Патент USA US2411287код для вставки
Nov. 19, 1946. ‘ ` ` F. c. MocK ` `calname FORMING DEVICE 2,411,287 ` Filed Dec. 29, 1941 ............ ., ' ` 2 sheets-sheet 1` s Patented Nov. 19, `194,6 , « 112»411».287 @UNITED STATI-:s PATENT. orrlcs y - i. , " " 12,411,291" 5 CHARGE FoRMnvG DEVICE` e ` ` ` ` u `Frank c. Mock, south Bend., Ina.,ïa`ss1g`nor to l. - Bendix Aviation Corporation; South Bend, Ind., `acorporation of Delaware ‘ > , , ‘ Application December 29, 1941, serial No. 424315` , . 11 Claims. , mixture controls therefor for modifying or con trolling the- richness’of the mixture supplied to the engine in response to variations, in the veloc ityoru density of thejairiiowing through the de c 2 . , orvelocity of air flow. These assumptions are This invention relates to charge forming de vices for internal combustion engines, principally of the aircraft" type, and more particularly to substantially correct through the relatively low range of air velocities previously experienced in carburetors and as a consequence an altitude mixture control which modified the richness a given percentage in accordance with the altitude ` would >inherently correct the richnesslat all `air flows at that altitude. vice.V The instant mixture control is particu larly adapted for use witha charge forming de- i „ Ithas been found, however, particularly car- l vice of the pressurefeed type disclosed in my `co- 10 buretors in which the fuel is not injected into the venturi, that the Venturi`depression does not ' pending U. S. application Serial No. 202,206, illed vary as the square of ‘the velocity in the "high April 15, 1938, now‘Patent` No. 2,390,658v dated velocity ranges now experienced, but rather de Dec. 11, 1945, `is an improvement ‘over the mix ` f parts suddenly and drastically therefrom Áas the ture control disclosed therein. ` " e Y e The recent trend in aircraft engine‘design is 15 velocityàpproaches some high or critical value, toward higher supercharging capacity so‘that the ‘full or rated` horsepower of?n the engine may and as Va consequence the mixture richness is greatly increased. This effect` is at least par be`_deve1oped`_up toas great an altitude as pos‘ tially compensated for in carburetors in which sible, a. boost control or other limiting device being used to prevent overcharging the engine at fuel is delivered into the venturi as the `fuel ` vaporizes" andl tends topartially satisfy or over lower altitudes. Since substantially the same weight ofairisfrequired by the engine at rated horsepower regardless 'of altitude, it is apparent come the the excessive suction; however, no such compensation is obtained when the fuel is not delivered into the venturi. Analtitude mixture that the air velocity “through the venturi or controlo! conventional constant percentage type, other air metering device of the lengine carbu 25 although able to properly compensate the mix turethrough the low range of veloci-ties, Í`pro` buretor is proportionately increased as the air density decreases so as to supply the required weight of` air.` Thus, if rated horsepower‘is, maintained up to an altitude of 20,000 ft., at which theair` density is roughly one-half that at ground level, the air velocity in the venturi will be double the maximum air velocity expe riencedon the ground. Similarly, if the rated altitudev is 30,000 ft., the velocity will‘benearly vides insufficient compensation in the high 1 velocity range. ao It is accordingly an object of the present in vention to provide a carburetor having an im proved altitude ,mixture control of the automatic type. ‘ j ` 1 ` , Itis a further object of the invention to‘pro-ï vide `a carburetor altitude mixture control ca three .times that at ground level.< Thus, the re 35 pable of automatically correcting therichness of cent and substantial `increases in rated altitude the mixture through wide ranges of air density l necessitate that the carburetor operate satisfacï and Venturi air velocity.> torily through a ‘very much higher range of 3 e e „ _ `It is fa further object of the invention to pro Venturi air velocities than heretofore.` ` ‘ Considerable diiliculty lhas been experienced vide a carburetor' altitude mixture control .in in obtaining proper fuel-air proportioning'with such increased air velocities, particularly `be-` jected to a pressure varying as a function o_f the cause the differential pressure created' bythe venturi increases much more rapidly than de sired in the high `velocity range.