US2887309A - Carburetors - Google Patents

Description

May 19, 1959 AG. E. RAYNOR CARBURETORS Filed Sept. 6, 1957 INVENTQR. 6776er! E /Qaynor BY ATTOR/VY United States Patent CARBURETORS Gilbert`E. Raynor, Tulsa, Okla. Application September 6, 1957, Serial No. 682,428 7 Claims. (Cl. 261-50) Patent No. 2,841,374 dated July 1, 1958 and entitled- Carburetors An internal combustion engine, or the like, is normally utilized in combination with a carburetor provided with a venturi throat for reducing the pressure of the incoming air stream in order to siphon fuel, such `as` gasoline, from a supply reservoir into the air stream. The vaporized fuel is mixed with the air stream to provide for combustion thereof as required to supply the power for operation of the engine. Most of the carburetors in use today are provided with a venturi throat of a xed size wherein the pressure drop or pressure differential created thereby is varied by the change of the quantity of air being drawn through the carburetor,

by the suction force of the engine. If the fixed venturi throat is small enough to create suction pressures for fuel ow at low engine speeds, it will usually restrict the ow of air and fuel at the higher engine speeds wherein a Ihigh rate of ilow is required. In order to solve this prob-lem, many fixed venturi carburetors have been developed having multiple barrels in order to more eiciently supply the air-fuel mixture to the engine throughout the operating range thereof. These multiple barreled carburetors are of a complex structure and are usually Very expensive in construction.

` The present invention contemplates a novel carburetor provided with a variable venturi section which automatically adjusts the throat area to the quantity of air required by the engine, and maintains `a substantially reduced venturi pressure which is proportional to the engine requirementsthroughout the operating range of the engine. Thus, a more accurate proportioning of the fuel with respect `to the air may be provided for the engine operation. The variable venturi provides the Suction pressure required for fuel flowwith only a small drop in the `pressure maintained in the lower pressure section `of the carburetor. As a result, more pressure is available for moving the fuel-air mixture into the engine cylinders, thereby permitting more power to be produced fby. the engine. A `metering pin is provided for regulating the fuel iiow, .and the venturi maintains a `vacuum even during idlingconditions of the engine. Thus, no special idling systems are needed with the novel carburetor. The variablcventuri section automatically maintains the most desirable `pressure drop and flow of air therethrough, fand the `metering pin functions to assure an optimum `fuel-air ratio for the various `engine operating conditions. 1 l

tially conical shaped outer housing 12. The housing12` with respect to the quantity of air flowing through the venturi to provide the most desirable fuel-air ratio for the engine throughout the operating range thereof.

Another object of this invention is to provide a novell carburetor having a venturi section of variable throat size for maintaining a substantially reduced pressure drop of the air stream passing therethrough which. is proportional to theengine requirements throughout the operatingrange of the engine.

A further object of this invention is to provide a car-` buretor w'herein the fuel is dispersed radially into the air stream passing through the venturi section for providing an optimum vaporization of the fuel.

A still further object of this invention is to provide a carburetor wherein a portion of air is mixed with the fuel prior to dispersal of the fuel into the primary air stream, thereby facilitating the vaporization of the fuel.

Still another object of this invention is to provide a novel carburetor having an automatically variable venturi throat which is simple and eicient in operation and economical and durable in construction.

`Other objects and advantages of the invention will be evident from the following detailed description, read in conjunction with the accompanying drawings, which illustrate my invention.

In the drawings:

Figure 1 is a sectional elevational view of a carburetorl embodying the invention.

