US1809507A - Carburetor - Google Patents

Description

Patented dune lddl unite anti WELLIAM C. CARTER, (Mi FLEET, MICHIGAN cnanroa Application filed April 22, 159%.. serial Ito. 350,100.,

This invention relates to carburetors of the type that are equipped with a plurality of venturis or suction amplifiers.

One object of my invention is to provide a carburetor oi the general type mentioned,

that is equipped with a means by which the operator in charge of the engine on which the carburetor is used, can cut on the supply oil air to all of the venturis or suction amplifiers to in zero or extremely cold weather, and cause air to be drawn directly into the fuel passageway of the nozzle or main fuel supplying element of the carburetor so as to produce an aerated charge of fuel that facilitates startila ing the engine;

Another object is to provide a carburetor of the general type mentioned, i. e., a multi-venturi carburetor, in which the venturi that produces the first stage of suction amplificaac tion has an air inlet of substantially the same diameter or of greater diameter than the outlet of the carburetor which communicates with the intake of the engine, thereby makin it practicable to equip the carburetor with t at least three venturis which are of such relative diameter and arrangement that the volume of air flowing through all of the venturis will be great enough to float the fuel or insure the particles of fuel bein carried to freely into the main passageway o the carburetor.

Other objects and desirable features of my invention will be hereinafter set forth.

Figu as of the carburetor embodying my present invention.

Figure 2 is a vertical sectional view of said carburetor; and a Figure 3 is a vertical sectional view, taken to on the line 3-3*ol Figure 2..

Referring to the drawings which illustrate the preferred form of my invention, A designates the main passagewa of the carburetor, formed by a bore in the ody B of the carat buretor, C designates a throttle valve at the upper end of sand main passageway, D designates an air chamber in the body of the carburetor, E designates the float chamber, F designates a float in said float chamber that f governs a valve G which controls the supply re 1 of the drawings is a top plan view i fication arranged of liquid fuel to the fioatchamber and ll designates an accelerating well whose upper end communicates with the air chamber l). The main fuel supplying element of the carburetor is herein illustrated as consisting of a vertically-disposed nozzle l arranged inside of the accelerating well and projecting upwardly from the bottom of same, said nozale being surrounded by a tubular'm'ember J- of less diameter than the accelerating well which projects upwardly from the bottom of said well, The carburetor is also equipped with a means of the general type disclosed in my pending applications for patent Serial No. 206,030, filed July 15, 1927, and Serial No. 226,684, filed llctober 17, 1927, for supplying fuel to the main passageway A above the throttle valve when thethrottlevalve is closed or only partly open, saidmeans being herein illustrated as consisting of a vertically-disposed fuel tube K (see Figure 2) mounted in the body of the carburetor in such a manner that its lower end communicates with a fuel-duct 1 that leads to the bottom of the accelerating well and its upper end communicates with a fuel duct 2 that leads to an adjustable terminal portion K for the fuel tube whose discharge end can be arranged in various positions with relation to the throttle valve by manipulating an adjusting device 3, which I will not describe in detaihas it forms no partof my present invention.

As previously stated, the carburetor is equipped with a plurality of venturis or suction amplifiers arranged between the throttle valve and the main fuel supplying element of the carburetor and consisting of a venturi L positioned in the lower end portion of the main passageway A of the carburetor for producing the first stage of suction amplification, a venturi M for producing the second stage of suction amplification arranged inside of the air chamber D, with its upper end disposed in concentric relationship with the 95 air intake end of the first venturi L and projecting upwardly into same, and a venturi O for producing a third stage of suction ampliat the upper end of the tubular member J in the accelerating well, with 100 its u er end projectin upwardly into the air iiil zike end of the sec nd venturi M. Due to the fact that the air intake ends of the first and second venturis are arranged inside of the air chamber D, air can pass from said chamber and flow upwardly through the annular space between the lower end of the venturi L and the upper end of the venturi M and also upwardly through the annular space between the lower end of the venturi M and the upper end of the third venturi O. The third venturi 0 receives its supply of air from the accelerating well H through verti cally-disposed air slots 4 in the tubular member J in the well, whose upper ends terminate above the normal level of the fuel in the float chamber, represented by the brokendines m in Figures 2 and 3, the upper end of thenccelerating well being in direct communication with the air chamber D, so that air can pass from said chamber and flow downward- 1 into the accelerating wellfthence inwardly through the slots 4:, and thence upwardly through the annular space between the upper end of the nozzle I and the third venturi O.

