US2228292A - Fuel pump - Google Patents

Description

w. A. woon 2,228,292

FUEL. PUMP Original Filed Dec. 9. 1935. 2 Sheef.s-Sheec l 1 Jan. 14, 1941.

INVENTOR.

aaa/I @uw ATTORNEYS.

Jan. 14, 1941. w. A. WOOD 2,228,292

' FUEL PUMP Original Filed Deo. 9. 1935 2 Sheets-Sheet 2 INVENTOR.

ATToRNEys.

Patented Jan. 14, 1941 .PATENT oFFlcE FUEL PUMP Walter A. Wood,

Detroit, Mich.

Application December 9, 1935, Serial No. 53,528

Renewed October 19, 1939 3 Claims.

The present invention relates to pumps particularly designated to move fluid fuel for automotive internal combustionl engines, from the storage tank of the vehicle to the carburetor or` charge forming device.

In the conventional vehicle itisl customary to locate the fuel tank at the rear and at a somewhat lower level than the carburetor.

Further,

' 4 in order to enable the latter to functionproperly,

it must be equipped with a constant -level device such as a lioat bowl in which a float controls the inflow of liquid fuel. But, because ofthe usually small capacity of such float bowls, the valve operated by the float is incapable very high pressures.

of withstanding The problems, therefore, confronting the designer of fuel pumps include that of elevating the fluid fuel variable distances, due to the departure of the vehicle from av truly horizontal position' the delivery of such fuelA to the carburetor under a pressure less than that required to force open the float controlled valve, and the meeting of the variable demands for fuel by the engine under changing load conditions.

In addition to these problems, there are yet others "which cannot be disregarded, and not the least of these is that of insuring against'the socalled vapor lock which is due. to evaporation of fuel in the fluid line and in the pump, and the consequent. failure of the pump to supply fuel to the carburetor.`

Among the objects of the present invention is to overcome-'the objections to many of the forms of pumps intended to solve the above problems and provide a structure which will deliver a sufcient quantity of fuel under all conditions' at such a pressure `as will permit an easy, even flow into the carburetor without danger of flooding.

Another object is to overcome the annoying and dangerous vapor lock by providing pump i actuating means permitting the location of the pump and other` fuel containing parts sufficiently amounts large enough to cause evaporation of fuel.

other'objects will readuyappear tonhose skiueq inthe art upon reference to the -following de'- scription and accompanying drawings in which- Figure 1,. is a longitudinal vertical section through a preferred form of the pump.`

Figure 2 is a similar view of ar slightlydifferent form of pumpl and also showing the pneumatic operating means.

Figure 3 is a vertical section .ci a back pres*- indicating the hook up with a carburetor.

Referring particularly to Figure '1, the pump is o indicated as comprisinga body member 20, provided at one end with an inlet conduit 2|, the outer end of which is threadedto enable the connection of suitable tubing (n'ot shown) leading from a fuel tank (also not shown). The inner 10- or other end of conduit y2| opens through a boss 22 to the under face of body 20, the boss projecting substantially centrally of a seat 23 upon which is secured, -with the interposition of a gasket 24, a settling chamberl.

Surrounding the boss 22 andf-covering the chamber 25 is a screen element 26, this being dished as shown to permit the projection into the upper part of the chamber to some distance, of an outlet tube 21 to thereby form a gas or air 20- lled pulsation cushioning chamber rabove the liquid in the settling chamber.

The outlet tube 2 1 from chamber 25 is a part of the inlet conduit for the pump proper and forms a seat for pump inlet valve'3l opening 25y into which is secured a tube 39 communicating with a pulsating means such as is shown in Fig- 5 ure 2. Cover plate 31 is also' provided with a u lateral` boss 31a into which is secured a plug/31h having a lcapillary passage 31e, the purpose ofv which will be described later. Leading from chamber 35 is a short tube 45 forming a part of 40 outlet valve 41 which is substantially the same asvalve 3|. i 4 Conduit 46 and its continuations lead tothe point of discharge (usually a carburetor) and .in `order ,to properly regulate such discharge it is preferred to insert in this conduit a pulsation dampener arid also a pressure regulator.