` It has gen' erally been assumed that the Venturi differential It is a further object of `the invention, to pro videf a `carburetor‘altitude mixture `control in which the sensitive element ,is responsive to pressureffor aconstant `entering» air density, which the pressure responsive element` is sub Venturi air velocity and air density. ‘v Í , l ‘ variations in the enteringair temperature and varies substantially as` the square ofthe velocity of flow, and since fuel flow through an orifice varies in accordance with the -same law, substan tially constant fuel-air‘ proportioning is ob tained. It has further been assumed v‘that a change in air density, as with change in alti pressure, and Venturi air velocity. ‘ f r Other objects and‘advantages will` be readily apparent to one‘skilled in the art from thelfol lowing description'talreninV connection with the accompanying drawin'gsingwhich: ` ` ‘ tude, increases theirichness ofthe mixture a Figure 1 is a dmgrammaucl‘sjecuonal view ory e a carburetor of the pressure feed type embody-` fixed percentage throughout the range of weight 55 ing the invention;` ‘ l 9,411,287 Y Figure 2 is a p_artlal view in section of a modi- ' -treme inward movement ofthe valve 84:.’LA sec fled form of the invention; ond tapered valve 89 is operated by the throttle Figure 3 is a similar view of a further modifica , through link 10 and bell crank 1I, and isadapted tion of the invention; to variably restrict-the passage 59 as the throtg tle approaches closed position. The double lock Figure 4 is a partial view in section of an other modiilcation ofA the invention; and nut arrangement 12 permits adjustment of the ‘ ' valve 89 relative to the throttle. As shown the Í Figure 5- is a graph of the inherent and un corrected metering characteristics of single and multiple Venturi carburetors at various altitudes. the range of air flow having been. extended be valves 64 and 89 cooperate with the opposite ends of a single orifice 59 ;.however,` it will be appar ent'that each could cooperate with separate ori ñces in series relationship. The economizer ori fice 58 is controlled by a spring closed valve 14 rsecured to a diaphragm 15, one side of which is 4subjected'to the .pressure in the unmetered fuel y yond that normally experienced in a carburetor. With reference yto Figure 1, in which much of the structure is as shown in my said copending application Serial No. 202,206 an air passage 10 leads to a blower or supercharger II of> either a chamber 38 throughpipe 18, and the other side single or multi-stage type having a- discharge.: is> subjected to the pressure in the metered fuel ring I2 in communication with the cylinders of. . . chamber 38. A small calibrated vent 11 is 'pro an internal combustion engine. 'I'he _passage I 9 vided for eliminating air and vvapor to permit _a has an air entrance section I4 which'normally complete fuel filling of the device.> opens in the direction of travel of the craft and 20 vThe metered fuel chamber' 39 is connected to . is referred to as a scoop. A throttle I5 controls ' the induction passage through duct 6I, a pipe 80, _ the passagek and is operated by a rody I6 ex and a discharge nozzle 8I having asprlng closed, tending from the pilot’s compartment. _The valve 82. vA. diaphragm 83 is secured to the valve pilotv thus directly controls the air charge of the 82v and is urged iria direction to open the valve engine -Íwhile the fuel charge isautomatically 2,5 by. 4the- pressure ofthe fuel supplied tothe houle. controlled by apparatus hereinafter described. lThe chamber 40 is connected to »the annular Anterior to the throttle is a large venturi 'I8 chamber 23 of the primary venturif2tthrough having an annular chamber I9 which is in com an air passage 85fand is therefore subjected .tol munication with the air entrance through a the pressure existing at the throatfof the` primary plurality of circumferentially spaced` impact ' venturi.` The chamber 4Iv is connected tothe tubes- 28. A small venturi 22, positioned within annular chamberßby an air passage 88, ports the venturi I8 in the customary manner, includes 81 and 88 and passage 89, and is thereforesub-l an chamber >23 `opening substantially jected to the pressure in thefair scoop. -. A cali into the >Venturi throat.4 , v brated port 90 interconnectsthe ,Venturi pas y A fuel pump, indicated generally atV 25, is of 35 sage 85 and the air chamber 4I.v 4,Port 88Íis con the slidingvane type having` a by-passîpassage ` Vtrolledby a spring> closed ïvalve „92 whichfmay 21 controlled by a spring-loaded valve 28. `'I'he pump receives fuel through a pipe 29 and delivers be opened, in case of anÁemer'geney :to by-pass the port 81, by extremel .movement of link 85by" it through pipe 30 to'an annular Vchamber' „32 of means of the bell`-crank__66, a link 93 and a bell a main fuel regulator indicated at 34. @A vapor venting pipe 35`leadsback'tofthe fuel supply . crank 94 having an overrunninglconnection with the valve-9|. tankv from the uppermost portion of chamberßfd i f and is controlled by a float type valve 38. , vThe ‘fuel regulator 34 comprisesjnve cham# bers 38, 39,40, 4|'and 42 separated from ,each other by two large plate-backed actuating dia-, y „ _ ì, , described conformswith the device .shown'in my ’ preformed with 'an annular groove adjacent the I outer periphery. to permit axial displacement , freeend of >a. lsealed capsule 961 mounted `in`, a chamberf91. A’I'he device of`Figure-1 als s’oÍf'ar ¿` phragms 43 andx'44, and’by two small sealing ` diaphragms 45 and 45. 'I'he diaphragms are each . , The port'81 is controlled byfa` tapered auto-` matic mixture control valve95 connectedíto the ‘ `5o ' thereof without;v change in effective are‘a.¿. 'I'he « 1» diaphragms aresecured to a central> control rod above-mentioned ` copending.. application ' Serial INo. 202,206 ; however, linthe said appucauontue cham-ber 91 is' infreeîcommunication Withßhe ` air inlet ywhereas in accordance with .theeinstant invention the chamber communicates with the air inlet I4 through a ycalibrated port- 98> and ~ 5I) having a spherical guide portion- 5I at one end and a slide valve 52 connected thereto at its other end. f The valve 52 controls a 'set of ports 53 be with the Venturi air passage 85 l.through acalië bratedport 99. The port 99 is normallylarger than vthe port 98 so that the pressure in cham tween the‘an'nular chamber 32 andthe unmetered ber 91, although intermediate between,_the-yen",-` turi and >air scoop pressures, willtendV to_ more fuel lchamber 38 whereby axial movementof the diaphragm-valve assembly varies the effective area of portsV 53 and the quantity of fuel flowing nearly` approach that >at the venturi ¿than-that in the‘lair scoop. However, the relative 4size of ‘ therethrough. vAn idle spring 54 urges the con 60 the ports 98 and 99 maybe varied to obtain any trol rod 5I) and valve 52v in a. direction to main desired relationbetween the pressurez’inV cham- . , tainV a slight- opening of the ports 53.l ber f91 and the pressures inV the venturi and ' ‘ " -A passage 58Iin the control rod 50 forms a pressure transmitting connection between the chamber 42 and the vunmetered fuel chamber 38. scoopyhoweverl the port 98 maybe omitted if ‘ desired and the chamber91 subjected to the; full suction of the venturi. 'I'he continuous flowof The chamber’38 -is' also connected'to the metered air fromlthe scoop. :through port; 98, across the fuel vchamber 39 by means of a'fuel duct 58, a surface of «bellows 96 and'out port99 .tendsito pair of oriilces~59 and 88 in parallel relationship " make the‘bellowsguickly responsive to variations n I 65 fand a fuel duct 5I. If desired, a calibrated ori in the temperature Aof the’vair entering‘theinè» flce 62 maybe used in duct v58 anteriorto the 70 duction V,Duringpassage. operation'of i , r the engine, i the ~ air ' .flow orifices 59> and> 60. A tapered .valve “controls the effective area- of the ori?ce 59~ and Amay be through the induction passage creates a differ variably positioned by the operator. through a link 65 and pivoted lever 6,8, .-A disc 81 is secured to the valve 64 and closes the orifice '59 upon eX ential inthe pressures in theçannular vchamber ‘ 23 of the venturi 22` and thewannular chamber, 75 I9 which, at least.through~.the low, rangeof £411,987, velocities in the induction passage, varies sub»- , , 'when the economizer valve 14 is open the ori fice 82 is the primary metering restriction, at` stantially as the square of the rate of air flow n therethrough. Thesev pressures, transmitted v which time movement ofthe valve 64 willhave f i substantially no 'eiîecton the‘richness of the through‘passages 85 and 86 to chambers 40 and y4I, acting on opposite sides of diaphragm 44 l mixture.` The arrangement ofthe oriñces €2,59, create a force tending‘to move the c’ontrol‘rod..