US3100449A

US3100449A - Fuel injection pump

Info

Publication number: US3100449A
Authority: US
Inventors: Einar S Dahl
Original assignee: Borg Warner Corp
Current assignee: Borg Warner Corp
Priority date: 1959-02-04
Filing date: 1959-02-04
Publication date: 1963-08-13
Anticipated expiration: 1980-08-13
Also published as: GB943200A; FR1246661A

Description

Aug. 13, 1963 E. s. DAHL FUEL INJECTION PUMP 2 Sheets-Sheet 1 Filed Feb. 4. 1959 fnveni or" [zlrzczr j pail Aug. 13, 1963 E. s. DAHL.

FUEL INJECTION PUMP 2 Sheets-Sheet 2 Filed Feb. 4, 1959 fur/6722 57- I Enar 5 J United states i atent 3,106,449 FUEL INJECTEON PUMP Eiuar S. Dahl, Decatur, Ill, assignor to Borg-Warner Corporation, Chicago, lll., a corporation of Illinois Filed Feb. 4, 1959, Ser. No. 79l,tl81 Claims. (Cl. 103--2) that is reciprocated for pumping fuel and is rotated for distributing the fuel and that is adapted to supply the correct amount of fuel to all of the cylinders for all conditions of load and speed of the engine.

it is an additional object to provide a pump in accordance with the preceding object which is designed to minimize leakage past the pumping plunger.

'It is also an object to provide a single improved fill valve for the pump which is adapted to supply adequate amounts of fuel for all speeds of the operating range of the pump.

It is another object to provide an improved fuel injection pump incorporating improved metering means in the form of a spring loaded piston, the stroke of which is adjustable and which measures a portion of the fuel pumped during each stroke of the pumping plunger.

It is a more particular object to provide a rotating pumping plunger having an axial bore and a radial distribution slot in communication with said bore and a spring loaded check valve positioned within the bore and adapted to cooperate with the metering piston for metering each charge of fuel distributed through the distribution slot.

It is an additonal object to provide a fuel injection pump designed so as never to cut off a flowing column of fuel under pressure, thereby eliminating high pressure wear at the juncture of the cut-off ports.

It is another object to provide an improved fuel injection pump utilizing a relatively large fuel supply reservoir immediately adjacent the fill valve of the pump and means for maintaining a substantially constant pressure at the fill valve seat.

It is also an object to provide an auxiliary fuel circul ating system for supplying additional starting fuel, for filling the fuel injection pump, and for purging air and vapor from the pump.

It is another object to provide a fuel injection pump having a rotating and reciprocating plunger, a reciprocating metering piston and improved leakage fuel return means for thereby salvaging the leakage fuel and eliminating the necessity for high pressure seals around the plunger and piston.

It is still another object to provide a fuel injection pump of a given predetermined capacity that is adapted to be used on engines within a certain size or power range and which pumps only the fuel required by the particular engine.

it is another object to provide an improved fuel injection pump having a single pumping plunger, 2. single inlet valve, a single metering piston, and a single delivery valve which cooperate to supply equal metered charges of fuel to a plurality of engine cylinders and which actually pumps only the fuel required to satisfy engine demand and to make up for leakage losses.

The invention consists of the novel constructions, arrangements, and devices to be hereinafter described and claimed for carrying out the above stated objects and such other objects as will appear from the following description of a preferred form of the invention illustrated with reference to the accompanying drawings wherein:

ice

1G. 1 is a longitudinal sectional view of the improved pump of the present invention;

FIG. 2 is a sectional view taken on line 2-2 of FIG. 1;

FIG. 3 is an enlarged sectional view of a portion of the pump shown in FIG. 1; p

FIG. 4 is a fragmentary sectional view taken on line 4--4 of FIG. 3; and j FIG. 5 is a schematic illustration of the pump of FIG. 1 as it is used with an internal combustion engine.

