US2635863A - Carburetor - Google Patents

Description

E. OLSON CARBURETQR April 21, 1953 Filei sept. 25. 195o EA MKM a mw N 7 l a 4Z3 M am 4 7N E JM 3. .4.. v Il .lb 7 a W 7 a 7 0 w u u 4 Z5 a M o ./W .1L 9 K ELMER OLso/v (daaro, M v 5ML ATToe/vys Patented Apr. 21, 1953 :alcance-y cAaBURE'roR:

porationof Delaware Application September'i-23, 1950' Serial No; 186,421"

l'fGlamSQ-s (Cl. 261-343 1 11 The-invention relates tocarburetorslfor. ine` termal` combustion# engines andwparticularlyvto; carburetor-s i for automotive use.` As illustratedY i-rif'this` application, the invention-is `embodied' ina` carburetor suclr-aswshownf` in applicants copend4 ingapplicationSerial- Non 109,347;` filedA` August 91,1 1949, but theinventior-rLisd applicable `tciany carburetor employing an accelerator pumpl` The--purpose of this-inventionismto prevent fuel-`-being drawn--into the ymxtureepassage-from tlle^cylinderozetlie'acceleratorL pump through vthedischarge'- nozzle of-suclr pump -by the suction`- which is maintained in the mixture passage: In acceleratorpumps which- -are-provided to supply additional fuel to enrich the'mixturefor purposes` offacceleration; the discharge passage is frequently providedwthf a check valvewhiclfr4 is normally held inA closed 'positionV bya spring* and Which-is unseated by the pressuref of fthepum-ph piston-on the active Vstroke of `therlatter-so-as to permit iuelito flow -from the` pump cylinder through the discharge-nozzle and into-the -mixturepassage.- The spring isodesigned to-hold the valve closedlat all timesfexcept 'during the-active stroke of the-pump piston; Whiclr-occurson` open-ing movements of l" the throttle; to preventthe suctionmaintained-'in theemi-xture-passage acting-fte drawwfuel from'thepump througlr the discharge nozzle thereof.

Somee difculty #has-f been encountered-j defvicesof Lthis kind* under `certainJ4 l circumstances;- The-J4 suction inu theA mixture passage becomes quite highl upon loccasi'onseand` ifastrong-Aenough spring isl used to prevent-,i opening-cio tlie Acheclr valver--by suction under 4 all operatic' conditions, it i'sf necessary@ to use;- a=- spring offsmilcient strength to -appreeiab'l-y-f delay @thewopeningwotithe checkvalvebythepressure createdby-thecpump pistenton-itsv acti-ve stroke. This results-eind a momentary`V lagv in) thewacceleratifonlof-thefengine andi vehicle whichis olojectionalofle.-2`

The` primary-- objectof the i present1= invention is to-- provide means i011- controlling Lthefuel-dis-i chargepassage foffsanacceleratoiepump whiehvis effectivel-V at z` all.` i' times v-toif pif-eventi any lpossilciledischarge lof .fuel. throng-ln suoni passage except duringetlie; activezstroke oftrthepump piston; but which will permtfan `immediate dischargeY oi fuelltherefromz when Ltheipistomis .opeixatedf onfits pumping@ stroke; with substantially noa` delay 1V or. lag; inzffche'.V fuel` ihechar-'gev` According 2 to: the;A present f. invention-i; this; che

'jeciefisaaccnmplishedi theeprouisiomotf; a-,frball cl'iecie; valveewhichfrsi norm alla .cheld 1 im rpositiom exerts sollittle-forceonethe balle that-very# little pressurefwil'l" unseat the-ballf aga-instlthe--- clos'- ing forceof "such spr-ing Theloallfandthe piston passageandtliissuction, ofi course; tends to unseat the balla'` However; since `thepistorrJ is largerthanl -tlfeball-i the-suctionk movesv ther pistonte-tcollapse the sprlingsothat-ap-in` .carriedbyA-thepiston engages the-ballano #holds itlc'losed.

4 Iieotfier Words,= the effect-of suctionwclosesethe check'- va-lve instead of-opening-itf Furtheie objects andiadvantages oethe present invention will be" apparent" from the `followingdeseripti'on-, reference bezit-1g` hady toi; theraccompartying drawings wherein-u a preferredfembodie menti of thei present@inventionW is clearly showm Inthe-drawings;

Fig;` l Lisavertical section through` the: car-- buretor. 5 Figs2 isJ afragmentary vertical section through themeans forl controllingjthe Adischarge passage ofi-theyaccelerator pump:

Fig.;V 3"'sfan enlarged -detail^view in elevation of the piston whichis shown in `section in;` ZE-"ig,V 2.

