US3057300A

US3057300A - Pump and metering apparatus

Info

Publication number: US3057300A
Application number: US719566A
Authority: US
Inventors: Otmar M Ulbing
Original assignee: Individual
Current assignee: Individual
Priority date: 1958-03-06
Filing date: 1958-03-06
Publication date: 1962-10-09
Anticipated expiration: 1979-10-09

Description

Oct. 9, 1962 o. M. ULBING 3,057,300

PUMP AND METERING APPARATUS Filed March 6, 1958 2 Sheets-Sheet 1 Oct. 9, 1962 o. M. ULBING PUMP AND METERING APPARATUS 2 Sheets-Sheet 2 Filed March 6, 1958 United States Patent 3,057,300 PUlVIP AND METERING APPARATUS Otmar M. Ulbing, Lisle, N.Y. (R.D. No. 1, Berkshire, N.Y.) Filed Mar. 6, 1958, Ser. No. 719,566 Claims. (Cl. 103-2) This invention relates to pumping apparatus in general and more particularly to pumping apparatus of the rotary type which are suitable for use in fuel injection systems.

The fuel injection apparatuses known heretofore have been complex and expensive devices, diflicult to manufacture and diflicult to service. Prior art positive action pump designs specify tolerances in the order of a few millionths of an inch and extremely critical surface finishes creating production problems which are frequently insuper'able as a practical matter. Injectors which have overcome this tolerance problem to a certain extent, inject fuel at a constant rate. This is objectionable, particularly at low engine speeds, since complete atomizatfioln of fuel is impossible and hence it is inherently waste- Pumping apparatus for use in fuel injection systems are required to supply predetermined amounts of fuel in an efiicient and reliable manner. Such pumping apparatus should be compact, such that they occupy little space and thus mounting is facilitated, and should require little adjustment and servicing.

Accordingly, it is an object of this invention to provide a reliable pumping apparatus designed such that a minimum of critical manufacturing tolerances are specified and which requires little or no adjustment in operation. It is a particular object of the invention to provide a compact and eflicient rotary pump particularly adapted for use in a fuel injection system.

Another object of the invention is to provide a simple but accurate metering apparatus adapted for use in a fuel injection system.

Another object of the invention is to provide a reliable fuel injection apparatus which may be produced at competitive cost. A further object of the invention is to provide a rotary pump and metering apparatus in which the output thereof may be varied in an infinite number of steps throughout the capacity of the pump.

Still another object of the invention is to provide a rotary pump and metering apparatus which may be assembled in a compact unit and which is suitable for use in fuel injection systems. The preferred embodiment of the invention includes a constant displacement rotary pump having semi-cylindrical cam followers which provide improved sealing and dynamic characteristics. The cam followers and other cooperating parts are preferably manufactured from a suitable plastic material such as teflon. As the followers are not subjected to excessive hydraulic loading in operation they are preferably manufactured from a deformable material so that they will conform to any slight irregularities in the cam surface. Thus, critical production tolerances may be minimized and, in addition, excellent sealing is assured. These followers are the only elements in the device which oscillate, all the other moving parts operating in rotation.

Adequate cooling is provided by passing a quantity of fluid through the pump and metering apparatus substan tially in excess of the output of the pump. In this manner, the temperature of the device does not exceed the limits imposed by the characteristics of the plastic material components thereof nor those of the fluid which is pumped.

The rotary pump utilizes a flow divider system which eliminates the use of complex loaded poppet valves. The pump is self priming as gas and liquids may be pumped with equal facility and an initial pressure does not need to be built up to open a valve or valves.

A novel metering apparatus cooperates with the preferred embodiment of the pump which enables the optimum amount of the pumped fluid to be distributed as desired and in response to a significant independent variable. The unwanted portion of the pumped fluid is automatically returned to the fluid source.

The entire apparatus is extremely compact. Further it is feasible to construct the device from light metal alloys and plastics as extreme hardness and wear resistance are not required of any one of its components.

A particular feature of the invention lies in the relatively simple, hence inexpensive and trouble free, apparatus of the preferred embodiment of the invention.