Like characters ofrefereuce designate like parts in the several views. 1

Referring to FIG. 1, the improved pump of the presen invention is designated generally by the numeral 10 and comprises a drive section 11 and a metering and distributing section 12. The drive section 11 comprises a casing 13, a drive shaft 14 journalled within the casing 13, a cam 15, and a plurality of rollers 16 which function as cam followers. The drive shaft 14 has a tang 17 formed on an end thereof which extends into a transverse slot 18 formed in the cam :15. The rollers 16 are journalled on shafts 19 which are mounted in the casing 13 with their axes normal to the axis of rotation of the drive shaft 14. The cam 15 is formed with an undulating cam surface 20 which is maintained in contact with the rollers 16. A coupling pin 21 is mounted transversely in the cam 15 at right angles to the tang 17. A pumping plunger 22 has a head 23 formed with a transverse slot 24 which engages the pin 21. The head 23 is received within the cylindrical recess 25 formed in the cam 15. A spring 25 and a spring retaining cap 27 surround the pumping plunger 22 and the cap 27 is fixedly attached thereto by means of a split ring washer 28 which fits into an annular groove 29 formed on the pumping plunger 22. fThe spring 26 forces the retaining cap and head v23: of the plunger 22 into contact with the cam 15 which in turn forces the cam surface 20 into contact with the rollers '16.

In operation, rotation of the drive shaft 14, preferably at camshaft speed, causes-the pumping plunger 22 to be driven at a 1:1 ratio therewith, and the undulating cam surface 20 in moving overthe rollers 16 imparts a reciprocating motion to the plunger 22. The cam surface 20 is provided with as many lobes as there are engine cylinders to be supplied. The coupling between the plunger 22 and drive shaft 14 by means of the cam 15 andparticularly the tang 17 and the pin 21 corrects for any misalignment of the pumping plunger 22 with respect to the drive shaft 14.

The metering and distributing section 12 comprises a casing 39, the plunger 22; a till valve 31, and a metering portion 32. The casing 30 is fixedly attached to the casing 13, and the pumping plunger 22 is disposed within a longitudinal cylindrical bore 33 formed in the casing 30. The cylindrical bore 33 is enlarged at 34 to define a pumping or compression chamber adjacent the free end of the plunger 22. The casing 30 is also formed with a plurality of radial fuel delivery ports 35, each of which are connected .to a fuel injection nozzle 36.

The plunger 22 is formed with an axial central bore or fuel passage 37 and a radial distribution port or slot 38 communicating with the bore 37 and which is adapted to be aligned successively with the poits 35 as the plunger 22 rotates. A plug 39 is'threaded into the open end of the axial bore 37. The plug 39 is formed with a central bore 49 and a fuel delivery or discharge check valve 41 having a tapered head 42 tends to form a fluid tight seal on the inner end of the bore 40. A pin 43 is mounted axially within the bore 37, and a spring 44 surrounding the pin 43 acts against the valve 41 tending to maintain it in a fluid sealing position.

The fillvalve 31 comprises a plug 45 threaded into the pumping chamber 34, a ring shaped sealing member 46, and a spring 47. The plug 45 formed with an i 46 is adapted to form a fluid tight seal against the

surfaces

51 and 52 closing the annular groove 49 from the pumping chamber 34. The ring 46 is formed with a plurality of radial spacing tabs 53 and a central hole 54. The spring 47 is disposed under compression within the pumping chamber 34 and forces the sealing ring 46 into contact with the

surfaces

51 and 52.

The metering portion 32 of the pump 10 comprises a plug 55 threaded into a radial bore 56 formed in an extension of the casing 30, a movable piston or shuttle 57,

an adjustablemetering stop pin 58, and a spring 59.

The piston 57 and pin Share slidably disposed in a cylindrical bore 6 0,fornied in the plug 55. The spring 59 is compressed between the piston 57 and the pin 58 and tends to force the piston '7 to the limit of its motion toward the left. The inner end of the bore 56- defines a meteringcavity :or chamber 61 which is in communication with the pumping chamber 34 through a port 62. The stop pin 58 is formed with an internal central bore 63, an annular groove 64, and radial passages 65 connecting the central bore 63 withthe annular groove 64. The grooves and passages collectively constitute a leakage fuel return means for the pin 58. The plug 55 is also formed with an annular groove 66 and radial passages 6? connecting the annular groove 64 with the groove 66.

