US2287478A - Fuel pump for engines - Google Patents

Description

E. A. JOHNSTON ETAL FUEL PUMP FOR ENGINES June 23, 1942.

Filed April 20, 1940 6 Sheets-Sheet 1 IN ENTORS EAJoHNsToN RE. PETERSON BY- MG AW'Y.

June 23, 1942. E A. JOHNSTON ETAL FUEL. PUMP FOR ENGINES Filed April 20, 1940 6 Sheets-Sheet 2 mm W 1 A s E W] n- RLPETERSON ATI'Y.

June 23, 1942. E. A. JOHNSTON ETAL FUEL PUMP FOR ENGINES Filed April 20, 1940 6 Sheets-Sheet 3 INVENTORS EAJoHNsToN REPETERsoN BY MO.

ATTY.

June 23, 1942.

E. A. JOHNSTON EIAL FUEL PUMP. FOR ENGINES Filed April 20, 1940 6 Sheets-Sheet 4 N N mmm 0MB T H J P M ER 2 mm.

Mum-FM ATT'Y.

June 1942- E. A. JOHNSTON ET AL 2,287,478

FUEL PUMP FOR ENGINES Filed April 20, 1940 6 Sheets-Sheet 5 INVENTORS I EAJOHNSTON RE. PETERSON BY P'QMQPW J1me 1942- E. A. JOHNSTON ETAL 2,287,478

FUEL PUMP FOR ENGINES Filed April 20, 1940 6 Sheets-Sheet 6 INVENTORS EAJOHNSTON RE. PETERSON Patented ame 23, 1942 a at EdwardA. Johnston, Chicago, and Raymond E.

Peterson, Riverside, Ill., assignors tc linternational Harvester company a corporation of New Jersey Application April 20, 1940, Serial No. 330,75d

20 Claims.

This invention relates to fuel injection pumps for internal combustion engines of the Diesel type.

One of the principal objects of the present invention is to provide a fuel pump for a multiple cylinder engine in which a single injection plunger is utilized for injecting the fuel to a plurality of cylinders.

Another object is to provide a simplified drive mechanism for a pump construction utilizing asingle injection plunger and a plurality of timed delivery valves for delivering the charges of fuel in timed relation to independent cylinders.

Another object is to provide a simplified govfor the different units with the use of a minimum number of parts and bearings.

Another object is to provide a pump construction in which the essential parts areformed as removable units which can be readily removed for service or replacement.

Another object is to provide a low pressure fuel supply pump as a separate unit cooperatively arranged with respect to the main pump drive mechanism so as to be driven thereby.

Another object is to provide a Diesel injection system with scavenging means continuously operable to withdraw leakage oil from the pump and the associated parts thereofand to return it to the supply tank without creating sub-atmospheric pressures in any of the parts from which the leakage oil is withdrawn.

objects of the invention have been accomto, operate the governor shaft at four times the speed of the cam shaft. This high speed rotation of twice the engine speed is very satisfactory for operating a centrifugal governor. The speed is also ample to give sufflcient plunger strokes of the injection plunger to supply all .of the cylinders with fuel charges by means of a single plunger.v The injection plunger cylinder and housing, therefore, is formed as a special unit removable as such from the'pump casing. The

application, Serial Number 330,749, filed April 20, 1940. Distributor valves-are also mounted in a unit assembly which can be readily removed from the pump casing. The low pressure fuel supply pump and the scavenging pump are formed as a single unit readily removable from the casing.

The above brief description gives the general arrangement of the parts making up applicant's improved fuel injection system.

In the drawings:

Figure 1 is a diagrammatic view showing the exterior outlines of a pump unit embodying the invention and the fuel lines connecting the supply tank and the fllterwith the pump;

Figure 2 is a side elevation of the pump unit with the attaching housing at the end removed and with the side of the casing wall broken away in section to show the adjacent parts of the internal mechanism;

Figure 3 is a vertical section taken substantially on the center line of the governor and'plunger driving shaft with the distributor valve mechanism shown in elevation;

Figure 4 is a vertical section taken on the line 4-4 of Figure 3;

Figure 5 is a vertical section taken on the line 55 of Figure 3;

Figure 6 is a section taken on the line 66 of Figure 4;

Figure '7 is a section taken on the line 'I-1 of Figure 4;

Figure 8 is a. vertical section taken on the line 8-8 of Figure 7;

Figure 9 is an end view of the primary fuel supply pump unit in the nature of a section taken on the line 9-9 of Figure 2;

Figure 10 is an end view of the same unit from the other end;

Figure 11 is a horizontal section taken on the line IIH of Figure 9;

Figure 12 is a section taken on the line l2-l2 of Figure 9; 4

Figure 13 is a section taken on the line I3-II of Figure 10;

Figure 14 is a top plan view of the main pump casing with the cover, distributor block unit and plunger unit removed;

Figure 15 is a section taken on the line |5--l5 of Figure 14;

Figure 16 is a section taken on the line l6--i6 of Figure 15;

Figure 1'7 isa section taken on the line "-51 of Figure 15; and,

details of this unit are covered by the co-pendin 56 Figure 18 is a vertical section taken through the center of the plunger unit transversely of the pump casing.