Figure 2 is a perspective view of a ing the invention and with a for purposes of illustration.

carburetor embodyportion thereof cut away Referring to the drawings in detail, reference character` 10 refers in general to a carburetor comprisinga substanis open to atmospheric pressure at one end 14 thereof, as shown in Fig. 2. A suitable threaded connection member 16 extends transversely into the housing 12 in the proximity of the lowerportion thereof for connection with a fuel supply line (not shown) from a fuel pump (not shown) or other fuel source, for a purpose as will be hereinafter set forth. A reduced neck portion 18 is provided on the housing 12 opposite the open end 14 thereof and is provided with a suitable throttle valve 20 secured therein in any well known manner. An outwardly extending circumferential flange member 22 is provided on the outermost end of the neck portion 18, and isprovided with a plurality of circumferentially spaced apertures 24 for securing the carburetor 10 to1 the induction system of an internal combustion engine, or the sleeve member 30 therein. The sleeve 30 like (not shown). l

A diametrically disposed cross bar member 26 extends across the open end 14 of the housing 12, and is provided with a central aperture 28 for rigidly supporting a tubular is concentrlcally disposed within the housing 12 and extends downwardly therein, as clearly shown in the drawings. d The sleeve member 30 is provided with an outwardly extendi cir` cumferential ange 32 at the inner or lower end thereof i d for receiving one end of a suitable helical spring 34 which is disposed around the sleeve 30 thereabove. A plurality of circumferentially spaced apertures 36 are provided in` the flange 32`for a purpose as will be hereinafter set" forth. A cylindricalhousing 38 is slidably disposed around the sleeve member 30 for encasing the spring 34.

The cylinder 38 is provided with an inwardly extending circumferential ange 40 at its upper end for receiving the uppermost end of the spring 34 thereagainst, as clearly shown in the drawings. A plurality of spaced ports 42 are provided in the cylinder 3 8 for admitting bleed air at atmospheric pressure into the interior of the cylinder 38X.

`A movable cone assembly 44 is suitably secured or integral with the lower end of the cylinder 38. The cone assembly 44 comprises an upper plate member 46 of a substantially annular conguration. A circumferential tapered portion 48 is provided around the outer periphery of the platel 46. The outer rim or tapered portion 48 is shaped to form an` inlet for a venturi throat section 50 between the movable cone assembly 44 and the inner peripheryof the` housing 12. A sleeve member 52 of aj' diameter' than the, cylinder 38 is4 Centrallyy disnosed 9.111 the. plat@ 46ml extends downwardly there.- from to provide an air well portion. The upper end 54 of the sleeve 52 is open and is in communication with the` interior of the cylinder 38. Thus, ai-r at atmospheric pressure which enters the cylinderl 38 through the ports 42 will be communicated to the air well 52. The apertures 36 in the flange 32 permit the air to flow Adownwardlyifrom the cylinder 38 into the air well S2 at all times'during the operation of the carburetor 1d. A central aperture 56 is provided in the bottom of the well 52 to provide a bleed air orifice. A tapered metering pin 58 is threadedly secured within the spring hanger sleeve and extends downwardly through the bleed air orifice 56 for regulating the flow of air therethrough as will be hereinafter set forth.

A vent plate 60 is rigidly secured to the under side of the -upper plate 46 by means of suitable spaced vent bushings`62. The plate 60 is spaced from the plate 46 by means of circumferential shoulders or outwardly extending anges 64 provided on each of the bushings 62. Thus, a fueldispersal space 66 of a substantially annular configuration is provided between the upper plate 46 andthe vent plate 60. A float bowl 68 is carried by the vent plate 60 and extends downwardly therefrom to provide a leakproof container for fuel. The vent bushings 62 extend through the plate 60 to freely admit air at atmospheric pressure into the float bowl 68. A cylindrical housing 70 extends downwardly from the central portion of the vent plate 60 and is concentrically disposed around the sleeve member 52 to provide a fuel emulsion well. I'he housing` 70 is open at the top thereof for communication with the fuel dispersion area 66. A centrally disposed fuel orice 72 of a smaller diameter than theV orifice 56 is provided at the bottom of the housing 70, through which the metering pin 58 extends into the fuel bowl 68K. The outer periphery of the fuel bowl 6 8 cooperates with the housing 12 to provide an outlet 74 for the venturi throat 50.

