US2689116A - Carburetor - Google Patents

Description

J. C. RICHARDSON 2,689,116

CARBURETOR 2 Sheets-Sheeb l nventor W Gttomeg 5' Sept. I14, 1954 Filed May 8, 1950 Sept 14 -1954 J. c. RICHARDSON 2,689,116

CARBURETOR Filed May 8, 1950 2 Sheets-Sheet 2 UNITED STAT ES?u esule Pneu 'rM ortica.,

CARBURETORJ",

JameslvC. Richardson,

N augatuck,` Conn.

Application May'8,-1950, Serial No. 160,645;e,

8 Claims. 1v

This invention relates to fuel-airffmixingrde vices or carburetors for internall 'combustion fen-1 l gines, and particularly to=carburetors of the.type'.y intended to provide a thorough intermixturefbe'- tween a=volatile-uid fuel; suchl as gasolinefand 5 all".

The artof earburetor: building-.hasseenfprog ressirlA many directions; -carburetors "having been$71 developed-:which attempt tov take'care lof f'a large number of yarying conditions, and many `oiizvhi'chareueasonably successful. Many-'Yfifnotallof i these advancedcarburetors howeverfarevtotally unsuited toordinary-use,- for exampleoni the usualpassenger motor car. kThey -arefnot/only'- excessively'costly initially, but they lals'olre'quire unusual 'skill' for their maintenancewhich Would! make their upkeepltoo*precariousI and'too costly" for ordinary use.

The fact that-developrnentand 'improvement of fcar-buretors for specialized! purposes'fhasfap parently requiredJmultiplieationfof-inoving par-ts?- controls", nand Iadj ustments; seems -to have diverted f1' the-iinvestigationrelating to the improvement-1- of ordinarycommerciall gasoline engiriefcarbu-l retors-such-as arefused onautomobil'es `from iter-25 proper A channels. One of fthemain considera--A tions inthe design-of l'a carburetor forwide public use-is simplicityfandfreedom', insofarfas *pos-1A sible', from -delicat'e'i-movingparts and'adjuste' ments, withfcorresponding-v reducedfiinitial" cost-"30 and =upkeep expense; Itfhasapparently `ybeen-tlie J general` 'sentiment that` furthensteps in 'fth'is" di. rection'--were impossiblewithout sac-ric'ing fueltf economy 'and -engine performance# for 1no=-prac 1l tures have appearedin user Presently l used'- commercial y' carbu-retors L are complicated' bythe presence'offuel reservoirs-' or oat chambers :which require fang-altogether" unrealistic complexity of the-body`1structu`re`for 40 casting, not'to men-tion the presence 'of tempera'- A mentali-floatl valveswhichy can 'cause' severe re hazards -by-their `failure-to operate -fr"eely`.i F`ur=`- ther -complic`ations lintroducing initial jcosts"-asff- WellE as upkeep expenses' include accelerating-145 pumps frandrwells; plural Venturis',-- controllable fr mixture altering mea-ns v"-such; as stranglerorl f choke Valves,- automatic *controls-fonsuch choke valves; and*automa-tic` air -valveswithiorrwitlil e outA interconnected fuel metering controls It is anrobjectI of'r'the invention* to proyideaLA carburetor` Which'canlbe operated in conjunction with the conventional 4fuelpumpbut 'Whichis" at the same time -proofagainst'pressure ejection of fuel due tostickingqfloat Valves,n andfhence 55 aowA against the severe rire hazard' occasioned? thereby.J

Itiisfanotherfobject ofthe/invention to -pro-- vde a carburetor Which-takes full advantageof r modern vfuelf pump characteristics andwhichre problems.

It' is another 'purposefo :this-invention: topro- Vide a carburetor suitable for yconventional stockl motor: ,vehiclesf-which: reduces fthe mixing of *Afuel andl .airf rto its-simplest terms-whereby ,to reduce bothwinitialwcost tand-i maintenance expense'. of

the carbureton'but which' at: the `same time -maintains modern standardsof performancewithfre gard to reliable starting and idling,smooth1ac+ celerationrand-high power aty full throttle.

the direction!` of y -fuel economy, fas-compared Witl'nl present lstock carburetorsf-land. the attainment" of Sthisfendw-inr: concert rwith lthe satisfaction of the@fabove-rnentionedipurpose relating. .to si-mplicity and performance.

be prepared Y riorv use byff a i plura1ityv'of-straight drilled passages, and plugs and inserts-ltherefora` it is another object of the inVentionto-provide 'fa f carburetor r in` which the f--fuel induction passage.' Where yfluidy fuel fromA the jets under fuel pump pressure isV atomizcdV to form-a richmixture with a portion of the air prior to its introductionn into .the n:.ain-.air stream;a--portionfof said -ai-r passage forming-:a nonrestrictive 'delecting nozzle for introduction of the premix into the mainaairhy stream whilesubstantially,completing the atom= ization of the fuel.

It iszfstill anothern-obfjectv. offthe inventionto ,provide -ay carburetor inv Whichffthe vmoving sopa-V erating parts.- fconsist g-essentially of. f a` ltl'i-rottleY- valve and a main jet meteringrod/mechanically interconnected; but, --wherein--the properv cond-i-V tions iorfstartingyrunningiat all ordinary speeds, f` accelerating,I andi high lpower or" speed Scan still ,l

be furnished with reasonable accuracy .andl at substantial. economy over. f presentlylused types of carburetors.

Another object offthis invention is the` provision of 1a carburetor which providesrel-iable A -fu'rther object of the-invention is the `effectv ing.;` of a marked -improvement ofi carburetion -in f jet or jets communicate with anf-,=au2;iliaryairn U starting performance and still avoids. the use of a strangler or choke valve and automatic controls, and hence eliminates the attendant disadvantages.

Still another object of the invention is the provision of an arrangement of air passages such that a metering of the fluid inlet in consonance with the throttle movement is all that is necessary to provide adequate mixture control under all conditions.