' The dampener is indicated at 5U and shown as a small chambered velement; opening downwardiy into conduit 4s;whue a suitable form of 50 pressure regulator is shown to the right thereof in this figure. This form of'regulator consists of a short tubular continuation 5I of conduit 46 having a cross tube52, closed at one end 53 and' dished flange 54 over which is secured a. flexible diaphragm 55 pressed toward conduit 5I by a spring 56 mounte'd in a suitable cap 51 provided with a` small opening 58. The diaphragm 55 carries a plug member 60 lying in the cross tube 52 and loosely fitting therein and provided with a circumferential groove 6I arranged to be in line normally with the bore of tube5l. When [back pressure develops in the delivery conduit, iiuid passes along the plug body to the underside of diaphragm 55 and lifts the latter and, of course, the plug 60, .thereby partially or entirely cutting off flow through the conduit, by virtue of the groove 6I being moved out of registry with the passage or bore.

A somewhat different form of back pressure regulator is shown in Figure 3. This form shows v...a body into which iluid flows from the delivery side of the pump at 46a. This inlet passage is as shown bent at a right angle and counterbored to provide a valve seat 62, the counterbore providing a. space for a uted valve member 631 cooperatingl with the seat 62 to throttle or stop iiuid flow. f

Also opening into chamber 64 is a tube 61 arranged parallel to the valve counterbore and containing loosely therein a rod 68 having at its lower end a small cross arm or plate 69 serving to maintain the valve 63 within .the counterbore and to move it to seating or unseated position in accordance with the movement of the rod 68. This rod 68 is attached at its upper end to a. di

aphragm 55a which is mounted and operates in- Y. rangement of the pump and associated regulator and carburetor, the latter being indicated at C..

Referring now to Figure 2, this shows a pump involving substantially the same elements as that of Figure 1, exceptingthe backV pressure regulator. In this figure, the settling chamber :and its associated screen, inlet valve, etc. is the same in form and function as that already described `and will be designated as a whole as 25. The

-ing to the pulsator and the other end of same similarity of construction exists in the pump chamber 35, outlet valve 45-41, outlet passage 46 and'chamber element 50. 4

The pump body, however, contains a second chamber 15, for convenience located in alignment withpump chamber 36 and of lenticular shape.

This chamber-is divided by a diaphragm 16, conveniently an. extension of the pump diaphragm, and the upper portioncommunicates ,l

through a passage 11 with outlet passage 46.

Coacting with the underside of diaphragm 18 is a valve member 18 which is cylindrical and is provided with an annular groove. normally registering, or substantiallyso, with the passage 39a, to one end of which is connected a tube 39h leadwhich is connected to the pump chamber 35.

Valve member 18, as implied, 'extends across passage 39a and into atubular boss 19, in which,

' ,Y or a tubular extension thereof Y81|, it is supported and held against. the diaphragm 16 by a suitable spring 8l. 'I he valve member 18`preferably fits snugly in its tubular guide so as to effectively valve the passage 39a and, in order to permit free movement, it is necessary to provide for balancing the pressure in the small chamber or space under diaphragm 16 and inthe tube 80. This may be accomplished by providing a passageway 16a connecting the two spaces, either through` the member 18 as shown or through the pump body.

This valve member 18 and its associated operating parts serve also as a back pressure regulator in that pressure developing in passage 46 causes depression of diaphragm 16 and thereby moves valve member 18 downwardly so as to throttle or substantially entirely cut ofi passage of pulsations through passage 3 9a to the pump chamber.

In this form of pump as well as in the others shown, including Figure 1, already described, pulsations of alternating increase and decrease of pressure are produced in passages 39, 39a and corresponding passages, through their being connected through a suitable tube 39h to a pneumatic pulsator such as is shown in Figure 2.

This device comprises a cylinder 85, ilanged as at 86 for attachment to the wall 81 of an enf gine crankcase adjacent to the camshaft 88. The

-shaft 88. The outward return of the piston 90 is accomplished by means of a spring 92 acting between flange 86 and a suitable ange or cover plate or both 93 on the projecting end of piston 90.

