US1740453A - Carburetor - Google Patents

Description

Dec. 24, 1929. w, Q CARTER 1,740,453

CARBURETOR Filed Jan. 20, 1923 INVENTOR williar? C'. Carien ATTORNEY Patented Dec. 24, 1929 PATENT OFFICE WILLIAM C. CARTER, F WELLSTON, MISSOURI CARBURETOR Application led January 20, 1923. Serial No. 613,919.

This invention relates to carburetors for internal combustion engines.

One object of my invention is to provide an efficient carburetor of sim le design, in which the air valve and the `uel valve are both controlled by a diaphragm.

Another object is to provide a carburetor of the general type referred to that is compact and inexpensive to manufacture.

Another object is to provide a carburetor that is equipped with a novel means of simple design for varying the proportion of air admitted to the air passageway or mixing chamber by the air valve.

Another object is to provide a carburetor that can be adjusted or regulated easily to vary the mixture produced by the carburetor by simply changing the position of a device that governs the suction created in a chamber provided with a movable element that' controls the air valve and the means that admits liquid fuel to the air passageway of the carburetor.

And still another object is to provide a g5' carburetor that is economical at ordinary running speeds and also well adapted for high speed work. Other objects and desirable features of my invention will be hereinafter pointed out.

Figure 1 of the drawings is a vertical longitudinal sectional view of my improved carburetor, showing the parts of same in the positions they occupy when the throttle valve is closed; and

Figure 2 is a vertical longitudinal sectionall view of said carburetor, showing the throttlll` valve open. n

I have herein illustrated my invention Aembodied in a carburetor of the side outlet type that is adapted to be arranged at one side of the intake manifold of the engine with which the carburetor is used, but itwill, of course, be obvious that it is immaterial how the carburetor is arranged with relation to the intake manifold of the engine.

Briefly stated, my improved carburetor consists of a mixing chamber or air passageway A to which liquid fuel and air are supplied` a throttle valve B for governing the escape of the mixture from said mixing chamber or passageway to the intake manifold of the engine on which the carburetor is used, an air valve C for governing the circulation of air through said passageway, a means, designated as an entirety by the reference character D, for admitting liquid fuel to said air passageway, and a diaphragm E for controlling the air valve C and the means D which admits fuel to the air passageway A. Various means may be used for admit- @o ting liquid fuel to the air passageway or mixing chamber A, but I prefer to use a means consisting of a fuel nozzle l arranged in the mixing chamber and provided with a fuel supply orifice 2 that is controlled by a needle 65 valve 3 that is combined with the air valve C in such a way that said elements will move in unison, thereby causing the supply of air and the supply of liquid fuel to the mixing chamber to be governed by the diaphragm E. The diaphragm E is so constructed and arranged that when the throttle valve B is open the suction that is created in the mixing chamber at ordinary running speeds will be exerted on the diaphragm in such a way as to maintain the air valve C and the fuel valve 8 in such positions as to cause the proper proportions of air and li uid fuel to be supplied to the mixing cham er, and when said throttle valve is opened suddenly to accelerate the speed of the engine` the proportion of liquid fuel supplied to the mixing chamber will be increased suiliciently to produce a rich accelerating charge. I accomplish this desirable result by arranging the fuel supplying 35 device D between the air valve C and the intake of the engine and by arranging the diaphragm E so that it forms one wall of a chamber F that is directly connected with the mixing chamber A by a duct 4 formed preferably 90 in the stem 3a of the fuel valve 3 andprovided at its inner end with an orifice 4a that is arranged in the mixing chamber, as shown in Figure 1`v thev opposite end of said duct 4 communicating with the chamber F of which 95 the diaphragm forms one wall. An expansion spring 5 that is arranged in the chamber F normally exerts pressure on the diaphragm E in a direction tending toholil the air valve C and the fuel valve 3 in their closed 10o positions, but Whenever a suction or partial vacuum is created in said chamber F by the suction produced in the mixing chamber, the diaphragm E Will move in opposition to the spring 5, and thus open the air valve and the fuel valve.