A further object of the invention is the provision of an air inlet for the auxiliary air passage so arranged as to draw its air from a source protected by the conventional air filter, and to tap the main air stream in such a way as to measure its velocity and proportion the air velocity in the auxiliary air path thereto.

A further object of the invention is the provision of a parallel arrangement of a main jet and an idling jet so that the fuel issuing from either or both will pass into an auxiliary air current in atomized form prior to the admission of such current to the main air stream.

Another object of the invention is the provision of a carburetor in which the main fuel induction nozzle which introduces the fuel mixture into the main air stream is a conduit intermediately apertured for fuel escape and in which one end is connected to the auxiliary air passage and the other end communicates with an area of variable reduced pressure at the manifold side of the throttle valve.

Another object of the invention is the provision of a carburetor in which the introduction of fuel into the air stream can be effected without the necessity for severe restriction therein, such as venturis and the like which limit the power output of the engine.

A still further object of the invention is the provision of a carburetor having any or all of the foregoing features and advantages, and in which the average fuel consumption for a given automobile under comparable conditions and for all ordinary types of operation can be reduced at least twenty percent on the basis of the fuel consumed using a stock carburetor of the float chamber, plural jet, accelerator pump type currently in use and in prime operating condition, and using equivalent performance adjustments for both types.

Additional features and advantages will hereinafter appear.

In-v the drawings:

Figure 1 is a front elevation of the carburetor of this invention.

Fig. 2 is a side elevation of the device of Fig. 1 taken from the right hand side and looking towards the left.

Fig. 3 is a section taken on line 3--3 of Fig. 2.

Fig. 4 is a section taken on line 4-4 of Figs. 1 and 3.

Fig. 5 is a detailed section taken on line 5-5 of Fig. 1 and 3.

Figs. 6, 7 and 8 are elevations of interchangeable metering members usable with the carburetors of Figs. 1 to 5 and illustrating several different suitable profiles.

Fig. 9 is a partial section similar to Fig. 4, but illustrating a modied form of the mechanical interconnection between the throttle and the fuel metering means.

The carburetor of this invention comprises a body member ID which is preferably a single, integral casting. A large passage I2 running through the center of the body I0 constitutes the main air duct and mixing chamber. The upper end of the body I0 is provided with means such as the seat I4 for receiving the collar I6 of a conventional air filter. The lower end of the body I0 is shaped to provide a sealing flange I8 which is bolted to a corresponding flange 20 on the intake manifold. On one side of the body I0 is an integral enlargement or boss 22 which, together with another integral boss 24 on the opposite side, provides for most of the principal operating parts and connections to the carburetor as will hereinafter appear. A small boss 26 near the lower end of the body I0 provides for the conventional vacuum connection 28 communicating with a port 29 opening in the air passage I2 for controlling the spark advancing and retarding mechanism.

Throttle valve assembly The carburetor of this invention is essentially a posterior throttle carburetor, in that the throttle valve is located at a position in the main air stream, downstream from the fuel emission apparatus.

A horizontal bore 3U rotatably carries the throttle shaft 32 which extends diametrically of the bore I2 at the lower part thereof, and beyond each side of the casting, and has mounted thereon a butterfly Valve 34 of the proper size and shape to open and close the main air passage I2. An enlarged bore 36 is formed in the lower end 38 of the boss 22 in line with the bore 30 to form a gear housing in a manner which will presently appear, and the same is closed at its outer end by a combined cover plate and bushing member 40. Rotatably mounted on the end of the shaft 32 is a sleeve 42, one end of which is housed in the bore 36 and provided with spur gear teeth 44. The other end has the configuration of a worm Wheel 46 and extends through and outside the cover plate 40. Surrounding the outer end of the shaft 32 as well as the sleeve 42 is the drive sleeve 48 integral with an operating lever 50 which is connected to a member 52 in the conventional throttle operating linkage (Fig. 2). Sleeve 48 is firmly attached to the end of shaft 32 by means of a set screw 54 and extends into the central opening of the bushing 40 to rotatably support the shaft 32 and the sleeve 42 therein. A worm` or screw 56 is rotatably mounted in a socket 58 in the sleeve 48, meshes with the worm wheel 46 on sleeve 42, and is provided with friction means 60 for retaining it in adjusted position. The angular relationship of the operating lever 50 and the attached throttle valve 34 to the spur gear 44 is accordingly normally fixed, but it can be readily adjusted as desired by means of the worm and worm wheel connection 46, 56 for a purpose which will hereinafter appear. The other end of shaft 32 is received in a collar 62 which is fixed thereon by means of the set screw 64. The collar 62 also carries an arm 66 in which is threadedly received the stop screw 68 arranged to engage a surface of the boss 24 to prevent the valve 34 from closing altogether and for adjusting the size of such minimum opening. The arm 66 is preferably split and sprung so as to frictionally retain the screw 68 against inadvertent rotation due to vibration and the like. Arm 66 also includes a stop surface 6I which cooperates with a portion of the boss 24 to prevent opening of the throttle 34 beyond full open position.

Auzcilary air path Another substantially diametric bore 'I0 crosses 5 thgnthroati of; time,Y maimfairepassage I 2f; and @ist formed: in A:the l upperfportiomv'l Zofzithedc Deel2 2 sas` wellies the `lippenportion. of theboss.:24;. ldmiozzle`v tubelrlll iW-ith-oriiicesi 'II'ein athefbottom:'thereofxis'sinsertedisfrom:theeopenfendfofizthe boreiin f bossf. 5

245i whichiJ istthenaclosedf .with ia :screw:A cap: @181 Preferablyethererareuseveral orifleeseil S-fofr suchl 1. sizesasxostotalapproximately the; internal.,;cross section iof:etlietubes14.-.;` Ai smaller-portami iis;

drilledlffin: lthe; upper portion-x12 t offboss 222 l,inn 10 i alignmentrwithnthe -centraliiopening fof;fthe-stubsv 14s andfits-foutenrend =is1.-iclosedl byia :plugnz: At plugged: horizontalraboresi communicates; withiz thezrborernandf'withvan upwardly-1 slopingybore.;l