A suitable connection member 76 is provided at the bottom of thefuel bowl 68 for receiving one end of a flexible conduit 78. The opposite end of the conduit 78 is suitably connected to the connection member 16. In this manner, communication is established between the fuel pump or other fuel supply source (not shown) and the fuel bowl 68, It is to be noted that the conduit member 78` is of a exible construction, and therefore does notl in any manner hinder the. reciprocal movement ofl thel cone assembly44. within the housing 12, as will be hereinafter set forth. An annular iloat member, 80 is disposed within the fuel bowl 68 around, the housing 70. A bell crank or lever arm 82 is suitably secured to the lowersurface of the float 80 for alternately opening and closing a needle valve member 84 upon actuation of the tloat 80 to maintain a relatively constant fuel level in the float bowl 68 as is well known. The needle Valve 84 controlsthe ilow of fuel from the connection member v76 into the fuel bowl 68, It will bel apparent from Fig.

l that a raised position of the oat will move the lever arm 82 for closing the needle valve 84, thereby precluding the flow of fuel into the fuel bowl 68. Conversely, a lowered position of the float 80 will move the lever arm 82 to a position for opening the valve 84, thereby permitting `fuel to ow through the valve and into the fuel bowl 68.

The entire inner conc assembly 44, including the fuel bowl 68 and upper cylinder 38, is free to move reciprocally within the outer housing 12. The spring hanger tube 38 functions as a central guide for assuring an eiiicient reciprocal movement of the cone assembly 44: The pressure of the spring 34 bearing upwardly against the flange 40 of the cylinder 38 sconstantly urges the entire cone assembly 44 toward an upward direction whereby the outer periphery of the tapered section 48 will be in contact with the inner periphery of the housing 12, for closing the venturi throat 50. The metering pin 58 may be threadedly adjusted within the sleeve 30 for placing the lower end 86 of the pin in substantially any desired` longitudinal position within the fuel bowl 68 whereby the reciprocal movement of the inner cone assembly 44 will move the orifices 56 and 72 to positions relative to the taper of the pin for metering the liow of fluid therethrough. The downward movement of the cone assembly 44 will be limited by the flanges 4i) and 36 and the spring 34 disposed therebetween. ln order to simplify the explanation of the operation of the carburetor 10, the chamber 88 within the housing 12 and above the cone assembly 44 will be designated the inlet chamber, and the chamber 90 within the housing 12 below the cone assembly 44 will be designated the low pressure chamber.

Operation The operation set forth herein relates to the carburetor 10 as utilized with an internal combustion engine (not shown). lt will be apparent, however, that the carburetor is also applicable to utilization in other fields.

The carburetor 10 is suitably secured adjacent the engine with the neck portion 18 in alignment with the intake pipe (not shown) of the engine as is well known in the industry. The tiow of iiuid through the neck portion 18 into the engine is controlled by the throttle valve 2i) in the normal manner. When the engine is at rest, the pressure in the inlet chamber 88 and low pressure chamber 9i) will be equal, and the spring 34 will urge the inner cone assembly 44 toward its uppermost position within the housing 12. ln this manner, the venturi throat 50 will be closed and no air will be delivered therethrough to the engine. In addition, the largest crosssectional area of the tapered lpin 58 will be disposed in the orifices 56 and 72 when the cone assembly 44 is in its uppermost position. Thus, since there is no flow of air through the venturi S0, no suction pressure will be present to move fuel into the fuel dispersal space 66. However, both the orifices 56 and 72 are disposed below the level of the fuel within the fuel bowl 68. Thus, the fuel will ow by force of gravity past the metering pin 58 to fill the emulsion well 52 to a depth equal to the level of the fuel within the bowl 68. It will be apparent that the metering pin 58 may be adjusted, or lowered or raised within the sleeve 30 by means of the threaded connection therebetween, thus regulating the fuel ow and eliminating the necessity of special idling systems for the, carburetor' 10.

