US2265997A

US2265997A - Pump

Info

Publication number: US2265997A
Application number: US233523A
Authority: US
Inventors: Albert T Bremser
Original assignee: Bendix Aviation Corp
Current assignee: Bendix Aviation Corp
Priority date: 1938-10-06
Filing date: 1938-10-06
Publication date: 1941-12-16
Anticipated expiration: 1958-12-16
Also published as: GB535301A

Description

Dec. 16, 19 41. A. -r. BREMSER PUMP Filed Oct. 6, 1958 0 0 7 4 4 9 z Z 3 5 B2 22 a 3 n o T I O i m m A x w o fiwmfifw 1 62 l fl E R Q N 16386 5; 3.354 $5 Tm a mm 5 m 5 "m m m m W. 7

ATTORNEY,

Patented Dec. 16, 1941 UNITED STATES PATENT OFFICE- 2,265.,997 v PUMP Albert '1. Bremser, Sidney, N. Y., assignor to Bendix Aviation Corporation, South Bend, Ind., a corporation of Delaware Application October 6, 1938, Serial No. 233,523

9 Claims.

This invention relates to pumping means and more particularly to liquid pumping apparatus,

such as fuel injection pumps for use in solid fuel injectioninternal combustion engines.

In the operation of fuel injection pumps here-- of the fuel passages also materially reduces the life of the pump and affects the efliciency of operation thereof. Difficulty has also been experienced in pumps of the character provided by the present invention in obtaining a smooth and consistent suction of fuel from the source of supply, this latter difficulty being caused, in part at least, by'the turbulence of the fuel in the supply passages, particularly in the vicinity of the intake port of the pump, and by the breaking up of the fuel, in turn caused by the wire drawing thereof and by the same striking the walls of the fuel passages at high velocity.

It is-accordingly one of the objects of the present invention to provide novel pumping apparatus wherein the above-mentioned dimculties are obviated.

Another object of the invention is to provide novel means in a fuel injection pump for reducing the turbulenceof the fuel in the vicinity of the intake port thereof at the time of the suction stroke of the pumping plunger.

A further object is to provide a novel fuel injection apparatus which is so constructed as to minimize erosion of the fuel passages and the damaging effects thereof.

A still further object is to provide anovel fuel injection pump wherein proper lubrication of the drawing. It is to be expressly understood, howlatter purpose being had ever, that the drawing is for the purpose of illustration only and is not intended, to define the limits of the invention, reference for this primarily to the appended claims. I l

In the drawing wherein like reference characters refer to like parts throughout the several views,

Fig. 1 is a side elevation, partly in section, of

one form of pump embodying the present invention;

Fig. 2 is an outside elevation view of the pump shown in Fig. 1, as viewed from the right; and, Fig. 3 is a sectional view of the pump. casing, with parts broken away, the section being taken substantially on line 3-.3 of Fig. 1.

- A single embodiment of the invention is illustrated in the drawing, by way of example, in the form of a fuel injection pump assembly having a delivery valve incorporated therein. In the form shown, said pump assembly comprises a tubular casing 5 having laterally projecting ears 6 by means of which the same may be connected to an engine or other support (not shown). Mounted in casing 5 intermediate the ends thereof is a pump cylinder 1, the latter being supported on an internal shoulder 8 in the casing and held against rotarymovement therein by a screw 9 which threadedly engages the casing wall and extends into an axially extending groove [0 in the cylinder wall. A pair of axially spaced ports H and I2 are provided in the walls of cylinder 1 adjacent the upper end thereof, as viewed in the drawing, for directing the flow of fuel to and from the cylinder in a manner to more fully appear hereafter.