86 which opens on theointeriorwof-.L-the;mainsairx:l51

passage 1I 2in:the boss integrally :formed thereinizi Firmin fafitoned-inttheJoossttianglfextendmg;A upw-rcllmtherefromeissfunnelsshapedrair- `-ad` mittance member or.-.ain.sco op5llfwhioh projects;

intiandfpanallelsi.approximately v,the direction,l of N20 f Flaftsfpot Control Passage Anmadditionat passage, Afor:-modifying. `sonf1e-1-` fthe auxiliary'air;:pathiinfa .man-i :describe ,i ,CQnSistStoff afyertica-lw.;

horfiaontal-if bores; 9F12 landt the; communicating;y

plugged, ,unwardlrzfsloping :bore .198,2 the, bereist.: openingfuncn :theymainrairjstream; stammt 5| mr;4 litdlt thsfaothe Side off-the throttle-Valve 34g; fromthe; noazfletube I\4,zand .the bore 93. vopening -,f10-"\pound;bore c I 4= @which aintersectsfthezbore 5,10

through fthetsclewrcap gli; intoy l tl-1e. interior -of-fY tube '14.

M'cifb-` fuelfiet, metefinassembly' 7and throttle?,

interconnection Afgyerticalnbore; 1I 02` starts; at, the :top-.offboss 2 2r @mi ommungatesz With-.r the 'enlargedfbores ori gQfl'zhUl-Sgrrlgv 3 5; Landwirt-h the.v :reduced .bore=f80f1of I. theffauuiliaryrairfrpathri. Anguideobloek millis-`A DI1QSS bore@ ggandthe-sime. snugly butv slidably receives;u anpperatingqpin 065, A1so.;located inthe bore I B2i justnabove ithefintersecting .reduced bore 8022 is la pressF-ttlduelijet insert'Y IIJ8.5 A bore 1I IvD- (Figa-g Lhedlpner Dart ofy thevbossv=12`1inter v 55 sects berbere, I Marius-t above the rjet insert I B8: l and? rovided A with; a .fitting :I I2 for connection. tottliggfuelgline I I4-iwl'iichlleads to the conventionultifllflapllmpdnotshownl.. Afbore II5 cony nests thebQjtDm-,of the; gear.. housing 36with the V130 airilasage dxtoxdrainfoany leakage :fuelfrom y thefhousing 56;, 'Iliesrupper -end of i the bore |02r1 islenlargedzandmappedgto; receiveV cap screw I I6 wtii closes the upperA end. of the sbore` I 02 Y and retain the ',-upnergend fof: fa c-r-coil Y spring.v I I 8,1 the; 65 lovvenyl-er-iflg of;l '-whichfzpresses against: the :urgess downwardly a tug; I2Itzwhichf fills .the :bore NI B2i` and osirslidab herein; The plug' e I 2 0 :has anE nligl'alidepelfllllgfplojzectione:I22";which passesl:4v

through and normallywlseajis fintheforicetoffjet -70' iin that bore: I IJZ.H below-stifleV i recluced--.A 50' engagement withi theruppemendsoffthe @opel-.attinge pin.-.I 06s Arbore-il 2dr parallelto': andf offsetvfroms; thelboreel Ozifopens aat.. .ther-bottom` ofh-vthelowerf section-3B fof rthez-boss 22;'andiis closedsby-1aiscrewfi= f plug-JI 26. The1bore1l24 'communicates withrthe gear-:housingl36:,zand ;by-.a,fslot.':l 2B withfthe bore |02: Slidablymunted'inf-the bore -124 isf-a racks; member, f. I 30e the gtoothedf; portion cfa; whiohriss; meshedgiwiththefspur gear-44.12. Thetupper ^wende;- v'ofi-,the rack member-.VI 30V carries faalateral: projet: tion; I 3 2 .iwhichipassesethrough slot fI 2 8 nndundeI-elies the lower endiof theoperatingzroddIIS'zinrp sition to actuate these-mes, Itlwillbefseen .thatrr rotationgoflthe=shaftz32i toproduce kopeninganoxnee clockwise rotation as shown in Fig. 4, will revisen` the .racksmemberd 3 Il and feWith it the operating pineA |06 sto thereby :lifztithe:meteringsprojectionn I 22 i and. lprovide 1a. ,slowly f,but, ,progressively-:1r en-tfn `larging :annular ,y oriiice cbetweenr :the tjet and-.fsthes meter-ing r projection: CloekWisei-rotation :.oiftliel shaft=32 retractsthe fraek I3IIiandv allowsffspringig: I ILS to: depressrthemeteringmemberd 210,5 |22 andr` operating pin IIlfandfrultimatelyato., returnithemn yto the position shown in Figa/l:H It shouldalsabe c; noted` that the partsofsboss 2 Zi'mayrbe ssolga ranged if desired,-` that ibore I 0253's in'v .line bore AI2tni'whereupon:lateral: projection: .I 32 wouldn be:dispensedl with'and operatingrrodi- ;I Ulfcouldii 1either','restuidirectly zon' 'o1'.A ykbe integrali withrraokr:

member |32. The .-series;soffelementszyjusty den scribed,- including spur gear .4 Larack .,.I 3U, operati-J;q

ingpinf I 0E. tand metering membersI 2l:provide:fiori.;- mechanical interconnection 4between :the fthrottlez, Va-lve :andthe main fueljet-orificeV riorfa,-fpurposeza. toibe :more :fully described. hereinaftenrr.

Idling iet,

The idling fuert supply `is; provided :byra 1 :comet:

Connection,and.ad:ustment .The Acarburetor is iinstalled Aand` 'connected'.aswl shownizwith. the. air filter collar f I6,". thel intake-fz manifold -lange 520,1; the fuel pump output dine# I I-4,-fand,the suction yline -2 8; to the..spark-@advance=.- mechanism; whereupon the Ldevice is in condition to -be adjusted 'and used. The adj ustrnentsneo-t essary consist merelyvof themain mixture :settingfw andi the idling speed.'