In a carburetor of the multi-venturi type it is essential that the annular passageways of all of the venturis be of great enough crosssectional area to permit a sufficiently large volume of air to flow through said passageways to float the particles of fuel and carry is in use to insure the fuel being carried upwardly into the main passageway of the carburetor. One convenient way of accomplishing this highly desirable result is to provide the first venturi L with an enlarged portion having an air passageway whose side wall tapers or diverges from the air inlet at the lower end of the venturi whose diameter is such that the greatest diameter of the air passageway in the venturi L is equal to or in excess of the diameter of the main passageway' A of the carburetor. Preferably, the venturi L is provided intermediate its ends with a throat or contracted portion that is arranged above the point of. greatest diameter of the air passageway in the venturi L. As shown in Figures 2 and 3, the enlarged portion of the venturi L that contains the air passageway of gradually increasing diameter, is mounted in a counter bore at the lower end of the main passageway A. of the carburetor. From the foregoing it will be seen that notwithstanding the fact that the first venturi L is positioned in the main pass innate? sageway A of the carburetor, the intake portion of said venturi hasa diameter equal to or in excess of the diameter of the main passageway A, thereby permitting the second and third venturis M and 0 to be made of greater diameter than would be possible if the first venturi L were constructed in the form of a tubular member of the same external diameter throughout its length, positioned in a bore of uniform diameter in the body of the carburetor, as has heretofore erably,.the first venturi L is mounted in such a manner that in moderate weather the operator can move said venturi downwardly, so as to cut oil the supply of air to the annular space bet-ween the said venturi and the second venturi M, and the second venturi M is so constructed and arranged that a continued movement of the actuating device employed to shift the venturi L will cause said second venturi M to be moved into such a position as to cut oil the supply of air to'the annular air passageway of same and also to the annular air passageway of the third venturi In the form of my invention herein shown the first venturi L is reciprocatingly mounted in the body of the carburetor and the second venturi Nis sustained or carried by a yielding supporting structure composed of two reversely arranged, cup-shaped members 5 and 6, as shown in the drawings, the member 5 being arranged with its side wall project ing upwardly and disposed oppositely to a flange 7 on the lower end of the venturi L, and the member 6 being arranged with its side wall projecting downwardl thereby permitting air to pass from the air chamber D through the s ace between the top edge of the on 5 and the flange 7 and through the space Between the edge of the inverted cup 6 and the bottom wall of the air chamber l) when the parts are in the positions shown in Figures 2 and 3. The yielding supporting structure that carries the second venturi M is sustained and normally maintained in the position shown in Figures 2 and 3 by springs Means is provided for enabling the operator in charge oil the engine to more the venturi l1 downwardly into. engagement with the cup 5, or downwardly still farther so as to compress the springs 8, and thus cause the bottom edge of the cup 6 to engagethe bottom wall of the air chamber ll), said means being herein illustrated as consisting of a manually-operable lever 9 attached to a stud 10 on an oscillating device 11 in the body of the carburetor that is prpvided at its inner end with an eccentrically-disposed pin 12 that enters a hole or annular groove 13 in the exterior ofthe venturi L. When the lever 9 is rocked in one direction, the venturi :llj will be moved downwardly, so as to cause the flange 7 thereon to engage the cup 6, thereby cutting off the supply of air to the venturi L and facilitating the starting of the engine. In extremely cold weather or zero weather a continued movement of the operating mechanism that is used 'tto actuatethe lever 9, causes the venturi L to continue to move downwardly, after it has engaged the cup 5, thereby compressing the springs 8, and causing the cup 6 tomove downwardly into such a position that air cannot flow through the annular passageway of the second venturi M, or flow downwardly into the accelerating well H. As soon as the operator releases the operating mechanism that is used to actuate the lever 9, the device 11 rocks in the opposite direction under the in.-