Slidably extending. into the lower end of cylinder 1 is a pump plunger or piston l3 which also functions as a slide valve for controlling the flow of fuel through ports H and I2. For

a purpose which will more fully appear from a description of the operation which follows, plunger I3 is provided with an axially extending passage [4 and connecting radial passages I5 which continuously connect the upper end or pressure chamber of cylinder 1 to a, pair of diametrically disposed helical grooves I 6 and I1. Groove l6 cooperates with port l2 and constitutes a, metering or cut-off groove whereas groove ll serves as a lubricating and pressure balancing groove.

Means are provided for angularly adjusting piston I 3 to change the relation 12 and thereby vary the effective pumping stroke of the piston.

In the form shown, said means comprises a sleeve l8 loosely surrounding the lower end of cylinder 1 in an enlarged portion of casing 5. Gear teeth is are formed on the upper end of sleeve l8 for cooperation with a rack 20 slldably mounted in casing 5, the movement of said rack on the upper surface of-an inwardly extending flange on a ring 24. The latter is positioned against a shoulder in casing and held in place by any suitable means, such as a snap ring 25. It will thus be seen that by reciprocating rack 20, angular adjustment of sleeve I8, and hence plunger l3, may be effected without hindering the longitudinal or pumping movement of the latter. i

Means are also provided for reciprocating piston l3 in cylinder 1 without subjecting the former to any lateral force or pressure which would cause unnecessary friction and binding. Said means, in the illustrated embodiment, include a tappet cup 26 slidably positioned in the lower end of easing 5 for engagement with an enlarged head portion 21 at the lower end of piston 3-.

The latter may be moved upwardly by means of a rotating cam (not shown) which engages the closed end of tappet cup 26 in a manner well understood in the art. The return or downward movement of piston I3 is effected by a spring 23 interposed between the flange of ring 24 and a slotted washer 29 which engages the upper shoulder of head 21.

The upper end or pressure chamber of cylinder 1 may be connected by any suitable means to an injection nozzle (not shown) in an internal combustion engine cylinder. The means shown for this purpose comprise an adaptor element 30 constituting a guide and seat for a delivery valve 3|. Adaptor 30 rests upon the upper end of cylinder l and is held in fluid tight engagement therewith by a nipple or sleeve nut 32 which engages internal threads in the upper end of casing 5. A suitable packing washer 33 may be interposed between the inner end of member 32 and an external flange on adaptor 30' to further insure fluid tightness. The upper end of mem ber 32 terminates in a threaded portion 34 having a passage 35 therein whereby a conduit (not shown) leading to a fuel injection nozzle of an engine cylinder may be attached.

Adaptor 30 has a central passage therein through which the flow of fuel from cylinder 1 into member 32 is controlled by delivery valve 3| which has a tapered head portion, and a hollow stem. A seat is provided in the adaptor for the head of said valve and the upper end of the stem thereof is guided by the adaptor. The hollow center of said stem is always in communication through a plurality of radial passages 36 with an enlarged portion of the bore through the adaptor immediately above the valve seat. Valve 3| is normally held in closed position by spring 31 which: is centered by tubular member 38 mounted in nipple 32 and having communication with-Pass ge 35.

In order to minimize erosion and the effects thereof and to insure smooth and consistent suction by pump 1, l3 novel means are provided in casing 5 for directing the flow of fuel to and from cylinder 'Ithrough ports II and |2. Preferably, said means are constituted by an insert or lining 39 of stainless steel or other hard metal, cast or otherwise fixed, in a peripheral groove or recess formed in casing 5. Lining 39 and said casing are provided with registering openings 4| and 42, respectively, which communicate with a source of liquid fuel supply (not shown) through

conduits

43 and 44, said openings being spaced from and preferably diametrically opposite ports II and 2. r

Lining 39 is channehshaped in radial crosssection to provide a fuel passage around cylinder 1 and is provided with a radially extending internal rib 45 which engages the outer wall of cylinder 1 between ports II and I2 to thereby form a pair of

grooves

46 and 41 in said lining, both of which grooves are in communication with fuel'supply opening 4|, 42. In the embodiment shown, rib 45 engages the wall of cylinder 1 throughout substantially half thecircumference thereof and then tapers off as at 48 (Fig. 3) toward opening 4|, 42.