The fscrewfV M4, whichsappears at first'glance tot adjusttheidlingrnixture;L is :in fact a 4iix'ed acl-W justment and is seldom-:ifever-touchedi Undei-'w thesfuelfpump pressures normally usedlth'e :dis-m charge of fuel from'the orifice of valveflIULIIlZi is quite. sufficient: for idling `when thisori-lce-f-isvl extremely small'and When=the screw IIUIappears``l to bee tightrdo'wn onvits seat ldllnasfshown-inJH Fig. 3.'. This screw construction is'v used as fthe most expedient andsimplest means for obtaining" an l exceedingly minute orifice which 1 can alsogbe c adjusted-when necessary; Once-a proper'value for the idler jet-forice-settingfor 1a -given :set nf conditions (particularly *for ta given fuer-pump" pressure and motor displacement) has been determined by experiment and road test, the same is readily duplicated as follows. The maximum vacuum which can be pulled by a small vacuum pump or air exhausting mechanism is determined, and the drop in said maximum vacuum which the test orifice produces when connected to the intake of the exhausting mechanism is noted. Orifices on other carburetors can be similarly set with great accuracy, then, by merely connecting them to the intake of the same or a similar air exhausting device and adjusting the orifice to reduce the maximum vacuum by the same amount. If desired, means for locking or sealing this adjustment, once made, can be provided.

In order to adjust the carburetor all that is required is that the idling speed adjustment screw 68 be set up a few turns to insure that the throttle 34 has a substantial opening, that the engine will turn over with moderate speed, and that the operating rod |06 has some substantial lifting effect on the metering projection |22 to open the main orifice at jet |08 a significant amount. It is then merely a matter of experimenting with the screw or worm 56, which is capable of producing a very slow adjustment in response to large operating movements, until the engine turns over most rapidly for the given throttle setting as already determined by screw 88. This adjustment of worm 56 produces the proper orifice at the main fuel jet as determined by the annular space between jet |08 and metering projection |22, to correspond with the predetermined opening of throttle valve 34. It likewise produces correspondingly proper orifice openings for all other conditions of running and openings of the throttle valve 34 provided the metering projection |22 is suitably configured in accordance with principles which are set down hereinafter. This adjustment of screw 56, is, of course, maintained by virtue of its coaction with worm wheel 46 and friction means 60. Once an accurate mixture setting is thus obtained, the idling speed adjustment screw 68 is merely returned to a position wherein the idling speed has any appropriate or desired value. With these two basic adjustments properly made, the carburetor of this invention will be found to operate properly over the full normal range of operating conditions.

Operation-in general As in most plain tube carburetors there is .an air flow in the direction of arrow A, Fig. 3, through passage I2 which iiow is induced by the pumping action ofthe engine cylinders on intake stroke, and the speed for any given loading of this flow is roughly proportional to the engine speed. At the same time, in the carburetor of this invention, there is also produced a parallel or auxiliary air current through the passages 90, 86, 84, 80, '|4, 16. This current is probably much reduced in speed by virtue of its tortuous and high friction path, but is also probably essentially proportional to the main air current A by reason of the position of the inlet funnel 90 which is so directed as to take an approximate reading of the velocity in the main air stream. The speed of the air current through the auxiliary path is, however, probably sufficiently reduced that the depression effect thereof on the liquid fuel jets |08 and |40 can be ignored, especially by comparison with the fuel ejective effect of the pressure due to the convcntional fuel pump. This pressure is about p. s. i. in most vehicles and is capable of being very accurately predetermined and of remaining accurate over long periods of service in practically all modern fuel pumps. It is also contemplated that even better results than are described below herein will be obtained if, when the carburetor of this invention is installed, the usual fuel pump spring is replaced by one which increases the fuel pump pressure to a maximum safe value for the fuel system of the particular automobile in'question, in order to take the fullest advantage of the benefits of the present invention. It is likewise probable that when use of the invention becomes general, fuel systems having slightly higher safe pressure values will also be installed to put the invention to its fullest use.

The liquid fuel under pump pressure, when forced through the tiny orifices at jet |08 or jet |40 or both, is thoroughly broken up into exceedingly minute droplets and reaches a high state of atomization in the auxiliary aircurrent which retains for the most part its gaseous form and issues into the main air stream at ports 16. The fuel mixture while still in the auxiliary path is, of course, excessively rich, but when diluted by mixture with the main air current A, it assumes approximately the desired 15 t0 l ratio under most circumstances and is then readily usable by the engine. While, because of their size and number, no restriction in area occurs at the openings 16, it should be noted that the sudden deviation in path together with the break-up of the flow into a plurality of small streams results in the further and practically complete atomization of any possibly remaining droplets of liquid y pressure probably insures a high vaporization rate of any tiny liquid fuel particles which might remain suspended in the stream.

From the foregoing description it can be seen that since the rate of fuel emission from the jets is not under the control of the air stream as in the ordinary suction nozzle corburetor, provision must be made for increasing fuel flow as the main air stream A increases in speed. This speed-up of both air streams occurs in response to increased speed of the engine which is brought about by opening the throttle valve 34 as in the ordinary carburetor. Enlargement of the orifice between jet |08 and metering projection |22 occurs in concert with the opening of throttle valve 34 which controls the air flow due to its interconnection therewith by sleeve 48, worm 56, sleeve 42 including worm wheel 46 and gear 44, rack member |30, |32 and operating rod |06. The orifice |68, |22 consequently sprays more liquid fuel under fuel pump pressure into the auxiliary air stream. Since the auxiliary air stream is travelling at a proportionately faster rate as determined by the speed of the main air stream, its mixture value remains about the same, and the final mixture with the main air stream also retains its designated fuel-air ratio. The foregoing remarks, of course, apply to a deliberate advance in throttle opening where no sudden changes are involved and running mixtures are called for rather than maximum power.