Any suitable type of air valve C may be used, but I prefer to use a Substantially diskshaped valve that is rigidly connected to the stem 3a of the fuel valve and which is so arranged that it seats against a valve seat 6 atthe inlet end of the portion of the main air passageway that constitutes the mixing chamber vvherein the liquid fuel is mixed with the air. In view of the fact that the suction in the mixing chamber is exerted on the airvvalve C in a direction tending to hold it seated and said air valve is moved into its open position by causing the suction in the mixing chamber to be exerted on the diaphragm E in an opposite direction, it is essential that. said diaphragm be of considerably greater diameter than the air valve. Therefore, it is desirable to make the air valve as small as possible, so as to overcome the necessity of using an abnormally large diaphragm. I accomplish this by using an air passageway A of the Venturi type, provided intermediate its inlet and outlet with means for speeding up the air traveling through said passageway. In the form of my invention herein illustrated the means ust referred to consists of a contracted, reduced or tapered air inletthat increases the suction at the inlet of the mixing chamber suiliciently to compensate for the reduced diameter of said inlet, and thus causes practicallythe same quantity of air to be drawn into said mixing chamber when the air valve is open as if said chamber were of uniform diameter thoughout its entire length.

When the throttle valve is closed, as shown in Figure l, the air valve C will bear against the valve seat 6, thus closing the inlet of the mixing chamber A, and the needle valve 3 will project into the discharge orifice 2 of the fuel nozzle 1 to such an extent as to nearly close said orifice. At ordinary running speeds, When the throtle valve is open, as shown in Figure 2, the suction in the mixing chamber A causes air to be sucked out of the chamber through the duct 4, thereby exerting a pull on the diaphragm in a. direction tending to flex it to the left, and thus causing the air valve C and the fuel valve 3 to be maintained in such positions that air and liquid fuelvvill be admitted to the mixing chamber in proper proportions to producen combustible mix'- ture suitable for ordinary running speeds. As the position of the throttle valve is changed gradually to vary the speed of the engine, the suction in the chamber A will vary, thereby causing the diaphragm to vibrate and open and close the air valve C and fuel valve 3 more or less, so as to vary the supply of air and fuel to the mixing Chamber without changing the relative proportions of fuel and air. If the throttle valve is opened suddenly, however, to accelerate the speed of the engine, the proportion of liquid fuel admitted to the mixing chamber Will be increased abnormally, due to the fact that the duct 4 which establishes communication between the diaphragm chamber F and the mixing chamber A is not of sulcient cross-sectional area to cause 'the air to be exhausted from the chamber F rapidly enough to cause the air valve C to open quickly. In other Words, as the opening movement of the air valve C is effected by sucking air out of the diaphragm chamber F through a restricted opening or small ori lice 4* in the duct 4, a sudden increase in the intensity of the suction in the mixing chamber A, produced by opening the throttle valve suddenly, results in a large quantity ot fuel being drawn out of the fuel supply orifice 2, but it does not result in a proportionally great quantity of air being drawn into the mixing chamber past the air valve C, because the air cannot escape from the diaphragm chamber F through the duct 4 rapidly enough to compensate for the increased suction in the mixing chamber and permit the air valve to open quickly. It Will thus be seen that while the proportions ot fuel and air will remain practically constant, at ordinary running speeds when. the throttle valve is moved gradually to vary the speed of the`engine, a sudden opening ot the throttle valve to accelerate the speed of the engine causes the high suction which is then created in the mixing chamber to be exerted directly on the liquid fuel supplying device` with the result that a rich starting charge will be admited to the mixing chamber.

The proportion of air admitted to the mixing chamber by the air valve C can be changed in various ways, but preferably by changing the position of said air valve relatively to its seat 6. In the form of my invention herein illustrated the valve seat 6 is constructed in such a Way that the position of same relative to the air valve can be changed to increase or diminish the proportion of the air supply at any speed of the engine. One convenient Way of accomplishing this is to form the valve seat 6 on an adjustable member G that can be moved longitudinally of the direction of movement of the air valve C, said member G being ol tapered form and constituting the reduced air inlet of the mixing chamber A. When the member .G is set in its extreme position to the right the air valve C will be spaced farther away from the valve seat 6 when the diaphragm flexes tothe left, due tothe suction in the mixing chamber, thus causing a relatively large quan tit-y of air to be admitted to the mixing chamber, and when said member G is set in its extreme position to the left, a relatively small amount of air will be admitted to the mixing chamber when the diai`n Figure 1.

phragm flexes to the left under the influence of the suction in the mixing chamber, due, of

course, to the fact that the air valve is then an operating device (not shown) is adapted to be connected. When the member G is rotated in one direction the externally screwthreaded portion 7 thereon will cause it to move to the right, thus increasing the proportion of the air supply, and when said member is rotated in the opposite direction, the screw-threaded portion 7 thereon causes it to move to the left, thus decreasing the proportion of the airsupply.