` j and 60" is the same asis shown in my‘abovefmen "50 to the rightjtol open valve 52.' If this force ` tioned copending application. , As is generally` knmwn,A the` venturi-méan `scoop differential fpressure created by a given was valve not counteracted, 52:“however,itaswould the valve completely opensopen fuel_ the supplied to pipe 30 by the pump 28 flows into the unmetered fuel chamber 38, through orifices 82‘ and“, into the channel 6l communicating with the metered fuel chamber 3,9, through pipe 80 to the dischargeriozzle 8|, and discharges into the induction passage, The flow of fuel through ‘weight of air ñowfper minute `will increase with decrease in air density and if applied across the diaphragm 4,4‘w`illfproduce`an increase in 1the fuel flow and consequently a‘richermixture. lIt has further been discovered thatas the airve locity through `the venturi increases-‘beyond a relatively` high value, 'the Venturi l, differential pressure increases at a ratefconsiderably greater than >the square `of the air` velocity, thus vpro ducing an enrichment‘of thelmixture,` at` high the orifices 62 and “results in a differential in the pressures in chambers 38 and 3B `which‘varies ` substantially as the square of the rate of fuel flow therethrough; ' These pressures acting‘ on t diaphragm 43 urge kthe rod 5U and valve'52` to the 20 air ` velocities.. Atics are clearly shovvnin the graphof Figure‘âiin ‘ which the mixture `richness has `been plotted . action of ‘the air force on diaphragm 44 and the fuel force on ‘diaphrag'm“43, and thereby regu late the quantity of fuel in `accordance `with the quantity of air. Thus, if thelquantity of air in creases, the air force on` diaphragm 44 `will in crease and will open the valve 52 to increase the ` fuel ?ow sufllciently to increase the fuel differ' 1 The _foregoinginherentimetermg characterisf- ,l . left tending to close the ports 53( The Acontrol rod 50 and valve 52 therefore iloat under the against the weight of air iloivfor various alti 25 tudes.” The characteristics of -aîsingle Venturi carburetor` are shown in full lines and those "of ` " a multiple ‘Venturi’ carburetor in >broken lines. ` The richness scale` in y Figure 5 jutilizes unity (1.0) to‘designate‘ the desired richnessfor opera tion at ground level, and theweight of air `scale utilizes unity ;(1.0) to designate the maximum K ential pressure and the fuel force on diaphragm 30 43 lto balance the increased air force.` `Constant fuel airrproportioning will thus be vobtained as weight` of air which `can be drawn through the Venturi system with an entering air density corresponding to yground level', at which timev the air velocity inthe main venturi reaches its maxi long as the fuel and air forces on the diaphragms vary in laccordance with the quantity of air and ffuel flow tothe engine, unless the balance on the 35 mum or critical value. "The circled termination` ' ` control‘rod is upset by some extraneous force point of each of the curves corresponds to criti cal flow‘ ‘at that particular altitude. It will be such as idle spring 54. At idle, the force of spring ` 54 is an appreciable factor in ‘urging the rod 50 tothe right, and consequently, an increased fuel noted that the‘metering ‘characteristics of single multiple Venturi carburetors are substantially force isrequired to balance both the `airforce and 40 or the same through the major portionpi the air the spring force thereby creating a rich mixture flowfrange but sharply diverge‘asthe maximum ‘ at idle as desired."` Atrhigher air flowsthe force ` flow isapproached._ Thisfresultsfrom the fact 'of the idle springfis very small in comparison that the velocity'ín the small venturiisÁ greater with the relatively large air force and conse . than that in the main venturi and asa conse quence reaches a condition of critical flow. before » quently `has but `a ‘negligible ‘effect on the rich ness `of _the mixture. ‘ IIt has been found desirable the main venturi. Atthis time the depression in` ’ todesign spring `54 to produce a richer mixture ‘ at idle' than desired and tense the throttle con- , ` the small venturi, which determines the fuel flow, a maximum: and subsequent increase in trolled valveV 69 to restrict> the fuel orifice 5‘9> at 50 reaches flow through theflar'ge venturíï‘to its critical ilow closed throttle to obtain the `desired richness of rate increases the total air iloW‘without increas `1n'ixture.`` "Ñ ing the‘fuel ñow. "The mixture richness through . It willbe apparent that the regulator 34 main tains the differential fuël"` pressure 'across dia phragm 43 at a value depending upon the air flow, andthat a change in the effective area of the fuel meteringjoriñce will correspondingly change the richness of the mixture. "I'hus, opera this range is therefore decreased as indicated by thebroken lines which diverge from the solid 55 tion of the link 65 will vary the position of the `tapered valve $4 and -will therefore vary the rich-> ness of the mixture.