In the drawings, the main pump casing, or

- housing, is formed as a casting, openings be- This type of construction is usually referred to as flange mounting," all of the drive construction being enclosed. A transverse, vertical partition 24 divides the pump casing into two compartments. Said partition is of suillcient thickness to provide a vertical bore 25 in which the pump plunger unit, to be hereinafter described, is mounted. The bore '25 is uniform for a sub stantial distance, extending downwardly from the top face 26 of the casing 20. A second bore 21 of a substantially smaller diameter extends beyond the bottom of the bore 25 into the interior of the casing. An undercut channel, or recess, 28 is provided at the bottom of the bore 25 in the radial distance existing because of the difference in bore. Said channel forms an oilcollecting and transfer means, as will be hereinafter described.

At one end of the casing 20 a drive shaft 29, which is adapted to be connected to drive mechanism from the engine by means of a drivingv element 30 rigidly keyed thereon, extends into the casing through a ball bearing assembly II diagrammatically shown, fitted in a bore 32 and held therein by suitable retaining means. Said shaft extends within the casing terminating in a ball bearing assembly 33 diagrammatically shown, mounted in a, bore formed in the partition member 24. A plurality of cams 34 are formed on the shaft 29, each of said cams engaging the head portion of a tappet member 35 mounted for reciprocation in a bore 36 extending upwardly through the top wall 26 of the casing terminating in an enlarged bore 31. An oil-collecting channel It is formed in the annular space provided by the difference in diameters of the bores 36 and 31. Said channel has an upwardly directed edge which acts as a scraper to remove oil from the surface of the tappet member 35. A drainage channel 29 connects each of the channels 38 and extends at an .angle downwardly. as shown in dotted lines in Figure 3 and in full lines in Figure 14. The leakage oil collected by said drainage means flows into the bore 25 collecting in the channel 28, previously described.

A gear 40 keyed on the shaft 29 drives a gear 4i mounted on a combined governor and plunger driving shaft 42 in a speed ratio of one to four. The shaft 42 extends through a ball bearing assembly 43 shown diagrammatically, mounted in a bore 44 formed in the end wall of the casing and retained therein by the mounting member 23. Said shaft also extends through the center partition 24 of the casing, being rotatably mounted therein by a ball bearing assembly 45, shown diagrammatically, mounted in a bore 48.

Beyond the partition 24 the shaft 42 is formed with an eccentric 41 on which a needle bearing assembly 48 is mounted, the needles contacting the eccentric 41 and the shell forming a drive the bore ll.

assure means for englllinl atappet cup 40 mounted for reciprocation in the bore :1.

Suitable means including a nut 44 are provided forretainingtheneedlebearingassemblyinpositionon theeccentric 4l. Areduced end portion ll oftheshaftflextendingbeyondthenutll isformedsquareincrosssectiomasbestshown inFigure5, toengagewithdrivingrelationa coupling member If pinned on a shaft II. The shaft it drives the low pressure fuel supply pump and the scavenging pump, as will be described in detail.

. The low pressure primary fuel supply pump for transferring fuel from the fueltank to the injection plunger, and the scavenging pump are formed in a single casing l4. At the outer end a cover plate ll closes two intersecting bores It and I1,- as best shown in Figure 9, in which pump gears II and It are mounted in pumping engagement with each other. The gear II is keyed on the shaft 53. The gear II is free to rotate on a shaft I. A fuel inlet compartment II is formed in the casing in communication with the bores II and IL; A conduit 82 communicating with the compartment it leads to the sidewall of the casing where it is connected by a fitting to a supply conduit I leading to the bottom of a fuel supply tank '4, as shown in Figure 1. A fuel delivery compartment formed by a bore 4| communicates with the, bores It and I1 to form an outlet. Said bore is connected by a conduit 62 with the top side of the casing where it is connected by a suitable fitting with a discharge line OI leading to a filter II, as shown inFlgure 1.

It is necessary that a supply pump be provided which at all times pumps fuel in a quantity greater than is utilized by the injection plunger and at a uniform pressure. For that reason, as shown in Figure 12, a by-pass conduit '1 is connected to the conduit '84 and to a bore '0 communicating with the inlet compartment I. A pressure relief valve it is mounted in the bore 68, being held in position by a compression spring ll. Said valve regulates the prmsure in the discharge linefrom the supplypump, returning the excess fuel'to the'inlet side of the pump.

The scavenging pump is formed by intersecting bores." and 12 extending into the casing 54 from the end opposite he location of the supply pump. A gear'll moun on the shaft I3 is located in A mating gear 14 located in the bore I2 is mounted on the shaft 20. As shown in Figures 10 and 12, an inlet compartment II is provided in communication with the bores II and 12. A cover plate II extending over the face of the casing at the scavenging pump end thereof, closes the pump compartment, it being held in position by cap screws one of which is shown in Figure 3. A bore 'I'I, shown in Figure 12, forms a communication between the drainage system of the pump casing, which will be further described in detail, and the inlet compartment 15 of the scavenging pump. An outlet compartment I8 communicating with the bores H and 12 is connected by a conduit II and a conduit II with a boss M to which a return fuel line 22 is connected by a suitable fitting, as shown in Figure I. Said return line extends into the tank terminating above the highest liquid level therein whereby at no time will oil drain back through the return line into the pump.

The main drainage channel 3! leading from the distributor valves, and the channel 24, located at the bottom of the bore 28, have already been aaa'ravs described. A transverse bore 93 intersects the channel 28, as shown in Figures 3, 14, and 15.