fluence of a torsion spring let, thereby causing the venturi L to be moved upwardly bacl: to its normal position, and permitting the springs 8 to expand and restore the second venturi M to its former normal position shown in the drawings. lit will thus be seen that my improved carburetor is provided with two separate and distinct choking devices, one consisting of the first venturi L that is capable of being shifted into such a position as to cut ofl the supply of air to a same in moderate weather, and the other out of consisting of the yielding supporting structure that carries the second 'venturi M and which is capable of being shifted into such a position in zero weather or extremely cold weather as to cut oil' the supply of air to the second and third venturis. At such times, i. e., after the venturi L has been moved downwardly far enough to cause the bottom edge of the inverted cup 6 to be pressed against the bottom of the air chamber D, and thus cut off the supply of air to the annular passageways of all of the venturis, air will be supplied to the fuel passageway of the nozzle l by an air duct 15 whose intake end s in communication with the atmosphere and whose discharge end is in communication with an air orifice 16 located beneath the fuel nozzlell at'the center of an annular fuel passageway 17 from which. the nozzle I receives its supply of fuel, the air that flows upwardly through the orifice 16 becoming mixed with the fuel that is drawn upwardly the fuel passageway 17 by the suction exerted on-the nozzle, and thus producing an aerated charge that greatly facilitates the starting of the engine. The air duct 16 not only supplies air to the center passageway of the nozzle 1 when the carburetor is choked, but it also supplies air to said nozzle at all other times, when the suction exerted on the upper end of the nozzle is suflicient to cause fuel to be drawn upwardly into said nozzle from the annular fuel passageway 17, at the lower end of the nozzle. Accordingly, in my improved carburetor means is provided for introducing an aerated jet of fuel directly into the third venturi'O of the carburetor located at the upper end of the nozzle l. The duct 15 that supplies air to the orifice 16 beneath the nozzle can be formed in various ways without departing from the spirit of my invention. In the carburetor herein shown the inlet end of the air duct 15 terminates in "a ball-shaped portion 18 on a standard 19 that serves as a support for the piston 20 of a ump of the kind shown in my applica ion erial No. 359,096 filed of even date herein, but ll wish it to be understood that said pump forms no part of my present invention. The ball-shaped portion 18 just referred to is arranged in a socket 21 on the underside of the pump piston 20, and the retaining plate 22 in the lower end of the piston that holds said ball in its socket is provided with air inlets 23 that establish communication between the atmosphere and the socket 21 in the piston, and thus permits air to enter the passageway 15 and flow to the air orifice 16 beneath the fuel nozzle.

Fuel is supplied from the float chamber E to the lower end of the accelerating well H by a fuel orifice or duct 24, as shown in Figure 2. A separate fuel supply duct or orifice 25, also shown in Figure 2, is provided for admitting fuel from the float chamber to the annular fuel passageway 17 located at the lower end of the fuel nozzle. The fuel duct 25 is preferably made large enough so that it is not liable to become clogged with foreign matter in the fuel, and in order to prevent said duct 25 from supplying too much fuel to the nozzle at high speeds, the carburetor is equipped with a fuel economizing device that consists of an air vent 26 that leads from the upper end of the float chamber E to the upper portion of the accelerating well H. When air is flowing from the air chamber 1) downwardly through the well H, said flowing stream of air creates .a suction or partial vacuum in the upper portion of the float chamber that is exerted on the fuel in the float chamber in such a manner as to retard the escape of fuel from the float chamber through the duct 25 that leadsto the fuel passageway 17, thereby effecting a considerable saving in the consumption of fuel at high speeds. The air that is supplied to the orifice 16 through the air duct 15 also has a tendency to reduce the quantity of fuel which the nozzle it introduces into the main passageway imcertain positions of the throttle valve, due to the fact that the air which flows upwardly from the orifice 16 into the fuel passageway of the nozzle it cuts down the suction that is created insidecof the nozzle. It is f tle valve is moved into its wide open position,

