US2142086A - Fuel pump - Google Patents

Description

Jan'. 3, 1939. C( R. ALBEN 2,142,086

FUEL PUMP Filed Sept. 9, 1933 2 Sheets-Sheet jg a fui-9:5 l 410 Patented Jan. 3, 1939 UNITED STATES FUEL PUMP Carroll R. Alden, Detroit, Mich., assgnorto Ex- Cell-O Corporation, la corporation of Michigan Application September 9, 1933, Serial No. 688,815

9 Claims.

The present invention relates generally to fuel pumps and more particularly to improvements in metering and distributing pumps such as are used to supply fuel to internal combustion engines.

One object 4of the present invention is t'o provide a novel f orm Yof fuel metering and distributling pump which is adapted for eective and efficient operation throughout a Wide range of both capacity and timing adjustment.

Another object is to provide a pump of the type described which may be' readily disassembled and reassembled for purposes of inspection and repair.

A further object resides in the provision of a novel fuel metering and distributing pump which avoidsthe use of spring actuated valves, and which has a novel arrangement of control ports and coacting areas effective to prevent inter-leakage.

Further objects and advantages will become apparent as the description proceeds.

In the accompanying drawings,.Figure 1 is a longitudinal sectional View of a pump embodying the invention, the view being taken mainly along line i-I of Fig. 2 and in fragment along line IL--la of Fig. 2.

Fig. 2 is a transverse sectional view taken along line 2-2 of Fig. l and showing the pump in end elevation.

Fig. 3 is a transverse sectional view. taken along line 3-3 of Fig. 1.

Fig. 4 is a transverse sectional view taken along line 4-4 of Fig. 1.

Fig. 5 is a transverse sectional view taken along line 5--5 of Fig. l.

Fig. 6 is a transverse sectional view taken substantially along broken line 6 6 of Fig. 1.

Figs. '7, 8, and 9 illustrate details of the drive connection for the rotor.

Fig. 10 is a perspective view of one of the ele- ,ments in the pump drive.

While the invention is susceptible of various modications and alternative constructions, I have shown in the drawings andwill herein describe in detail the preferred embodiment, but it is to be understood that I do not thereby intend to limit the'invention to the specific forny disclosed, but intend to cover all modifications and alternative constructions falling within the spirit and scope of the invention as expressed in the appended claims.

Referring more particularly to the drawings, the invention is shown herein as embodied in a fuel metering and distributing pump 2| (Fig. 1)

(Cl. 10S-173) adapted for use in connection with various kinds of internal combustion engines, and particularly suited for multiple cylinder engines. In general, the fuel metering and distributing device or pump 2| receives fuel, such as naphtha or gasoline, from a suitable source and delivers it in metered or measured charges for use in respective engine cylinders. The delivery is timed by the pump in relation to the sequential operation of each engine piston, a charge of fuel being delivered for each cycle of each piston. The capacity of the pump, that is the measured quantity of fuel delivered in'each charge, may be varied by adjustment of the pump as hereinafter described. Both the timing and capacity of the pump may be adjusted by suitable automatic mechanisms (not shown) 'or manually as desired.

In the preferred embodiment of the invention, the fuel metering and distributing device or pump 2| (see Fig. 1) may be driven by an associated engine, and is adjustable in capacity and also in phase relation vto the engine. More particularly, the pump 2| comprises an outer casing which is formed of two end sections 24 and 2B and an intermediate section `25 in end abutting engagement. `The sections have interlocking ends to secure accurate registration, and are suitably held in assembled relation by means of a plurality of tie bolts 2l. One of the sections, namely the section 26, is adapted to be mounted on a suitable support, and to this end is provided with an outer end wall 28 defining a peripheral shoulder 29 which may be secured against a suitable support such as a gear housing on the engine block.

Mounted in the section 24 and abutting at its inner end against an annular shoulder 3| therein is a cylindrical pump body 32. A circular end plate 33 is disposed in the outer end of the section 24 to close the latter, and abuts against the outer end of the body 32. The body 32 and the plate 33 are secured in position by means of a lock ring 34 threaded into the outer end of the section 24 against the plate.