Referring'-to'1'ig;l;the carburetor shown thereinA comprises three separate castings numbered` l,` 2`-a1r1d'i3,5respectively;y The, castingv I'isjth'e carl uretor-outletwhieh is adaptedto be conf nectedjwiththe "intake: manifold in, theV usual;

( manner; `the casting f2 lis positionelaloove the out? let casting l 'and'hasr a' constant level fuel chamberl 2a, formedjthjerein, While .the .casting` 31f'orrnsa` coverfor, the. fuelchamber and: also has ,the air intake l #"folmed fthereinw T liese, three castingsareseparatedfbygaskets to form i,tighlt joints, and` td limit` the transie'i". of, heat ,ubetweengthe feast ingsas much aspossible lcypreveritinggar1y-1x1 e.v tallc contact of the castings with eachoth,er.`

In. theioutletzcastingf. I a, throttle `Vshaft "5v, is sui'fabl-y;l iQuimallai-fr and Secur or, suoi-1'` sha-it is ther-,usualthnottlevalyeaslyw cheislgrnanuallyl adgiustablet by `means notAI sleeuzvn1 to `controlI l the.l volumen oflf combustible mxturefwhich; is".` suny plied bym/the--caizburetorf-to: thee engine;V

Mathew a3 fa-nchokee alveel and-this-fvalvev' secureduwfalshaft a 1 suitablytmounted the castineltfon rotation Ilna` choke, valve@` in f the; carburatore disclosed: h erei i manually operated anmwthenothezlerre Theu springiadapted to be positioned in wide open position so as not to restrict the quantity of air entering the carburetor, but is adapted to be closed, or partly closed, by the manual operating connections when the engine is started cold in order to facilitate starting, the position to which the choke valve is moved being dependent upon the temperature at the time of starting. The choke valve is adapted to be moved to different positions by means of the arm numbered 9 which is adapted to be operated by a connection leadaccuses ing to the dash which is not shown herein, but l is a conventional construction. The arm 9 operates the choke valve through mechanism which need not be described herein, but is fully shown and described in the copending application above referred to. It may be said, however, vthat the operation of the choke valve by the arm 9 is eiected through a spring III which holds theA choke valve yieldingly closed, so that when the engine starts to run under its own power, the increase in engine suction which then occurs can pull the valve open to some extent against the force of the spring I, so` as to prevent over-v choking.

In the carburetor shownA herein, the choke valve is also designed to operate the throttle so as to move the throttleslightly toward open position when the choke valve is moved to its fully closed position in order that the idling speed may be somewhat increased when the choke valve is closed. This is done for the purpose of providing a somewhat faster than normal idling when the choke valve is closed at low temperatures which is desirable to prevent stalling. The operating connections between the choke valve and the throttle valvefor effecting this movement are indicated generally by the reference numeral II. Since this mechanism has nothing to do with the invention in this application, it is not illustrated in detail and will not be described, but such mechanism is fully shown and described in the aforesaid copending application.

As. already indicated, air is admitted to the carburetor through the air inlet 4 and fuel is supplied to the carburetor through a main fuel nozzle I2 which terminates at the throat( of a small Venturi tube I3 which, itself, terminates at the throat of a large Venturi tube vI4 integral with the casting 2 and forming a partA of the mixture passage which extends vertically through the carburetor. lIhe purpose of these Venturi tubes is, of course, to increase the velocity of air flow past the end of the main fuel nozzle I2 to create a partial vacuum adjacent the nozzle outlet in the usual and well known manner. Fuel is also supplied to the intake passage by an idling fuel inlet which is not shown herein, but which terminates in an orifice communicating with the intake passage at the point adjacent and slightly posterior to the edge of the throttle Vvalve 6 when the latter is in closed position.

