US2737167A - Pressure controlling valve system - Google Patents

Description

March 6, 1956 J. w. DICKEY PRESSURE coNTRoLLNG VALVE SYSTEM Filed Oct. 30, 1952 5 z3 a a W i 4 M M w w E E @y 7 ai 1M u mv+m 3 n mw 7 E I a Emu.. :rw oo 5 u 6\ /m\ .Ilil Z Mm U 7\l 6 6 w C u@ e 6 y 5 F 1 l 1 1 ||,r|||||| l 51C BYE United States Patent PRESSURE coNrRoLLING vALvE SYSTEM JohnI W. Dickey,.Newlield,.N..Y.assignor to` Bendix Aviation Corporation, a-corporation of Delaware Application October 30,. 1952,. Serial No. 317,793 1 Claim.. (c1. 12a-139) The present invention relates to a pressure controlling valve system for liquid fuelv supplying devices and more particularly to an arrangement for limiting the pressure of fuel supplied by a pump to a carburetor or similar fuel" feeding device.

In fuel feeding systems for internal combustion engines in which the fuel' is pumpedvv from a storage tank tothe carburetor, and the level of fuel' in the. bowl'. of the carburetor is maintained by a oat-operated valve, it is; desirable that the pressure of the fuel at the float valve be maintained substantially constant irrespective of' the: volume. of fuelf admitted by said valve. Otherwise, the fuel level inthe carburetor bowl may vary .with concomitant variations. in the delivery of the fuel iets. This requirement necessitates the provision. ofv a pump. system having a much larger capacity than would? be required if considerable. latitude in pressure: betweenA no delivery and fully volume of deliveryy couldy be tolerated. Furthermore, particularlyE whenA constantly operating pumpsy of the reciprocating type are employed, there is a tendency for fuel' pressures tov buildf up, under conditions. of insignificant volume of fuel demand, to. a point where,V liooding, of thel carburetor may; occur.

Moreovenin fuel feeding `Systems. for' automotive vehicles iny which the fuer feeding; devicev for the internal combustion engine. is supplied from: aremOtelyr located storage tank, it: is desirable that the,y pumpJ whichjtrausfersr the fuel from thev storage taule tothecarburetor be located: closel to, or actually within, theY tank; in order to avoid the accumulation of gasified fuel' in the supply conduit;l which condition, popularly' known as; vapor lockp. may render the fuel system temporarilyinoperative. However, wherrthe fuel tankl is; locatedf at a considerable distance in front' or to,` the rear of the engine as; is; frequentlyV the4 case,y particularly in commercial and milita-ry" vehicles,I the pressure; of; thefuel suppliedv to the carburetor by a tan-k mounted pumpf is subject to import-ant variations? due, tothel changes in the hydrostatic. head between: the ends; of the;v feed line as; the vehicle ascendsf orj descends: obstructions or decliyities. These variations in pressure-.may affect theflevely of; the fuel in the carburetor bowl, as controlled by the conventionaltv float"y va1ve,'to sucht an extentv as, to. have a significant effecton. the; fuely mixture. supplied to the engine lt is` an` objectof the present invention to provide'k a novel: fuel pressurev controllingvalvesystem for internal combustion` engines which maintains the, pressureat; the pointjof ldelivery substantial-ly' constant irrespective 'of variations in theA volume` of fuel'y delivered, and in, the angle of'pitch ofa vehicleY on whichgitfmay be mounted. Iti sanother objectto` provide suoli'V a device kwhich is arranged' to# positivelyl prevent pulsations in pressure of the fuel supplying device from building up pressure at the point of delivery at times when little or no fuel is being used by the engine.

It is another object to provide such a device incorporatice ing means for automatically increasing the fuel pressure at the carburetor of the engine responsive to opening the throttle. valve in order toI enrich the fuel mixture at times of engine acceleration.

It is another object to provide such a device which is adapted' for use insealed fuel systems such as those employed on vehicles capable of operation while submerged.

Further objects. and advantages will be apparent from the following description taken in connecti n with the accompanying drawing, in which: `f

Fig. l is a semi-diagrammatic illustration1 of a fuel system incorporating a preferredembodiment of the invention, the pressurel controlling valve being shown in longitudinal section;

Fig. 2: is a detail view'of a portion of Fig. v1 showing the structure modifiedv to. provide for the controlof delivered fuel pressure in accordance with engine'intake vacuum; and

Fig. 3 is a vertical substantially mid-sectionaly view of anv embodiment of the invention in which the pressurelimiting valve is incorporated as a unit with the' fuel supply pump. A l

In Fig. l of the drawing there is illustrated a fuel supply system for an internal combustion engine comprising a storage tank 1, a fuel pump Z mounted' thereon, a pressure controlling' valve indicated' generally by the numeral 3y mounted on theV carburetor 4 of the engine, a-nd a conjduitl 5 connecting the fnel pump to the pressurelimiting valve; It isy to be understood thatthefuel pump maybe of' any suitable construction, but it isy preferred toemploy an electromagnetic reciprocating type of pump suclr asdisclosedV in thev patent to DickeyV et al., No. 2,472,067 issued .l une17', 1949'.