These novel features, together with further objects, advantages and features of the invention will be more readily understood when considered with a description of the preferred embodiment and a modification thereof in connection with the drawings, in which:

FIG. 1 is a sectional view of the preferred embodiment of a rotary pump and a metering device particularly adapted for fuel injection purposes;

FIG. 2 is a sectional view along the lines 2--2 of FIG.

FIG. 3 is an exploded view of certain of the pumping elements;

FIG. 4 is an exploded view of certain of the elements in the metering apparatus;

FIG. 5 is a sectional side view of a modified version of the metering and pumping apparatus;

FIG. 6 is a sectional view along the lines 66 of FIG. 5;

FIG. 7 is an exploded view of certain of the elements in the pumping apparatus; and

FIG. 8 is an exploded view of certain of the elements in the metering apparatus of the modified version.

With reference to FIG. 1, the pumping and metering apparatus according to the preferred embodiment is encased in a housing 10 and contains the two basic elements. A constant displacement pump which transmits an amount of fuel dependent upon the rotational speed of the pump elements is in the lower part 11 of the housing or casing 10; and a metering device which is responsive to a selected condition is housed in the upper part of the casing. Both elements are connected to a shaft 12 and are driven thereby.

Certain parts of the pump are shown in an exploded view of FIG. 3. These include a lower plate 14, a pump cam 16, two

cam followers

18 and 20, a ring 22,

torsion springs

24 and 26 and an upper plate 28.

The fluid to be pumped is admitted through passageway 64 into

conduits

66 and 68 in the shaft 12 and from there into a passage 50 in the cam 16. As the cam 16 is fastened to shaft 12 and rotates therewith the passages 50 and 68 are always in registration.

The lower plate 14, which does not rotate, has four holes spaced at about the shaft hole 32 through which a certain amount of the fluid is discharged and returned to the fluid source. In addition, two rectangular holes 34, 36 admit the

torsion springs

24 and 26 respectively.

The driver 16,

cam followers

18 and 20 and ring 22 are assembled, together with the

torsion springs

24 and 26, as shown in FIG. 2. The torsion springs serve to maintain light contact pressure by the cam followers against the periphery of the cam. The cam followers are positioned within the circularly shaped pockets 38 and 40 in the ring22, and are permitted to oscillate therein. The cam 16 consists of a flat piece of suitable material, the periphery of which is comprised of two

semicircles

42 and 44 of different diameter with

short transition portions

46 and 48 between them. The fuel inlet passage 50, at approximately one-half the height of the cam, connects the shaft passageway 68 to the cam transition surface 48. A fuel discharge passageway, on the opposite side of the cam, includes a horizontal portion 52 which intersects a vertical outlet portion 54 which has an outlet port at each axial end of the pumping disk. These outlet ports are driven along a circular path so that the outlet portion 54 and the latter is alternately in registration with a set of discharge apertures in the form of holes 30 in the lower plate 14 and with a set of discharge apertures in the form of holes 56 in the upper plate 28. Each aperture in plate 14 is circumferentially offset from the apertures in plates 28 and the two sets of apertures are disposed along the cir cular path through which the outlet portion 54 is rotated.

Thus, the fuel inlet passageway 50 is connected to a space which increases in volume as the cam rotates clockwise and the

passageways

52 and 54 are connected to a space which decreases in volume as the cam rotates. The vertical passageway 54 is in registration with either the holes 30 or the holes 56 and preferably it is never blocked in order to prevent an undue buildup of internal pressure. This action divides the flow of fluid equally between holes 30 and56. Holes 30 are connected to a return passage 58 (FIG. 1) through which the fluid may be returned to the tank. Preferably, the

followers

18 and 20 are positioned so that they are required to move only during that time when passageway 54 is in registration with one of the holes 30, at which point the internal pressure in the pump is very low.

The

cam followers

18 and 20 are of the type which eliminate some of the production and operational difficulties commonly encountered with rotary pumps having fiat sliding vanes. The large contact area of the rotational or

oscillation cam followers

18 and 20 with the pockets 38 and 40 creates a varying surface designed to withstand the highest pressure. They are cylindrical in shape having a portion 60 cut out of their periphery. This portion is preferably an arc and should be shaped so as not to unbalance the operation of the cams due to hydraulic and dynamic forces. If more effective sealing should be required the design of the surface 60 could be modified so that more efficient sealing within the cavities 38 and 40 is provided. The slots 62 are provided in the

cam followers

18 and 20 to permit entry of the torsion springs 24, 26 therein. Preferably these cam followers are manufactured from a somewhat elastic material such as teflon.