Fuel is supplied to both of these fuel inlets from the fuel chamber 2a and fuell is supplied to the latter through a coupling I5 which is screwed into the casting 3 and to which a fuel supply pipe extending to the main fuel tank of the vehicle is adapted to be connected. Fuel which is supplied through the coupling I5 enters a passage I5 formed in the casting 3 and flows through a passage in a nipple I l, which is screwed in the wall of the casting 3, and communicates with the fuel bowl 2a when the parts fuel through the passage I'I into the bowl is controlled by a valve I8 which cooperates with the passage II and rests on one arm of a lever I9 which is pivoted on a pin 28 fixed in position in the wall of the fuel chamber 2a. The lever I9 is connected to the float mechanism which is not shown, but which is received within the chamber 2a and when the fuel level in said chamber reaches a denite height, the float lifts the lever I9 so as to close the valve i8 and cut off the flow of fuel into the float chamber in the usual way. The float mechanism is of conventional construction and has nothing to do with the invention which is claimed in this application. Y

Before describing the fuel passage which conveys fuel from the fuel chamber 2a to the main and idling fuel inlets, the accelerator pump will be briefly described. The specific construction of the pump, itself, constitutes no part of the present invention and may be of the same construction as shown in the aforementioned copending application. This pump includes a cylinder 25 into which fuel can flow from the fuel chamber 2a, through a passage which is ,not shown, and slidable in the cylinder is a pump piston 25 which is operated by a spring 2l which is received between the piston 26 and a washer 23 which engages the under side of the horizontally extending part 29 Yof a vertical rod 30 connected by a link SI to the throttle operating arm 32. The part 29 projects through a slot 33 formed in a rod 34 extending upwardlyfrom the pump piston 26.

when the throme is opened at moderate speed,

the spring 2l is compressed by the part 29 and the piston is moved downwardly through` the medium of the spring. If the opening of the throttle is very rapid, the spring will be com-` pressed enough for the part 29 to engage the bottom of slot 33 and positively move the piston downwardly during the opening of the throttle at the end of which the spring will expand, forcing the piston further in a downward direction. In other words, on sudden and relatively large opening Amovements of the throttle there is an pansion of the spring. Y

Y, During the described movements of piston 26, fuel is forced from the cylinder 25 through the discharge passage which leads to the mixture passage and through which the flow of fuel is controlled in a manner to be later described.

In the device disclosed herein, fuel may be conveyed from the constant level fuel chamber 2a through a fuel conduit of the same construction as that shown in the earlier copending application. This fuel conduit comprises 4three parts or passages which together make up a conduit shaped substantially like an inverted U, one part of the conduit being substantially vertical and extending downwardly into the float chamber from the casting 3 to which it is secured. This connects with a. horizontal passage formed in casting 3, which, in turn, connects at its other end with a substantially vertical passage formed in the Wall of casting 2, which `leads to the idling fuel inlet, through a passage formed in the casting I, which is not shown herein. As shown in Fig. 1, the aforementioned fuel conduit includes the vertical passage 4I! formed in a member-4I which is secured in any suitable way to the casting 3 and separated therefrom by a gasket 42.v

are assembled ,as Shown 111 .Fig- 1 The ,flew 9i is The member 4I 'extends ecwnwerily inte ture'passage which tends to open said valve, a member controlling the operation of said valve, a spring normally holding said valve closed and holding said member out of engagement with said valve, and means for communicating the suction of the mixture passage to said memberin order to move said member into engagement with said valve so asio prevent opening of the valve when the pump is not being operated. Y

3. In a charge. forming device for an internal combustion engine having a mixture passage, a fuel supply chamber, air yand fuel inlets supplying air and fuel to said mixture passage, a throttle controlling the flow of mixture from said mixture passage, an accelerator pump having a piston operated by said throttle for supplying additional fuel for acceleration' on opening movements of said throttle, said pump having a fuel discharge passage communicating with said mixture passage and subject to the suction in said mixture passage, said pump discharge passage being enlarged between the pump and the discharge end of said passage to form a cylinder, a valve positioned in said cylinder and controlling the flow of fuel through said discharge passage, a piston slidable in said cylinder and movable into engagement with said valve to hold the valve in closed position, a spring positioned between the valve and said piston and normally effective to hold the valve closed and the pistonin a positionwhere it does not engage said valve, and a suction passage connecting the space in said cylinder between the valve and piston with the mixture passage, whereby the suction in the mixture passage is effective to move the piston into engagement withsaid valve, so as to hold the valve closed when the pump is not being operated.