i Another feature of my invention which I believe to be novel, is providinga carburetor of the tvpe in which the supply of air and liquid fuel to the air passageway is controlled by an element governed by thesuction in said passageway. With a device that can be adjusted or operated so as to modify or vary the suction produced on said element by the suction in the mixing chamber. The device just referred to can be constructed and arranged in various Wavs, but in its simplest form it will consist of a valve that controls either an air inlet or an air outlet tol a chamber equipped with a movable elementthat actuates the air valve andthe fuel valve. In the carburetor herein shown thewmovable element just referred tois formed by the diaphragm E and the diaphragmv chamber F is provided with a valve I that controls an air admission port 9 which leads to said chamber. v If it is desired to diminish the supply of air to the mixing chamber A when theengine is in operation. theV valve I can be ad# j usted so as to partially open the air inlet port 9 leading to the diaphragm chamber F. therebv reducing the suction that is created inv said chamber by sucking air out of said chamber` through the duct 4, and consequently, reduc` ing the degree ofmovement of the` air valve C under the influence ofthe suction in the mixing chamber. The chief functionA of the valve I, however, is to choke theair valve C or holdf said valve in. its closed position, so as to produce a rich/starting' charge. Normally, the valve I isset in-such a position as to close the air inlet port -.9, as shown in` Figure 2, but if it AisNdesired' to produce arieh starting charge, said valveis moved into a Dosition to ope'n the air inlet port 9, as shown When said valve I is set in the position last referred to the actof opening the throttle valve will not cause the air valve .to open. due, of course, lto the fact'that the diaphragm lchamber F is then in direct comthe' intake manifold of the engine withoutA munication with the atmosphere. Consequently, the suction in the mixing chamber A will c ause liquid fuel to be drawn out of the oriice 2 in the fuel nozzle 1, and will cause a small quantity of air to be drawn into the mixing chamber through the duct 4 and oritice 4, previously described, thevair valve C l being held seated at such times by the expansive force of the spring 5. So far as this feature of my invention is concerned, it is immaterial what typeor kind of movable element is used for controllin the air valve and the means that admits liquid fuel to the main air passageway, so long as said element consistsv'of a movable device vcombined with a chamber which in turn is connected with the air passageway of the carburetor in such a manner that the suction in said passageway is exerted on said device in a'manner tending to change the position of same.

For economy in operation at low speeds it is essential that the liquid fuel be split up into fine particles before it enters the intake manifold of the engine, but when high speed and power are desired and economy in the consumption of fuel vis not a factqn better results are obtained if'the liquid fue `is-not split up or divided into as small particles as possible before it enters the intake manifold of the engine. All prior carburetors with which`I am familiar are constructedeither in such a way that thev will be economical in the consumption of fuel but not particularly well adapted for high -speed work, or constructed in such a l 'wav that they will be particularly welladapted for high vspeed work but will -be uneconomical in the consumption of fuel vat low speeds. One object of my invention is to provide a carburetonwhich. ingadditionl to being ecof nomical inthe consumption of fuel at low speeds; is also well adapted 'for high speed work. A

To obtain such a carburetor I arrange the throttle valve B betweenithe fuel sfupplying means and the inta-ke of the engine and arrange one or more auxiliary throttle valves B in tandem relation with saidthrotftle valve B- and operatively connect "said" auxiliary v'alve or valves with vthe throttle valve byra link 10 or other means connected toarms 1l on the stems of said valves. Preferably, the auxiliary throttle valve B is of the same diameter as the main throttle valvevB. At

'nuterparticles' by reason of having to-pass several times through contracted openings,

to wit, the annular openings between the pe-'-' ripheraledges of the throttle valves .and the side wall of the passagewav in which-said valves-are arranged, but vwhen thefthrottle valves Band B are wide open, the mixture can travel from the mixing chamber A into having to pass numerous times through contracted openings. The result is that the liquid fuel in the mixture willnot be split up or divided into small particles when the throttle valve is wide open, thusmaking the carburetor particularly well adapted for high speed work on account of' the fact that the fuel in the mixture enters the intake manifold of the engine in a, practically raw state. t low speeds, when the throttle valve is partly closed, the liquid fuel in the mixture will be Atorn up into line particles before entering the intake manifold, thereby making the carburetor economical in the consumption of fuel at ordinary running speeds.