The plunger 22 is also formed with anannular leakage fuel return groove 68. The groove 68 is connected with the annular groove 66 through a channel 69 formed in Ithe casing 30, and both'grooves are connected through a portionl70 to a fuel return line which carries the leakage fuel. back to the fuel supply tank.

The pump .10 also includes 'acylindrical casingportion 71 formed with a relatively large cylindrical cavity 72 which'- defines a fuel supply reservoir. A flexible diaphragm 73 is provided on top of the casing 71 and is held in place by an end cap .74. The reservoir 72 is in communication with the bore 48" of the plug 45 and is con:

1 n ected through a fuel inlet port 75 to a primary fuel;

supply pump. The primary fuel supply pump supplies fuel to :the reservoir 72 under pressure of, for example, 40 psi. and this pressure is maintainedsubstantially constant by means of the diaphragm 73, as will be described hereinafter.

In operation, the pump functions as follows:

The drive shaft 14 is driven at a fixed speed ratio with respect to the crank shaft of the engine to which fuel is to be supplied and as the drive shaft it rotates, the cam '15 is driven and it moves downward for one portion or" its cycleof operation. The spring 26 forces the plunger 22 downward, thereby reducing the pressure within the pumping chamber 34 for the fill stroke of the plunger 22. Fuel under pressure within the reservoir ,72 forces the ring 46 off its. seat and fuelis allowedto enter the pumping chamber 34 from the annular groove 49. As the drive'shaft 14 rotates further, the cam forces the plunger 22 upward, closing the valve '31 and compressing the fuel within the chamber 34. A portion of the fuel within the chamber 34 is forced through the port 62 into the cavity 61 where it acts upon thepiston 57 forcing it to the right against the action of the spring 59. When the piston 57 reaches the limit of its motion against the stop 58, the remainder of the fuel within the pumping chamber 34 actsagainst the valve 41, forcing it off its seat and the fuel enters the bore 37. The fuel distribution slot 38 is in register with one of the ports during the entire compression stroke ofthe plunger 22 and when the valve 41' opens, fuel Within the passage 37 Y is forced out through the slot 38 and the port 35 to a respecthe plunger 22 moves downward again and the cycle is repeated for the next port 35.

The quantity of fuel displaced into the metering cavity I 61 is determined by the position of the metering pin 58 which is adjustable in accordancewith the engine demand. It is important that the spring 44 tending to maintain the valve ill ir1=itS fluid sealing position be stronger than the spring 59 which acts on the metering piston 57. Wilh this provision, the valve ll remains seated until the'pistcn 57 has been forced to the limit of its motion to the right. The pumping plunger 22 has aconst-ant displacement for eachstroke, and the portion of the fuel compressed within the pumping chamber 34 thatis not displaced into-the cavity '61 is delivered to a nozzle 36. Since the operation of the fill valve 31, the check valve 41 and the metering piston 57 is the same for each pumping stroke, for a constant setting of the metering pin 53, the charges of fuel delivered to ml'of the nozzles 36 should be identical.

it should be noted that during the fill stroke of the plunger 22, the filling of the pumping chamber 34 is facilitated by the return of fuel from the metering chant valveSltosupply the amount delivered to the engine cylinder and to make up for leakage losses past the metering piston 57 and the plunger 22.