The-pump body 32 isformed with an axial bore 35 opening therethrough, and with a plurality of parallel bores, six bores 36 to 4| in the present instance, constituting pump cylinders arranged in parallel to and uniformity spaced relation about the axial bore. The bores 36 to 4| open at their outer ends to a closed chamber 42 Within the inner end of the casing section 24 and between the intermediate casing section 25 and the pump body 32, and at their inner ends are closed and peripherallyenlarged .to define pressure chambers 43 to 43 respectively. Opening from the periphery of the axial bore 35 in a common transverse plane (see Fig. 3) respectively to the inner ends of the pump chambers 43' to 48 are a plurality of inlet passages or ports 49 to 54. Similarly, a plurality of delivery passages or ports 55 to 60 open in a common transverse plane (see Fig. 4) respectively from the other ends of the pump chambers 43 to 43 to the periphery of the axial bore 35. The inlet and delivery ports for each pump chamber, for example the ports -49 and 55 opening from the chamber 43, preferablyare located in a common longitudinal plane.

Mounted respectively for reciprocation in the cylinders 36 to 4I are a plurality of pump pistons 6i to 66. Each of the pistons is cylindrical in form, and has a reduced axial extension 61 with an enlarged head 68 on its free end projecting into the chamber 42. In operation, the pistons 6| to 66 are reciprocated harmonically in uniformly timed sequence.

A valve member 69, in the form of an elongated and generally cylindrical rotor, extends through and is rotatable'in the axial bore 35 in timed relation to the reciprocation of the pistons 6I to 66. 'I'he rotor 69 is formed with a shallow peripheral groove 13 of substantial width which delines a low pressure fluid area or belt projecting through the transverse plane of the cylinder inlet ports 49 to 54. Fluid from a suitable low pressure source (not shown) is adapted to be supplied to the area 19 through an inlet passage 1I formed in the pump body 32. Preferably, the passage 1i is located in the same plane as the inlet ports 49 to 54, and intermediate two of the ports. A uid supply conduit 12 is connected to the body 32 by means of a hollow screw fitting 13, and communicates with the outer end of the passage 1|.

The rotor 63 is formed with a land area 14 projecting longitudinally into one side of the uid area 19. and adapted for movement successively across the inlet ports 49 to 54 to interrupt communication thereof with the :duid area. '111e phase relationof the revolution of the land area .14 to the reciprocation of the pistons 6I to 66 is such that each inlet port will be closed during a predetermined period of the pressure stroke of the associated piston, and will be in communication with the uid area during the remaining portion of the cycle. Preferably, the foregoing period is timed to occur at or near the middle of the pressure stroke when by reason of the simple harmonic drive the rate of piston area 14 is tapered in width nso that the period of cut-oi! may be varied in duration. Preferably, the land area 14 tapers uniformly toward its .free end. and has a leading edge 14* parallel to the. axis of rotation, .and-a trailing edge l14b inclined thereto. l

A Formed longitudinally in the pumpbody 32 in staggered relation `-to the two sets of ports 49to 54 and 55 to are a plurality -of discharge passages 15 to 39, one for each of the pump cylinders 36 to 4l. These passages are in communication respectively with a plurality of conduits 6| to 66 (see Figs. 1 and 2) attached by means of hollow screw ttings 31 to the end plate 33, and leading to the engine cylinders (not shown). The inlet ends of the passages 15 to 30 terminate in radial ports 36 to 93 which open in a common transverse piane tothe periphery of the axial bore 35, v

cylinders 36 to 4|, no

vided.

and which are staggered in relation to the ports 55 to 6|).

The rotor 69 is formed with means for connecting the cylinder outlet ports 55 to 60 in timed sequence to the respective discharge ports 33 to 93 during cut-oi of the associated cylinder inlet ports 49 to 54. In its preferred form, this means comprises two elongated slots 94 and 95 formed in the periphery of the rotor 69 and extending longitudinally thereof. A passage 96 formed Within the rotor 69 serves to connect the slots 94 and 95.

