US1912202A - Fuel pump - Google Patents

Description

HJHUEBER May 30, 1933.

FUEL PUMP Filed June 26, 1931 Jwumtoo Heirs Huber dumm mm May 30, 1933 UNITED STATES PATENT OFFICE HENRY HUEBER, F BUFFALO, NEW YORK, ASSIGNOB TO TBIGO PRODUGIS CORPORATION, OF BUFFALO, NEW YORK FUEL ruin Application filed June 26,

This invention relates to means for transferriug liquid fuel from a storage tank to an internal combustion engine, or the like, and it has particular reference to a device for this purpose which may be operated by fluid pressure, preferably a reduced or subatmospheric pressure. 1

The tendency in present-day automotive design is to substitute for the well-known vacuum tank a less expensive and more efli- :ient fuel pump. Certain of these fuel pumps are driven mechanically and positively" by connection with some moving part of an internal combustion engine. The lack of equilibrium between the rate of movement of the engine and the volumetric quantity of fuel required to produce that movement under the many and varying operating conditions renders such devices obj ectionable.

In an attempt to compensate for the wide variation presented in the ratios between en-v gine speed and fuel consumption variousfrictional driving means have been introduced into the constructionof these pumps.

both of the following reasons: first, the wear on the frictional driving elementsv and on their associated parts presents mechanical difliculties; second, in certain of these devices, the pumping mechanism receives an impulse with each revolution or stroke of the actuating part on the internal combustion engine, and whether or not that stroke is completed and results a complete cycle of movement in the pump, the strain upon the pumping element in receiving the original impulse is substantially equivalent to the strain which would be incurred if the opera-- tionwere'completed. v 4

In view of the foregoing it has been found advantageous to, introduce to the pump, as a motive force, a, source of subatmospheric pressure, so that, when suflicientresistance is offered by the carburetor to the delivery of fuel thereto bythe pump, the subatmospheric pump-actuating pressure is' merely overcome by that resistance and the operation of the pump is suspended until the pressure inthe fuel line, from thepump to the carburetor, falls to a point where further This expedient is objectionable for either one or 1931. Serial No. 547,185.

pump operable by fluid pressure which overcomes objections and disadvantages ordinarily encountered in the design and construction of such devices. The kinetic energy produced by the pressure is transmitted to the pumping diaphragm in such a way that it is not necessar to introduce any sliding or moving parts into the pumping chamber from the outside. This minimizes the danger of leakage and eliminates costly. and cumbersome packings.

' Another aim of the present invention is to provide a device which will supply a continuous flow of fuel to the carburetor of the engine and thus eliminate the" idle return strokes and the consequent pulsating flow of fuel which characterizes a single acting pump.

A pumping means is therefore provided, which supplies continuous flow .of fuel to the carburetor; which eliminates objectionable features inherent in :mechanical, and particularly in frictional, driving, devices; and which renders it unnecessary to introduce moving parts from outside the pumping chamber to the interior thereof, thereby facilitating leak-proof construction of the pumping device.

Other mechanical and structural advan-. tages to be derived from a device constructed in accordance with the principles of the present invention will appear from the follow-v ing description and from the accompanying drawing, in which: I y

Fig. 1 is a longitudinal cross section of a device constructed in accordance with the present invention showing the pumping chamber and the liquid entry and exit ports.

Fig. 2 is an end elevationof the device 'showmg the pressure directing valves and valve passages in .cross section.

Fig. 3 is an enlarged bottom plan view of 9 and the cap 31.

5 The main body of the pumping device is composed of upper and lower dish-shaped members, designated 11 and 12 respectively, which cooperate to form a pump compartment. The pump compartment is horizontally divided into upper and lower fuel chambers, 13 and 14 respectively, by a flexible diaphragm or piston 15 which is held, about its outermargin, between the outer marginal portions of the component body members 11' and 12.