said means being of such a character that it increases the proportion of the fuel relatively'to air, that is supplied to the nozzle when the throttle valveis wide open. In addition to modifying the action or effect produced by the fuel economizing device, said means also compensates for the diminution of the discharge of the fuel froni'the nozzle, produced by the admission of air to the interior of the nozzle through the'air duct 15 and air orifice 16. In the form of my invention herein illustrated the means above referred to consists of an air vent P leading from the upper portion of the float chamber to the air chamber D of the carburetor, and a valve or closure R for said vent P that is governed by the throttle valve shaft 27. The

valve R consists of a vertically-disposed rod mounted in the body of the carburetor and provided at its lower end with a projection 28 that is adapted to enter a reduced portion of the air vent P and serve as a closure for same. When the throttle valve A is in its closed or intermediate positions the valve rod R is engaged by the throttle valve shaft and maintained in such a position that the projection 28 thereon cuts off communication between the air chamber D and the upper portion of the float chamber, but when the throttle valve is moved into its wide open position, a flat rtion 27 on the throttle valve shaft comes into registration with the upper end of the valve rod-R, thereby permitting said rod to move .upwardly under the influence of a spring 29, with the result that the projection 28 on the valve rod will bewithdrawn from the air vent P, thereby establishing direct communication between the upper portion of the float chamber and the air chamber D of the carburetor. Due to the fact that the air chamber D is under a lower pressure than the accelerating well to which the air vent 26 leads, the effect produced by opening the air vent P is to reduce the suction or partial vacuum that exists in the upper end of the float chamber, thereby modifying or reducing the retarding efl'ect produced by the air vent 26 and permitting the fuel to flow freely from the float chamber through the duct 25 to the nozzle I, and consequently, increas' ing the proportion of fuel relatively to air, to

such an extent that the nozzle will supply suificient fuel to the main passageway A to effectively take care of the condition that exists when the engine is subjected to a heavy load with awide open throttle,as, for example, when the automobile propelled by the engine is pulling through sand or pulling up a steep grade. It is, of course, immaterial what particular type or kind of valve or the like is used to open and close the air vent P leading from the upper portion of the float chamber, and while I have stated that said air vent P preferably leads to the air chamber D of the carburetor, this is not essential. The essential thing, so far as this feature of my invention is concerned, is that the air vent P lead to theatmosphere or to an air passageway or chamber that is under a materially lower pressure than the pressure which exists in the upper end of the accelerating well when air is flowing downwardly through the same. As previously stated, the auxiliary air vent P and the throttle-controlled governing device for same not only modifies the action of the fuel economizing device consisting of the air vent26, but it also compensates for the diminution in the discharge of fuel from the nozzle I into the'third venturi 0, produced by admitting air to the interior of the nozzle through the orifice 16 and air duct 15.

By constructing the carburetor in the manner described I not only obtain a free vacuum carburetor that is exceptionally-economical in the consumption of fuel, but I also obtain a carburetor in which the volume of fuel relatively to air for the fuel nozzle I, will be increased sufficiently when the throttle valve is moved into its wide open position to insure the main passageway A being supplied with a relatively great quantity of fuel at times when the engine is operating under a heavy load with a wide open throttle.

Having thus described my invention, what I claim and desire to secure by Letters Patent 1. A carburetor provided with'a main passageway, a throttle valve for saidmain -passageway, a main fuel supply device, a plurality of venturis arranged in superimposed and concentric relation between the throttle valve and said fuel supply device, means for enabling the venturi that produces the first stage of suction amplification to be moved tion a position wherein it serves as a choking device which cuts off the supply of air to said first venturi, and means whereby the venturi ill) dll

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inseam? ity of venturis arranged in superimposed and concentric relation between the throttle valve and said fuel supply device, a shiftable structure that carries the second venturi, an operating device that is adapted to be actuated to move the first venturi into engagement with said shiftable supporting structure to cut ed the supply of air to the first venturi, and means whereby continued movement of said actuating device-causes said supporting structure to be moved into such a position that the supply of air is cut ed from the annular passageways of the second and third venturis.

