US2128140A - Injection fuel pump - Google Patents

Description

.Aug. 23, 1938. D. a. GREEN INJECTION FUEL PUMP Filed June 26, 1936 Dmm B. GrEE/f.

INVENTOK ATTORNEY.

103. PUMPS Patented Aug. 23, 1938 UNITED STATES Search Room PATENT OFFICE INJECTION FUEL PUMP Dana B. Green, Ithaca, N. Y.

Application June 26,

3 Claims.

This invention relates to a high pressure, constant stroke fuel pump of the so-called solid or direct injection type for serving a power cylinder of a semi-Diesel internal combustion engine or the like purposes, and more particularly pertains to a high pressure fuel oil pump provided with a latchable resilient plunger drive which after having energy stored therein after being unlatched, serves to impart a quick acting stroke to the plunger at the time of fuel injection so as to maintain a rapid discharge velocity through the fuel injection nozzle at all running speeds.

The present devices are especially suited for moderate speed stationary or portable engines and essentially comprise a reciprocative drive gear and an actuated floatingly mounted pump plunger having an elastic impulsion agency interposed therebetween. The fact that the rate of nozzle discharge is not fixed by the slow movement of such actuating gear in the manner of a rigid drive, allows my plunger to operate effectively at slow-starting speeds without impairing the atomization of the injected fuel oil.

The fuel delivery may herein be controlled by bodily shifting a ported pump block assembly toward or away from the operative end of a single acting plunger. Such block port is alterably overrun under the influence of regulating means so as to variably by-pass in accordance with requirements, all remaining fuel trapped in the pump body subsequent to port closure being sent forth into the combustion chamber. A distinctive feature resides in the use of a latching device adapted to retain my resilient plunger drive in a charged condition until released by timed trip gear means by the use of reciprocative crosshead means located intermediate the plunger and said impulsion spring and all of which accessories are operatively assembled about a stationary sleeve member as a self-contained fuel injector.

The object of the present invention is to devise a relatively simple and inherently effective fuel pump of the character indicated that can be marketed in differently sized standardized units for use as new equipment or as a substitute accessory adapted to replace conventional carburetors installed on existing gasolene engines and thereby convert the same for the eilicient burning of atomized fuel oil with or without electric ignition means. Embodied herein are also certain structural aspects designed to facilitate the cited conversion and to otherwise promote the end in view, all of which features will hereinafter be more explicitly set forth.

Reference is bad to the accompanying one sheet 1936, Serial No. 87,431

of drawings which are illustrative of a certain preferred embodiment of my fuel pump, and in which drawing:

Fig. 1 presents an elevational side view of my pump assembly taken in partial section and Fig. 2 a similar front view thereof, the structure being substantially symmetrical about their respective vertical center lines.

Fig. 3 schematically shows a cam actuated gear for timing my plunger release.

Referring now in detail to the drawing, my pump comprises a single acting plunger 10 preferably provided with an enlarged drag shoulder l I at one end thereof. The other or operative plunger end is lap fitted to reciprocate within the bore of the cylinder block or tool steel barrel I2 without need of a stufling box. Said barrel is shiftable axially and intermediate its ends provided with one or more fuel intake ports 13 directed radially inward as shown in Fig. 1. A recessed jacket I4 may be press fitted around the barrel to provide for an annular oil feed chamber l5 that interconnects with said ports. A laterally resilient supply pipe 16 furnishes fuel oil to said chamber, this pipe being preferably coiled to permit a limited movement on part of the shiftable cylinder block.

The plunger and barrel are concentrically mounted within a. stationary sleeve member ll of which one end may be internally threaded at [8 and is thereby fixedly secured to a supporting bracket such as I9 by the use of the tubular bolt 20. As will be understood, said bracket is-intended to be attached to some suitable engine part and preferably carries the plunger in an upright position. The threaded extremity of such a sleeve will for identification be referred to as the lower end thereof, although my .pump need not necessarily be placed vertically.

An apertured crosshead 2| encircles the shouldered region of my plunger and is provided with oppositely overhanging wrist pins such as 22, the sleeve Il having a pair of longitudinal slots such as 23 cut therein through which the wrist pins respectively extend. Depending from and interconnecting said outstanding pins is a stirruplike link or connecting rod 24 of which the cross bar is intended to be operatively connected to a rocker arm or the like drive means adapted to reciprocate the crosshead in synchronism with the engine speed. To this end, a spacer pin 10 may cross-connect the pair of rods 24 and be reciprocated by the rotatable disc shaft "II, which in turn is intended to run in unison with the engine crankshaft. As schematically indicated, the disc of such shaft may be provided with a socketed crank pin 12 arranged to actuate an overhanging extension of the pin 10. If desired, a group of such pumps may be similarly actuated in shifted phase relationship.