Said bore extends downwardly at an angle, as shown inFigure 15, the upper end being plugged and the lower end communicating with a vertical channel formed by a bore 95 shown in Figures 15, 16, and 17. The bottom end of the bore 95 is bore 95 near its lower end and connects ,with a bore 9I shown in Figure 16. Said bore registers with the opening II in the cover plate 16, thereby drained by gravity into the channels provided forthat purpose.

The injection plunger unit is fitted into the bore 25. The housing of said unit consists of a lower sleeve member I and an upper enclosure member II. The sleeve member is provided with a shoulder at the top which centers the unit in the bore 25. A flange I02. at the-top plugged. A transverse bore 96 intersects the of the sleeve member seats on the'surface 26 of the casing. The sleeve I00 is provided with a reduced lower end portion I03 whichextends within the tappet cup 49. A generally cylindrical piston control member I04 is provided with'an upper bearing shoulder I06 fitted in a bearing surface I01 formed at the upper end of the sleeve member I00. The lower end of the member I04 is of a smaller diameter to conform to the shape of the sleeve I00 and is provided with a bearing portion I08 fitted for rotation in a bearing surface provided-at the lower end of the sleeve I00. Said sleeve is cut away intermediateits ends to provide for the engagement of a control rack I09 with gear teeth IIO formed around the intermediate portion of the control member I05.

An injection plunger III is mounted for rotation and reciprocation in a bore II2 formed in a cylinder member H3. Said member is provided with a head portion II4 fitted in an annular recess H5 formed in the flange of the sleeve member I00. The piston member is supported entirely from its flanged head portion, the remainder of the member being suspended out of contact with the control member I04.

The piston III is provided with a plurality of lugs H6 engageable with spline-like grooves. III formed in the .lower end of the piston control member I00. This construction provides for reciprocation of the plunger with respect to the control member and connects the members for rotation together whereby the angular position of the piston may be adjusted by movement of the control member I08. I v

Thelower end of the plunger III is provided with a head II8 on which a spring retainer H9 is mounted. A compression spring I20 abuts the retainer H9 at its lower end and seats at its upper end against a shoulder formed at the bottom of the sleeve member I00. The spring I20 is located entirely within the tappet cup 49 and the head II8 of the plunger abuts the bottom of the cup thereby determining the piston position.

The upper end of the plunger III is formed with an annular channel let, a vertical channel I22, and a spiral fcut ofi channel I23 Joining the vertical and the annular channels. This type of piston is well known in the prior art, being utilized to meter the fuel injected bythe plunger dependent upon the position of the spiral cut-0E portion'with respect toinlet and by-pass openv ings in the wall of the cylinder.

Figure 3 shows the construction of the inlet and by-pass ports for the pump plunger. The head portion I02 of the piston member is formed with a pair of recesses I24 extending downwardly from the top surface of the member. Transverse bores I26 extending axially through the head portion intersect the recesses I24 and terminate in the cylinder bore. Screw plugs I26 are fitted to seal the outside ends of the bores, recesses I27 being formed in the head portion to accommo ,date the screw heads when the piston member is dropped into position. The particular construction of the injection unit including the delivery of fuel thereto and therefrom, and the piston control construction are covered by the co-pending application Serial Number 330,749, filed April 20, 1940, and are described here only in so far as is necessary to make a complete and adequate showing of the invention of this application.

A spacer member I29 seated on the top of the cylinder member II3 contains fuel supply conduits'in the form of bores I29 and a substantially central bore I30 which provides a guide .for a discharge valve I3I. The head of said valve is "seated on the top of the spacer member and is held against opening until the required pressure is obtained by a compression spring I3I'. Said spring fits in an alined bore I32 formed in a second spacer member I33 mounted on the spacer member I3I. As best shown in Figure 18, discharge means from the plunger unit are provided by a screw threaded member I34 threaded into a bore formed in the spacer member I33 communicating with the vertical bore I32. The member I34 is formed with an internal channel I 35 communicating with a channel in a connecting member I36 held in position against the spacer member I33 by the member I34 with the use of suitable sealing gaskets.

The cover or housing member IOI, previously referred to, is provided with an internal bore of the same diameter as the external borev of the spacer blocks and the head portion of the piston I I4. Said member also houses a filter I31 through which fuel passes from an inlet coupling I36 before passing downwardly to the supply ports of the cylinder. The member IOI is provided with a flange I39 by means of which the entire unit is secured to the casing 20 by means of student.

threaded into a bore I39 in the casing 20 as shown in Figure 14. A fuel supply conduit I40 leading from the filter 66 connects with, the coupling I36 tosupply-filtered fuel to the final filter I31. I

The connecting member I36 which is provided with the internal conduit I, as shown in Figure 2, leads to the fuel distributor unit. Said unit consists essentially of a lower valve carrying block I42 and a distributor block I43. Said blocks are rigidly secured together with the abutting faces lapped to form a fuel-tight joint.

