US1804659A

US1804659A - Carburetor

Info

Publication number: US1804659A
Application number: US168529A
Authority: US
Inventors: Percival S Tice
Original assignee: Stewart Warner Corp
Current assignee: Stewart Warner Corp
Priority date: 1927-02-16
Filing date: 1927-02-16
Publication date: 1931-05-12
Anticipated expiration: 1948-05-12

Description

May 12, 1931. P. s. TICE CARBURETOR original Filed Feb. 1e 1927 level of the n respect to the carburetor does not afect the Patented May 12,l 1931 UNITED STATES Laatse PATENT oFFIcE rnnoIvAL s. TICE, or CHICAGO, ILLINoIs, AssIGNon ro s'rEwAnr-WARNER conroRA- ATIoN, or CHICAGO, ILLINoIs,-A CORPORATION or VIRGINIA CARBURETOR Application led February 16,1927, Serial No. 168,529. Renewed May 1, 1930; Y,

The purpose of this invention is to provide 'a carburetor for an internal combustion engine adapted to deliver fuel to the fuel mixture conduit under pressure suitable to the 5 running conditions of the engine, unaffected by the height of the fuel column anterior to the carburetor, and therefore unaffected by change in the height of said column resulting from consum tion of fuel lowering the filel in the fuel supply tank or other fuel source.- Incidental to this purpose it is the purposeof this invention to provide means in a carburetor for producing by engine suction ahead of fuel in the 15 duct by which the fuel is discharged in the fuel mixture conduit, for maintainingin periods of engine inaction and consequent interruption of suction, on the fuel in the fuel chamber from which the fuel mixture conduit derives the fuel element, a predetermined minimum pressure for holding seated a valve which controls flow of the fuel supply to the carburetor. The invention consists in the elements and features of constructionfor the purpose stated, shown and described as indicated in the claims.

The drawin is a vertical section of a carburetor embo ying this invention, axial with respect to the fuel mixture conduit and also with respect to the fuel duct therefrom to said conduit.

In the drawing the fuel source is indicated by a tank, A, which is represented as connected to the carburetor by exible pipe, B, so that the tank may be shifted from a-position below the carburetor to a position above, and vice-versa, as indicated by the showing of the tank in dotted line in the two positions. This, it will be understood, is merely to indicate that the level Vof theV fuel source with operation, and that such source may be at any suitable height above or below the carburetor without affecting the operativeness or the specific operation of the carburetor.

The carburetor comprises a fuel mixture conduit, 10, adapted for connection to the intake manifoldI of the vengine asindicated by the attaching flange, 11, and havin an air inlet as indicated at 12; a fuel cham er, 20;

a fuel duct, 30, leading from the fuel chamber, 20, through a nozzle, 31, extended for dlschargeI upwardly within the fuel mixture conduit; a fuel How-restricting. device of the character commonly called a metering plug interposed in the last mentioned duct; a balanced valve, 80, for controlling flow of fuelto the fuel chamber from the fuel source at whatever level; a iexible diaphragm, 50, formmg a wall of the fuel chamber operatlvely connected with said balanced valve for holding the valve at seated or open position accordlng to 'the osition of said liexible wall determined by t e pressures operating at opposite sides thereof as hereinafter explained. In the specific structure illust-rated the fuel chamber, 20, has the movable wall consisting of a .flexibleJ diaphragm, constitutmg the bottomv of the chamber; but it will be understood that the movable wall may constitute the whole or any part of the wall at any side of the chamber whether lateral or upper or lower. This diaphragm wall is held to the chamber body b being bound at its margin between the sur ace of the cham,- ber body marginal with respect to the chambercavity and the correspondin marginal area of t-he bottom cap, 25,-whic is bolted to the chamber body, clamping the diaphragm between said marginal areas as seen .1n the drawing. The cap, 25, has at its center an apertured and interiorly threaded boss, 25, into which` there is screwed an adjustable plug, 25", between which and the diaphragm there is interposed a compression coil spring, 60, suitably centered on the end of the plug and on the central disk shoe, 61, of the diaphragm which is clamped between said shoe and a washer, 62, on the opposite side by an eye bolt, 63, and a nut, 64, formed for centering the compression spring as mentioned. The top wall of the chamber is bored through at Q, to receive at the inner end a bushing, 70, and counterbored at the opposite end to receive a bushing, 72. The bushing, 70, is inserted from the inside ofthe fuel chamber and has a valve seat, 71, at the noA inner end facing outwardly with respect to as lndicated by the' guide ribs,v20c,' and seat! ing at the seat, 71, is connected at the opposite end to the diaphragm, 73, and has an axial bore seen at 81, extending inward from its seated end, atthe upper end of which axial bore there is pivotally connected a link, 83, extending from said pivotal connection down through the axial bore, 81, and through the valve seat into the chamber; and pivotally connected at its lower end to the eye bolt,

63, at the center of the diaphragm, 50.