Acceleration When we modify the preceding state of facts to the extent of opening the throttle rapidly with the intent of developing smooth, quick acceleraopened when i: no '-longer needed.

ztion o'f uthe iengine, fafdifferent :state ofiaiairs f-is aobserved. lively ithrdttle `opening :normally irdoesnot causefimmediate increaseiinl-air velocity shecause time: isrirequiredlor `the-:engine :to receive `its :added charge rand to speed fup. :At 4:ordinary ifulliezconomy mixtureifand :undenload:thissspeedyup :can only :take :place sratherislowly, so that a `zfull zpower mixture, *substantially :richer than mrdinary, is required :duringithe accelerating n- 'tervaliforsatisfactory performance ain this rerspect. Whereasithis'exigencyisztakengcareiof :hy automatic :pumps or :self-emptying :wells in :the msualcarburetonn'o such expensiveiccmplication .of theistructure isifoundrnecessary in the device of this invention. It will .be notedithatga wideopen positionpfgthrottle 34,alsocopens the main jet orifice |08, T22 `to its fullest extent. Inasmucna'sr neither.t air path has .Aasyyeti been fspeeded .zupsthei fuel :ejected-z iszmuch ihigheriinj proportion itoitheairzthan .ordinarily softhatzthe auxiliar-y air `,path-'mixtureianclitheiinal mixturezare both eniriched substantially .fbeyond normal ,condition :and hence giveffull-:power andrsmoothfaccelera- "tion :performance Furthermore, `ithe degree -of this enrichment, proportionedfalmost vexactly nto -lthe dilerence i between present speed-and the terminal fspeed "corresponding vto fthe throttle l'openin-g so v.that .the fenriching effect is .promptly idecreasedtas ,speedgpicks up; and,promptly termif nated as desiredlvelocity nis lreached lgiving., just the ilexpenditure :of :fuel `needed-,for i proper, per- .Lformance with .none wast-ed i in :periods tof .frich :mixture production when: therei is; in fact; node- :fmand ztherefor.

LStarting *aww-idling Difficulties with starting uunderaordnary `f carburetion,x and attendant,damagingA effects on the engine canbelaid directly at vthe `door of the iusualrstnan'glerior choke valve. rSincei the :crank- .ingsspeed ofi thei zengine isrextremelyrsloyw .corretspondingfainspeedzinithexusual:carburetor-.throat .1:isninsuilicientto: .drawxoiT-renough I fluid .fuel from thenczzlef to-bring fthefsmixture ratio .fupz 11o-,firing -valuaf or :rat: any rate, -zthe ,ilu-id, .'fuelvlin =,the air stream isi-:so;-poorly cbroken@upgdue to flow-air r'speediand fa '-coldfmaniiold; :that thefeectiveA mix- @tureV ofthe/gaseousl portion fofthe :chargefwhen Vit reachesrithe::cylinder-:is: signicantlyabelow :comthustifbleproportions. :'Iloxcorrect this, it is -a-lmost universal to employ aifchokerfor,stranglersyawe -Which closes off or restricts the air stream: ahead Y of the fuel nozzleandlhence appliespall or av por- `tionwofthe static engine depression'directly to the fueljet todraw off ay higher' proportion of .i liquid Ifuel. With lmore droplets present .to yaporize, the truly gaseous portion of themixfturescanlbe' :broughtnup: =to. combustion value; ali. though thefactualfweight Vratioof the fuel present -to the air present is much higher than the appron priate 1 to 15. VThis is manifestly a wasteful prof cedure, but can lbe'tolerated'if the choke adjustnment isprop'erlyvtended and the choke valve Since the manual adjustment is ticklishand bothersome, itii isfsimpler for the'operator: to leave it rich long after` vit -is needed, -f with consequent' `fuel waste, Twashing down of'cylinder Wall-lubricant, and :dangerous Adilution of the crank casecontents. `Most'vrnodern carburetors attempt to'avoid this --waste and` potential engine damagebyencumber- .ing the choke valve `with superimposed automaticrcontrols-which 'frequently give trouble and failU-to function properly. The foregoing waste, @damage-:and-inconvenience is obviated 'bythe- 4 1'0 `.present :invention wherein-.no choke valveat all present ,and nonezisneeded. Startingposition ,of fthe .carburetor is vmerely that `in which :the i'throttle valve 34is ,closed asfar as possible `with stop screw 68 .againstthe boss 24. Under these circumstances V,the ;main :jet 58, l2`2 is closed and little ifiany ifuel .is allowed to pass there- :through .even under ifuel pump pressure. In this -connection it should .be `noted ithat the spring l pressure of spring 118, even :though `not particuilarly'heavyis.suicient to substantiallyseal the -opening'in jet L08 due to the verysmall taper of the` sealing-portion of the metering projection :ii-22. Fuel induction, therefore, ,is effected-mainly through `then-exceedingly :minute .orice .at :the idling ,jet .14.0. While it ,is conceivable ,that -:idling jet f, |40could1berdispensed Withand means provided for adjusting'theminimum opening of jet |08 as a substitute therefor, the structure shown is regarded as more practical in many .,respects, :and is described in detail as .the .pre- ,ferredformJ ,-Normallythe setting of this'` ori- .ce between jet M0 and needlevalve I .42 issuch ,as to cause a mixture justequalto or slightly richer thanthe most economical settingipossible :for the. air speeds involved at idling speedof the engine. When .the engine is to be started,;of course, v,the f cranking speed and induced .air speeds in themainand auxiliar-yair pathsare substantially .less .than at idling speed so that, `assuming fulLfuel p umppressure, the -mixture -fedto the cylinders ,would be much richer than the ordinary economical-mixture. There maybe `^eertaintendencies. such ase-pulsating of the fuel pumpat slow ,engine speeds, or an instantaneous .laginvfuel ,pump pressure build-up Whichrwould freducep-fuel outputat the .jetld for yjust VVamo- `ment,-wherel oy the mixture lWouldlce leaned to ideal combustion ,proportions b ut f,vvhei-,her this -`occurs -or not the range Vof-,mixtures which-the yjetM10-.causes to Yexist vin `the intakemanifoldis ,never such as to,preventringvofthe,engine, for :initialii'lringcan occur Veryreadily over a wide `range-of mixturesfrom just slightlyleaner `than 45,ideal running mixture to quite rich. Once the A,engine has caught, the mixture present `is-in- ,-stantaneously adjusted-*to proper idling value .by theV pick-,up in. air speedrvthrough bothv air, paths, which vfinally steadies -down at .the speed for vv,which the output-of the orifice at jet M0 Vis :accurately set, andthe mixtureis thereafter aul tomatically taken care of Without :attention 'by .the operatorY and-without anyv of the` complicated controls `normally .considered desirable forthe pstartingoperation. -Sincemixture control is in- ,-stantaneousonce the engine is started it will be seen-,that there is no,fuel waste due to the long perodiof operation ata rich mixture Y setting -fwhich yso -often occurs -with the conventional manual choke. Furthermore the1 full atomizing etfectof thepump'pressure atiet itlitogether ,Withtthebreak-up and deection of the auxiliary air `current-atV orifices-1,6 `brings about substanz'tialily: complete subdivisionl of the` uid fuel, as in G5 xordinaryrunning, in. spite of the relatively-slow airspeed through the carburetorunder cranking .and :idling conditions For `this reason the :,danger, fever-present. in .conventional carburetors `.of flooding'the-engine vwith fluid fuel droplets -;Whichf,so enrich-subsequent charges as topre- .vent'starting is practically 'obviated `Likewise danger to-cylinderV Wallsand crankcase lubricant .due towtheccleaning fand-.thinning effects `of. the fiuelwhen in fluid form -is-almost entirely avoided. @It should-also be notedf-thatlthedegree ofatomization which the carburetor of the present invention effects is such that the temperature of the intake manifold loses much of its significance with respect to starting, and the engine will idle properly immediately after starting cold due to the fact that the Weight of fuel employed is taken full advantage of. Another way of expressing this same condition is to state that the apparent mixture (overall weight of fuel to overall weight of air) is substantially equal to the effective mixture (the ratio of the weights on the basis of the part of the fuel which is in substantially gaseous state and hence usable). Thus the necessity for the operator to tend the apparent mixture by a choke or strangler valve, or the necessity for complicated automatic controls governing the apparent mixture during warm-up idling is obviated.