As shown in Figure 7, fuel under injection v pressure from the injection plunger enters: the valve block I42 through a threaded securing and conduit member I43. Passing through a transverse conduit I44, the fuel passes upwardly through a conduit I45 into a bore I46 formed in into the distributor block. Each of said bores communicateswith a vertical bore I 5I extending vertically entirely through the valve block I42. A distributor valve I52 is mounted for reciprocation in each of the bores I5I. The lower end of each valve is positioned to be engaged by one of the tappet members 35, previously described. The head portion I 55 of each of the valves is provided with a seat adjacent the top of the bore I5I and is held against the valve block in seated position by a compression spring I53 located in the bore I58. It will be noted that the valve member is cut away adjacent the top to form an annular space therearound below the head portion I53. Fuel delivered to said space when the valve is opened is delivered through an angular conduit I54 to a vertical con duit I55 extending upwardly through the distributor block I43. Each of the conduits I55 is in communication with a fitting I55 threaded into the top of the distributor block.

To provide a dust-tight enclosure for the distributor unit, a housing I51 is mounted over the top of the casing 28. The fittings I55 and the inlet connection I38 of the fuel plunger unit project through openings in the top of said cover.

A conventional fly-ball governor is shown mounted on the shaft 42. The weights I58 are pivoted on a carrier I59 keyed on the shaft 42. The entire governor construction may be of any conventional type and has not been shown in detail. Force exerted by the fly-balls, or weights, I58, is exerted against a sleeve I58 rotatably and slidably mounted on the shaft 42. Said sleeve abuts a ball-bearing assembly I8I adapted to transmit the thrust of the governor to trunnion pins I52, as best shown in Figure 4, carried by a rockable control member I53. Said member is mounted on a shaft I54 carried by roller-bearing assemblies I55 and I55 suitably mounted in bores formed in the side walls of the casing 28.

The control member I53 is provided with an upwardly extending arm I55 at one side of the casing, as best shown in Figure 2, which is formed with a generally circular head portion I55 located between two thrust portions I51 of the control rack I89, previously described. Said control rack is mounted for reciprocation in the central partition 24 of the casing. At the end opposite the control member the control rack I85 is provided with an adjustable stop mechanism I58 adapted to abut a stop in the form of a boss I58 on the casing wall to limit the maximum amount of fuel which can be injected by the pump.

The control member I53 is also provided with an upwardly extending arm I59, shown'in Figures 3, 4, and 5, to which a tension spring I18 is secured. Said spring is secured at the other end to a lever I1I rigidly secured to a shaft I12 extending transversely of the casing. Said shaft carries an adjusting arm I13 by means of which the tension on the spring I18 may bemanually adjusted. To provide a maximum position, an adjustable stop mechanism I14 is located at one end of the casing 28 engageable with an extenassrs sion of the lever III beyond the connecting point of the spring I18.

Although the operation of certain units of the fuel injection system of this invention have been explained in connection with the description of the component parts, a complete operation will now be described. a

Fuel in the supply tank 54 is delivered through the conduit 55 to the inlet compartment 5| of the low pressure primary fuel supply pump. Said pump, being of a geartype, has a positive'displacement depending on the speed of rotation of the driving shaft. The pump is built so that this displacement is sufficient to pump a larger supply of fuel than is used at any time by the injection system, the excess fuel being-by-passed through the conduit 51 and the valve 55 back to the inlet ofthe pump. The spring 15 acts on the valve 55 as a pressure regulating means whereby the pump supplies fuel under a constant pressure to the conduit 55 leading to the oil filter 55. From said filter fuel passes through the conduit I45 through therllter I 31, the bores in the spacer members I33 and I25, and into the recesses I24 formed in the flanged upper portion of the cylinder member II5.

From the crankshaft 'of the engine through suitable conventional gearing, not shown, power is transmitted to drive the primary shaft of the unit, which is the cam shaft 29, and through the gears 48 and H the secondary shaft of the unit, which is the governor drive and plunger operating shaft 42. With a four-cylinder pump, as illustrated, the cam shaft is driven at a speed one-quarter of the plunger operating shaft in order toprovide an inJection stroke for each of the distributor valves. In a two-cylinder pump it will be necessary to drive the plunger shaft at only twice the speed of the cam shaft. There is, however, a distinct advantage in driving the shaft on which the governor is mounted at a high speed, as greater power and better operating characteristics can be obtained from a centrifugal type of governor operating at high speeds The eccentric 41 of the plunger driving shaft 42, through the needle bearing assembly 45, drives the tappet cup 49 which in turn engages the bottom head portion II5 of the plunger III. Said plunger is held against the cam by the spring I28 and is adjusted to vary the effective injection stroke by means of the control rack I89 operatingin engagement with the gear III on the control member I54. As pointed out in the description, said control member is provided with axially spaced bearing portions which give accurate allnement of the member with a minimum of bearing surface, allowing the governor mechanism to act with a minimum of frictional resistance. The provision of a reduced end portion I on the sleeve member I55, which carries the injection lunger unit, allows the tappet cup 45 to extend upwardly over the lower end of the sleeve member. This construction reduces the overall height of the unit while permitting the use of a spring of suitable length and a tappet cup with sufficient bearing surface.