`^A- manual mixture control is thus provided. `Extreme movement to the left of link 65 causes thedisc 61 to fully close‘orifice' , lines. . f ` ` ` ` It must be borne in mind that these curves ex--` tend into regions of velocity far in excess of those previously orl at"`present experienced, or even contemplated, in carburetors forinternal come 60 bustion engines',`-but have been here shown Vmere~` U \ ly to indicate the full characteristicpf ysuch `>de-` vices. Up until but a few years ago,„few airplanes ‘As the power output from the engine increases were able toreachaltitudes above 20,000`ft. and utilized `maximum air flow values roughly indie A the fuel consumption and consequently the fuel diiferential pressure `across diaphragm 43 and >weight of airisupplied to the `engine_decreasing increase.` When the >fuel differential pressureV ` range of altitude and air flow, as determined by 59 >to shutoff the‘fuel flow` so as to stop _the engine. ‘ therefore across `diaphragm 15 correspondingly reaches :some predetermined value `the dia-" ‘ 4phragm 'l5 opens the economizer `valve 14 and thereby increases the richness of the mixture for high power operation, as is desired.` Theoriñce cated byi the dotted ,line a--bgthe maximum ‘ with increase in altitude. Through this limited the line a-b and ,the ground level and 20,000` ft. s curves, a carburetor tends to produce a substan tially constant richness of mixture `at each alti tude. ‘ In' order to obtain a ` mixture richness at altitude equal to thatfat ground level,V the alti- , Slis normally greater` than the effective area `of tude mixture control may apply a percentage cor the orifice 59 but smaller than the sum of the 75 rection dependent‘upon the altitude.` ¿ areas of orinces 5S and 60." Asa consequence ~ .au 1,237 _ _ nti‘end of’superchargers- andI l.iin ?'lar to that of Figure 1 and differs therefrom -prin- i proved charging of the vengines the maximum inthat the bellows chamber 91 communi air-‘now at‘each altitude was' somewhat increased f` cipally catesiwith _thethroat of the large venturi. I8 as indicated by the line ced; howeven substan-` ' tially constant richness is vobtained'at each alti Ul __by. means ofv` an open-ended tube |.|l| extending tude even throug_lÍ_i'|:'hisl somewhat enlarged range, ‘ _into the `venturiin _thedir'e'ctionot air now. `A calibrated restriction land an altitude control iunctioning solely in re" sponseto variations'in"_ent_ering. air density satis |02 is provided' in fthe tubev > _ |0|. ` Asfbetore, the rchamber91,_`c`ommunicátes 'l ~ i with the air; inlet through Àone orvmoreports 98. ’ factorily compensatesthe richness of the `mix ture _at various altitudes regardless of. the rate 10 ofair'lìow.> With proposed highly supercharged‘and boost 15 ` lranges now experienced,`particularly at altitude, _similar to that of Figure land has been given corresponding ` In Figure 3, reference corresponding numerals.'` partShaVmE-been _ t given corresponding'referencefnumerals'with the . ' controlled engines the maximum airflow‘at each ` altitude is substantially as de'ñned by ythe lline ¿_eff.. `Through the’I greatly increased velocity "The remaining structure ,disclosed in Figure 2_is addition` ‘of 100, a> large venturi;> _||,8, >positioned anterior. to .the throttle |l|5, isprovided with two annular chambers. I |9 and |2|, theforme'r com the richness no‘longer tends to "remain constant municating with the. inlet throughimpact .tubes Vat each altitude, but rather increases sharply |20, and the latter communicating 4with’substan-` i with the increased `velocity._` A_n‘altitude mixture 1 control which at a` given'altitude applies the 20 tially the throat _of the venturi through fa plu rality of ports |24. I Annular chambenlnin'the necessary percentage correction atr low air -flows, Smau venturi |22 comuniones .with the cnam.- " provides insufiicient compensation at the high air flows. . ` ' . ' b_e'r 48„ofjtheregulator through vthe passage |88 ` " and the annular chamber ||9 communicates .with 'To accomplish the desired mixture correction the chamber 4| >_0f the regulator through passages for _variations in altitude and' velocity I provide, 25. referring againto Figure l`1, thevalve 95 Afor vari _ably restricting the port 8_1. vWhen the' valve 95 |86 and |89_and port v|81 controlled by ithebel-_ lowsactuated valve |95. l_The chamber. |91__en~ closing` the bellows |96 is connected yto the ah a passage |41 havingf _a . is ‘withdrawn from “the port„.as'a1í` low power. ground level'operation, thefcalibrated port 98, calibratedrestriction |48, and is connected tothe . chamber |2| by a passage |54 and a calibrated being o_fnfïsmall size in comparison with the port 81,' 'has substantiallyno effect on the' pressures .port |55.