The metering portion is positioned above the pump portion and consists of a rotor 70 which is connected to the shaft 12 so that it rotates at the same rate as the cam 42. Rotor 70 is positioned Within ring 71 which is provided merely to effect a liquid seal and to prevent leakage of any fluid which might seep between the rotor 70 and the plates above or below it. The rotor 70 includes a slot 72 having a pair of parallel sides through which the flow of the pumped fluid passes for metering purposes. The rotor has an upright tubular portion 74 having a helical slot 76 therein which is adapted to coact with a pin 78 which also rides in the slot 80 in shaft 12. By means of these elements the angular position of the slot 72 with respect to the cam may be regulated in accordance with a desired parameter such as manifold pressure. As shown in FIG. 1 a diaphragm 82 is positioned between the upper housing member 84 and the intermediate housing member 86. The chamber 88 formed between the cut out portion of the housing 84 and the diaphragm 82 is connected to the manifold by the means of passageway 90. An adjusting means consisting of a collar 92 which fits over the end of the shaft 12 and whose lower end acts against the pin 78 includes a bearing 94 positioned at its upper end and a support member 96 which is secured to the diaphragm 82. A spring 98 and adjusting means 100 are provided such that the initial relationship of the slot 72 with respect to the cam 16 may be varied. In operation, an increase in the manifold pressure forces the diaphragm downwardly and drives the sleeve 92 down carrying the pin 78 with it and forcing rotation of the rotor 70 through the coaction of the pin 78 with helical slot 76. Thus an increase in pressure will cause the rotor 70 to turn relative to the cam 16 in a clockwise direction as viewed from the top and a decrease in pressure will cause the rotor to turn in a counterclockwise direction.

When used in a fuel injection system a decrease in manifold vacuum, which indicates a necessity for increased fuel supply, causes the pin 78 to be driven downwardly thus rotating the rotor 70 clockwise.

The critical positioning is that of slot 72 with the passageway 54. When passageway 54, one of holes 56 and slot 72 are in registration fuel will be transmitted to the upper portion of the apparatus. The position varying apparatus determines whether slot 72 is to be in registration with a series of metering apertures in the form of an outer ring of holes 102 in the metering plate 104 or with a second series of metering apertures in the form of an inner ring of holes 106. The holes 102 are connected to passageways 108 and the holes 106- are con nected to passageways 110. Holes 102 are connected to the actual injection outlets of the device through passageways 108 and holes 106 are connected to the fluid source through passageway 110. The distance 112 between the corresponding holes 102 and 106 in the plate 104 is equal to or slightly less than the width of slot 72 such that a pressure buildup of undue magnitude is prevented. When rotor 70 is fully advanced relative to cam 16, the slot 72 will not be in registration with any hole 102 when it is in registration with hole 56 but rather will be continuously in registration with holes 106 such that all the fluid will be returned to the tank and no fluid will be introduced into the injection passageways 110. If, on the other hand, the rotor 70 is fully retarded the slot 72 will be in registration with a hole 102 throughout the entire pumping cycle (when it is in registration with a hole 56) and the maximum amount of fluid will be transmitted. Intermediate settings, infinitely variable, will divide the flow of fluid between the

passageway

108 and 110.

Preferably, when this apparatus as used in a fuel injection system, the shaft 12 should be driven at one half the crank speed and synchronized with the motor to insure delivery of the fuel at the proper time. Very efficient internal cooling of this injector is insured because of the relatively large amount of fuel constantly passing through it, the greater part of which is normally returned to the tank. Other contemplated modifications include the utilization of additional cam followers. For example, the use of four cam followers and a cam having surfaces separated at intervals would improve the hearing loading as the pumping forces would be diagonally counterbalanced and could be suitably used in many hydraulic pumping applications. Where it is desirable to inject fuel into an odd number of cylinders for example, it would be desirable to utilize an additional cam follower and an appropriately designed cam to supply fuel to one or more cylinders at the proper times.