Flatspot correction In the development of the carburetor of the present invention it was found that with the structure substantially as illustrated in the drawings, but lacking the conduit 98, 94, 96, substantially all of the foregoing features of operation were present. The only readily detectable difference from the model as shown in the drawing was that the response to accelerator operation was sluggish and unfavorable at a medium throttle setting corresponding to a car speed of about 30 M. P. H., but was proper at all other speeds. Even then this fiatspot could be adjusted out by a resetting of the mixture control screw 56, but with some slight reduction in fuel economy at other speeds. Certain conditions existing in the ordinary suction nozzle carburetor wherein there is usually a transfer of the fuel emission from a pilot jet operated either by static engine depression or by air flow at the edge of the throttle, which drops oif from maximum to zero, to a main jet operated by kinetic depression due to air flow past the nozzle which picks up from zero and increases to a maximum, are usually considered to be responsible for a flatspot when the pilot operation is not sufficiently extended, the main jet is too long in coming fully into action, or both. Since the only structure corresponding to a pilot `iet in the present device, namely idling jet |40, |42 is fully operative at all times, no similar cause for the flatspot obtains. One theory which has been advanced and which appears to provide a possible explanation for the iatspot is that the geometry of the auxiliary air path 90, 86, 84, 80, 14, 'I6 is such that a certain air speed within the range of air speeds employed sets up a material vibration of the air column in said path, or some significant portion thereof. This vibration may have limited the flow through the auxiliary path and prevented its bearing the proper relation to the main air stream flow, thus temporarily leaning the mixture to a degree unsuitable for brisk performance.

Whatever the cause of this phenomenon, it was found that by merely providing a constricted passage connecting the end of nozzle tube 14 with the main air stream at a point which lies at the other side of the throttle valve 34, the conditions were sufficiently changed to correct the atspot condition described even using the mixture adjustment of screw 56 which is the best for economy in all ranges. As previously described the fiatspot correcting conduit consists of the passage 98, 94, 96 and is of materially reduced cross section so that little if any of the fuel mixture ever reaches the main air stream by way of orifice |00 even when the throttle is in idling position, and its function appears to be: merely to correct the condition which produced the impedance in the auxiliary air path resulting. in the flatspot, possibly by so changing the geom-- etry of the auxiliary air path that the vibratory response if any is displaced to an air speed out-- side of the range employed. Other forms of thev flatspot correction conduit are also suitable and it has been found, for example, that a small readily bendable tube of copper or the like attached to the body |0 by the usual tube fittings may be conveniently and successfully used in place of the passage consisting of drill holes 98, 94, 96 in the boss 24.

Economy of operation Tests have been run by operating the same automobile with conventional stock carburetors in good condition, and then with the carburetor of this invention. Where the maximum ehiciency attainable with the particular vehicle selected was found to be 18 miles per gallon with the stock carburetor during any extended periodi of running under average conditions, the best efficiency attainable with the carburetor of this; invention on the same vehicle for a similar period of average operation has been found to be 261 miles per gallon, and in no case has the efciency been found to drop below 22.75 miles per gallon for any extended period of running even though some severe upgrade tests may have been included therein. From the foregoing gures it can be readily calculated that the fuel saving effected is 20% at the minimum and would normally be significantly more, up to 30% being possible, and 25% being a safe average.

Adaptability to varying applications It has been found that the carburetor of this invention is extremely adaptable with very minor revision. The only alteration necessary to provide for use with different types of engines, or to modify the economy-performance relationship in most respects is a tailoring of the metering projection of the metering member to suit particular conditions. In fact a wide variety of such metering members may be made in quantity and carried in stock for experimental purposes, since the same are readily replaced by anyone capable of removing the cap screw ||6.