According-'to the present invention, the pressure-limiting valve 3- comprises a hollow cylindrical body 6 whichis threadedv as showny at 7r andl 8 for connection to the conduit 5' and' carburetor 4, respectively, and i's provided withf an internal shoulder 9 against which is located an O-ringf, 11 of suitable elastically deformable material such as: rubber or the likev which forms a seat for a conical valve member 112' mounted ona valve stem 13- protruding fromthe valve body 6.

- A dished plate member 14 is rigidly mountedas indicated at 1-5; on the, end of thevalve body6, and a exible diaphragm 16 is sealed at its rim to the periphery of the plate memberI 1 4 by' means ofV a cap 17, the rim 18 of which?isgcrirnped'aroundI the peripheries of the diaphragm and plate, preferably with the interposi't'ionA of a suitable sealing-'ring 19'. A clamp nut 21 is threaded? on the protruding endl off the; valve. stem 13 and extends through a central opening in the diaphragm 16". A pressuredis:- tributing disc member 22 is rigidly mounted-on the nut 21 and presses the central portion of the diaphragm i6 against a sealingring 211i.1 which i's backed' by a ange 24 of the. nut,y the di'sc 22 being retained' on the nut'- by suitable. means such as.` al lip, or flange 25 formedy on the nut.

A spring 26 is mounted on the valvel stem 13', bearing at one end: on anv internal shoulder 2.7 in thev valve body 6and, at its other end pressing againstthe valve member 12 to urge it away from the. valve. seat *1-1' and thereby admit fuel into the chamber28` formed between the plate member 14 and' the. diaphragm 16.

In this, embodiment of the invention, the. capA 17 isy provided with breather openings 29 which maintain ambient pressure-within the. cap and against the outer side of the. pressure-l distributingI plate 22J and' diaphragm 1'6.

In the operation of the device as above described, when the fuel pump 2 is in operation, fuel under pressure is supplied to the valve 3, and since the valve is initially held open by the spring 26, the fuel ilows into the chamber 28 and into the bowl of carburetor 4. As soon as the carburetor bow is filled, its float valve closes in the usual manner. Pressure immediately builds up in the chamber 28 and causes the diaphragm 16 to overcome the pressure of the spring 26 and move the valve member 12 into engagement with its seat 11. The area of the diaphragm 16 is so related to the strength of the spring 26 that the desired unit pressure for the carburetor is effective t close the valve member 12 and prevent further admission of fuel from the feed line, except what is necessary to replace that which is withdrawn from the carburetor bowl by the operation of the engine.

It is important to note that in this arrangement, the .flow of fuel into the valve 3 from the conduit S responsive to the action of the pump 2 has a tendency to move the valve member 12 toward closed position. This insures that when little or no fuel is being consumed by the engine, the pulsations of pressure from the pump merely tend to press the valve member 12 more tightly on its seat and thereby prevents the building up of pressure in the chamber 28 beyond the desired normal condition,

In Fig. 2 of the drawing there is illustrated a modification of the valve structure in which the vents 29 in Vthe cap 17 are eliminated, and a tting 31 is mounted on the cap to receive a conduit 32 which may be connected either to the air intake to the carburetor or to the intake manifold of the engine. By this arrangement, the system .becomes sealed from the atmosphere whereby the operation is not affected by changes in ambient pressure and may be operated normally even though the vehicle is partially or completely submerged in water. If the connection is made to the intake manifold, the outer side of the diaphragm 16 is subjected to the subatmospheric pressure existing in the manifold. Since this reduction in pressure within the cap 17 assists the fuel pressure in the chamber 28 to hold the valve member 12 against its seat, when a high vacuum exists in the intake manifold, as when the engine is idling, the fuel pressure in the chamber 28 and consequently on the carburetor fioat valve is reduced. When the throttle is opened to accelerate the engine, however, the concurrent reduction in the intake vacuum is effective to cause a corresponding increase in the fuel pressure in chamber 28 and consequent enrichment of the fuel mixture supplied to the engine due to raising of the level of the fuel in the carburetor bowl.