4. In a charge forming device for an internal combustion engine having a mixture passage, a fuel supply chamber, air and fuel inlets supplying air and fuel to said mixture passage, a throttle controlling the flow of mixture from said mixture passage, an accelerator pump having a piston operated by said throttle for supplying additional fuel for acceleration on opening movements of said throttle, saidV pump having a fuel discharge passage communicating with said mix-- ture passage andisubject to the suction in said mixture passage, said pump discharge passage being enlarged between the pump and the discharge end of said passage to form a cylinder, a valve positioned in said cylinder and controlling the now of fuel through said discharge passage, said valve being subject to the suction maintained in the mixture passage which tends to open said valve, a piston slidable in said cylinder in response to the suction in the mixture passage and movable thereby to a position to prevent opening of said control valve in response to suction, said piston having a head of approximately the same diameter as that of the cylinder in Which it slides and a smaller body portion, a circumferential rib on said body portion of substantially the same diameter as Vthe piston head and an axial groove through said rib to permit a flow of fuel therethrough and to communicate the suction of the mixture passage to the interior of said cylinder.

5. In a charge forming device for an internal combustion engine having a mixture passage, a fuel supply chamber, air and fuel inlets supplying air and fuel to said mixture passage, a throttle controlling the ow of mixture from said mixture passage, an accelerator pump having a additional fuel for acceleration on opening movements of said throttle, said pump having a fuel discharge passage communicating with said mixture passage and subject to the suction in said mixture passage, said pump discharge passage being enlarged between the pump and the discharge end of said passage to form a cylinder, a valve positioned in said cylinder and controlling the flow of fuel through said discharge passage, said valve being subject to the suction maintained in the mixture passage which tends to open said valve, a piston slidable in said cylinder in response to the suction in the mixture passage and movable thereby to a position to prevent opening of Ysaid control valve in response to suction, said piston having a head of approximately the same diameter as that of the cylinder in which it slides and a smaller cylindrical body portion spaced from the wall of said cylinder, and a spring positioned Within said cylindrical body portion and engaging said valve whereby said spring is normally eiiective to hold said valve closed.

6. In a charge forming device for an internal combustion engine having a mixture passage, a fuel supply chamber, airgand fuel inlets supplying air and fuel to said mixture passage, a throttle controlling the ilow of mixture from said mixture passage, an accelerator pump having a piston operated by said throttle for supplying additional fuel for acceleration on opening movements of said throttle, said pump having a fuel discharge passage'communicating withrsaid mixture passage and subject to the suction in said mixture passage, said pump discharge passage being enlarged between the pump and the discharge end of said passage to form a cylinder, a valve positioned in said cylinder and controlling the flow of fuel through said discharge passage, said valve being subject to the suction maintained in the mixture passage which tends to open said valve, a piston slidable in said cylinder in response to the suction in the mixture passage and movable thereby to a position to preventopening ofsaid control valve in response to suction, said piston having a head of approximately the same diameter as that of the cylinder in which it slides and the mixture passage to the interior of said cylin.

drical body of the piston. A

i 7. In a charge forming device for an internal combustion engine having a mixture passage, a fuel supply chamber, air and fuel inlets supplying air and fuel to said mixture passage, a throttle controlling the flow of mixture from said mixture passage, an accelerator pump having a piston operated by said throttle for supplying additional fuel for acceleration on opening movements of said throttle, said pump having a fuel discharge passage communicating with said mixture passage and subject tothe suction in said mixture passage, said pump discharge passage being enlarged between the pump and the discharge end of said passage to form a cylinder, a valve of smaller size than said cylinder positioned therein and controlling the flow of fuel 315mg operated by said throttle for supplying g5 through said discharge passage. a piston of larger 1"wwwiniiuiuiiiiiiiiuiy1iiiiiiiiiummm size than said valve slidable in the cylinder and movable into engagement with the valve to hold it in closed position, a spring in said cylinder between the valve and piston, said spring being normally operative to hold the valve closed and the piston out of engagement with said valve, and a suction passage connecting the space in said cylinder between the valve and piston with the mixture passage, whereby the suction in the mixture passage is eiective to move the piston into engagement with said valve, so as to hold 10 the valve closed when the pump is not being operated.

ELMER OLSON.

References cited in the fue of this patent UNITED' STATES PATENTS Number l Name Date l 1,873,919 Ball et a1. Aug. 23, 1932 2,199,509 Olson May 7, 1940 10 2,274,467 Ban Feb. 24, 1942 2,403,390 Moseley et al. July 2, 1946

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