The crosshead 2| rests upon a circular flange 25 of the plunger extension 28 and may have a fiber or other anti-knock washer interposed therebetween. The upper end of said extension is threaded for the reception of the plunger nut 21 which couples the plunger drag shoulder H in axial alignment with the extension 25. A tubular guide 28 carries the depending shank of said extension and the flared rim of this guide may be adjustably screwed and supported in the sleeve thread IS. A helical spring or the like resilient agency 29 thrusts between the flange 25 and. said guide rim, the loading capacity and allowable deflection of the spring being made commensurate with the diametral plunger size and maximum unit pressure to be borne thereon.

Referring further to the control means whereby the pump barrel l2 may be shifted axially within the sleeve I! for controlling the fuel delivery, these may comprise a regulating wedge piece 3| transversely disposed through a pair of opposed openings such as 32 that are respectively cut through the side wall of said sleeve. The lower horizontal face of this slidably mounted wedge is kept at right angles with respect to the plunger axis and in alignment with the adjacent upper face of the nut 35, while the respective top edges of said openings are inclinedly cut at different levels to serveas wedge stop edges.

Said wedge straddles a tubular delivery section 33 aligning with the plunger axis. Said section has a counterbored retaining flange 34 at one end thereof which is secured in place by the gasket nut 35, said nut being arranged to screw into bored threads formed in the jacket l4, as shown. When drawn into place, this nut seals the ring gasket 36'. The upper end of the cylinder bore is provided with a ground beveled seat which is closed by the spring loaded discharge valve 31 delivering outwardly through the section 33. A depressible or the like vertically yieldable discharge tube 38 leads to the atomizer nozzle that sprays fuel oil into the combustion chamber (not shown).

A demountable .collar 39 rests upon the upper end of said sleeve I1 and has a compression spring 40 disposed to thrust downwardly upon the collar and upwardly against the locked check nuts 4| carried on the delivery section 33. This compression spring serves to automatically lift the slidable pump barrel together With its appurtenances and thereby yieldably retains the inclined face of said wedge against the sloping upper stop edges of the sleeve openings 32 so as to prevent the barrel from being drawn downwardly during each plunger suction stroke. Said wedge is intended to be regulatably shifted lengthwise between its full-lined and dotted positions through a stroke marked S by a suitable governor, the contracted end of said wedge being forked to freely clear said delivery section. When the regulating wedge 3| is thrust inwardly into its fulllined position, this will correspondingly shift the barrel l2 and its intake port l3 into a lowermost or full load position. Should the wedge be withdrawn into its dotted position, the pump barrel and all its accessories will be raised into its up permost or light load position under the influence of the spring 40.

Attention is now directed to the storing of energy within my spring agency 29 and the releasable tripping thereof. For this purpose, I preferably provide for one or more upturned keeper fingers or trip levers such as 43 of which an end may be exteriorly pivoted at 44 to the lower portion of the sleeve l'l. Intermediate the respective trip lever ends, there is provided a latch lug 45 which extends through said sleeve into overlapping engagement with the circular flange 25, as shown. Said lug and the flange perimeter are cooperatively beveled so as to thrust each lever I outwardly against tension of the retaining spring 46 to allow the descending flange to pass into latched engagement when the lowermost plunger position is reached. A stop pin 41 limits the inward movement of such lever.

Each swinging finger end presses inwardly against a circular cam or beveled trip face 48 carried by a slidable tubular pilot 43 that may telescopically embrace the sleeve II. The upper end of said pilot may be loosely surrounded by an annular hub 50 having opposed trunnions that pivotally connect with the pilot 49. An intermediate region of said hub is shown linked at 52 to the upper portion of the sleeve I! while the opposed swingable hub region may be shiftably actuated about the pintle 53. In Fig. 1, the hub lies in its horizontal or mid swing position.

As schematically shown in Fig. 3, the tie rod 54 may be interconnected to the free end of a fulcrumed timing lever 55 having a roller 55 thereon. A knockoff cam 51 may be carried by the rotatable engine shaft 58 and this cam serves to periodically depress the upwardly inclined end of the hub 50 against thrust of the lever return spring 59 in a definite relationship to the plunger movements so as to constitute a timing gear. By adjustably shifting the lever 55 lengthwise into a different fulcrum position by the grip 50 or the like, the timed release of the latch 45 may be a1- tered at will without engine shut down.