A modified version is illustrated in FIGS. 5-8. The FIGS. 5-8 show essentially the same parts in the same relationship as did FIGS. l-4 for the preferred embodiment. In order to simplify a reference to the modifications, substantially unmodified components have been identified with the same reference numeral as used in the preferred description of the preferred embodiment but with the addition of a prime, as, for example, the diaphragm in the modified version is identified as 82.

In the fuel injection apparatus shown in FIGS. 5-8 there is a pumping device and a metering device mounted within the housing 10'. A wall of the pump cavity is defined by the interior wall of a casing member 22 which is formed in the shape of a ring. This ring is mounted within the apparatus housing A rotatable shaft 12' extends through the housing and through the pump cavity. Mounted on the shaft for rotation therewith is a pump disk 130 and a metering rotor 70'. Positioned below the pump disk in the assembly is a plate 14' which includes two discharge apertures 30 and positioned above the pump disk is a plate 28 which includes two other discharge apertures 56'. The apertures 56' are offset from apertures 30 so that the two sets of apertures are adjacent each other in plan view but no portion of either overlies another. Thus the pump cavity is defined by the two plates 14' and 23 which form the upper and lower walls of the cavity and by the interior wall of the casing ring 22 which is formed to provide two

cam surfaces

120 and 122. Fuel may be injected into the cavity through line 132 and channel 114.

Cooperating with the pump disk 130 are two cam followers 18', 20' which are biased by springs 128 such that a surface of each rides against the casing ring wall. Each cam follower includes a vertical outlet passageway 118 and a horizontal connecting passageway 134 which provides communication between the pump cavity and the passageway 118. The cam follower 18', 20' are of the oscillation type, being generally cylindrical in shape with a portion cut away from their peripheries to form a distinct surface adapted to ride against the cooperating casing ring wall. The outlet passageway 118 is disposed at the center of the cylinder parallel to axis of rotation of the driving shaft 12 and the connecting passageway 134 is positioned approximately equidistant from the upper and lower surfaces of the follower. Each follower is positioned within an aperture in the pump disk which is somewhat more extensive than semicircular in configuration so that the follower is securely held therein relative to the pump disk. The cavity defining elements, the ring 22', the disk 130, the plates 14, 28' and the followers 18, 20' thus cooperate to define two spaces each having a volume which varies cyclically as the disk is rotated by the shaft 12'.

'When the pump disk 130 is rotated, fluid is pumped from the cavity through the passageways associated with the cam follower which is riding against cam surface 122, alternately to

apertures

30 and 56. There is no pressure build up within the cavity as the passageway 118 is of suflicient diameter to bridge the gap between an aperture 30' and an aperture 56'. Thus during a transition between pumping to the upper and lower apertures the passageway 118 is in communication with both apertures.

Mounted above the plate 28 is a ring 71' and positioned within that ring is the metering rotor 70. The metering rotor 70 has passageways 72, 73 which are aligned with the passageways 118 in the cam followers. The angular position of the rotor apertures 72, 73 with respect to the pump passageways 118 is adjustable and is responsive to changes in pressure in the same manner as in the embodiment shown in FIGS. 1-4. The rotor has a tubular extension 74 which has a helical slot 76' in it. The slot is adapted to cooperate with a pin 78' carried within a vertical slot in the upper end of shaft 12'. A pressure responsive diaphragm 82' positioned in the housing above the shaft 12' has an extension 92 which acts on the pin 78 to cause vertical motion thereof, thereby shifting the metering rotor 70', with respect to the pump disk 130. This angular movement adjusts the position of the metering passageways 72, 73 with respect to the cam follower passageways 118.

Mounted above the metering rotor is a discharge plate 104' which has two groups of

metering discharge apertures

102, 103, 106 and 107.

The principal difference between the two embodiments is that in the second embodiment (FIGS. 5-8) the relationship of the cam elements in the pump have been reversed. That is, a cam surface consisting of surfaces and 122, is machined into the ring 22'. The