Any suitable means can be used for supplying liquid fuel to the fuel passagewayin the nozzle l, such as a conventional float chamber J, and the mixing chamber or passageway A can be formed by a tubular member H providedat one end with a flange H by which it can be attached to the intake manifold of the engine and provided at its opposite end with a hollow portion H2 having an air intake 12 at its upper end. The diaphragm E is preferably formed b v a piece oi impervious fabrieor a laminated structure composed of several thicknesses of flexible material, and said diaphragm is arranged inside ot the hollow portion H2 ot the member H and secured to a ring-shaped part 'i3 on said portion by a plate 14 of substantially concave-convex snape that forms the rigid wall of the diaphragm chamber F, said plate having a cup-shaped part l5 thereon in which the spring 5'is seated. The air valve C is integrally connected to a sleeve 16 .into which the stem 3a ot the fuel valve is screwed. .and said sleeve is provided with a flange l? that co-operates with a head 18 onthe stem of the fuel valve to cla-mp the diaphragm E to said valve stem, a wear plate i9 being preterabiy interposed between the diaphragm and the head on said valve sten-f1` so as to form a seat for the spring 5, and thus prevent said spring :from cutting the diaphragm.

Having thus described my invention, what i claim as new and desire to Secure by Leb ters Patentis: Y

l. A carburetor provided with a passageway, a manually-operable throttle valve for governing the escape of the mixture from said passageway to the intake of the engine, an air valve arranged between the throttle valve and the air intake to said passageway 'for admitting air to said passageway, a fuel port in said passageway for admitting VFuel to saine, a fuel valve forgoverning the admission of fuel from said port to said'passageway, connect-ed with said air valve so as to move in unison with 'the same and arranged between the air valve and the throttle valve, a chamber provided with a diaphragm that is connected with said air valve and .fuel valve so as to control said valves, and a duct leading from said diaphragm chamber and communicating with said passageway at a point between the air valve and the throttle valve, whereby a quick movement of the throttle valve into its open position closes the air valve and momentarily produces a high suction on the tuel supply portin said passage- Way, said suction thereafter diminishing while the pressure in the diaphragm chamber is balancing with the pressure in said passageway.

2; A carburetor provided with a passageway, a manually-operable throttle valve or governing the escape of the mixture from said passageway to the intake of the engine, an air valve arranged between the throttle valve and the air intake to said passageway for admitting air to said passageway, a fuel port in said passageway for admitting fuel to same, a fuel valve for governing the ad mission of fuel from said port to said passageway, connected with said air valve so as to move in unison with the same and arranged between Athe air valve and the throttle valve, a. char-ober provided with a diaphragm that is connected with said air valve and fuel valve so as to control said valves, a duct lead ing 'from said diaphragm chamber and comunicating with said passageway at a point between the air valve and the throttle valve, whereby a quick movement ot the throttle valve into its open position `closes the air valve and momentarily produces a high suction on the fuel supply port in said passageway, said suction thereafter diminishing while the pressure in the diaphragm chamber' is hal ancing with the pressure in said passageway, and a manually-operable means tor establishing atmospheric pressure in said diaphragm chamber, capable ot being operated when the carburetor is functioning, so as to change or modify the effect produced on the diaphragm by the suction in said passagen way,

3, A carburetor provided with a passa Ieway, a manually-operable throttle valve or governing the escape of the mixture from said passageway to the intake of the engine, an air valve arranged between the throttle valve and the 'air intake to said passageway for admitting air to said passageway, a fuel port in said passageway for admitting fuel to same, a fuel valve for governing the admission ot' fuel from said port 'to said passageway, connected with said air Valve so as to move in unison with the same and arranged between the air valve and the throttle valve, a chamber provided with a diaphragm that is connected with said air valve and fuel valve so as to control said valves, a duct leading from said diaphragm chamber and communieating with said passageway at a point between the air valve and the throttle valve, whereby a quick movement of the throttle valve into its open position closes the air valve and momentarily produces a high suction on the fuel supply port in said passageway, .said suction thereafter diminishing while thepressure in the diaphragm chamber is balancing with the pressure in said passageway, a seat for said air valve, and means for bodily moving said valve seat longitudinally of the direction of movement of the* air 'valve so as to change the relative position of said valve and valve seat and thus vary the resistance ofered to the air that is drawn into said passageway.

WILLIAM C. CARTER.

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