US1813866A - Carburetor - Google Patents

Description

July 7, F. H. ROYvC-E' CARBURETOR Filed Jan. 16, 1929 2 Sheets-Shet l 7 INVENTOR.

d4 da Julyn', 1931. I F H ROYCE 1,813,866

CARBURETOR Filed Jan. 16, 1929 2 Sheets-Sheet 2 @My/zw A TTORNEYK Patented July-1, 1931 UNITED STATES-.PATENT oFF-ICE rmrmrcxnmmxnorcn, or nnus'rnan, weer wrrrnamo, cnrcmisrnn, ENGLAND,

Assioma To noLLs ROYCE' LIMITED, or DERBY, ENGLAND CARBURETOR Application led January 16', 192,9, Serial-No. 832,969, and in Great Britain January-24, 1,928.

4This invention has reference to carburetors for internal combustion engines, in connection with which thepower output of the engine is frequently varying as in the case of a motor car engine. Itrelates to the type generally known as expanding carburetors, that is to say, in which the air way past the orifice or orifices from vwhich the petrol issues l into the mixing chamber and the metering lo constriction or jet are automatically varied in cross section `area to meet the changing conditions.

In all such carburetors the objects aimed at are that the speed of travel of the air past u the fuel orifice or oriiices should be as far as possible constant to ensure a constant atomization of the petrol or other liquid fuel and that the ratio of etrol, or other liquid fuel, to air should as ar as possible, be constant. It is also desirable that the tendency of the atomized liquid to 'condense and/or be deposited between the mixing chamber and the cylinder should be reduced to a' minimum.

The main object of this invention is to attain these ends better than has been done in carburetors heretofore in use. The invention has the further objects of enabling a carburetor of the type to be constructed with a straight through gas passage, of reducing friction of moving parts to a minimum, and reducing the possibility of particles of dust interfering with the working of the carburetor.

For the purpose of securing thebe'st atom- I arrange several featuresv in combination, namely, that the main air supply shall pass through the throat and 4not as in many carbu- 0 rotors be admitted beyond the throat, and

thirdly 'that before issuinoa 'from such orifice f the' gasoline shall have ibeen atomized means of an air-bleed device.

For the purpose of preventing deposit of gasoline during' the passage of the fuel mixture from the` throat to thev induction pipe I not only securethe best eneral atomization and diifusionof the galsoV ine throughout the air suppiyby means aforesaid, but in addition arrange the mechanical parts so that there ization of gasoline throughout the air supplyk need be no obstruction in thepassage from the section on line 4-4 of Fig. 2. Fig. 5' is ay part section on line 55 of Fig. 2, Figs. 3, 4 and 5 being drawn to an enlarged scale'and Fig. 6 iis a section through Fig. 5 on the line 6 6.

ais the main casting constituting the main body of the carburetor comprising the air in. let al, two coaxial circular orifices a2 and a3 to form andy accommodate the throat, an inclined tunnel a4 extending from the lower part of the air inlet to the top of the casting to accommodate an air bleed suction devie,