cam followers

18 and 20 are of the same type as in the preferred embodiment, i.e. they are of the oscillation type and consist of a cylinder, a portion of which is cut away. The cam followers are biased against the cam surfaces 120 and 122 by means of springs 124 which are inserted between suitable recesses 126 in the cam follower and corresponding recesses 128 in the driving member 130 which is secured by suitable means to the driving shaft 12'. The liquid to be pumped is admitted through the passageway 132 which extend-s through the casing 10' and the wall of the cam ring 22' and provides communication by means of an orifice 114 in the transition portion between cam surfaces 120 and 122. The operation of the pump may be best understood with reference to FIG. 6. The cam followers are rotated in a clockwise direction and fluid is admitted throu gh conduit 132 through the space between the driver member 130 and the cam wall 122. The fluid is forced into a passageway 134 in the cam follower and discharged from the passageway either through the apertures 30' which are connected to the return pass to the fuel tank or through the apertures 56' which provide communication with the metering apparatus. As the driver 130 rotates, a passageway 134 is first in communication with a discharge aperture 30 then in communication with a metering aperture 56', again in communication with a discharge aperture 30 and finally in communication with a metering aperture 56. When the communication with the last metering aperture 56' ends, the pumping process with that cam follower ceases and the pumping process associated with the second cam follower commences. Obviously the relative dimensions of the apertures 30' and 56- may be varied as desired depending on the amount of fluid which it is desired to transmit in contrast with the amount which it is desired to return to the fluid source.

The metering apparatus operates on similar principles to that described with the preferred embodiment. The orifices 102' and 106' function in a similar manner to the corresponding orifices in the preferred embodiment. A preferred arrangement is as shown in FIG. 8. Slot 72 is aligned with the inner ring of holes 102 and 106' and the other slot 73 is aligned with the outer ring of

holes

103 and 107. Thus fluid may be discharged into four distinct passageways during each pumping cycle. One pumping cycle supplies the outer ring and the other supplies the inner ring. Adiustment of the position of the metering apertures 72, 73 with respect to the pump passageways 118 by the pressure responsive mechanism affects the distribution of fluid to the

holes

102', 103, 106' and 107, which are connected through conduits to suitable utilization devices, such as fuel injection nozzles.

The apparatus according to the invention provides automatic compensation for the wear of pump parts. The components are easy to manufacture, as for example, the

plates

14, 28, 70 and 104 may be stampings which are batch ground on both sides to the requisite finish. Assembly of the apparatus is straightforward due to the inherent simplicity of both the pumping and metering sections. The entire apparatus is compact and requires little or no adjustment or other maintenance in operation.

It will be understood that while there have been shown and described herein a preferred embodiment, and a modification thereof the invention is not to be limited thereby or to all details thereof, and departures may be made therefrom within the spirit and scope of the invention as set forth in the following claims.

I claim:

1. Fluid handling apparatus comprising a casing member and a pump disk member rotatably disposed within said casing member and spaced therefrom so that a fluid cavity is defined between said disk member and said casing member,

a plurality of cam followers carried by one of said members and disposed within said cavity,

the other of said members having a plurality of cam surfaces of different radii which are sealingly engaged by said cam followers dividing said cavity into pumping chambers,

means in said casing member to introduce fluid to be pumped into the cavity between said casing member and said pump disk,

a fluid discharge passageway carried by said disk and having a first portion in communication with said cavity and an outlet portion extending through said pump disk member and parallel to the axis of rotation of said pump disk member,

said outlet portion having an outlet port at each axial end of said pump disk member so that said outlet ports are driven along a circular path as said pump disk member is rotated,

a first set of discharge apertures disposed in a flat plate fixed in position relative to said casing member immediately adjacent and above said pump disk member,

a second set of discharge apertures disposed in a flat plate fixed in position relative to said casing member immediately adjacent and below said pump disk member,

each aperture in said first set being circumferentially oifset from apertures in said second set and all of said apertures being located along said circular path so that at least one of said outlet ports is always in communication with at least one of said discharge apertures,

and fluid outlet means in said casing connected to each said discharge aperture on the side opposite said pump disk member to receive fluid pumped from said cavity through said apertures.

2. The apparatus as claimed in claim 1 wherein said cam surfaces are formed in the periphery of said pump disk member and said casing member carries said cam followers.

3. The apparatus as claimed in claim 1 wherein said cam surfaces are formed in said casing member and said pump disk member carries said cam followers.

4. The apparatus as claimed in claim 1 wherein adjacent ones of cam surfaces of different radii are connected by a relatively short transition surface, and

said means to introduce fluid to said cavity includes an orifice communicating with said cavity disposed in said transition surface.