In Figs. 6 to 8 are shown three types of metering members illustrating the manner in which the contour may be altered to provide for various conditions. Fig. 6 is merely the member |20, |22 which is shown in Figs. 3 and 4. This member is designed to give fuel economy within the range stated above, and which provides for the best average type of performance with top vehicle speed and best full power mixture at full throttle due to the second slightly sharper tapered tip portion |22 b. Fig. 7 represents a simple metering member |20, |22 wherein the metering projection |22 has a single taper of about 1 (similar to the taper of portion |22a in Fig. 6). This member gives slightly reduced top speed and slightly reduced power at full throttle as compared. with. the member of Fig. 6, and provides for a moderate increase in fuel economy. Fig. 8 shows the general contour of a metering member |20, |22 in which the metering member has a form of particular value in connection with a fuel pump pressure lower than average, e. g. about 2 p. s. i. While the fuel pressure will normally be adjusted rather than the metering projection changed; the pressure vbeing .zpreferablyfnp. s. l. or higher, the7structure in:Fig f'8'serves1toillustrate how this factor rmay` be readily compensatedfor vif inecessary; The tprojection: |2225",v in additionr to ai regular taper, has azslight. flare at the `top of its' operatingfportion which :causes the initial 'orifice'v opening to rincrease rapidly Which:Y compensates r forthe L decrease'df': fuel imipetus produced by the fueltv pump. Otherimeterf inglfmembers, notishovvnprmay be :madey using slightly differenttapers for use with? engines having 'different displacements, and :still other meteringmembers'may befspecially devised having even more complex contoursif :desiredto :K )rocluce-den sired: changesv A,nperformance or economyv over anyportionof the operatingrange.

Fig; 9 'illustrates a;slightly Imodifledtform :of the invention wherein all partsvvhichfare the same as inprevious' views .bear the `same :reference characters and thosewhich have correspondence 'to previously n described, parts 'bear `the same :refer` ence :characters "primed," The tbody. 'l andrboss 22' `are slightlyfmodied fini thatno provision Yfor therackl30 is requiredjat onesidefof the throttle shaft32. The 'sleeveflizhas been replaced-by; a sleeve t2 which4 is .the/same -exceptfor having thetcam 44" inlzplace yofgear. 44.-: A'folloWer 130'; slidesnin borel02, restsonftheearn-IHC andreceives fupon .its upper fsurface therthrust zof operating rodvlilli.A Thevcanfrllri` shownisin-fFig. 9 is :a straight. line fcam* giving affixed rise-,per :de-v gree :rotation of: :theyshaft '32, and the 'operation of ittheidevice is. inrall..respects'the-same as-the device of Figs. 3 andr 4. t While tailoring` ofthe surface of cam; 44"; isxaepossible methodffor modifyin'gA zthe operation-A -of the'` carburetonit is not preferredasince lthe t use pf interchangeable 'meterv ing members, or the-preparationuoffany special contour of metering member as previously describedds .much less cost1y morelexpedientrand accurate and is consequently the form at present preferred;

From the foregoing description it can be seen that .this invention provides a carburetor offer.; ceedingly-simplified constructionr and which;` due to- .the particular featuresv above pointedf out',t Vis capable ofY directly -usingandrapplying fuel-pump pressuresHto the carburetion-ofithe uidfuel, whereby. improved performance characteristics together with markedly increased economy Iare achieved.,i

Variations. and modifications may be made withinthe scope of. the claims andf'portionsof :the improvements. may .beusedwithout others.

l:V A.carburetor comprisingemeans providingzfa main air supply path for connection with the intake manifold of `anfinternallcombustion engine; additional means providing an auxiliary air path" connected in paralleliyvith said main path, said additional means including an air scoop'extending into said main air path and opening in a direction opposite to the normal direction of air ovv therein, and a tube extending across said main air path and having a plurality of apertures formed therein; two fuel emission orifices, one of which is variable, opening on said auxiliary air path; means for supplying liquid fuel under pressure in excess of atmospheric to said orifices; a movable throttle Valve for controlling the flow in said main air path; and means for varying the size of said variable orice in accordance with the position of said throttle valve including means for adjusting the relationship of the orice size to the throttle position.

2.1 A'carburetor comprising .atubularfshellhaxY ing` aailange: :at .one end; for r'connecton: to-"fthe intake manifold :of Van* mternalcombustion engine; an .integral boss :,'oncthe outside cofV =said:;shel1;. :a throttle valve for opening andufclosingsaidtube near cnet end L and having s: an; operatingf'; shat mounted :for rotationrronfsaidfshell; said :b'oss t be-f ingsapertured :to ;receive .;one fend. of: Lsaidrsh'aft; a" nozzle member -mounted finnsaicl boss.;an'd ,exe tending into the interior of the-shelllatanfintere mediate :point in :its flength; an air- .scoop extending from saidy .bosssinteriorly of saidrfsh'ellx anear the other `end. thereof .'andrin afdirectionz'opening away from :said kthrottle r-valve, said. boss: being provided vvith anf air passage connecting said` air scoop and 'said' nozzle; meanson..saidzbossffor makingconnection with the foutput. line ofafcoIr-P ventional 4motor 4vehicle -fuel pump; saidfboss have ingformedthereinra fuel passage connecting;said pump connection:` means directly Withi saidrf-air passage; means i carried 'by saidrboss for #variably Irestricting saidfuel passage;Y andrfmeans carried bysaid boss and mechanically connected With said "shaft -forrcontrollingthe operationof said'restricting means as 1an. incident tofmovee ment of 'said/throttle valve.