In this regard, the

' pump of the present invention should be compared with constant displacement pumps of other designs wherein a portion of the fuel is spilled during each pumping stroke. In order to obtain accurate metering, another detail of some'irnportance is the fact that the port 62 connecting the meterin cavity 61 with the pumping chamber 34 is referably located at the lowermost part of the pumping chamber 34.- This location is provided to minimize the amount of new fuel entering the metering cavity 6f. It has been found thatfuel having air bubbles mixed therein does not have the same pumping characteristics as fuel from which the air bubbles have been removed; The

location of the port 62 enhances the accuracy of the metering'function because the fuel used for metering purposes is recycled and only a minimum amount of new fuel allowed to enter the metering cavity 61. 1 It is necessary to removethe'leakage fuel from behind a metering piston 57 in order to prevent an'accurnulation' of fuel there thatwould interfere with the normal reciprocation of the piston 57. The pressure within the leakage release conduit 59 should preferably be quite small, that is, only sufficient to return the leakage fuel to the supplytank. A very low pressure in the leakage conduit 69 eliminates the necessity for high pressure seals around the lower end of the pumping plunger 22 and around the stop pin 5%, which seals would interfere with the normal reciprocation of these members. The removal of leakage fuel also prevents dilution of lubricating oil within the drive section ll.

The pressure developed within the pumping chamber 34 establishes a pressure gradient along the length of the plunger 22 between the chamber 34 and the annular groove 68, and also along the length of the shuttle piston 57. This pressure gradient causes a small amount of leakage fuel to drift through the bores 33 and 6th to the fuel release port 76. A certain amount of leakage fuel is necessary for lubrication of the plunger 22 and piston 57. It should be noted, however, that the leakage past the pumping plunger 22 has been minimized by the fact that only a single opening 33 in the plunger 22 is provided. In this regard, the pump of the present invention should be compared with similar pumps having a plurality of fuel inlet and outlet or spill ports in the pumping plunger and wherein leakage becomes a problem of considerable importance.

Fuel is supplied to the pump 16 from a primary fueli a minute.

. paratively large. This primary supply pressure also tends to flex or distort the diaphragm 73. It had been found previously that rapid opening of the fill valve tended to reduce the pressure instantaneously in the fuel supply line. This sudden reduction in pressure inhibited proper filling of the pumping cavity 34. To overcome this problem, the large volume within the cavity '72 is provided and the flexible diaphragm '73 functions to maintain the pressure within the cavity 72 substantially constant when the valve 31 opens. It should be noted also thatat high speed of operation, for example, with an eight cylinder engine operating at 5,000 r.p.m.,the fill valve 31 is open for only 4 of At this speed or a comparable speed, it is necessary that suflicient fuel be admitted to fill the pumpingcavity 34 as rapidly as possible. Merely increasing the size of the fill valve so as to increase its flow capacity is not a logical solution because this also increases its mass. To solve this problem, the configuration of the fill valve 31 is provided which allows fuel to flow from the annular groove 49 through the central hole 54 in the valve ring 46 and also around its outer periphery. As compared to a solid flat disc or poppet-type valve of comparable size, this configuration of the valve ring 46 provides a substantially greater flow capacity to mass ratio. For optimum operation of the pump 10, it has been found that the valve 41 should have an opening pressure of approximately 150 psi. and the piston 57 should respond to a displacement pressure of approximately 130 p.s.i. The nozzles 36 used with the pump should be of the spring loaded valve type and preferably should have an opening pressure of approximately 200 psi.

The size of the springs 44 and 59 provided to establish slot 38. This feature obviates the possibility of high pressure wear at the edges of the ports and slot 38.

It should be understood that the structure and the opcrating pressures described are by Way of example only and are not intended to limit the scope of the present invention.

Referring now to FIG. 5, there is illustrated a schematic diagram of the fuel injection pump 10 as used with an internal combustion engine. The complete fuel supply system for the pump 10 comprises a fuel tank 80, i

a primary filter 81, a primary fuel supply pump 82, a secondary filter 83, and the fuel injection pump 10. The primary filter 81 is connected to the fuel tank 80 through a conduit 84; the supply pump 82 is connected to the outlet of the filter 81 through a conduit 85; the secondary filter 83 is connected to the supply pump 82 through a conduit 86, and the port 75 of the pump 10 is connected to the outlet of the filter 83 through a conduit 87. The fuel delivery ports 35 are connected to the respective nozzles 36 through nozzle lines 88, and the port 70 is connected to a fuel return conduit 89 which leads back to the fuel tank 80.