A assage 16 is provided in the lower body mem er 12 in communication with the lower fuel chamber 14 and this passage communicates with an inlet passage 17 and an exhaust passage 18. The inlet passage 17 connects with a tube 19 leading from the source of fuel supply, and the exhaust passage 18 connects with a tube 21 leading to the carburetor of the engine which the pumping means is designed to serve. A valve 22 is provided in the inlet passage 17 to allow fluid movement in the passage in one direction only, that is, from the tube 19 into the lower fuel chamber 14. A valve 23 disposed in the exhaust passage 18 allows fiuid in that passage to move only from the fuel chamber 14 to the tube 21.

The upper fuel chamber 13 is provided with a passage 24 which leads into an inlet passage 25 and an exhaust passage 26. The passages 25 and 26 connect with the tubes 19 and 21 respectively, and are provided with valves 27 and 28 respectively, which operate in a manner similar to the valves 22 and 23. The body member 12 is provided at its lower side with a circular opening 29 concentric with the fuel chamber 14. The opening 29 is closed by a flanged, cup-shaped cap 31 which forms a reduced lower extension 32 of the lower fuel chamber 14. The space 32 is divided from the fuel chamber 14 by a flexible diaphragm 33 which is stretched across the opening 29 and is held, about its outer margin, between the body member 12 A somewhat similar cap 34 and a diaphragm 35 are associated with an opening 36 in the upper side of the upper fuel chamber 13. In the present embodiment the diaphragms 33 and 35 have been 3 shown as being of substantially smaller diameter than the diaphragm 15.

Flanged and rigid plate members 37 are preferably provided adjacent the upper and centrally thereof, and similar but smaller vided adjacent the upper and lower sides, respectively, of the diaphragms 33 and 35, I for maintaining substantially rigid the central portions of the respective diaphragms.

lower sides of the diaphragm or piston 15,

All three diaphragms and the flanged plate members associated with them are provided with concentric apertures adapted to receive a connecting pin 42. The connecting pin 42 is provided at its lower end with an enlarged head portion 43 which seats against the lowermost washer 41 and is externally threaded at its upper end to engage a nut 44. A pair of spacing collars 45 and 46 encircle the pin 42 between the diaphragms 35 and 15, and between the diaphragms 15 and'33 respectively. In this manner all three diaphragms areinterconnected so that any vertical movement of the central portion of one of the diaphragms is accompanied by a corresponding movement of the central portions of the other two diaphragms.

A casing 47 is secured to the upper side of the upper cap 34 to house means for connecting a source of suction or other operating pressure, alternately into a pressure chamber 48, formed by the upper cap 34, and into the lower compartment or pressure chamber 32, and for opening the chamber which is not in communication with the source of suction to the atmosphere.

The lower compartment 32 connects with a horizontal passage 49 in the casing 47 through a tube 51, Fig. 2. A pair of vertical passages 52 and 53 extenddownwardly from the horizontal passage 49 and communicate with the chamber 48. The passage 52 is provided with a pair of spaced valve seats 54 and 55, and the suction, which is conductedfrom the intake manifold of the internal combustion engine with which this device is generally used, connects with the passage 52, between the valve seats 54 and 55, as through a passage 56. A valve stem 57 is positioned in the passage 52 and is provided with spaced valves 58 and 59 for cooperation with the valve seats 54 and 55 respectively. These valves are so spaced on the valve stem that vertical movement of the valve stem 57 in an upward direction will seat the valve 58 against the seat 54 while movement in 'a downward direction will seat the valve 59 against the seat 55. The upward and downward movements of the valve stem 57 are limited by the seating of the valves.

The vertical passage 53 is also provided with spaced valve seats 61 and 62. Intermediatethese valve seats is a port 63 which communicates with the atmosphere. A valve stem 64 is positioned in the passage 53 and is provided at its upper end with a valve 65 the upper pressure chamber 47 through the open valve seat 58 and the lower pressure compartment 32 W1 be connected with the atmosphere, through the tube 51, the horizontal passage 49,. the u per portion of the vertica passage 53, an through the open valve seat 61 and the passa e 63. When the fuel chamber 13 far exceeds the tendency of- .the smaller diaphragm 35 to increase the volume of the chamber 13. This differential existing between the displacement of the diaphragms represents the volume of fuel which is ex lled through the exhaust passage 26- and elivered to the carburetor.