When the engine is started, the action of the pistons (not shown) therein will reduce the pressure in the engine intakemanifold. Thus, the pressurein the low pressure chamber 90 will be reduced accordingly. The periphery of the fuel dispersal space 66 is open to this reduced pressure since the space 66 is disposed below the upper plate member 46. Therefore, the initial pressure drop resulting from the starting of the engine will reduce the pressure in the fuel dispersal space 66 and inthe emulaseaaos sion well 70 which is in communication therewith. The atmospheric pressure admitted through the vent bushings 62 into the fuel bowl 68 and acting on the surface ofthe fuel therein and atmospheric pressure admitted through ports 42 and apertures 36 to the bleed air well 52 will force the fuel in the emulsion well 70 and bleed air well 52 upwardly and out through the fuel dispersal space 66. In this manner, a -rich priming mixture of the fuel will be supplied to the engine for starting thereof.

A continued piston action of the engine further reduces the pressure in the low pressure chamber 90 until a stifli- `ciently great pressure differential is created between the low pressure chamber 90 and the inlet chamber 88 to overcome the tension of the spring 34. When this occurs, the movable cone assembly44 is moved downwardly within the housing 12 and toward the enlarged portion of the housing. This opens the venturi throat 50 whereby air will flow therethrough into the chamber 90. Simultaneously, the orifices 56 and 72 are moved `downwardly with respect to the metering pin 58 whereby asmaller cross-section of the pin will be disposed in the orifices. Thus, air at atmospheric pressure will be permitted to ow downwardly from the bleed air well 52 into the emulsion well 7 0` for mixing with the fuel admitted to the emulsion well70 through the fuel orifice 76 prior to dispersal thereof from the periphery of the dispersal space 66. It will be apparent that the lower the movement or the greater the distance travelled by the cone assembly 44, the greater the quantity of air" and fuel which will be directed to the fuel dispersal space 66. This pre-mixing of a portion of the air with the fuel starts the vaporizing of the fuel prior to discharge into the dispersal space 66 and greatly facilitates the full vaporizing and mixing of the fuel with the air for passing to the engine.

The velocity of the primary air moving through the venturi throat 50 is increased as it passes through the venturi, inY accordance with known laws of physics. The increase in air velocity creates a decrease in the air pressure at the throat of the venturi 50. This lowered pressure is communicated to the emulsion well 70 through the dispersal space 66. The atmospheric pressure acting on the surface of the fuel in the fuel bowl 68 will thus force the fuel past the metering pin 58 in the fuel orifice 72 and move the fuel upwardly therein. Simultaneously, the atmospheric pressure in the bleed air well `52 is forced downwardly around the metering pin 58 in the `ori1ice56 and into the emulsion well 70 wherein the air mixes with the fuel in the well 70 to provide a fuelair emulsion. This fuel-air emulsion is discharged through the fuel dispersal `space 66 for mixing with the primary air entering the carburetor through the venturi throat 50. It will be apparent that the-pressure differential between the inlet chamber 88 and low pressure chamber 90 will be determined by the engine `requirelments. Thus, the reciprocal movement of the inner cone assembly 44 will be in accordance with the operating requirements of the engine for automatically supplying the optimum quantity and ratio of air-fuel mixture to the engine.

The bleed air in the air well 52 facilitates the passage of the fuel through the emulsion well 70 and into the dispersal space 66 by reducing the tendency of the fuel to adhere to the inner surfaces thereof. Furthermore, the pre-mixing of the air with the fuel permits the fuel to start vaporizing during its movement toward the venturi 50. In addition, the bleed air assures an even distribution of the fuel through the fuel dispersal space 66. thereby providing a more even mixing of the fuel with the primary air at the venturi throat 50. The addition of more bleed air in proportion to the increase of fuel at higher rates of the fuel ow is necessary to maintain the advantages of the bleed air at the higher ow rate ranges. As hereinbefore set forth, the bleed air flow is automatically increased as the inner cone assembly moves downwardly within the outer housing 12, thereby assuring an efficient operation of the carburetor 10 throughout the operating range of the engine utilizing the carburetor.