The injection plunger III is of a conventional construction known as the piston control port type. At the bottom of the stroke. fuel is drawn in through bores I25 intersecting the I24 and the cylinder. As ,the plunger rises on the injection stroke. the top edge of the piston first passes over and cuts of! communication with the supp y p rts. As the stroke continues, fuel is delivered past the valve I3I into the conduit I4I leading to the distributor unit. When the curved wall of the piston passes over one of the inlet ports, fuel is by-pa ssed down through the vertical slot I2I relieving the pump of pressure and stopping the delivery of fuel. 1

Fuel delivered'to the distributor unit through the conduit I44, as shown in Figure '7, passes upwardly by the valve I41 into the longitudinal conduit I49 which supplies each of the bores I50 with fuel under pressure at each stroke of the injection plunger. The valve I41 acts to control pressure in the common conduit I49. Said valve does notopen until the pressure has reached an amountdetermined by the spring I46 and closes as soon as the pressure drops on the injection plunger side of the valve.

The valves I53 in the bores I50 are opened in timed relation by the cams 34 on the shaft 29. Said cams, as will be noted by inspection of Figure 4, cover only a small angular portion of the relatively large portion of the shaft 29 which engage the tappets 35. It is necessary in an injection engine of this type to deliver the fuel at a high rate and at a high pressure to the injection valve, and to cut off the pressure and supply almost instantaneously at the termination of injection. For that reason, the valves I52 are opened very rapidlyat the proper time and are also closed very rapidly. There is an important advantage in the distributor type mechanism of this type with utilization of a single plunger over the conventional injection system utilizing a separate injection plunger for each cylinder. It will be noted that the eccentric 41, which drives the injection plunger, is formed as a cylinder of a relatively large diameter. This construction provides for raising the pump plunger at a comparatively low rate of speed and for returning the plunger at the same rate. It is possible with a distributor valve unit to operate the plunger in this manner, as the valve which delivers the fuel to the injection nozzle may not be opened until the build-up of pressure in the system is sufiiciently high to provide for proper injection regardless of the speed of the plunger and its distance of travel. The possibility of using a true eccentric for the pump plunger results in a piston travel which does not at any time exceed the piston travel on a multi-' ple cylinder pump utilizing direct injection, al-

though in the case of a four-cylinder engine the pump plunger travels four times the total dis tance of travel of any one plunger in a multiple plunger injection pump.

It will be understood that the drive shaft 29 for a pump unit constructed for a four-cylinder engine of the four-cycle type operates at half engine speed, giving two injections'per revolution of the engine. The plunger driving shaft 42 operates at four times the speed of the shaft 29 or at two times the speed of the crank shaft of the engine, giving two injections per engine revolution.

The governor construction for controlling the quantity of fuel injected, as illustrated in the drawings, is of a conventional type, the basic principle being the control of the rack I99 by centrifugal governor weights I58 acting in opposition to the spring IIOon the control member I66. The mounting of one end -of the spring on the manual adjustable lever I'll provides means for setting for different speeds of operation. The adjusting mechanism I58 at the end of the control rack, provides means for adjusting the maximum injection of fuel as determined by the angular position of the injection plunger II I.

Although injection pumps of this type are made of the finest materials available and the parts are precision fitted, there is always a certain amount of leakage past the fitted parts, increasing with wear. It has been customary to provide means for draining the leakage fuel outside the pump housing and allowing'it to drip to the ground or be collected and discarded. In the pump of this invention'provision has been made for collecting the leakage fuel and return ing it to the fuel supply tank. The valves I52 fitted in the bores I5I necessarily withstand fuel at the injection pressures. There will therefore be some leakage past these valves into the recesses 38 at the bottom of the bores 31. The recesses are formed to provide knife-like edges which scrape the walls of the tappets 35 to remove fuel therefrom and prevent its passing downwardly through the bores I36 into the pump casing. Leakage fuel collected at the valves passes downwardly through the channel 39 into the bore 25 collecting in the channel 28 at the bottom thereof. Said channel is also shaped to remove fuel from the walls of the tappet cup 49. Inspection of Figure 18 will show that any fuel leaking past the plunger III will collect in the tappet cup 49 and overflow into the channel 28.

The leakage fuel collected from both possible leakage sources, as above pointed out, drains by gravity through the conduit 93 which, as best shown in Figure 15, intersects the channel 28 downwardly through the conduits 95, 96, 91, and 11 into the inlet chamber 15 of the scavenging pump, as shown in Figure 12. Said pump returns the leakage fuel to the fuel supply tank through the conduit 82, as shown in Figure 1. As the scavenging pump is of a capacity greater than the normal amount of leakage, an air line 99 is connected to the top of the fuel supply tank above the liquid level therein, and to the engine of the scavenging pump as shown in Figure l and Figures 16 and 17. This is an important element of the scavenging system as the creation of a partial vacuum in the collection conduits of the scavenging system would be very undesirable, acting to increase the fuel leakage and to draw lubricating oil past the tappets 35 and past the tappet cup 49 into the scavenging system. Another detrimental effect would be the drawing in of air through the seals and casing into the interior of the pump casing. Such air always contains dirt which is detrimental to the life of the wearing parts of the pump.

A general inspection of the fuel pump of this invention will show its extreme simplicity and accessibility for assembly and service. The casing 20 is such as to permit ready assembly of the drive shaft 29, which is inserted through one end thereof, and the driving shaft 42 which is inserted from the same end as a unit with the eccentric governor and the -ball bearings assembly. It is wholly necessary to mount the control member I53 and the spring control structure, including the lever Ill and the shaft I12, through openings in the casing. The center partition 24 of the housing provides means for mounting the inner end of the shaft 25 and is also of suflicient thickness to provide the plunger bore. 1 The tappet cup 49 is inserted from the top of the casing and the injection plunger unit is entirely assembled as a unit before being mounted in the casing. Referring to Figure 18, the sleeve member ill and the housin'gf'member it! enclose as'a un'it' ofjparts of the injection plunger 'mechani'sm. specific construction is covered 'by the copending application above referredto, However; the unitconstruction also forms a part of the presentinvention.