` Thebellows of Figure 3_is thus _sub in_chambers 40 `and 4|. However, movement 'of Jected to a pressure dependent upon the` abso » the valve 95 into a`restricting` position in port 81 lute pressure .at the large venturi and .the enter-> restricts the flow of air'` from _the annular ,cham ing impact pressure. „ . ber |9 :to thejchaxnber 4_1 and »consequently the . Figure4 disclosesthe induction passag‘eoffa o' Venturi suction in passagej 85 is effective to >par single Venturi 'carburetor in which the .venturi tially reduce the Ypressure in >chamber 4| and is similar in structure to the large venturioiV Fig thereby‘decreases'the differential pressure across ' Y diaphragm 44. ' The richness of the mixture is ure 3 4and, is formed with annular chambers || 9 subjected to the entering correspondingly decreased. ' The valve 95`is vari-‘ 40 air. _impact pressure and the Venturi throat pres ably positioned within theport 81 by the expansi sure'. The pressure in chamber l| I9 isV trans bleI bellows 96. subjectedr to _a pressure‘varying mittedto the regulator chamber _4| through pas in accordancewith‘th'e absolute >pressure _in a sages |86 and 1|89 and portV |81.. and the »pressure « venturi positioned <¿interior to vthe throttle and in. chamber i 2| is >transmitted to. the chamber '40 -preferably forming a ,portion of the` tuel meter andv |2| respectively ing instrumentality. In thev modiiicatlon’of‘Flg ofthe regulator through passages~ |54 and |51. enclosing the ,bellows |199 com?v ' municateswith ~the, chambery ||9 through pas sage- |41 and restriction |48 and with'the cham ber |_2| throughport |55 and passage_.|54.` f ï _ ' Thechamber |91 , ure 1 Athe bellows issubJected to variations in the , absolute pressure inthe ‘venturif`23 _by means of the port 99 _'i/ntercommunicating‘ vthe bellows chamber‘91 and the'Venturi passage 85. 'I_'he __ 50 Although several forms o1'.;the_invention have> 96 whereby it will quickly respond >to changes in f >modifications may readily be combined to torni .port 98 from chamber >91 into‘the air rinlet pro vides a continuous flow of air across `the‘bellows been disclosed, the Vvarious parts of _the separate densityl resulting’from variations in entering air temperature.A -The bleed 98 also rserves to par furthermodiflcations, for example, the chamber _ |91 of Figure 4 may, if» desired; _be connected to the 'air inietas in Figures; and 2 rather than tially destroy the suction within chamber 91 whereby any desired correlationmay be 'obtained to the impact pressure. chamber pas., similarly, _ _ , in the relative _responsiveness of the bellows to the modifications of Figuresl. and 2 may utilize variations in the air velocity as'reilected ‘in the absolute Venturi pressure and' to enteringair a connectionfromthe bellows chamber 91 to the . densityasreilected both in 'the pressure at port 60 9_8as well as the `pressure in the' _ venturi. Corre- _ lation o'ffthev contour of valve 95 and >the pres surey in chamber 91to produce constant fuel air stantially the same proportionîng at all altitudes.V the-emergency valve‘92 may be opened by ex prevent undueleanness which would otherwise occur upon reduction in altitude or air velocity `after the valve 95 jammed. t fromv. . e spirit of the invention ' ' and I- contemplate the use of alllsuch arrange,- « not clalmedherein are being claimed rin"myV col-Í> pending applications Serial No. 202,206, Vfiled ‘ Abrir `l5, 1938, _and Serial No.v 362,572, _-1filed"` y In the event that -thebellows controlled valve 95' jams or sticks `while _in_al restricting position, providingan air «by-'pass varound', the valve 95 to made in the arrangement of thevarious r`parts ` ' withoutdepartilíg ments falling, within the scope- of the~ appended claims. Portions of the structure disclosedv ibut ' proportioningat‘one altitude `will produce sub treme movement to- theright of link 65,v thereby impact ,chamber` I9 rathenthan_theconnection 9_8 to the air inlet., Manyother'changes may be 70 October 24, 1940. i Iïclaiiliî` _ _ . `1l i __ "i ‘1. In a fuel feeding system -for an engine,y an air passage, a throttle in the air passage, Venturi meansV in the air passage anterior to the throttle,- The embodiment of Figure 2 is somewhat simi- 75 a main fuel regulator responsive to variations in' , the pressure in the Venturi means for variablyA i .