As the fuel-air mixture requirements of the engine are lessened, such as by a slowing down of the engine speed, or a back up of the manifold pressure resulting during the process of rapid engine acceleration, the pressure differential between the inlet chamber 88 and low pressure chamber 90 is decreased. Thus, the spring 34 will function to urge the inner cone assembly 44 upwardly toward the small portion of the housing 12 and toward a closed position. This reduces the area of the venturi throat 50 to reduce the quantity of air flowing therethrough, and moves the orifices 56 and 72 toward the larger section of the metering pin 58 to reduce the quantity of fuel and bleed air admitted to the fuel emulsion well 70 and the fuel dispersal space 66. When the inner cone is returning to a reduced flow condition, the venturi vacuum will not be destroyed, however, and the fuel flow will thus continue to be proportional. That is, there will be no momentary conditions of lean fuel mixtures which normally result from a collapse of venturi vacuum and interrupts the fuel liow to the engine, such as would occur if the size of the venturi were fixed instead of variable. Thus, there is no need for an acceleration pump, or the like, as an auxiliary agent for the carburetor.

From the foregoing, it will be apparent that the present invention provides a novel carburetor having a variable venturi throat section for increasing the clciency of an internal combustion engine, or the like. During periods of engine acceleration, the venturi area and fuel orifice area is automatically adjusted to admit the fuel-air mixture required for engine operation regardless of the varying ow rate and the varying pressures developed in the eugines induction system during acceleration. Thenovel carburetor maintains the venturi suction and assures an uinterrupted `fuel flow proportionate to the primary air passing through the venturi throat, whereby supplementary fuel need not be provided for the engine, thereby resulting in a greater fuel economy. Conversely, when the engine decelerates, the venturi area and the area through the bleed air orice 56 and the fuel orifice 72 is reduced to regulate air ow and fuel flow in accordance with engine requirements while maintaining optimum fuel-air ratio. The carburetor is simple and efficient in operation and economical and durable in construction.

Changes may be made in the combination and arrangement of parts as heretofore set forth in the specification and shown n the drawings, it being understood that any modilication in the precise embodiment of the invention may be made within the scope of the following claims without departing from the spirit of the invention.

I claim:

l. A carburetor comprising a substantially conical shaped outer housing, a movable inner housing member concentrically `disposed within the outer housing, a fuel reservoir provided within said inner housing, spring means provided in the inner housing for constantly urging the inner housing in one direction, an inlet chamber provided on one side of the inner housing and open to atmospheric pressure, a low pressure chamber provided on the opposide side of the inner housing from the rst mentioned side, said inlety chamber and low pressure chamber providing pressure differentials across the inner housing for overcoming the spring pressure for moving the inner housing in a direction opposed to the spring pressure, means provided in the inner housing for dispersing the fuel from the fuel reservoir and into the outer housing, metering means for regulating the flow of the fuel from the reservoir, and means for controlling the flow of fuel into the fuel reservoir.

2. A carburetor comprising a substantially conical shaped outer housing, an inner housing reciprocally disposed within the outer housing, said inner housing cooperating with said outer housing to provide a variable aseroo venturi throat therebetween, an inlet chamber provided on oin'eside of the inner housingya lovvp'ressur'e chamber provided on the opposite yside of the inner housing, spring means provided in the inner lhousing for urging the inner housing in a direction tovvardfilie smaller portion of the outer housing to close ventri throat, said inlet chamber and 10W pressure 'chamber providinga p're'ssuredifferential across the inner housing for overcoming the spring pressure to open the venturi throat, afuel reservoir Iprovided witliih 'the inner housing, means fo'r 'direeting the fuel from the reservoir intothe venturi throat, means for mixing air Iwith the fuel before dispersal thereof, said fuel reservoir Lopen tio/atmospheric pressure for moving the fuel yout `ofthe reservoir, adjustable "metering means for regulating ythe flovvoffuel from the reservoir, and means for `eontrolling `the florvof fuel Yto the reservoir.