' The parts described are dimensioned for positioning the diaphragm, 50, at the seated position of the valve, 80, substantially without deflection either way from the plane in which it is clamped to the chamber wall; and thefadjustable screw plug, 25a, is adjusted to cause the pressure of the spring at said seated position of the valve to substantially balance the forces tending to depress the diaphragm from its normal position, said forces'including, when the chamber is arranged as shown with the diaphragm horizontal,`the weight of the diaphragm and the washers between which it is clamped, and the weight of the.

liquid contents of the chamber Iilled to a predetermined level as hereinafter described.

The'operation of the construction above described is as follows: h

All the parts being in normal position, the valve, 80, being seated and pressed upon its seat by its own weight, and that of the connected parts so as to require only a pre,

determined slight lowering of the pressure in the chamber to cause the diaphragm, 50,' to operate for opening the valve, upon the starting of the engine, the engine suction producing such lowering pressure in the chamber, and the valve being opened, the fuel will flow in and lill the chamber at once if the level of the fuel at the fuel source is above the level of the port controlled by the valve; and as soon as the engine suction becomes suf. icient to lift the fuel from a lower level, if it is below the port level. The fuel entering the chamber and eventually iilling it to the height of the port in the metering plug will be drawn by the suction through that port and fill the stand pipe nozzle, 31, from whose upper discharge end the fuel will be taken with the indrawn air throughv the fuel mixture conduit to the engine.

Under any given running conditions causing the engine suction to produce a given depression at the discharge of the stand pipe nozzle, the valve opening will be such as to ermit a rate of fuel flow just sufficient to maintain the rate of flow through the metering plu which that degree of suction and resulting epression at the nozzle discharge is capable of producing. l And however widely the valve may have been opened in response to the suction operating on the diaphragm before the chamber and the stand pipe nozzle became filled with liquid, after they are thus filled the valve will settle to a position affording just adequate supply for the flow capacity of the port in the metering plug under the stated engine suction; because if the fuel enters faster past the valve than it can be drawn by the stated suction through the metering plug, the degree of vacuum in the chamber which operates to open the valve will fall, and atmospheric pressure on the area of the valve-balancing diaphragm and the weight of the accumulated fuel will close the valve until the flow of fuel past it no longer exceeds the flow capacity from the metering port under the given suction; and if the flow past the valve is less than the flow capacity of the metering port, the vacuum in the chamber will increase,-the depression becoming greater,-causing the diaphra to operate for opening the valve more widely until the fuel flow past it equals the How capacity of the port in the metering plug. And in such operation, (which, in fact, will not consist of back and forth valve and diaphragm movement, except to an invisible extent,) the height of the liquid column from which the fuel suppl is derived past the valve, will have no e ect upon the degree o`f pressure existing in the chamber, because as to the. valve itself, the pressure of that columnis balanced, acting on the area of the valve for closing, and upon the equal area of the diaphragm, 80, for opening. And as to the pressure which is communicated through the valve opening to the chamber and to the liquid therein, any increase of that pressure acts on the diaphragm to close it and thereby reduce the access of fuel which causes outflow through .the metering port in response to engine suction for lowering the pressure in the chamber. And these theoretically backand-forth changes will be of infinitesimal duration, so that practically there will be no change ofV pressure in the chamber under any` given suction.

he adjustment of the spring, 60, for causing the valve to be normally seatedso as to be opened upon a predetermined minimum depression in the chamber, is taken into account in connection with the pressure which will be exerted by the fuel column in the stand pipe nozzle when the structure is in operation and in intervals of operation after once started; and`that pressure oper:- ating on the diaphragm for closing the valve becomes a measure of the lowest degree of engine suction that will cause the valve to remain open for admission of fuel after irst starting from the condition of an empty chamber.

discharge yin the fuel. mixture conduit at a' substantial distance above the fuel level of the fuel chamber; the mean-s for maintaining the predetermined pressure in the fuel chamber consisting of a conduit for fuel flow from the-source to said chamber, avalve in said'conduit and means by which the pressure of the fuel from the source is balanced in the opposite directions for seating and unseating the valve, said chamber having a movable wall for expanding and reducing .thechamber capacity, said Wall being operatively connected with said balanced valve for closing it by the chamber-expanding movement of said wall, and opening it more or less by its chamber-reducing movement, yielding means acting on -said moving Wall for chamber-reducing movement, and means for adjusting said ylelding means in predetermined relation to the pressure of a liquid column in the fuel duct leading from said chamber to the discharge of said duct in the fuel mixture conduit.