` 2,411,287 ‘_ sponsive „memberz being `located in“ said second ‘controlling the fuel flow _to the engine in response 'to variations in the air flow through said- Venturi passage so as to ‘be exposedto‘the air flowing therethrough, and means responsive to the pres sures at spaced‘points in saidlfirst passage for controlling the flow` of fuel to the engine. 1 » » means, and an automatic mixture controlcom `prising a chamber having a wall ,_ movable `in ` response to variations in absolute pressure in `said chamber, a control element actuated bysaid l, > 6. `,In a fuel supply system for an internal com A bastion engine having an` air conduitl ‘a throttle ` movable wall and operative to control the-rate in said conduit, Venturi means including `at least one venturi in the conduit anterior to the throttle, and a passageway connecting the chamber to a 10 a fuel regulator having two airchambers,A a >first `passageway connectingthe venturito one o'f the " low pressure zone in the Venturi means _whereby `air chambers, a second passageway connecting the the movable wall yis subjected .to a- pressure which decreases -` with increase inl air ,velocity through ' other of the air’chambers to -the air conduit at >the Venturi means and alsoawithçan increase in ' a point anterior tothe throttle andfspaced from altitude, said passagewayhaving an effective 15 theïthroat of said venturi, 'and means responsive `of fueldelivered‘to the engine byi the regulator vto .thereby control the richness ofithei mixture, to variations in the` differential of the pressures ` , insaidchambers for controlling the Vfuel flow" to .the engine: the combination «therewith of an cross-sectional area `whichremains constant with variations inthe positionof said control element. 2. In a fuelfeeding‘system for an enginehaving a throttle controlledair passage,` Venturi `means in said passage anterior to the throttle for creat 20 ing a pair of air pressures the difference Aof which varies with variations in the air flow through the passage, a‘fuel conduit for supplying fuel tothe i engine, means in said conduit for ‘creating'a pair automaticmixture control fori varying the quan tity of fuel supplied to the engine by the ‘regu-V lator fcomprising a i variable pressure chamber having a movable Wall responsive to the absolute `pressure in said variable,` pressure chamber, -a `valve connected to said wall to be actuated there of fuel pressures the difference' of which varies 25 by and operative to vary the pressure in one `ci.' said two air chambers, ‘and a passageway con- y with variations in fuel ñow through the‘conduit, necting said variable pressure chamber to the l a fuel valve in the conduit, diaphragms opera tively connected to the valve and responsive to ` Venturi means whereby the pressure in said `var iable pressure' chamber is decreased with in said pairs of' air'and fuel pressures, and an alti crease in air velocity through the 4air conduit and , tude mixture control comprising an air chamber, a sealed capsule l? the air chamber having a also with increase in altitude, saidv vlast named passageway remaining open during all periods of wall movable in response to variations` in the engine operation. Y ’ absolute pressure and temperature of the air in ‘7. In a charge forming device for an engine, said air chamber, a control element actuated by said wall and operative to vary at least one of 35 an air passage having an inlet portion, a throttle in said passage, means in the air passage anterior the air pressures on said diaphragme,r and a pas to _the throttle` for creating a', pressure' varying ' sageway „of fixed cross-sectional area during periods of engine operation connecting the air chamber to a zone of ,reduced pressure in the ` Venturi means. i 3. 'I'he invention deilnedin claim 2 compris- ' _ing in addition a second passageway connecting the air chamber to a‘zone of relatively higher pressure in the air passage anterior to the throttle. 4. In a fuel feeding system for an engine, an air conduit for` supplying air to the engine, a throttle in the conduit, a venturi in the conduit anterior to the throttle, a passage including a restricted portion connecting the venturi adjacent 40 with variationsin the rate of air flow through the air passage.