The fuel injection system also includes an air intake manifold 90 for the engine and a. butterfly valve 91 positioned in the throat of the air intake manifold. The nozzles 36 are mounted in the manifold 90 at points adjacent each of the intake valves of the engine cylinders. A control mechanism'92 is mounted on the pump 10 and is adapted to control the position of the metering pin 58 in accordance with engine demand. For this purpose, manifold vacuum is utilized and is supplied to the mechanism 92 through a restricted orifice 93 and conduit 94. The orifice 93 is located in the manifold wall at a point below the throttle valve 91. The manifold vacuum supplied to the control mechanism 92 is modified some- What by ,means of an idle adjustment valve 95. The .valve 95 includes a spring loaded needle valve 96 and an orifice 97 which is'adapted to be closed by the needle valve 96. The orifice 97 is located in the manifold wall adjacent one edge of the blade of the throttle valve 91 and is connected through a channel 98 to the conduit 94. The needle valve 96 is adjustable for controlling the amount of airbleed past the throttle valve 91 into the conduit 94. The control mechanism 92 may be of a type capable of transforming this manifold vacuum into amechanical motion [for adjusting the position of the metering pin 58.

An auxiliary fuel circulating system for the pump 10 is provided and which comprises a solenoid operated valve 99, a temperature responsive valve 100, and a pressure regulator valve 101. The valves 99, 100, and 101 are connected bymeans of a conduit 102 to a fuel outlet port 103 formed in the casing portion 71. A restriction 104 of approximately .025 inch is provided in the conduit 102 for limiting the quantity of fuel flow therethrough. The conduit 102 terminates at a jet 105 which opens into the air intake manifold 90 at a point below the throttle valve 91.

The solenoid valve99 is connected to the electrical starting circuit of the engine, and normally blocks the conduit 102 at a port 106 except when the solenoid is enengized.

The temperature responsive valve comprises a bimetallic element 107 and a needle valve 108 which is adapted to restrict a port 109 leading to the jet 105. The valve 100 is responsive to ambient temperautre conditions and controls the amount of fuel flowing through the port 109 and jet while the engine is being started.

The pressure regulator valve 101 comprises a casing portion 110- formed with a cylindrical cavity 111, a 'ball112, and a spring 113. The casing portion 110 is formed with a fuel inlet port 114 which is connected to the conduit 102. A spring retaining plug is threaded within the cavity 111 and is formed with a fuel outlet port 116. The fuel outlet port 116 is connected through a conduit 117 to the fuel return line 89 whichleads back to the tank 80. The spring 113 acts against the ball 112 which tends to block the port 114 and functions to regulate the pressure within the conduit 102 at a predetermined value;

In operation, the primary fuel supply pump 32, which is preferably electrically driven, draws fuel from the tank 80 and transports it through the filters and the conduit 87 to the fuel injection pump 10. The primary supply pump 82 establishes a pressure of approximately 40 psi. within the supply reservoir 72. A portion of the fuel within the supply reservoir 72 is allowed to pass through the restricted orifice 104 into the conduit 102. The pressure within the conduit 102 is regulated by means of the valve 101 at a desired predetermined pressure of approximately 10 to 25 psi. The fuel released by the regulator valve 101 passes through the port 116 and

conduit

117 and 89 back to the fuel supply tank 80.

The fuel under pressure Within the conduit 102 is available for -supplying additional fuel to the engine for starting it. The solenoid operated valve 99 is energized by the starting circuit of the engine which opens the port 106 and allows fuel to pass through the port 109 and jet 105 into the air intake manifold 90. The quantity of fuel passing through the port 109 and jet 105 is controlled by the valve 100. In cold weather, When additional fuel enrichment is desired, the valve 100 allows a greater quantity of starting fuel to pass through the jet 105 than in warm Weather.

Thefuel circulated through the conduit 102, the valve 101, and the conduit 117 serves the additional functions each of said ports.