a part a forming a cylindrical cavity for the reception of the meterin device, the float ,tank c of quasi vhorse s hoe s ape (embracing the upper half "of the air inlet, the orifice a2, the inclined tunnel, the metering device hereinafter described," and a tube containing a connecting rod hereinafter described) and fan extension a" having a Hat upper surface and with an opening to the air avto support other parts hereinafter Deferred to. a is a hole connesting the said 'tunnel and said cavity. The fixed member of the throat is formed in two arts, to wit, by the curved walls of the orice a2, and the tuhuiar part b which' is 'threaded screwed into the casting ca 'b1 is a tuhuiar member secured :by bolts (not shown) to the .sting c, b2 the throttle valveand t `the inductionpipe provided with a heating gieelret. e is the moving member of the throat.' c1 a sieeve threaded for part of its iength and screwed into the member c, supporting a divided annular member c2, and telescopically slideabie over the upstandingy sieeve cs of the member et, which is seated iny `the vorice a? inthe casting a, and held in position by means of .the member` c5 which rests, on one side, on a shoulder formed ou the casting aand, on the other side, is secured by means of shank c'i pivotally hingedon the casting a, and formed with a thread, engaging a slot in the member 05, and having'the buttery nut S screened thereon. d and d1 are two oats in the fioat tank attached to a spindle dprovided'with projecting jaws da which enga-ge the valve needle di'. e is a tubu lar member, the lower part of which is of irregular cross section shape as shown in Figure 2, and the upper part of which is a cylindrical shape, being e1 of Fig. 1, mounted on the part al of the casting a, and formed with a downward projecting cylindrical part c2 which tits into a hole in the part a". e3 is a piston slideable in the cylindrical part e1 With a downward projecting cylindrical part e4 which slideably lits for part o1c its length in, and is guided by the cylindrical projection e2. eis a diaphragm across the piston es. e are a row of holes through the wall of the said piston. e7 1s a cover enclosing with an air tight joint the upper end of the cylindrical part e1. e3 is a member to secure the cover el held in position on one side by the shoulder e9 and on the other side by a rod el", swinging on a pivot e, and engaging alslot e formed in the member es, and the butteriy nut e. e14 is al spring reacting between cover e7 and diaphragm e5. The member e is secured to part a7 by setscrews e (see Fig. 2) f are a number of holes through the fixed member of the choke communicating with an annular s ace 1 which is in communication with the interior of the cylindrical parte1 via the conduits f2 and f3. g is a rod pivotally hinged at the upper end to the cylindrical projection c4', and at the lower end to one arm of the lever g1, rocking on a fulcrumy'2 be-r tween and supported by two' ears g (one only shown) on the casting a, the other end of which lever is pivotall hinged at g8 to a rod g which is connected y a ball and socket joint g to the moving member c of the choke. y The diffuser now to be described is contained in thetunnel aL of the casting a. h is a plug with a cylindrical part h? externally threaded engaging a tapped thread in the tunnel at, 71.2 and h? are tubes within the tunnel a4| and cofaxial therewith, forming the annular spaces or conduitsh'i' and h5, the space h4 terminating at the upper end against Y the part h1 and the space h5 being in free communication at its upper end with the inside of the tube k3 which is in free communication atv its lower end with the air, k6 are rows of holes through the wall of the tube k2, It? an annular space around the tube h2, ha a conduit, it an annular space in the fixed member of the throat, and hm aI row V of holes leading to the mixing chamber. f

The metering device is constructed as follows l z' is aptubular member havin a narrow diameter part il which fits into t e cavity in part a5 of the casting a, and an enlarged part 2 externally threaded to engage a thread tapped in the casting a, and having a row of holes is through its Wall. t is a valve needle tapered at its lower end, and at its upper end shaped to receive the cylindrical end 5 of a lever e hereinafter described. The lever G rocks on a pivot i7 projected ec centrically from a shaft i8 (see Figs. 5 and 6) and is actuated by a'push rod if extending through a tube im passing through holes in the casting a and expanding at each end to make a tight lit therein. The push rod at its lower end is a loose lit in a hollow plug @'11, inserted in tube 1 and is provided with a flat terminal which rests on a roller 1112 rotating on a pivot projected from. the lever g1 and at its upper end is provided with aA spherical end 14 which engages a spherical socket 15 in the lever 6. 4

The hand control is illustrated in TFigures 5 and 6. i

j is a hollow bracket, having a part jl cut away to receive the end ot the lever i, secured to casting a by stud j5 and located by dowel pin '54 and with a hole 555 therethrough tangential to, but with halits diameter within, the bore of the bracket. The shaft 8 has an annular groove corresponding to the hole j, and when assenibled'in the bracket is secured by a screw j", j? is a lever secured to the shaft and actuatable by the driver.