To further insure against erosion adjacent cutoff port |2, a hardened steel screw 49 may be threaded into casing 5 with the pilot tip 50 thereof extending through insert 39 radially outward from said cut-off port I 2. Screw or plug 49 may also be used as a vent plug when the pump is mounted in a horizontal position. A vent plug 5| is provided for this latter purpose when the pump is mountedin upright position. Screw 49 ,may also be replaced by pipe fitting and this fitting connected to an outside conduit so that the fuel which is by-passed through port l2 may be returned to the fuel supply tank without first entering the supply line attached to fitting 44. In that case, internal rib 45 may completely surround cylinder 1 so that grooves 4.6 and 41 may communicate with each other only by way of ports II and I2, passage 4, l5

valve stem and tubular member 38, and then through passage 35 to the injection nozzle. When the desired quantity of fuel has been injected into the engine cylinder, as determined by the angular setting of piston i3, metering groove I6 overlaps cut-off port |2 thereby permitting a free discharge of fuel and relieving the pressure in the pump, whereupon delivery valve 3| is closed by spring 31. The instant that groove l6 moves into overlapping relation with port |2 the fuel in the upper end of cylinder I, passages l4, l5 and grooves l6 and I1, is under tremendous pressure. Accordingly, fuel is discharged through the small initial opening of said port at an extremely high velocity and strikes the walls of easing 5, 39. In pumps heretofore provided, this sudden rush of fuel through the initially small opening has resulted in erosion of the pump casing and a breaking .up or atomization of the fuel as well as a setting up of a turbulence about the intake port and fuel sup- 2,265,997 ply passages which prevents smooth and 'con-- departing from the spirit and scope of the insistent suction by the pump on the down stroke of the pump plunger, thus causing unequal and indeterminate quantities of fuel to be pumped to the engine cylinder.

The provision of the hard metallic insert 39 and hardened steel plug I9, 50 substantially reduces erosion caused by the discharge of high pressure fuel through cut-ofl port l2, and permits the use of light alloys, such as aluminum,

partition 45 in said insert prevents the effect of fuel turbulence and of any broken down fuel on the suction of the pump hereby provided, since the turbulence of fuel in groove 41 does not materially affect the solid fuel supply in groove 46 adjacent intake port H. Accordingly, after plunger l3 reaches the top of its stroke and is moved downwardly by spring 28, metering groove l6 first moves out of registry with port I! so that further movement of the plunger creates a vacuum in cylinder 1'. When the plunger uncovers intake port II the comparatively undisturbed solid fuel, adjacent said port in groove 46 is drawn into cylinder 1 completely filling the space therein so that the pumping of a predetermined charge to the engine cylinder during the next upstroke of the pump piston is insured.

To vary the effective pumping stroke and hence the quantity of fuel pumped to the engine cylinder during each up stroke of plunger l3, rack 20 is moved to the right or left, as viewed in the drawing, to thereby angularlv adjust sleeve l8 and hence plunger l3. It will be clear that angular movement of the latter changes the point in the upward stroke of the piston at. whichwould press the plunger to one side and thereby break down the oil lubricating film on said side, as well as increase the clearance adjacent ports H and and permit leakage of fuel under high pressure back into the supply-line.

There is thus provided a novel fuel pumping apparatus which .is so constructed as to operate efficiently and accurately overa long period of time. Novel means are provided whereby erosion of the fuel supply passages is minimized and the quantity of fuel pumped to the engine cylinder is not affected by turbulence or breaking vention. For a definition of the limits of the invention, reference is had primarily to the ap- ,casing, said cylinder having two axially spaced ports in the wall thereof in communication with said groove at points diametrically opposite said opening, a metallic insert lining the walls of said groove and having an opening in registry with said first-named opening, a radially projecting rib in said insert engaging the outer wall of said cylinder between saidports for a substantial distance circumferentially of said cylinder on both sides of said ports, a hardened metallic plug threaded into said casing and extending through said insert in line with one of said ports, and a reciprocable plunger in said cylinder for controlling the flow of fuel through said ports.