As regards the operation of my fuel pump, this may be traced as follows: Assuming the connecting rods 24 to have drawn the plunger into its full-lined lowermost position of Fig. l to allow the engaged latch 45 to retain the impulsion spring 29 under compression, then such downward movement of the plunger will create a partial vacuum within the pump chamber. At this particular period, the upturned face of the plunger will have overrun the intake port l3 somewhat and thus opened the cylinder block I2 to a charge of fuel oil as fed through the supply pipe ii. In Figs. 1 and 2, the wedge 3| is thrust inwardly toward the inclined stop edges of the sleeve openings 32 which bodily shifts the entire block assembly into its lowermost or full-load position.

After the cylinder block becomes charged with fuel, the knockoff cam actuates the tie rod 54 which in turn depresses the bevel trip face 48 so as to simulaneously withdraw the latches 45 and thereby release the compressed impulsion Spring 29. As a result, the charged cylinder block will be subjected to nozzle injection pressure immedi ately after the returning plunger closes the port l3, thus sending forth a measured high pressure charge of fuel oil to the power cylinder through the discharge valve 31.

In the event that the engine governor should withdraw the regulating wedge 3| into its extreme dotted or outermost position, this will allow the collar spring 40 to bodily raise the block assembly into its uppermost or light load position. Assuming the plunger to be again latched in a position identical with that shown in Fig. 1, the

block assembly will now be raised so as to materially delay closure of its port i3 which then. serves to by-pass substantially all of the released plunger displacement into the supply pipe I6 and thereby correspondingly reduce the fuel delivery into the power cylinder. It will be obvious that any intermediate wedge position, will proportionately regulate the fuel delivery in accordance with engine requirements.-

By virtue of my pump devices, I am enabled to inject fuel at a substantially maintained injection pressure throughout the speed range .of an engine. By shifting the lever roller 56, the injection timing may be altered with respect to the engine dead center position while running, or if desired, said roller may be shifted out of engagement with the cam 56 so as to manually arrest the delivery of fuel into a power cylinder independently of the setting given to the wedge 32.

Itwill be apparent that while a single plunger pump has been chosen for illustrating an example of my invention, the same underlying principles apply equally well to a multiplunger pump; also that in certain instances my drive spring 29 may be replaced by a rigid gear so as to likewise bring about a change in pump delivery when the assembled pump body is shifted lengthwise of the plunger axis. Furthermore, it is not essential that the discharge valve be embodied in the pump block since this may also be located at and combined with the injection nozzle. It is to be understood therefore, that I do not wish to be limited to the particular pump embodiment set forth since various changes in structure and coordination of my devices may be resorted to without departing 1. A pump comprising an actuated plunger and a drive gear reciprocating said plunger, a station ary sleeve circumscribing the axis of said plunger, a cylinder block assembly slidably mounted within said sleeve and which assembly includes a discharge valve andan intakeport located intermediate the respective cylinder ends and which intake port is overrun and opened by the plunger in one extreme travel position thereof, resilient impulsion means thrusting interiorly against said sleeve and urging the plunger in its delivery ,direction, said drive gear including a guided flange operatively connected to the plunger and disposed interiorly of said sleeve between the plunger and the impulsion means, a reciprocated crosshead member that periodically seats upon one face of said flange and which crosshead when seated serves to move the plunger on its suction stroke,

means for intermittently latching said flange while the'intake port is overrun by the plunger and which cross-head thereupon recedes from the latched flange, and means for releasing the latched flange in unison with the crosshead movements.

2. A pump comprising an actuated floating plunger and a drive gear for reciprocating said plunger with an impulsion agency interposed therebetween, said agency having energy periodically stored therein by said gear, a stationary sleeve circumscribing the axis of said plunger, a cylinder block mounted within said sleeve and having an intake port located intermediate the respective cylinder ends, said port being intermittently overrun and opened by the plunger in one extreme travel position thereof, a discharge valve, a latch lever fulcrumed upon said sleeve and serving to retain the plunger after said port has been opened, and pilot means slidably carried by said sleeve and provided with a trip face arranged'to release said latch lever in unison with the drive gear movements.

3. A self-contained pump comprising an actuated floating plunger, an apertured stationary sleeve surrounding the plunger axis, a drive gear for reciprocating the plunger, said gear including a crosshead and a faced flange that is slidably mounted within said sleeve about the plunger axis and has the plunger operatively connected thereto, a cylinder block also mounted within said sleeve and having an intake port located intermediate the respective cylinder ends and which crosshead is located intermediate one side face of the flange and said block, said cross head. conta'cting said one side face of the flange to move the flange and the plunger in one direction, a. discharge valve, an impulsion spring interposed to thrust between the other face of said flange and one end region of the sleeve, said spring being compressed by the drive gear to store energy therein, a latch lever fulcrumed upon the sleeve and provided with a-lug extending through the sleeve aperture into latched engagement with said flange after energy has been stored in said impulsion spring, and trip means releasing said latch in unison with the drive gear movements.

DANA IB. GREEN.

Images