Referring to Fig. 4, J is a bracket secured by set screw k1 to thecasting a and located bydowel pin k2, 7c3 is a coil spring reacting on the needle of the metering valve against the reaction of the lever 8. v

The 'functioning of the carburetor is as follows Gasoline from the float tank passes thence through the 'hole a to the air bleed suction device entering the annular space h4 and flowing through the holes It@ fills (to the gasoline level in the tank) the' annular space h5. When' the engine is .running the Gasoline 'm the spaces/L4 and h5 (atomized Ey air passing up the tube h3 down the space h5 and through holes he) passesinto the annular space L" and via. the conduit it@ an nular space it and holes h1 to the mixing chamber. l J

The vacuum in the mixing chamber is communicated to the cylindrical parte1 by way of the passages f2, f3, whereupon the piston e3 is lifted against the reaction of spring e14 and through the medium of the lever g1 and rod g4 the moving member of the throat 0 is drawn down, and through the medium of the rod 2' and the lever i the needle i* is lifted thus allowing a greater quantity of air and gasoline to be supplied to the engine. The arran ement of the vacuum cylinder e1 and the piston therein is such that there is no suddenv movement. The space between'` the piston and the rbottomy p-art of thecylinder 'e1 is not directly vented, and Vuntil air has v'passed throngl'i'-holes e6 and vleaked through the clearance between the cylinder wall and the piston, the movement oi the piston is delayed.

When the hand control is-exercised the ulcrum l is raised or lowered thereby lowering or raising the sphere end of the lever if" and with it the'needle of the metering valve.

obstructed passage from the throat to the The construction enables a straight and unthrottle to be provided thus reducing unintentional throttling of the mixture supply,

- and secures in a new and improved manner a constant speed o airpast the gasoline issuing orifices, with a resulting predetermined proportion of air and gasoline, and a varying supply of gasoline and air to meet varyingconditions of engine speed and throttleI opening, and further a handcontrol which while altering the proportion of gasoline to air does not disturb the required varying of supply. Further the friction' of moving parts` is reduced to a minimum. i

What I claim is 1. A carburetor for an internal combustion engine comprising a throat consisting of an annular fixed member and 'a movable member of circular cross section adapted to move co-axiall towards or away from such annular mem er, a mixing chamber, a variablemetering jet, an air bleed suction device arranged and adapted to vaporize the liquid .fuel between the meterin and mixing chambers and means indepen ent of the pressure of air on the movable member for automatically adjustin the members of the throat relatively and t e variable 4metering jet both consistently wlth-the vacuum in the mixingl chamber.

2. A carburetor for an internal combustion engine comprising a throat. consisting of an annular fixed member and a. movable member of circular cross section adapted to move coaxially towards or away from such annular member, one air way and thatthrough. the

v throat, a mixintg chamber, a variable metering jet, an air 1 leed suction device arran ed and adapted to .vaporize'the liquid fuel etween the metering and mixing chambers and means independent of the pressure of air on vmoved co-axially towards or away from ysuch annular member, a throttle valve, a mixing chamber consisting of a cylindrical passage way 'from the throat to the induction pipe cov Fe axial with the throat and unobstructed except for thethrottle valve, a variable metering jet, an air bleedisuction device arranged and adaptedl tov vaporize the liquid :fuel betweenlthe metering and mixing chambers and means independent of the pressure oi' air on themovable member` for automatically adjusting the members of the throat,rela-l atively andthe variable meteringjet. consistently with the vacuumin the -mixingg chamber.,

t. A carburetor for internal combustion engines comprising an'airway, a throat lconsisting of an annular-venturi projecting from the wall of' the air-way anda streamlined movable member adapted to be moved co- `axially towards or away. from such annular member, a mixing cham r, a variable metering jet, an air bleed suction device arranged and adapted to vaporize the liquid fuel between the metering and mixing chambers and means independent of the pressure oi air on the movable member for automatically adjusting the members yof the throat relatively land the i variable metering jet consistently with the vacuum in the mixing chamber..