2. In a fuel injection pump for solid fuel injection engines, a casing, a hard metal annular insert in said casing having a pair of circumferentially extending internal grooves therein, and an opening connecting said grooves to a source of fuel supply, a pump cylinder fixed in said casing and having a pair of ports, each of.

which communicates with a different one of said grooves at points circumferentially spaced from a said opening, said grooves having gradually diminishing radial depths from opposed sides of said cylinder towards said opening and terminating at the sides of said opening, and a plunger down of the liquid fuel in the fuel passages. The

novel pump provided may also be readily and inexpensively manufactured and installed.

Although only a single embodiment of the invention has been illustrated and described in detail it is to be expressly understood that the same is not limited thereto; For example, plug 45 may be eliminated, if desired, and groove 41 may be the only one which is provided with hardened metal walls. Other well known types of delivery valves and plunger actuating and adjusting means may also be employed. Various changes may also be made in the design and arrangement of parts illustrated, as will now be 'understood by those skilled in the art, without in said cylinder for controlling the flow of liquid tending internal grooves therein and an opening,

connecting said grooves toa source of fuel supply, a pump cylinder fixed in said casing and having a port communicating with each of said grooves at points diametrically opposite said opening, said grooves having. a gradually diminishing radial depth and merging into a single groove at said opening, anda plunger in said cylinder for controlling the flow of fuel through said ports.

4. In a fuel injection pump for solid fuel in jection engines, a casing having a pair of peripherally extending internal grooves therein and an opening connecting said grooves to a source of fuel supply, a pump cylinder fixed in said casing and having ports connecting the bore of said cylinder with each of said grooves at points circumferentially spaced from said opening, said grooves having a gradually radial depth and merging into a single groove at said opening, and

a plunger in said cylinder for controlling the flow of fuel through said ports.

5. Apparatus of the; class described comprising a unitary metallic casing member having a bore ing a port in communication with each of said last-mentioned grooves.

grooves to a source of fuel supply, a pump cylinder having two axially spaced ports in the wall thereof and mounted in said casing with each of said ports in communication with different ones of said grooves at points circumferentially spaced from said opening, and a reciprocating plunger in said cylinder for controlling the flow of fuel through said ports.

7. In a fuel injection pump for solid fuel injection engines, a hollow casing having a periph eral internal groove intermediate the ends there of, a channel-shaped annular insert of hard metal, such as steel, lining said groove, a pump cylinder in said casing, said cylinder having an inlet port and a discharge port, the latter having communication with said groove, means for connecting said intake port to a source of fuelsupply, and a plunger in said cylinder for controlling the flow of fuel into and outrof said cylinder through said ports;

8. A fuel injection pump for solid fuel injection engines comprisinga cast hollow casing, an annular insert of hard, wear-resisting metal, such as steel, fixedlwithin said'casing, said insert being internally grooved and having a radially extending passage therethrough in registry with an opening in said casing, a pump cylinder mounted in said casing and slidably extending through said insert, said cylinder having a port in the wall thereof in communication with the grooved inner periphery of said insert at a point circumferentially spaced from said passage, and a piston reciprocable in said cylinder for controlling the flow of fuel through said port.

9. A fuel injection pump for solid fuel injection engines comprising a hollow metallic casing, a hard'metallic ring, such as steel, secured within said casing, said ring having a peripherally extending internal groove therein and a radially extending passage in the wall thereof connecting said groove with an opening in said casing, a pump cylinder mounted in said casing and ex-' tending through said ring in close contact therewith, said cylinder having a port in the wall