The distributor mechanism isformed as a unit including all of the parts of the" assembly within the two blocks 2 and I". These blocks may be removed as a unit for replacement or repair;

It will be seen that the fuel injection system as described is outstandingly simple and that it is composed of removable units which can be assembled rapidly and with accuracy and can be removed for replacement or repair. Although only certain preferred embodiments of the different units have been illustrated, it is to be understood that applicant claims as his invention all modifications falling within the scope of the appended claims. j

What is claimed is: v j" n 1. In a fuel injection pump, having a casing, a high pressure injection plunger mounted there-' a in, a driving shaft and in combination there'- with, a low pressure fuel supply pump mounted on the casing, means for supplying vfuel to the inlet of said pump, means for conducting fuel under pressure from the pump tothe injection v plunger, a scavenging pump mounted on the easing, said casing being provided with a drain conduit for collecting leakage fuel in communication with the scavenging pump, conduit means in communication with a source of air at atmospheric pressure being also provided for drawing air into the scavenging pump to maintain sub stantially atmospheric pressure in the leakage 4. A drainage system for fuel injection pumps having a plurality of movable elements working against fluid under high pressure comprising leakage collecting means adjacent each element through which it is possible for leakage to occur,

drainage means connecting said'collecting means,

a positive displacement scavenging pump having an inlet, conduit means for delivering the collected fuel to. said inlet, an outlet conduit from the scavenging pump, and an air vent line connected with the scavenging pump inlet whereby pressure in the 'drainagemeans is maintained at substantially atmospheric pressure.

5. A drainage system for fuel injection pumps 1 having a plurality of movable elements working against fluid under high pressure comprising 1 6. In a drainage system for fuel injection pumps having a casing with driving means and an injection-plunger unit mounted therein, said fuel collecting conduit, and means for returning system.

2. In a fuel injection pump having a casing, a high pressure injection plunger mounted therein, a driving shaft and in combination therewith, a low pressure fuel supply pump mounted on said casing, means for supplyingfuel to the inlet of said pump, means for conducting fuel under pressure from the pump to the injection plunger, a scavenging pump mounted on the casing at a low level thereon, said casing being provided with a drain conduit in communication with the scavenging pump for delivering leakage fuel thereto by gravity, conduitmeans in communication -with a source of air at atmospheric pressure being also providedfor di'awing air into the scavenging pump to maintain substantially atmospheric pressuregin the leakage fuel collecting fuel from said scavenging pump to the fuel supply means, and means for returningfuel from said scavenging pump to the fuel supply system.

3. In a fuel injection'pump having a casing,

driving means within the casing, a high pressure injection plunger mounted therein and driven by said means, a fuel supply pump mounted on said casing and driven by the drlving'means, means for supplying fuel to the inlet of said pump and means for conducting fuel under pressure from tion with a source of air at atmospheric pressure being also provided for drawing air 'into the scavenging pump to maintain substantially atmospheric pressure in the leakage fuel' collecting means, and means for returning fuel from said scavenging pump to the fuel supply system.

casing serving as a lubricant reservoir, the combination ofleakage collecting means adjacent each element through which it is possible for leakage to occur, said means being independent of the lubricant reservoir, drainage means connecting said collecting means, a scavenging pump I casing serving as a lubricant reservoir, the combination of leakage collecting means adjacent each element through which it is possible for leakage to occur, said means being independent of the lubricant reservoir, drainage means connecting said collecting means, a scavenging pump having an inlet, conduit means for delivering the collected fuel by gravity flow to said inlet, a fuel supply tank, an outlet-conduit from the scavenging pump extending into said'tank and terminating at a level above-the maximum fuel level therein, and an air vent conduit connected with the scavenging pump inlet' and with the tan above the maximum fuel level therein.

8. In a fuel injection pump construction, a unitary casing having. a horizontal top face, a vertical bore formed in the casing from said face, a removable injection plunger unit including inlet and-outlet conduits fitted on the top of the casing and depending. within said bore, a drive shaft rotatably mounted in the casing, a

. plurality of bores extending: downwardly from the top face of the casing, tappet members mounted for reciprocation in said bores, said drive shaft being provided with cams engageable with said tappet members, a fuel distributor unit removablymountedvon the top face of the casing over said tappetmenibers, a driving shaft rotatably mounted in the casing parallel to the tending downwardly from the top surface of the drive shaft, gearing for driving said shaft from the drive shaft, and cam means carried by said shaft for operatingthe plunger unit.- I

9.- m a fuel injection pump construction, a unitary casing having a single surfaced face, a vertical bore formed in the casing from said face, a removable injection plunger unit fitted on said face and depending within said bore, a drive shaft rotatably mounted 'in the casing, a

plurality of bores extending downwardly from the face of the casing, tappet members mounted.

for reciprocation in said bores, said drive shaft being provided with cams engageable with said tappet members, a fuel distributor unit removably mounted on the face of the casing over said tappet members, a driving shaft rotatably mounted in the casing parallel to the drive shaft, gearing for driving said shaft from the drive shaft, and cam means carried by'said shaft for operating the plunger unit.