The slot 94 extends through the plane of the outlet ports 55 to 60 for communication therewith in all axial vpositions of the rotor 69, and has leading and trailing side edges 94a and 94b inclined to the axis of rotation. 'Ihe relation between the land area 1 4 and the slot 94 on one hand to the respective sets of inlet and outlet ports 49 to 54 and 55 to 60 on the other hand is such that the leading edge 94B will move onto any one of the outlet ports just beforelor at the same time the leading edge 14a outs oif the associated inlet port, and that the trailing edges 94b and 14b will leave the respective ports simultaneously. To insure cut-off of the outlet port simultaneously with relief of the inlet port in all axial positions of the rotor 69, the trailing edges 14b and 94b are made parallel. The slot 95 has leading and trailing side edges 95 and 95b parallel to the axis of rotation, and is so related to the discharge ports 86 to 93 and to the land area 14 that the leading edge 95B will move onto any one of the discharge ports at the same time that the leading edge 14* cuts-off the associated cylinder inlet port.

It will be evident that the land area 14 determines the duration of each period of fuel injection, and hence the volume of each fuel charge. Referring for example to cylinder 36, when the inlet port 49 is cut-off from the fluid area 19 by the leading edge 14* of the land area 14, the pump piston 6I, which is moving along its pressure stroke, forces the trapped fuel from ,the pressure chamber 43 through the, outlet port 55, the slot 94, the passage 96, the slot 95, the discharge port 38 and the passage 15 to the conduit 3|. Thus, the start of injection is determined by the leading edge 14, and is constant in relation to the engine cycle. Upon relief of the pressure chamber 43 through the inlet port 49 past the trailing edge 14b to the iiuid area 10, injection ceases. Thus, the end point of injection is determined by the trailing edge 14h, and is variable depending on the axial position of the rotor 59. Simultaneously with the opening of the inlet port 49, the trailing edge 94b of the slot 94 cuts-off the outlet port 55 so that return flow from the discharge passage 15 is prevented. By providing the three port arrangement herein described, narrow land/ areas between different pressure sources are avoided, and hence leakage is effectively eliminated. Since the discharge conduits ill-to` 86 are not connected directly to the pump check valves need be pro.

In some instancesit may be desirable to place the fuel under compression immediately before the start of injection. In this event, the leading edge 94l of the slot 94 is timed to move onto the outlet port 55 a short time-afterthe leading edge 14 'of the land 14 leaves the inlet port 49. Thus, the fuel inthe chamber 43 is trapped for a short time so that the energy stored up therein by movement of the piston 6l will create a pressure surge at the start of injection.

It may also be desirable in some instances to of shoes |29 (see Fig. 10).

short time before cut-olf of injection. In this event, the trailing edge 14b of the land 14 is timed to uncover the inlet port 49 a short time before the trailing edge 951 of the slot 95 leaves the discharge port 88.

It will be evident that the rotor 69 constitutes a fuel throttle which is adjustable axially to vary the capacity of the pump 2|. To facilitate such adjustment, a bore 91 in axial alignment with the bore 35 and adapted to receive the outer end of the rotor 69 is formed in and opens through the end plate 33. The outer end of the bore 91`is closed by means of a cap screw 98. The outer end of the rotor 69 has a reduced axial extension 99 with an enlarged head |00 on its free end. Ro-

tatably embracing the extension 99 between the body of the rotor 69 andthe head |00 is a split sleeve |0| formed in the periphery with a socket or recess |02. A ball |03 on the end of a pin |04 engages in the recess |02. The pin |04 is secured eccentrically to the inner end of a transverse shaft |05 journaled in a-bore |06 opening from the bore 91 radially through the plate 33 and the casing section 24. A spline pin |01 threaded into the outer end of the plate 33 engages in a peripheral groove |08 formed inthe shaft |05 to hold the latter in axial position.`

Fixed on the outer end of the shaft |05 is a crank arm |09 which affords means whereby the rotor 4 .peripheral flange ||3 on its inner end embracing the extension 61 and abutting against the inner side of the head 68; A like constructionis provided for each of the other pistons.