3.' A- carburetor comprising a tubular shell hav-- ing'af'ange at oneendffor connection toLthe take manifold of an internalfcom'bustion engine; an integral 'boss on-theoutside Iof 'said shell?" a throttle Avvalvevfor'opening fand= closing-'said 'tube near one end and having VVanoperatingrshaft mounted for rotationon saidfshell, said boss being apertured'to receive one endof-"said-y shaft; a nozzle member mounted in said boss and extendf ing into the interior of the shell at'an 'intermedi-1 ate point in itslength'; an airscoop;extending from said Vbossinteriorly of saidi shell :near "the other end-'thereof 'and in adirection opening away from said throttle valve;=said boss being-,provided with' an *air passage-fconnectingf'said iairl scoop and" said `nozzle; means =on "said boss for making connection With the Aoutput line of: a conventional motor vehicle fuel pump, said boss havinghfdrmed therein a fuel'duct ileadingfrom'saidfpump connection means, andhaving a straight boreintersectingf saidffuehduct, said air passage `and. 'said shaft receiving=aperture;l a-fuelf v-jet "inf said bore between' the -fuel duct Vand 'the lair passage; a meteringeelement slidable-.in said'bore and having a projection cooperating with =saidjet for-pro viding Y avrvariabl'e lorifice vand ioperatingl lmeans slidabl'e infsaid bore; in contact with said meteringelement Iand *actuated by=mechanism on said shaft-for enlarging and irestrictingfsaid orifice in response to rotation-ofsaid shaft.'

4;- A-vV carburetor -comprising f a tubular shell having alange at -one-r end v"for lconnection to the intake `manifoldiof` 'an internal combustionfen' gine:l an= integral-boss 'on-the'outsideof said Shell;

a throttlefvalve-foropeninglandfclosingfsaid tube near one end and having an operating shaft mounted for rotation on said shell, said boss being apertured to receive one end of said shaft; a tubular nozzle member mounted at one end in said boss and extending across the shell at an intermediate point in its length; conduit means connecting the other end of said nozzle member with the interior of the shell at the end beyond said throttle valve; an air scoop extending from said boss interiorly of said shell near the other end thereof and in a direction opening away from said throttle valve, said boss being provided with an air passage connecting said air scoop and said one end of the nozzle; means on said boss for making connection with the output line of a conventional motor vehicle fuel pump, said boss having formed therein a fuel passage connecting said pump connection means directly with said air passage; means carried by said boss for variably restricting said fuel passage; and means carried by said boss and mechanically connected with said shaft for controlling the operation of said restricting means as an incident to movement of said throttle valve.

5. A carburetor comprising a tubular shell having a flange at one end for connection to the intake manifold of an internal combustion engine; an integral boss on the outside of said shell; a throttle valve for opening and closing said tube near one end and having an operating shaft mounted for rotation on said shell, said boss being apertured to receive one end of said shaft; a tubular nozzle member mounted at one end in said boss and extending across the shell at an intermediate point in its length; conduit means connecting the other end of said nozzle member with the interior of the shell at the end beyond said throttle valve; an air scoop extending from said boss interiorly of said shell near the other end thereof and in a direction opening away from said throttle valve, said boss being provided with an air passage connecting said air scoop'and said one end of the nozzle; means on said boss for making connection with the output line of a conventional motor vehicle fuel pump, said boss having formed therein a fuel duct leading from said pump connection means, and havifng a straight bore intersecting said fuel duct, said air passage and said shaft receiving aperture; a fuel jet in said bore between the fuel duct and the air passage; a metering element slidable in said bore and having a projection cooperating with said jet for providing a, variable orice; and operating means slidable in said bore, in contact with said metering element and actuated by mechanism on said shaft for enlarging and restricting said orifice in response to rotation of said shaft. p

6. In a carburetor, means providing a main air supply path for connection to the intake manifold of an internal combustion engine; moderately restricted conduit means connected at two points with said main path and constituting means for providing a parallel auxiliary air path between two locations in said main air path; a throttle valve for controlling the flow in said main air path, located therein to one side of said auxiliary air path; highly restricted conduit means connected between that portion of the auxiliary air path from which air is returned to the main air path, and the main air path at the other side of said throttle valve from said auxiliary air path; and means for discharging liquid fuel under pressure in excess of atmospheric into the air flowing in said auxiliary air path.

7. In a carburetor, a tubular shell; a small laterally apertured tube extending transversely across said shell; a throttle valve for opening and closing the passage in said shell at one side of said tube; an air scoop entering the passage in said shell on the same side of the throttle valve as said tube with its opening directed away from said throttle valve; conduit means connecting said air scoop with one end of said apertured tube thus constituting means for providing a parallel auxiliary air path between two locations in said shell; restricted conduit means connected to the other end of said tube and to the interior of said shell at a point located on the other side of said throttle from said apertured tube; and means for discharging liquid fuel under pressure in excess of atmospheric into the air fiowing in said auxiliary air path.

8. In a posterior throttle carburetor, a frame providing an air passage, a jet on said frame opening on said air passage for admitting fluid fuel under pressure into said air passage; a metering element disposed in said jet and slidable therein for varying the effective orice thereof; a throttle valve shaft rotatable on said frame; means connecting said throttle shaft with said metering member for controlling the position thereof in accordance with the rotative position of said throttle shaft; and a readily accessible adjustable connection between said shaft and said means for adjusting the effective orifice of said jet with respect to a given position of said throttle shaft, said adjustable connection comprising a worm rotatably connected with said shaft, and a worm wheel mounted concentrically on said shaft in engagement with said worm and incapable of rotation with respect to said shaft except in response to rotation of said worm.

References Cited in the flle of this patent UNITED STATES PATENTS Number Name Date 1,658,484 Ensign Feb. 7, 1928 1,961,775 Mills June 5, 1934 2,035,636 Chandler Mar. 31, 1936 2,035,681 Udale Mar. 31, 1936 2,150,081 Schorsch Mar. 7, 1939 2,225,194 Melcher Dec. 17, 1940 2,247,189 De Guyon June 24, 1941 2,261,794 Carlsson et al Nov. 4, 1941 2,314,170 Snyder Mar. 16, 1943 2,432,283 Chandler Dec. 9, 1947 2,457,765 Winkler Dec. 28, 1948 2,462,696 Warburton Feb. 22, 1949 FOREIGN PATENTS Number Country Date 192,149 Great Britain June 25, 1923

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