10. In a fuel injection pump construction, a unitary casing having a horizontal top face, a vertical b'ore formed in the casing, a removable injection plunger unit fitted on the top face of the casing and depending within said bore, a drive shaft rotatably mounted in the casing, a plurality of bores extending downwardly from the top face of the casing, tappet members mounted for reciprocation in said bores, said drive shaft being provided with cams engageable with said tappet members, a fuel distributor unit removably mounted on the top face of the casing, said unit being formed with conduits for delivering fuel to a plurality of cylinders and a common supply conduit, valves carried by said distributor unit positioned to control the conduits therein, said valves being positioned to be engageable bythe tappet members, a driving shaft rotatably mounted in the casing parallel to the drive shaft, gearing for driving said shaft at a speed which is a multiple of the speed of the drive shaft equivalent to the number of distributor valves, and cam means carried by said shaft for operating the plunger.

11. In a fuel injection pump construction, a unitary casing having a surfaced face, said casing being provided with a partition wall, a bore formed in the casing in the partition wall thereof, a removable injection plunger unit fitted on the face of the casing and depending within said bore, a tappet member mounted in said bore for driving the plunger unit, a drive shaft rotatably mounted in the casing, a plurality of bores extending from the face of the casing, tappet members mounted for reciprocation in said bores, said drive shaft being provided with cams engageable with said tappet members, a fueldistributor unit removably mounted on the face of the casingover-said tappet members, a driving shaft rotatably mounted in the casing parallel to the drive shaft, gearing for driving said shaft from the drive shaft, and cam means carried by said shaft for operating the plunger driving tappet member.

12.In a fuel injection pump construction, a unitary casing having a horizontal face, said casing being provided with a vertical partition wall, a vertical bore formed in the casing in the partition wall thereof, a removable injection plunger unit fitted on the top of the casing and depending within said bore, a. second bore formed in the partition in alinement with the first named bore, a tappet cup mounted in said bore for driving the plunger unit, a drive shaft rotatably mounted in the casing, a plurality of bores excasing. t ppet members mounted for reciprocationin said bores, said drive shaft being provided with cams engageable with said tappet members, a fuel distributor unit removably mounted on the topisurface of the casing over'said tappet members, a driving shaft rotatably mounted in the casing parallel to the drive shaft, gearing for driving said shaft from the drive shaft, and cam means, carried by said shaft for operating the plunger driving tappet member.

13, In a fuel injection pump construction, a unitary casing forming'alubricant reservoir having a horizontal top face, said casing being provided with a vertical partition wall, a vertical bore formed in the casing in the partition wall thereof, a removable injection plunger unit fitted on the top face of the casing and depending within said bore, a tappet member mounted in said bore for driving the plunger unit, a drive shaft rotatably mounted in the casing, a plurality of bores extending downwardly from the top face of the casing, tappet members mounted for reciprocation in said bores, said drive shaft being provided with cams engageable with said tappet members, a fuel distributor unit removably mounted on the top face of the casing over said tappet members, said unit being formed with conduits for delivering fuel to a plurality of cylinders and a common supply conduit, valves carried by said distributor unit positioned to control they conduits therein, said valves being positioned to be engageable by the tappet members, a driving shaft rotatably mounted in the casing'parallel to the drive shaft and extending beyond the partition wall, gearing atone end of the casing for driving said shaft from the drive shaft, cam means vcarried by said shaft for operating the plunger driving tappet member, an auxiliary pump unit mounted on the casing at the end opposite the gearing, said unit including a supply pump and an independent scavenging pump, means for driving said pumps from the extending portion of the driving shaft, I

means for supplying fuel to the supply pump and therefrom to the injection plunger unit, and means independent of the lubricant reservoir for delivering leakage fuel from the distributor valves and the injection plunger unit to the scavenging. pump.

14. In a fuel injection pump construction, a unitary casing having a horizontal top face, said casing being provided with a vertical partition wall, a vertical bore formed in the casing in the partition wall thereof, a removable injection plunger unit fitted on the top face of the casing and depending within said bore, a tappet member mounted in said bore for driving the plunger unit, a drive shaft rotatably mounted in the cusing, a plurality of bores extending downwardly from the top face of the casing, tappet members mountedfor reciprocation in said bores, said drive shaft being provided wtih cams engageable with said tappet members, a fuel distributor unit removably mounted on the top face of the casing over said tappet members, said unit being formed with conduits for delivering fuel to a plurality of cylinders and a common supply conduit, valves carried by said distributor unit positioned to control the conduits therein, said valves being positioned to be engageable by the tappet members, a driving shaft rotatably mounted in the casing parallel to the drive shaft and extending beyond the partition wall,

gearing at one end of the casing for driving said shaft from the drive shaft, cam means carried by said shaft for operating the plunger driving tappet member, an auxlliarypump unit mounted on the casing at the end opposite'the gearing, and means-for driving and unit from the extending portion of the driving shaft.