The pistons 6| to .66 are moved positively through their working strokes against the action of the springs ||0. The means for this purpose comprises a plurality of plungers ||4 to ||9 respectively aligned axially with the pistons 6| to 66, and abutting against the heads 68 within the retainers ||2. The plungers extend reciprocably through a plurality of spaced parallel bores |20 to |25 which are formed in the intermediate casing section 25 and open therethrough from the chamber 42 to a chamber |26 dened by the casing section 26. It will'be evident that the plungers ||4 to` ||9 in effect constitute continuations of the pistons 6| to 66, but by reason of their separation from the pistons require less accuracy in construction than do the latter for eiiicient operation.

- To provide means for driving the'plungers I4 to ||9 in uniformly timed sequence and preferably harmonically, the outer ends in the chamber |26 are provided respectively with semispherical heads |21 in bearing engagement with complementary sockets |28 formed in a plurality These shoes |29 are loosely retained, as by means of removable snap rings |2911, in a plurality of sockets |30a formed iny one side of an annular follower plate |30. Preferably, the shoes |29 and the sockets |30a are circular in form, and of suiciently different diameters to permit independent movement of the shoes relatively to the plate |30 as necessitated by changing angularity of the latter. It

will be evident that the follower plate |30 is restrained against rotation by the heads |21 and theshoes |29. The other side of the follower plate |30 bears slidably against an inclined end face |33 on a rotary drive member or wobble plate |34. A drive shaft |42 extends through and is fixed in an axial bore |40 in the woble plate |34, and serves to rotate the latter. Preferably, an end bearing plate |35 is interposed between rthe end wall 20 and the wobble plate The inner end of the drive shaft |42 extends through the follower platev |30, and is formed with a spherical enlargement |3| which engages with a complementary surface |30b in the latter to locate same in a central position. The outer end of the shaft |42 isjournaled in a bushing |4| fixed in the end wall 28 of the housing section 26, and visv adapted to be connected by means (not shown) to the engine crank shaft. It will be evident that as the wobble plate |34 is rotated, a wobble motion will be imparted to the follower plate |30 to drive the pistons 6| to 66 harmonically in uniformly timed and overlapping sequence.

The rotor 69 may be driven by any suitable means, and is herein shown as connected to the drive shaft 42. Thus, the inner end of the rotor 69 is connected by a driver |43 (Fig. '7), for joint rotary motion and independent axial adjustment, to an intermediate shaft |44 slidably and rotatably mounted in an axial bore |45 having different diameters along its length, and opening through the intermediate casing section 25. The inner end of the drive shaft |42 extends fromA the follower plate |30 into the adjacent end of the bore |45, and is formed with axial bore |41 slidably receiving the adjacent end of the shaft |44. A pin |48 and slot |49 serve to connect the shafts |42 and |44.

The inner end of the rotor 69 is formed with an axial bore 69a intersected by a transverse bore' 69h, and with two diametrically spaced longitudinal slots 69c in the side walls of the bore 69a. A cylindrical plug |4|a (see/Fig. 9) is inserted inthe bore69b, and is formed with a longitudinal diametrical slot |4|b in one'end portion. An elongated pin |42a extends at one end axially into the bore 69a and is formed with a peripheral groove |42b loosely engaged with the sides ofthe slot |4I". Thus, the pin |422l has a loose connection through the medium of the plug |4|a with the rotor 69. At the other end, the pin |42a extends into an axial bore |44a in the adjacent end of the intermediate shaft |44, and is formed therein with a peripheral flange or shoulder |426. The driver |43 is axially disposed on the pin |425, and at one end has two parallel spline keys |43a disposed in the slots 69c and engaging at their ends against the plug |4|a. On the other end, the driver |43 has two parallel spline keys |43h which extend slidably in longitudinal slots |44b in the shaft |44 and which 'abut against the shoulder |42. Hence, the pin |42a serves to hold the driver in assembled relation with the rotor 69 for axial sliding spline connection with the shaft |44.

The slot |49 is inclined longitudinally to the axis of rotation so that axial adjustment of the shaft |44 will effect adjustment of the angular phase relation between the rotor 69 and the pistons 6| to 66. To provide means for adjusting the shaft I, it is formed with a peripheral groove |50. A split sleeve is rotatably secured in the groove |50, and has a socket or recess |52 in its periphery. A ball |53 on the end of a pin |54 bears in the recess |52. The pin |54 is secured eccentrically to the inner end of an adjusting shaft |55 which is journaled in and extends outwardly through a bore |56 in the casing section 25, and which is keyed in axial position. A crank arm |51 secured to 'the outer end of the shaft |55 affords means for angularly adjusting the shaft |55.