Conversely, this upward movement of the diaphragms increases the volume of the lower fuel chamber 14 and fuel is drawn thereinto through the inlet passage 17. When the position of the valves is reversed, that is, when the valve stems 57 and 64 are moved upwardly, suction is connected to the lower pressure chamber 32 and the upper pressure chamber 48 is open to the atmosphere and the direction of movement of the diaphragms is reversed. The means for changing the position of the valve stems 57 and 64 and for resiliently urging the valves against their seats in their several positions is located in the casing 47 and is shown in detail in Fi 3 and 4. This means may be any desirab e type of sna -over action and herein is shown as inclu ing a slow moving arm 66 and a fast moving arm 67, both of which are held in pivotal engagement with fulcrums 68, formed upon a boss or securing portion 69, by a coil sprin 71 which extends between the arms 66 and 6 v A stem 72 is pivotally fastened; at one of its ends to the slow moving arm 66 and extends downwardly into an opening 7 3 formed in the connecting pin 42 and terminates in an enlar d headed portion 74. A screw is threa ed into the up r end of the opening 7 3 and is provided wit a central opening of a size to permit sliding movement of the stem 72 and to retain the headed portion 74 thereof in the opening 73. y T When the diaphragms approach the upper limit of their movement the bottom of the opening 73 engagesthe headed portion 74 of the stem 72 and moves the slow moving arm 66 upwardly against the resistanceof the spring 71 until the. arm 66 asses a deadcenter position whereu n arms, 66 and 67, quickly assume their uppermost positions under the impetus of the spring 71. This latter movement causes the valve stems 57 and 64, which are connected to the fast moving arm 67 b a pin 76, to move to their upper position an so arrange the valves that the diaphragms begin. their downward movement.

It will be understood, that in the operation described, the fuel, under greater than atmospheric pressure, will itself constitute the motlvating medium in the pumping action When the parts are in the position shown in Fig. 1, for example, with atmospheric pressure maintaining in chamber 32 and suction in v chamber 48, atmospheric pressure will be exerted against the bottom or outer face of diaphragm 33; and atmospheric pressure will be exerted against the upper or inner face thereof by the atmospheric pressure of fuel entering chamber 29 through passage 19. Therefore the forces effective against the opposite sides of diaphragm 33 will substantially cancel and negative each other. Simultaneously, fuel in chamber 29, entering through passage 19, will exert atmospheric pressure against the under side of diaphragm 15, while fuel in chamber 13 and outlet passage 21 will exert greater than atmospheric pressure upon the upper face of diaphragm 15 and the under side of diaphragm 35. This pressure of fuel in chamber 13 will tend, therefore, to move the diaphragm 15 downwardly and will tend to move the diaphragm 35 upwardly since chamber 48 is under less than atmospheric pressure. As the latter tendency is greater than the former i. e., the differential between forces exerted against the opposite faces of diaphragm 35 is greater than the differential forces against diaphragm 15, the diaphragms willbe moved upwardly. Accordingly, the motivating force will be seen to be the fuel, under atmospheric or greater than atmospheric'pressure, in the discharge chamber.

- The above is, of course, but one practical application of the underlying principles of the resent invention. The diaphragms are pre erably of areadily flexible though nonresilient material, so that the fluid pressure acting on the smaller dia hragms will constitute the sole driving. orce for the fluid adjacent the central diaphragm, valves for I said passages operable by the movement of fuel to secure unidirectional fuel flow, a

source of less-than-atmospheric pressure, andvalve means operable by and during movement of the diaphragm for alternately connecting the other two chambers to said source of less-than-atmospheric pressure and to the atmosphere.

2. In a fuel pump, a hollow casing, three diaphragms extending across and dividing the casing interior into four chambers, the central diaphragm being of different diameter than theother diaphragms, a rigid member connecting the central portions of the diaphragms for movement together, valved fuel inlet and outlet passages communicating with two of said chambers, atmospheric and suction passages c0mmunieating with each of the other two chambers, and va ve means for alternately opening and closing said atmospheric and suction passages to alternately apply suction and atmospheric pressures to said other two chambers, said valve means being connected to said rigid member for operatiomthereby.

HENRY HUEBER.

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