3. A carburetor provided with a main passageway, a throttle valve for said main passageway, a main fuel supply device, a plurality of venturis arranged in superimposed and concentric relation between the throttle valve and said fuel supply device, a shit'table supporting structure that carries the second venturi, springs for sustaining said supporting structure, and a means that is adapted to be actuated to shift the first venturi into a position to cut oil the supply of air to the annular passageway of same and to thereafter move said spring sustained supporting structure into such a position as to cut oil the supply of air to the annular passageways of the second and third venturis.

i. A carburetor provided with a main passageway, a throttle valve for said passageway, a main luel supplying device, anlair orifice communicating with the atmosphere, through which air passes into the interior ofsaid fuel supplying device, a plurality of venturis arranged in superimposed and concentric relation between said fuel supplying device and said throttle valve, a supporting structure for the second venturi consisting of two reversely arranged, cup-shaped members, one of which is dis osed oppositely to the lower end of the first venturi and the other being disposed oppositely to the bottom of the air chamber of the carburetor, springs for sustaining said supporting struc ture, and means whereby the first venturi can be moved downwardly into engagement with the cup-shaped member disposed oppositely to same and thereafter downwardly still farther so as to cause the reversely arranged, cup-shaped member to bear against the bottom wall of the air chamber, for the purpose described.

5. A carburetor provided with a main passageway, a throttle valve for said main passageway, a main fuel supplying device, a plurality of venturis arranged in superimposed and concentric relation between said throttle valve and fuel supplying device, an air chamher, an accelerating well communicatin at its upper end with said air chamber an arranged so that the air supplied to the annu= lar passageway of the third'venturi ncust flow downwardly through said well, means for enabling the position of the first and second venturis to be changed so as to cut otl the how of air from said air chamber to said first and second venturis and to the accelerating well, and an air duct through which air is admitted to said fuel supplying device,

a A carburetor provided with a main passageway, a throttle valve for said passageway, a main fuel supplying device, three venturis arranged in superimposed and in concentric relationship between said throttle valve and said fuel supplying device, a float chamber, a fuel outlet of relatively great cross-sectional area leading from said float chamber to said fuel supplying device, an air duct through which air is supplied to the interior oil said fuel supplying device, and means governed by the throttle valve for varying the pressure that exists in the float chamber above the level of the fuel therein,

for automatically increasing the proportion of fuel that is admitted to the fuel supply ingdevice when the throttle valve is movedinto its wide open position,

7. A carburetor provided with a main pas sageway, a throttle valve for said passageway, an air chamber, a fuel nozzle, an accelcrating well surrounding said nozzle and arranged with its upper end communicating with said air chamber, three venturis arranged in superimposed and concentric relationship between the nozzle and the throttle valve, a float chamber, means for permitting liquid "fuel to pass from the lloat chamber to said nozzle and to said accelerating well,

an air orifice arranged so as to discharge a jet of air upwardly into said nozzle, means whereby the position of the first and second venturis may be changed to cut oil the suply of air to the annular passageways of all of the venturis, and a means governed by the throttle valve for varying the pressure that exists in the upper portion of the float chamber above the fuel therein, according to the position of the throttle valve,

8. A carburetor provided with a main passageway, a throttle valve for said main passageway, a main fuel sup ly device, a plurality of venturis arranged in superimposed relation between the throttle valve and said fuel supplying device, means for enabling one or said venturis to be moved into a position wherein it serves as a cholring' device that cuts 0d the sup 1y of air to said venturi, and means where y a venturi that produces a difierent stage of suctionamplification can be moved into a position to cut od the supply of air to all oil the venturis.

WILLIAM C. CARTER.

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