this point being from above the throttle, and therefore greater than the depression in the venturi below the throttle.

The idling by-pass 32 is open at its upper end to the throttle bore 6 through the reduced port 33 at a point above the throttle g, and such passage opens also into the throttle barrel below the throttle, through the port 34.

rlhe lower end of said by-pass 32 is extended into the depression chamber 3 by means of a tube 35 having a restricted end. 36; said tube 35 is inserted through a bore 37. The restricted end 36 is located approximately at a.

height corresponding with the lower edges of the adjustable overow ports 21.

rlhe lower end ot the lay-pass 32 is open to the passage l2 through the passage 38 and a reduced passage 32 in the boss 23 that connests said passage l2 with the passage 38.

ill/leans are provided to apply a depression except at very low speeds, upon the surface ot' the fuel in the -fuel supply chamber, to retard the flow ot fuel through the main fuel passage at motor loads about or below onehal to thereby diminish the ratio of fuel to air at such loads to obtain a higher economy during engine operation below halt motor load, except very low speeds. Such means comprise a suction operated piston 42 which is slidably mounted in a bore 43, and divides such bore into upper and lower chambers 44, 45 respectively.

Jhamher 44 is open to the throttle barrel above the throttle through the port46 and the chamber 45 is open below the throttle through the port 47.

rplug 48 is screwed into the upper end et the chaniher and has an extension 4 9 forming a stop to limit'the upward movement ot the piston. A spring 50 encircling the extension 49 operates between fthe head o2 'the screw 48 and the piston 42 to force the piston downward against a valve 5l which is loosely mounted in a bore 52, and has a guide 53 extending in the bore to prcventdisplacement of the valve. Said valve 5l seats on a valve seat 54 and is yieldingly held in seated position by the piston 42 and the spring 50, except when the depression beyond the throttle is sufficient to lift the piston against the pressure ot spring 50 when the valve 51 will seat by its own weight except when the depression applied through port 47 is suicient to raise the valve 5l from its Seat.

The lower chamber 45 communicates with the fuel supply chamber 1 through said bore 52, and passages 55, 55. The opening of passage 55 may be adjusted bymeans of a screw 56 threaded into the boss 57 and is locked in adjusted position by the loclr nut 58.

A choke valve 59 mounted on a shaft 60 controls the air which enters the air` intake and s.operation of the choke valve 59 also acts to operate a valve to destroy the equalizing edect obtained in the float chamber by the equalizer means 29. This operation is accomplished by the shaft 60 extending through and closing and opening the lower end of the passage 31 which is open at its lower end to the atmosphere preferably through a restricted orice 31".

Vhen the choke valve 59 is open alter the enginehas been started, the shaft 60 closes the lower end ot the passage 31 and when the choke valve 59 is'closed for starting purposes the shaft 60 is oscillated so that a hole 6l in shaft 60 alines with the passage 3l' and thereby opens the lower end of said passage to the atmosphere through the orifice 3l, and thereby increase the pressure upon the surface ora the fuel inthe fuel supply chamber above that applied by the equalizer vmeans and thus causes a greater `flow of :Fuel through the fuel passage during starting operation.

ll/ileans are provided to supply additional fuel ior accelerating and comprise a plate62 which forms the bottom ot the fuel supply chamber l, and is secured between the parts A and y Said plate 62 is provided directly.

beneath the r'uel aiorilice i9 with a jet 63. A diaphra 64 is also secured between the upper and yower pieces A and B and is mounted below the plate 62 in the chamber @which is connected to a point above the throttle by means of apassage 66 having a port 67 at one end and a port 68 at its other end which opens into the throttle barrel above the throttle. A headless screw 55( isorced into the lower end ot the passage 66,'-the purpose ot which will loe hereinafter explained. ing :fuel chamber 35, is formed hetween the diaphragm 64 and the plate 52.

Suitable paelrings 69 and 'Z0 are interposed above the plate 62 and between the plate and diaphragm 64 respectively, so as to form an air and gas tight lit between the chamher o and the tuel supply chamber l.

-l'n operation air enters the air intake 5 and4 lows past the cholre valve 59. stream line approach i4, proportioning throat 9, stream ine approach 11. mixing throat ll-at which point it receives fuel from the nozzle 24 and the mixture then continues on its way through the upper expanding portion f of the venturi past t barrel d into the engine manilold D.