15. In a fuel injection pump construction, a unitary casing having a horizontal top face, said casing being provided with a vertical partition wall, a vertical bore formed in the casing in the partition wall thereof, .a removable injection plunger unit fitted on the top of the casing and depending within said bore, a second bore of smaller diameter formed in the partition in alinement with the first named bore, the difference in diameter of said bores providing a leakage collecting channel, a tappet member mounted in said bore for driving the plunger unit, a drive shaft rotatably mounted in the casing, a plurality of bores extending downwardly from the top face of the casing, tappet members mounted for reciprocation in said bores, said drive shaft being provided with cams engageable with said tappet members, a fuel distributor unit removably mounted on the top face of the easing over said tappet members, said unit being formed with conduits for delivering fuel to a plurality of cylinders and a common supply conduit, valves carried by said distributor unit positioned to control the conduits therein, said valves being positioned to be engageable by the tappet members, a driving shaft rotatably mounted in the casing parallel to the drive shaft, gearing for driving said shaft from the drive shaft, cam means carried by said shaft for operating the plunger driving tappet member, a scavenging pump mounted on the casing, means for driving said pumps from the driving shaft, and means for delivering leakage fuel from the collecting channel to the scavenging pump.

16. In a fuel injection pump construction, a unitary casing provided with a vertical partition wall, a vertical bore formed in said wall, a removable inJection plunger unit fitted on the top of the casing and depending within said bore, a second bore formed in the partition in alinement with the first named bore, a tappet cup mounted in said bore for driving the plunger unit, a. drive shaft mounted in the casing, one end thereof being supported by one end of the casing, said partition wall being provided with a shallow bore coaxial with the drive shaft and providing a bearing for the inner end of said shaft, a plunger driving shaft mounted in the casing parallel to and below the drive shaft and rotatably supported by bearings in one end wall of the casing and in the partition wall, and gearing for driving said shaft from the drive shaft.

17; In a fuel injection pump construction, a unitary casing having a vertical wall formed with an attaching face, said casing being provided with a vertical partition wall, a vertical bore formed in the casing in the partition wall thereof, a removable injection plunger unit fitted onthe top of the casing and depending within said bore, a second bore formed in the partition in alinement with the first named bore. a tappet cup mounted in said bore for driving the plunger unit, a drive shaft mounted in the casing being supported by a bearing at the attaching end of the casing and a bearing in the partition wall, a plurality of bores extending downwardly from the top surface of the casing, tappet members mounted for reciprocation in said bores, said drive shaft being provided with cams engageable with said tappet members, a removable fuel distributor unit removably mounted on the top surface of the casing, said unit being formed with conduits for delivering fuel to a plurality of cylinders and a common supply conduit, valves carried by said distributor unit positioned to control the conduits therein, said valves being positioned to be engageable by the tappet members, a driving shaft mounted in the casing parallel to the drive shaft and rotatably supported by bearings with one end wall of the casing and in the partition wall, gearing for drlvingsaid shaft from the drive shaft, said driving shaft extending beyond the partition wall. an auxiliary pump unit mounted on the casing at the end opposite the attaching surface, said unit including a supply pump and a scavenging pump, means for driving said pumps from the extension of the driving shaft, means for supplying fuel to the supply pump and therefrom to the injection plunger unit, and means for delivering leakage fuel from the distributor valves and theinjection plunger unit to the scavenging Dump.

18. In a fuel injection pump construction, a unitary casing provided with a partition wall providing support for bearings, a bore formed in the casing in the partition wall thereof, a removable injection plunger unit fitted on the casing and depending within said bore, a drive shaft mounted in the casing being supported by a bearing at one end of the casing and a bearing in the partition wall,a driving shaft mounted in the casing parallel to the drive shaft and rotatably supported by bearings at one end wall of the casing and in the partition wall, gearing for driving said shaft from the drive shaft, a centrifugal governor carried by the driving shaft, 9. plunger control member mounted for reciprocation in the partition wall, and control linkage operatively connected to the governor and the control member.

19. In a fuel injection pump construction, a unitary casing being provided with a partition wall providing support for bearings, a bore formed in the casing in the partition wall thereof, aremovable injection plunger unit fitted on the casing and depending within said bore, a drive shaft mounted in the casing being supported by a bearing at one end of the casing and a bearing in .the partition wall, a driving shaft mounted in the casing parallel to the drive shaft and rotatably supported by bearings at one end wall of the casing and in the partition wall, gearing for driving said shaft from the drive shaft, a centrifugal governor carried by the driving shaft, a plunger control, member mounted for reciprocation in the partition wall, and a control member operatively connected to the governor and the control member, said member being pivoted on a transverse axis between the shafts.

20. In a fuel injection pump construction, a

unitary casing having ahorizontal top face, a.

vertical bore formed in the casing, a removable injection plunger unit fitted on the top of the casing and depending within said bore, a second bore of smaller diameter formed in the casing in alinement with the first mentioned bore, the difierence in diameter in said bores providing a leakage-collecting channel, a tappet member mounted in said smaller bore for driving the plunger unit, a plurality of bores extending downwardly from the top face ofthe casing, tappet members mounted for reciprocation in said bores, means for operating said tappet members, said casing being formed with leakmembers and including distribution valves and age-collecting channels around the top-of said distribution conduits, a scavenging pump mounttappet members, a leakage-collecting channel in ed on the casing, and means for delivering leakcommunication with said channels and with the age fuel from the leakage-collecting channels to leakage-collecting channels in the plunger unit 5 said scavenging pump.

bore, a fuel distributor unit removably mounted EDWARD A. JOHNSTON.

on the top face of the casing over said tappet RAYMOND E. PETERSON.

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