From the foregoing it will be apparent that the pump 2| is adapted to perform both timing and metering functions. As to its timing function, the phase of the pistons lil-66 can be adjusted with respect to the phase of the engine crank shaft, and hence the phase of the engine pistons, by shifting the adjustment lever |51. Similarly, the capacity of the pump, or in other words the quantity of fuelv in each metered charge delivered, can be adjusted through the.

medium of the lever |09 as heretofore described.

I claim as nur invention: 1. A pump comprising, in combination, a pump body formed 'with a pump cylinder, a fluid sup- Aply, an inlet and a spaced outlet opening vrespectively to and from said cylinder, and a discharge passage, a piston reciprocable in said cylinder, and means including a valve member driven in timed relation to sai'd piston for interrupting communication between said supply and said inlet and for simultaneously connecting said outlet to said discharge passage for a selectedvvariable portion of each pressure stroke of said piston, said valve member being adjustable to vary the duration'of said portion.

2. A pump comprising, in combination, a plurality of pump cylinders, a plurality of pistons mounted respectively for reciprocation in said cylinders, means for driving said pistons in timed sequence, a plurality of separate discharge passages onefor each cylinder and piston unit, each cylinder havingan inlet port and a delivery port, and a single rotary valve member driven in timed relation to said pistons, said valve member having a coacting axially tapered land and a recess portion operable for each cylinder to close the associated inlet port and to connect the associated delivery port to the associated discharge passage for a predetermined period during'the pressure stroke of the 4associated piston, said member being axially adjustable to vary the duration of said period.

3. A pump comprising, in combination', a pump body, said body being formed with acylinder closed at one end, and with a bore parallel tosaid cylinder, the closedl end of said cylinder being peripherally enlarged to denne a pressure chamber, said body being formed with 'an inlet port opening from said bore to the inner end of said chamber, with a delivery port in the saine axial plane as said inlet port and opening from the other end of said chamber to said bore, and with a discharge port opening fromsaid bore,- a piston reciprocable in said'cylinder and having a pressure stroke and a return stroke, means for driving saidpiston with a simple harmonic motion, a cylindrical valve member mounted for rotation and axial adjustment in said bore, me n; for adjusting said member axially, .and ve means for ,rotating said member continuously in one direction-at a constant speed in timedre- .lation to said piston, said valve member having a low pressure peripheral fluid 'area normally open to said inlet port, a raised longitudinal land area on said member projecting into one side of said fluid area for movement across said inlet port to interrupt communication thereof with said uid area over a predeterminedportion of each pressure stroke of said piston, said land area having a leading edge parallel to the axis of rotation and a trailing edge inclined thereto, said rotor having two vlongitudinally spaced elongated first and second slots movable respectively across said delivery and discharge ports, and a passage in said rotor connecting said slots, said rst slot having an inclined trail'- ing edge parallel to said first mentioned trailing edge and timed to leave said delivery port at the same time that said first mentioned trailing edge moves onto said inlet port, said second slot having a leading edge parallel to the axis of rotation and timed to move onto said discharge port at the same time that said first mentioned leading edge leaves said inlet port.

4. A pump comprising, in combination, a plurality of parallel annularly spaced cylinders, a plurality of pistons one reciprocable in each cylinder, spring means tending to urge said pistons4 outwardly, a rotary drive member having an inclined end face, a drive shaft connected to said member, a disk bearing at one side on said face,

said disk being formed in the other side with a plurality of annularly spaced individual circular sockets, a plurality of circular shoes freely disposed respectivelyA in said sockets, said shoes being formed respectively with a plurality of recesses in bearing engagement respectively with the outer ends of said pistons, and removable snap rings retaining said shoes .in place in said,

sockets.