The depression due to the pumping action oii the engine on which is superimposed vthe depression due to velocity at the proportioning point 9 is applied upon the fuel orifice 19 An ecceleratev throttle g in the throttle' lill) to lift fuel to be delivered to the main, air i stream through the nozzle 24, fuel is taken from the fuel well 4 through the 'restricted end 36'0f the tube 35 which is an extension of, and communicates with, the by-pass 32 which opens `into the throttle barrel 6 above the throttle g through the port '33. rlhis is caused by the depression above the throttle v being applied to the by-pass 32 through the port 33. 'llhe Iport 34 opening from a point below the throttle into-the idling by-pass l serves to reduce the suction upon the restricted end of the tube 35.

During lownloads the depression in chamber 3 is increased by the connection through the by-pass 32 thus causing an increased flow of fuel through'orifice 19 at such loads.

After the velocity of the air through the carburetor increases7 the depression at the mixing throat 11 'becomes greater and such depression is suilicientat all speeds, except very low speeds, to draw fuel from the fuel well 4 and deliver such fuel to :the main air stream from the nozzle 24, as the velocity increases, more and more fuel will be drawn' from the well, thereby lowering the height of fuel in the well 4 below the restricted end 36" of the idling' by-pass, and thus prevent further delivery of fuel from the Well 4 through theid'ling b -pass until the suction is reduced and the fue again rises to a level. above the re stricted end 36 of said by-pass. This em tying and filling of the well 4 supplies a di- -tional fuel for accelerating purposes.

As the velocity of the main air stream increases more and more fuel 1s wlthdrawn from the fuel well 4and the ports 28 will be consecutively uncovered thereby admitting more and more air into the well discharge passage to thus regulate and prolong the rate of delivery of fuel Afrom the accelerating well (lll during increase of engine speeds.

Simultaneous with the increase of air velocity at the mixing throat 11 the depression at the proportioning throat 9 is increased and such depression is communicated to the deression chamber 3 and causes anjincreased ow ot fuel from the fuel supply chamber into fuel well 4. i

The nozzle 24is such a small fraction of the area of the slots 10 ortho proportioning air passage 12 that the dow of air through the ports 23, passage 5, and nozzle 24 will not materially allect the depression imposedthrough passage 12 upon the fuel orifice`19 by the pumping action of the engine on which is superimposed the depression due to velocity Lectora at ,the proportioning 'point 9 operates to draw fuel into the fuel well 4 at all velocities through the carburetor, thus producing a correct mixture at all engine speeds, while the atomizing is done at the usual velocity and with ample air to produce the atomization.

"Whenl the depression applied to the nozzle 24 is sucientto draw or lift fuel from the well `4, but the velocity of the air stream is not sufficient to carry the fuelonward to the engine. manifold, such lifted fuel will Ibe taken fromv the nozzle 24 and ldelivered into the throttle barrel beyond the throttle through the annular chamber 39, passage 38, idling bypass 32, and port 33- by reason of the suction applied to the port 33 during the lower Speeds l s In vorder'to equalize or balance the depression applied to the fuel orifice by the'friction of the air dow up to the proportioning throat 9 during engineoperation, the same depression is applied upon the surface of the fuel in the fuel supply chamber by the suction at theend of the equalizer tube 29 which connects with thev fuel supply chamber through the passages 31, 31' and port K.

.lin order to give'high economy l reduce the fuel to .air ratio during engine operations with the throttle only slightly open, 'except at very low speeds. During Such range of engine operations the suction above the throttle applies a depression in', the chamber 44v through port 46. The iston 42 will be raised against the pressure o the. spring 50 releasing the valve 51. 'lhe depression below the rou throttle applies suction to the chamber 45 through the port 47 and when the latter depression is sucient it `reims the valve 51 from its seat 54 therebyopening the passage from the chamber 45 into the fuel supply chamber. The opening of the passage from the chamber-45 into the fuel supply chamber causes an increase 'in the depression on the surface of the fuel in the fuel chamber and thus reduces the fuel ilow through the fuel orihce' 19. v

llhe ring 50 is so adj-usted that the piston 42 will is' raised from idling speeds to approaimately 4half load and thereby permit .the valve 51 to be opened during such range vof speeds.4 ,'lhe valve 51 will be open from approximately half load to approximately onetenth of the load, when the passage 52 will be closed by the valve? 51 due to its own weight because the suction applied to the valve seat in the chamber 45 is not suficient to hold the valve 51 in open position.

'lbe extension 490i the screw 48 limitsthe upward movement of the piston 42 which in turn limits the upward movement of the valve 51.