2. A carburetor for internal combustion engines comprising in combination With a fuelmixture conduit adapted Vfor discharge connection into the intake manifold of the engine and having an air'inlet; a fuel chamber having connection with the fuel source,

and means for maintaining a predetermined pressure on the fuel in such chamber, a fuel delivery duct from said chamber extending for discharge inthe fuel mixture conduit at a substantial distance'above the fuel level of said fuel chamber; a Calibrating fuel flow restriction interposed in said duct; the means for maintaining said predetermined pressure in the chamber consisting of a conduit for flow of fuel from the source to said fuel chamber; a shut-0E valve in said conduit; means for rendering the rate of flow through said conduit independent of the level of the fuel source; said chamber having a movable Wall by Whose movement the chamber is expanded and reduced, said movable part being exteriorly exposed toatmospheric pressure for forcing it inward to reduce the chamber capacity; additional means yieldingly actuating said Wall in the direction for reducing the chamber capacity, and means for adjusting said yielding means in predetermined relation to the pressure of the liquid column in the fuel duct leading from said chamber fordischarge in the` fuel mixture conduit, and' operating connections from said movable wall for seating the shut-01E valve by the chamber- 4expanding movement of said wall.

3. A carburetor for internal combustion engines comprising in combination with a fuel mixture conduit adapted for discharge connection into the intake manifold of the engine and having an air inlet, afuel chamber having connection with a fuel source, and means for maintaining predetermined pres- .sure on the liquid in said chamber; a fuel delivery duct extending from said chamber for discharge in the fuel mixture conduit; a conduit for fuel flow from the source to said chamber; a valve in said conduit, and means by which the pressure of the fuel from the fuel source operates on the valve equally in opposite directions; said chamber having a movable Wall, said wall being positively connected With said `valve for movement both 'in seating and unseating direction; and a spring reacting on said moving Wall for valve-opening movement.

4. The construction defined in claim 3 hav-l ing the fuel delivery duct which dischargesin the fuel mixture conduit extendingv upwardly for holding a liquid column to react by hydrostatic pressure on the contents of the fuel chamber, the spring being arranged for reacting on the movable Wall of the fuel chamber correspondinglyto the 'degree of said hydrostatic pressure.

, 5. A carburetor for internal combustion enf gines comprising in combination with a fuel mixture conduit adapted for discharge connection into the, intake manifold of the engine and having an air inlet; a fuel chamber having fuel flowconnection `with a fuel source; a fuel delivery duct from the fuel inwardly; additional resilient means for exerting pressure on said wall member in chamber-reducing direction arranged to exert said pressure i'n a degree corresponding to the hydrostatic pressure of said fuel column, and operating connections from the movable wall for seating'the shut-off valve by the chamberenlarging movement of said wall member.

. 6. carburetor for internal Acombustion engines comprising in combination with a fuel mixture conduit adapted for discharge connection with the intake manifold of the engine,and having an air inlet; a fuel chamber having connection with a fuel source; a fuel delivery duct from said chamber extending for discharge in the fuel mixture conduit, said duct being arranged to carry a fuel column for reacting by hydrostatic pressure on'the content.V of the fuel chamber; a conduit for flow of fuel from the source to said fuel chamber; means for rendering the rate of flow through said conduit independent lof the level of the fuel source consistlng of a shut-off valve in the conduit and means for balancing the fuel pressure on the valve in the opposite of the valve seating direction,

said chamber having a movable Wall member, n

said Wall member and said pressure-balancing means being exposed exteriorly of said chamber and said conduit respectively to equal fluid pressures; additional means actuating said Wall member inwardly, said additional means arranged to operate correspondingly to the hydrostatic pressure of the fuel column in the fuel delivery duct, and operating connections from said lmovable wall member for seating the shut-off valve by the chamber-enlarging movement of said Wall member.

In testimony whereof, I have hereunto set my hand at Chicago, Illinois, this 11th day of February, 1927.

v PERCIVAL S. TICE.