In Fig. 3 there is illustrated a form of the invention in which thev pressure-limiting valve structure is incorporated with the fuel supply pump to form a unitary device. The pump illustrated is of the type shown in the patent to Dickey et al., above cited, and comprises a cylindrical casing 41 which has coaxially mounted therein a cylinder 42 in which a hollow magnetic piston 43 is caused to reciprocate electromagnetically and thereby pump fuel up .through the piston and a conduit member 44 into the outlet chamber 4Q. The conduit has an internal shoulder 45 which positions an O-ring 46 of elastically deformable material which forms the seat for a valve member 47 mounted on a stern 48.

The upper end of the pump casing 41 is ared out to provide a ange 49 against which the periphery of a flexible diaphragm 51 is pressed by the crirnped-over rim 52 of a cap 53 forming the upper end closure of the chamber 40. The center of the diaphragm 51 is fixed to a clamp nut 54 screwed on the end of the valve stem 48, by means of a pressure equalizing disc 55 suitably retained on said nut. A nipple 56 is mounted on the cap 53 in alignment wrth the valve stem 48, and loosely surrounds a cylindrlcal extension 57 of the nut 54. The nipple 56 is internally threaded, and a threaded thimble 58 is adjustably mounted therein and serves as an abutment for one end of a spring 59, the other end of which presses against a shoulder 61 on the nut 54, thereby tending to move the valve member 47 away from its seat 46. The open end of the nipple 56 receives a T fitting 62, one socket 63 of which communicates with the intake manifold of the engine by means of a tube 64, while the other socket 5S admits atmospheric air. Means for modifying the elect of changes of intake vacuum on the operation of the pressure-limiting valve is preferably provided in the form of an adjustable throttling valve 66 for restricting the passage connecting the pressure chamber 67 above the diaphragm to the intake manifold, and an adjustable bleeder valve 68 for controlling the admission of air to said pressure chamber. It will be understood that if the system is to be completely sealed for under-water operation, the bleeder opening will be connected to the air intake to the carburetor or to some other convenient source of atmospheric air as by means of a tube 69.

The casing 41 of the pump is provided with a nipple 71 for the reception of a feed line 72 connecting the pump to the engine carburetor.

In the operation of this embodiment of the invention, reciprocation of the plunger 43 forces fuel into the conduit 44, and if the valve 47, 46 is open, the fuel is admitted into the chamber 40 in the upper end of the pump casing and is conducted from this chamber to the engine carburetor. When the carburetor bowl is lled, the back pressure in the chamber 40 due to closure of the carburetor float valve operates on the diaphragm 51 t0 draw the valve member 47 against its seat 46 and prevent further admission of fuel except as it is consumed by the engine. The pressure in the chamber 40 may be manually adjusted by threading the thimble 58 toward or away from the diaphragm chamber 67, thus placing more or less pressure of the spring 59 on the equalizing disc 55 and diaphragm 51. The variation of fuel pressure in the chamber 40 responsive to variations in intake vacuum may likewise be controlled manually by suitable adjustment of the throttling valve 66 and bleeder valve 68.

Although certain structure has been shown and described in detail, it will be understood that changes may be made in the precise form and arrangement of parts without departing from the spirit of the invention.

In a fuel supply system for internal combustion engines, pressure regulating means including a delivery chamber having an inlet and an outlet, a valve controlling the inlet comprising a seat facing toward the inlet and an obturator member movable in the direction of flow to engage the seat and close the inlet, spring means operative to open the valve, a flexible diaphragm forming a Wall of the chamber opposite the inlet, and means connecting the diaphragm to the obturator operative to overcome the spring means and draw the obturator against its seat responsive to a predetermined pressure in the delivery chamber; including further a cap member enclosing the iexible diaphragm, and means for controlling the pressure in said cap; in which the means for controlling the pressure in the cap which encloses the flexible diaphragm comprises a tubular connection to the intake manifold of `the engine, a tubular connection to the atmosphere, and manually adjustable regulating valves in said connections.

References Cited in the file of this patent UNITED STATES PATENTS 2,136,959 Winfield Nov. 15, 1938 2,228,292 Wood Ian. 14, 1941 2,297,129 Bohnstedt Sept. 29, 1942 2,315,881 Thomas Apr. 6, 1943 2,341,257 Wunsch Feb. 8, 1944 2,587,728 Hoskins Mar. 4, 1952 2,611,592 Anderson Sept. 23, 1952 2,633,146 Witt Mar. 31, 1953 *we Nu.

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