Adjustment of the screw 56 opens or closes the passage 55, according to the direction said screw is turned and serves to control or adjust the amount ofthe depression in the lll ' spaced suchv distance from 4the fuel orifice 19 as is necessary in order that the filling `of the chamber 65 will-'not affect the flow o f fuel lfrom 'the fuel supply chamber into `said orilice. By spacing the fu'elj'et from the .fuel orifice a` greater distance than above mentioned, the flow of fuel for'acceleration may be regulatedl When a suction or depression is applied to the port 68, as for example, durj ing the lower speeds with the throttle partially closed, .a likegdepression is, applied through the passage' 66 and port 67gto the chamber underneath the diaphragm 64., and .this draws the diaphragmfdownward until it contacts with thebottoni wall m of the vchamber c', thereby preventing fluttering of the diaphragmf vandcon'sequent forcing .of fuel fromvthe jet63. By--thusv drawing the diaphragrndownward, the capacity ofthe acceleratingfuel chamber 65 lis increased and vsuch increase issupplied Aby fuel frm'the fuel supply chamber so that additional, fuel for acceleration is' accumulated and stored for use. .The flow of fair in the passage 66 t0 and from the chamber' c takes a spiral path around the threads of the screw 66 thus retarding the air flow in the passage 6,6 to prevent a fluttering of the diaphragm "64. Q

When the depression at the port l6 8 isdecreased, as for example, when the throttleis suddenly opened, the result is thatthe Suction holding the diaphragm down is removed and the diaphragm'will return by its own resiliency to normal position andcause fuel accumulated inchamber' to be projected linto the supply chamber from the jet 63 directlyl toward the fuel orifice 19,with such impulse as to effect an increase of fuel flowthrough the fuel orifice 1 9 during accelerating periods, without any positive pump-ing of fuel through such fuel orifice 19. In other words the stream of fuel forced from jet 63 into orifice .19 entrains 'fuel from the con. stant level fuel chamber into the fuel-passage thereby eiecting an increase of fuel o'w through the fuel orifice 19y during accelerate ing periods.

' lclaim.

l. In a carburetor comprising a Vfuel sup, ply chamber, and an air intake, a shaft mounted in said air intake; a choke valve mounted upon said shaft; a fuel orifice; means todeliver fuel from said fuel supply chamber through .said orifice tov` the a1r stream; means vto equalize the depression chamber; 'a valvein said. lower cham caused by. air resistance which would otherwise add to theowof Vfuel through said fuel orifice; and means controlled by operation of the choke valve to destroy the effectof the eq ualizermea'nsto c'ause'an inereasedtlow of fuel ori'ce 'during starting `control the flow ,of said air stream; afplate having a fuel jet spaced from and co-axial with said fuel orice; a chamberfa diaphragmmounted in said chamber and forming an acceleratingwell between said diaphragm and said plate, said 'acceleratngfwell being. adapted' to accumulate fuel from the fuel supply chamberthrough said' jet; and a passage connectingthe chamber below the diaphragm to the air stream above the throttle to apply a depression in said-'chamber to hold'the' diaphragm down when such depress sion isapplied, and to release said diaphragm whenthe depressionis removedv to force fuel f through said jet into said fuel supply chamber to cause additional fuel flow through'said fuel orifice. '3. A1 carburetor comprising a mixing throat, a throttle, a throttle barrel, and a fuel .supply chamber, a fuel .passage from said supply chamber to said mixing throat; a passage connecting said.l supply chamber` withl the throttle barrel below the throttle; a valve controlling said passage; and means operable I mit said valve to open. v

"4. In a carburetor comprising a fuel supe.

ply chamber, a fueldelivery passage adapted by the depression above-the throttle to perto deliver fuel from said supply chamber to v I 'the mixturepassage; a throttle to control the mixture passage; an upper chamber connected to the mixture passa e bya port above the throttle; apiston in sai chamber adapted. to be raised against resistanceby a depression applled tosald port; ia lower chamber cohnected to the mixturepassage through another port below the throttle; a passage connectiug said lower chamber with the supply er adapted to closesaid passage and also adapted to be raisedby a depression applied thereto through said-other ort only when said piston is raised and to c ose the passage when the depressionthereon is insuliicient to hold .the valve open.` y

' In testimony whereof, I have hereunto set my hand at Los Angeles, California, this 23rd day of November, 1923.' t

ROY F. ENSIGN.

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