__a_ fuel regulator responsive` to variations in said pressurefor variably‘controlling` the fuel flowto _the engine, and an automatic Y` mixture control comprising 4_an air chamber, a-` _ sealed capsule in said chamber having a wall mov,-> ' able in response to variations in the .absolute- pres sure in said chamber,4 a control ‘element actuated , by said movable wall and operative to control the rate of fuel delivered to the engine by the regu~ lator to thereby control theratio of fuel and `air l supplied the engine, and a; passageway lead the throat‘thereof to a point in said conduit 50 ing from the chamber and opening into the air passage anterior to the throttle at a point at anterior to the throttle and spaced from said which the pressure is less than'the pressure in' throat, a valve in saidipassage, an air chamber said inlet portion by an amount which increases in fixed and continuously open pressure com 'with increase in the velocity of air flow through munication with the venturi during all periods of engine operation, a sealed capsule in said cham-A 55 the air passage, the cross-sectional area of said passageway remaining nxed with variations in fber having a wall connected to said valve and the position of said control element.` e movableiin response` to'variations in the absolute 8. In a charge forming device for an engine, an pressure inA said chamber, a fuel supply duct, a air passage having an inlet portion. a throttle fuel control valve in said duct,`and means respon sive to variations in pressure in said passage for 60 in the passage, Venturi means including at least one venturi in the passage anterior to the throttle, ,actuating the fuel control valve. a fuel regulator responsive to variations in the l 5. In a fuel feeding system for an internal pressure in said‘venturi for variably `controlling combustion engine, an air conduit for supplying the fuel flow to the engine in response to varia air to the engine, a throttle in said conduit, a venturi in said conduit anterior to the throttle, 65 tions in the air flow through the air passage, and a mixture control comprising a, chamber having a first passage including a restricted portion and Y a wall movable in response to variations in the connecting the throat of said venturi to a point absolute pressure in said chamber, a control ele in said conduit spacedfrom said throat,` a valve ment actuated by said movable wall and opera in said passage, a pressure responsive member tive to control the rate of fuel supplied to the en« ‘ for operating said valve’to vary the air flow gine to thereby control the richness of the fuel-air through said passage, a second passage intercon mixture. and a pair of passageways of fixed effec , necting two spaced points inthe air conduit tive cross-sectional area during periods of engine anterior to the throttle atl which the pressures differ by an amount varying with the velocity i operation connecting the chamber to the Venturi of air now through the conduit, said pressure re 75 means and to the said inlet portion, whereby the , u ` ¿g movablewall is vI?’2.4113375 afpressure whiclizdes ` I ycreasesgwith_increase in air. velocitythroughy the air passaseand also withincrease inv altitud’e/ l; 9..,In` aA charge forming device _for anensine, l _ e,_va¿throttlein'the' passage, a main', „venturi-‘in the me anterior tothe throttle, l _ booster kVenturi means into the main' venturi, a main fuel regulator responsiveV to vari ations- inA pressure in the booster Venturi means for variably controlling the fuel’ilow/to the en-i î i, ~ in: an'inlet, a throttle-in the a malnven " turi in the passage anterior. to the> throttle, a small venturi discharzingintosaid large venturi,V fuel regulating xnealisv responsive to the pressure in the‘airV inlet 'and‘tcrthe4 pressure in the small ¿venturi for controlling the supply of fuel 'to the engine, and an automatic mixture controlcom prising a 'chamber having a wall movablefln re spense' to the absolute pressurein said chamber, ‘ a. control-element actuated by said movablewall sine. and anautornaticA mixture controlico‘mpris-v . andv operative to control the rate of fuel delivered ing a chamber, a pressure transmitting connection ' tothe engine lto thereby control the richness' `of i'romr-the’chamber to the main venturi, a sealedy , the mixture, anda- passageway connecting the capsule in- said chamber having a wall- movable inl chamber to the small venturi; said passageway l response to variationsJ in thevabsolute pressure in , Y being‘of nxed cross-sectional area. regardless ‘of v said chamber, anda controlelement'connected to. . _said wall and operative upon movement thereof l ' thepositionofsaid control" element. ` vv1‘1. The linvention' deñned in c1aim.10 compris»` ' to variably control the rate of fuel 4delivered to ing` in laddition a- passageway 'connecting'> the „the Iengine to control the richness of the chamber toa point in the air passage anterior ~to 10. In a fuel feedinl system, an airpassauzehav-> the throttle and spaced from the small venturi.' I ‘ I C. MQCK.