5. A pump comprising, in combination, a pump body, saidbody being formed with a cylinder closed at one end, and with a bore parallel to said cylinder, said body being formed with an inlet port opening from said bore to the inner end oi' said cylinder, with a delivery port opening from the'other end of said cylinder to said bore, and with a discharge port opening from said bore, a piston reciprocable in said cylinder and having a pressure stroke and a return stroke, means for driving said piston, a cylindrical valve member mounted for rotation in said bore, and

' having first and second slots movable'respectively across said delivery and discharge ports, and a passage connecting saidslots, said slots being timed to be Vin communication respectively with said delivery-and discharge ports at the same time that the inlet port is closed by said land 6. A pump comprising, in combination, a pump body, said body being formed with a cylinder closed at one end, and with a bore parallel to said cylinder, said body being formed with an inlet port opening from said bore to the closed end o! said cylinder, with a delivery port opening' from said cylinder to said bore and spaced longitudinally from said inlet port, and with a discharge port openingfrom said bore, a piston reciprocable in said cylinder and having a pressure stroke ousiy in one direction in timed relation to said piston, said valve member having a low pressure peripheral fluid area `normally open to said inlet port, a raised longitudinal land area on said member projecting into one side of said fluid area for movement across said inlet port to interrupt communication thereof with said fluid area over a predetermined portion of each pressure stroke of said piston, said land area being variable in width and having a leading edge and a trailing edge,said rotor having two longitudinally spaced elongated rst and second slots movable respectively across said delivery and discharge ports, and a passage in said rotor connecting said slots, said slots being arranged for simultaneous communication respectively with said delivery and discharge ports to establish a flow connection therebetween for a period of said predetermined portion of said pressure stroke, and having relatively inclined controlling edges for varying the duration of said period in accordance with variable cut-off of said inlet port by said land area upon axial adjustment of said valve member.

7. A pump comprising, in combination, a plurality of parallel annularly spaced cylinders, a plurality of pistons one reciprocable in each cylinder, means including a rotary drive shaft for reciprocating said pistons in timed sequence, an intermediate shaft telescoping at one end' axially with said drive shaft and having a pin and inclined slot connection therewith to effect relative `rotation therebetween upon relative axial move- Ament, a collar peripherally splined to said intermediate shaft and formed in one side with a socket, arock shaft extending transversely of said intermediate shaft and having a crank pin eccentrically mounted on one end and in engagement in said socket, a rotary valve member for controlling the inlet and discharge of fluid to and from said cylinders, and an axial spline drive connection between said intermediate shaft and said valve member.

8. A pump comprising, in combination, a plurality of parallel annularly spaced cylinders, a plurality of pistons one reciprocableiin each cylinder, means including a rotary drive shaft for reciprocating said pistons in timed sequence, an intermediate shaft having a generally longitudinal pin and inclined slot spline connection with.

said drive shaft for rotation with respect thereto upon axial adjustment thereof and formed in one end with longitudinal keyways and an axial bore, a rotary valve member for controlling the supply and discharge of fluid to and from said cylindersand formed in one end with an axial bore in alignmentwith said rst mentioned bore, a transverse bore and longitudinal spline keyways, an elongated pin extending axially into said aligned bores'and provided in said first mentiond bore with a peripheral shoulder, a plug jin said transverse bore for securing said pin to said valve member, a driver disposed on said pin and having spline keys on one end engaging in said first mentioned keyways and abutting against said shoulder and having spline keys on the other end engaging in said last mentioned keyways and abutting against said plug, and means for adjusting said intermediate shaft axially.

9. A pump comprising, in combination, means providing a pump cylinder, a. fluid supply, an

inlet and a spaced outlet opening respectively tov and from said cylinder, and a spaced bore having a -discharge'passage, a piston reciprocable in said cylinder, driving means for said piston, a

valve member in said bore including a driving connection with said driving-means permitting relative adjustment-of said member and beingL eective to actuate the latter in timed relation to said piston, said valve member being operable during a predetermined portion of Yeach pressure stroke of said piston simultaneously to interrupt communication between said supply and said `inlet and to connect said outlet to said discharge passage, and meansl for adjusting said valve member to vary the duration of said portion.

vcARRoLL R. ALDEN.

Images