While the relative proportions of the cylinder l85, tube 39h (bore and length) are not critical, it is necessary that they be such that the piston substantially completely displaces the air from the cylinder 85 intov the tube 39h and pump to produce a. quite high pressure therein and, conversely, when the piston moves outward, to permit a quick drop ,to sub-atmospheric pressure. Further, the tube 39h must be sufficiently long to enable the pump to b e located away from the engine to avoid undue heating, and of sufiiciently large b ore to avoid undue internal friction, not, however, so large as to materially reduce the pressure transmitted to the pump diaphragm. Satsifactory results have been obtained with 'a pump capacity of twenty gallons per hour at 2000 R. P. M. engine speed in using a pulsating ,cylinder of 11/2 inches bore and. inch stroke and a tube (39h) of 12 inches in length and with recognized.

Tests seem to show that the pressures in the pulsating elements should bev substantially maintained, so that if a longer tube 38h is necessary, or desirable.- 'it should be somewhat smaller, though not so small that the higher wall friction interferes with the rapid passage of air.

Mention has been made above of the capillary passage 3`Ic opening from the atmosphere into the air passages of the pumps shown in Figures 1 and 2. This isa veryimportant element of the pump construction and has several important functions. Y

In one of itsfunctions, this passags acts as a pressure stabilizer or air volume regulator in that it admitsalr when the average pressure within is` below atmospheric and allows escape of air when the average pressure is higher than atmospheric. The capillary dimensions of the passage, however,

prevents free passage of air because of the high wall friction and, therefore, the action of the rapid nuctuation of pressure d ueto theV movement of piston uponthe pumpdiaphragm is not materially ailected.

A second function ofthe passage 31o, more or less incidental to the rst, is that'of ventilation the air passages.

A third function, applicable particularly to the pump of Figure 2 is that of bleeding the pressure from passage 39a when the valve'18 has closed. i

This application is in part a continuation of the subject matter of my copending application, Serial No. 759,135, filed December 26, 1934, on Pumps.

lWhat I claim is:

1. In a liquid fuel pump'having a pump chamber, liquid inlet and outlet conduits connected thereto and valves for providing a one-Way flow lzo ofliquid fuel through such chamber, means for controlling the delivery of liquid fuel through said outlet conduit comprising a valve in said outlet conduit and opening in the direction of fuel flow, an operating stem for said valve, a diaphragm to which said stem is attached in operative relation and which is exposed to the "action of fluid in said outlet conduit, a housing chamber for said diaphragm arranged laterally of said conduit and communicating therewith through a passage in which said stem is loosely movable and acts to restrict the passage of uid fuel into Iand out of said diaphragm chamber, and spring means tending to force said diaphragm stem and valve toward valve-open position.

2. In a liquid fuel pump having a pump chamber, liquid inlet and outlet conduits connected thereto and valves for providing a one-way flow controlling the delivery of liquid fuel through said outlet conduit comprising avalve for said outlet conduit, an operating stem for said valve, a diaphragm to-which said stem is attached in operative relation yand whichis exposed to the action of fluid in said outlet conduit, a hbusing chamber for said diaphragm communicating with said outlet conduit through a passage in which l'said stem substantially fills the passage and is loosely movable therein to permit restricted ow of fluid into and out of said chamber around said stem, and spring means tending to oppose the action of said fluid upon said diaphragm. v

3. Means for controlling the pressure of liquid fuel delivered from a liquid fuel pump, said means consisting of a passage receiving such fuel, a valve in said passage and regulating ow therethrough, said 4valve having a stem, a chamber communicating with said passage, said stem being located in and substantially lling said communication but with sumcient clearance 'to permit restricted movement of fuel into and out of said chamber, a diaphragm mounted in said chamber and operatively attached to said stem, said diaphragm beingexposed on one side through said communication to uid fuel pressure in said conduit and on the other to atmosphericv pressure, and spring means arranged to oppose the action of said fluid pressure upon said diaphragm.

WALTER A. WOCD.

of liquid fuel through such chamber, means forl

Images