5. Fluid handling apparatus comprising a casing member and a pump disk member rotatably disposed within said casing member and spaced therefrom so that a fluid cavity is defined between said disk member and said casing member,

the other of said members having a cam surface which is sealingly engaged by said cam followers dividing said cavity into pumping chambers,

means in said casing member to introduce fluid to be pumped into the cavity between said casing member and said pump disk member,

a fluid discharge passageway carried by said pump disk member and having a first portion in communi cation with said cavity and an outlet portion extending through said pump disk member and parallel to the axis of rotation of said pump disk member,

said outlet portion having an outlet port at each axial end of said pump disk so that said outlet ports are driven along a circular path as said pump disk member is rotated,

each aperture in said first set being circumferentially offset from apertures in said second set and all of 5 said apertures being located along said circular path so that at least one of said outlet ports is always in communication with at least one of said discharge apertures,

a metering rotor positioned immediately adjacent said first set of discharge apertures and mounted for rotation with said pump disk member,

said metering rotor having a metering passageway extending parallel to the axis of rotation of said pump disk member and substantially aligned at all times with said outlet ports,

means to circumferentially adjust the position of said metering passageway relative to said outlet ports,

two series of metering apertures disposed in a metering plate fixed in position relative to said casing. member immediately adjacent and on the opposite side of said metering rotor from said first set of discharge apertures along a circular path so that said metering passageway successively communicates with apertures in each series,

each series of metering apertures including a metering aperture corresponding to and in relative alignment with each discharge aperture in said first set,

said adjusting means controlling the position of said metering passageway relative to said pump disk outlet port so that paths of communication may be established from the pump disk outlet port through the first set of discharge apertures and said metering passageway to either one or both series of metering apertures,

and separate fluid outlet means in said casing connected to each series of said metering apertures.

6. The apparatus as claimed in claim 5 wherein said cam surface is formed in the periphery of said pump disk member and said casing member carries said cam fol- 40 lowers.

7. The apparatus as claimed in claim 5 wherein said cam surface is formed in said casing member and said pump disk member carries said cam followers.

8. The apparatus as claimed in claim 5 wherein said 45 cam surface includes two surfaces of different radii connected by a transition portion, and

said means to introduce fluid to said cavity includes an orifice disposed in said transition portion and in communication with said cavity.

9. The apparatus as claimed in claim 5 wherein said pump disk member is mounted on a shaft which has an axially extending slot therein,

said metering rotor includes a tubular portion adapted to be positioned over said shaft,

said tubular portion having a helical slot therein,

and said adjusting means includes a pin disposed in both of said slots,

and means to move said pin axially along said shaft to circumferentially adjust the position of said metering passageway relative to the position of said pump disk outlet port.

10. The apparatus as claimed in claim 5 wherein two said fluid discharge passageways are carried by said pump 65 disk member,

said metering rotor has two corresponding metering passageways, each said metering passageway extending parallel to the axis of rotation of said pump disk member and being substantially aligned at all times with an outlet port of the corresponding fluid discharge passageway, said metering passageways being disposed at different radial distances from the axis of rotation of said ietering rotor, and two series of metering apertures corresponding to each metering passageway disposed in said metering plate,

the two series of metering apertures corresponding to one of said metering passageways being disposed along a circular path corresponding to the radial distance of said one passageway from the axis of rotation of the metering rotor,

and the two series of metering apertures corresponding to the other metering passageway being disposed along a circular path corresponding to the radial distance of said other passageway from the axis of rotation of the metering rotor.

References Cited in the file of this patent UNITED STATES PATENTS 1,231,640 OConnor July 3, 1917 1,661,399 Wishart Mar. 6, 1928 10 Hutchison Sept. 4, 1934 Stevenson Ian. 9, 1945 Kendrick Oct. 30, 1945 Kucher Apr. 1, 1947 Lee Nov. 9, 1948 Smith Mar. 31, 1953 Isreeli et a1 Oct. 11, 1955 Dolza et a1 July 15, 1958 Sylvander July 26, 1960 FOREIGN PATENTS Great Britain Feb. 14, 1918 Great Britain Nov. 26, 1940 Great Britain June 3, 1946 France Mar. 12, 1929 France June 6, 1936 France Jan. 3, 1942 Germany June 3, 1954