n 3. carburetor comprising a substantiallyy conical shaped outer housing, 'an inner housing 'reciprocally disposed Within the outer housing, 'said innerhousing icooperating with said outer housing to providea variable venturi throat, an inlet chamber provided ou one side of the inner housing and open to atmospheric pressure, a 10W pressure chamber provided on the opposite side of the Y inner housing for creating a pressure differential thereacross, said inner housing responsive to said pressure diiferential formoving the Venturi throatto variable posi- Itions ofopen, Va fuel reservoir 'provided Within the inner housing, 'means for moving the fuel from 4the reservoir to theA venturi throat inproportion to the air stream moving therethrough, adjustable metering means vfor regulating the fuelflo'w fromv'the reservoir, andmeans'fo'r -controlling the supply of fuel to the fuel reservoir.

4. A carburetor comprising a ysubstantially conical shaped outer housing, 'an inner housnigreciprocallyl disposed Within the outer housing, 'an Vinlet chamber Vprovided on one side of the inner housing'and open yto atmospheric pressure, a low pressure chamber'provided on the opposite side ofthe inner housing `for creating 'pressure differentials thereacross, said pressure differentials providing for reciprocal movement of the inner housing Within'the outer housing to provide a variable venturi therebetweem'a fuel reservoirprovided withinthe inner housing, fmean's for dispersing the fuel radially'from the inner housing to the venturi throat, metering'means for tproportioning `the `fuel flow inrelation to the air stream moving through the venturi, said metering means adjustable for regulating the fuel flow from the reservoir, and fmfeans for controlling the llo'w of fuel into the fuel resrroi 5. A carburetor comprising a substantially conical 'shaped outer housing, an inner housing reciprocally disposed within `the outer housing, an inlet chamber provided on one side of the inner housing and open to atmospheric pressure, a low pressure chamber provided on the opposite sidey of the inner housing for creating pressure Vdifferentials thereacross, said inner housing cooperating CET 8 Wirth said 'outer housing to provide a variable venturi throat therebetween, vspring 1iheans provided inthe inner housing for urging the inner `housing toward 'the smallest portion ofthe outer "housing t'oclose the venturi throat, said pressure diierential "provided for overcoming the spring pressure in order to move theinner housing in an opposite direction for 'opening of the venturi throat, a

"fuel reservoir provided Within the inner housing, a fuel dispersal channel Vprovided in the inner housing and in communication With the venturi throat, means for moving the fuel from the reservoir into the fuel dispersal space in proportiony to "the ilow of air through the venturi throat, adjustable metering means for regulating 'the liow of fuel from the reservoir, and means `'for regulating the fuel prior to discharge into the venturi throat for facilitating vaporization of the fuel, 'adjustable 'metering means for regulating the liow of fuel from the reservoir, and means to regulate the'ii'ow of fuel "into the fuel reservoir.

7. A carburetor comprising a substantially conical shaped outer housing, aninner housing eei'p'r'cally disposed `Within the Aouter housing 'to provide v'a 'variable 'venturi throat therebetween, 'an upper chamber provided in the outerhousing forcommunicating'atirosplrericl pressure to oneside yof the inner iho'u'sing, a lov'v'er chamber provided in the outer housing for creating a pressure'differental aeross the inner housing, "spring ineamprovided in the inner housing for urging the inner housingtoward the smallest portionof the outer housing for 'closing the venturi throat, said pressure diifere'ntial yprovided Yfor overcoming'the spring pressurey to openthe venturiy throat, a fuel reservoir provided within the inner housing, means provided inthe inner housingfor dischargingithe fuel into the venturi throat, means for regulating the discharge of fuel into the vventuri throat in proportion to the flow 'of air therethrough, adjustable metering means for regulating the llow of fuel from the reservoir, rneansffor mixing a portion'of'air with the fuel prior to'disehage thereof into the venturi throat, and meansfor "controllingthe `iiow of fuel into the fuel rservoir.

smc-Aug. 26, 1919 sept. 11, 1934

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