5. A carburetor as claimed in claim l, having a,- number of gasoline orifices issuing from the side of the annular venturi at the highest point of such venturi. f

(iQ-A carburetor for internal combustion engines comprising a throat consisting of an annular fixed member and a movable member of circular cross section adapted to be moved co-axially towards or away from such annular member, a float tank, a variablermetering jet, consisting of. a pipe through. which the gasoline passes in its passage from the lloat tank and a taper ended rod slidable in such pipe to obstruct, as required, the passage way therethrough, 'an air bleed suction 'device arranged and adapted to vaporize the lliquid fuel between the metering and mixing imil nchambers andmeans, independent of the pressure of air on the movable member, for

automatically adjusting the members ofthe l throat relatively and the variable metering jet, consistently with the vacuum in the mixing chamber. I

A carburetor for an 1nternal combus tion engine comprising a throat consisting of an annular fixed member and a movablemember of circular cross section adapted to be moved co-axially towards or away `from .suchnannular member, a variable metering jet, an'- air bleed suction device arran ed and adapted to vapori'ze the li uid fuel etween the metering and mixing c mbers,"consist. ing of a central andv two col-axial, spaced apart, upstanding pipes, the intermediate pipe having "a number of circumferentialv rows of holes therethrough, the central pipe" being open at ,the 'lower' end to the air, the central and intermediate `pipe being in free communication, but otherwise enclosed at the upper end, the spaces between the central and intermediate and the intermediatel and outer pipes being closed at the lower end, the outer pipe being at its upper endin direct communication with the issuing orifices, and

means, independent of the pressure of air on the movable member, for automatically ad- A annular member, a mixing chamber, a variable metering jet, an air bleed Vsuction de-' vi'cearranged and adapted to vaporize the liquid fuel between the metering and vmixing chambers, and`means, independent of the rpressure of air on the movable member, *for automatically adjusting the members of 'the throat relatively and the variable metering Ajet consistently with the vacuum in the mixing chamber, the means for actuating the moving throat member, consisting of a piston in a closed chamber one side of whi h is in communication with the mixing chamber, and the other side, by restricted air leaks, open to the air, a lever rocking on a -ulcrum intermediate its ends, one end begin operatively connected to the piston and the other end o erably connected to the moving member o the throat, and the means for actuating the metering valve consisting of another lever pivotally ipulcrumed at one end, its Afree end actuating the said valve against the reaction of a spring and a pushI rod engaged by the iirst said lever and actuating the sec-- ond said lever.

9. A carburetor as claimed in ciaim 8, with a hand operated control varying the ratio of, but not the automatic variability of the gasoline supply.

1G. A carburetor as claimed in claim number 8, with a hand. operated control varying the ratio of, but not the automatic variabilasians@l ing jet'consistentlywith the 'vacuum in the mixing chamber, a number of gasoline oriices issuing from the venturi in the plane of its highest point, the means for actuating themoving throat member consisting of a piston in a closed chamber, a circumferential row of holes issuing from the Venturi member of the throat in substantially the same plane as the asoline issuing'4 orifices communicating with onex side of the said piston, a series of restricted air leaks communicating with the other side of the said piston, a lever rocking o n aifulcrum intermediate its ends, one end being operatively connected 'to the piston and the other .end operably connected to the moving member of the throat, and the means for actuating the metering valve consisting of another. lever pivotally fulcrumed at one end, its free end actu-ating the said valve against the reaction of a spring and a push rod engaged by the said leverand actuating the second said lever.v

In testimony whereof I have hereunto affixed my signature.

' FREDERICK HENRY ROYCE.

ity, comprising a shaft on which the lever actuating the metering valve is mounted eccentrically and a lever projecting from such 'shaft operable by the driver.

l1. A carburetor for an internal combustion engine comprising an airway, a threat consisting of an annular venturi progected from the wall of. the airway and a movable member oi circular cross section adapted to be moved fao-axially towards or away from such .annular member, a mixing chamber, a

' variable'metering jet, an air bieed suction devicel arrangedy and adaptedto vaiporize the liquid fuel between the metering and mixing chambers and means inde endent of the pressure ci air on the Inovab e member for automatically adjusting the members-oi the throat relatively and the variable meter-

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