7 of initially filling the reservoir 72 of the fuel injection pump 10 and also of purging the reservoir 72 of any accumulated air or vapor therein. The restriction iii! in the conduit 102 limits the quantity of fuel flowing therethrough and thereforedoes not substantially increase the load on the primary fuel supply pump 82. 7

It is to be understood that this invention is not to be limited to the specific constructions and arrangements shown and described except only insofar as the appended claims may be so limited, as it will be apparent to those skilled in theart that changes may be made without departing from-the principles of the invention.

1 claim: V 3 1. In a fuel injection pump for an internal combustion engine, the combination of a casingformed with a longitudinal bore and a plurality of fuel delivery ports opening into said bore, a combined pumping and distributing plunger'disposed Within said bore,fill valve means for supplying fuel to said bore, means for reciprocating said plunger to compress fuel within said bore and rotating said. plunger-to distribute fuel through said ports, metering means comprising a spring loaded piston in direct communication with saidbore and adapted to be displaced a limited amount by fluid pressure developed in said bore with each stroke of said plunger and including control means for limiting the stroke of said piston in accordance with engine demand, whereby metered charges of fuel are formed and distributed by said plunger through 2. In a fuel injection pump for supplying charges of fuel to a plurality of engine cylinders, the combination of a casing formed with alongitudinal cylindrical bore-and a plurality of spaced radial fuel delivery ports in communication with said here, said bore defining a'purnping' chamber in one end thereof; fill valve means for supplying fuel to said chamber; a plunger rotatively and reciprocatively disposed within said bore and formed with an axial a radial fuel delivery port for connecting said passage in succession to said casing ports as said plunger rotates; a single delivery valve disposed in said passage; a single central fuel passage open to said pumping chamber and p metering piston movable between two limits and directly 7 connected to said pumping chamber and adapted to be displaced by fluid pressure developed within said chamber 1 and with the stroke of said piston being limited in accordance with engine demand; and drive means for reciprocating said plunger to pump fuel and rotating said plunger to distribute charges of fuel; said valvebeing effective during each stroke of said plunger to prevent the release of fuel from said pumping chamber until said piston has been displaced to one of its limits of motion, whereby metered charges of fuel are formed and delivered by said plunger through said casing ports to the engine cylinders.

3. In a fuel injection pump for supplying metered charges of fuel to a plurality of engine cylinders, the combination of a casing formed With a longitudinal cylindrical bore and a plurality of spaced radial fuel delivery ports in communication with said bore, a pumping plunger rotatively and reciprocatively disposed within said bore and formed with an axial central fuel passage and a radial fuel delivery port for connecting said passageto said casing ports, means defining a fuel supply reservoir for supplying fuel under pressure to said bore; means defining a fill valve including a ring-shaped valve member separating said reservoir from said bore; metering means including asp ring loaded piston in communication with said bore and adapted to be displaced toan adjustable limit by fluid'pressure developed within said hole and including control means for'adjusting said limit in accordance with engine demand; and a single spring-loaded check valve positioned in said passage, said check valve being effective during each compression stroke of said plunger to prevent the release of fuel through said radial port until said 7 by said plunger through said casing ports to the engine cylinders.

4. In a fuel injection system the combination compris- (1) a pump housing formed with a fuel inlet and a plurality of fuel outlet means;

(2) means defining first and second bore means in said housing;

(3) means'defining a pumping chamber formed in said housing at one end of said first bore means; 7 t

(4) a fuel pumping and distribution plunger disposed in saidfirst-bore means; t

(5) means for reciprocating said plunger in said first bore for pumping fuel; 7

viding fluid communication between said outlet'and inlet means; V i

(7) means for rotating said plunger for distributing said fuel to said-plurality of outlet means;

(8) means in said housing defining a fuel supply reservoir for supplying fuel under pressure tosaid pumping chamber; 7 t

(9) means defining a fill valve disposed between said reservoir and said pumping chamber; 7

(10) means including a flexible diaphragm for maintaining a substantially constant pressure within said reservoir when said fill valve opens;

(ll) fuel metering means in fluid communication with said pumping chamber for metering the amount of fuel pumped to said outlet means, said fuel metering means comprising a piston disposed in said second bore in direct communication with said pumping chamber and adapted to'be displaced by fluid pressure developed within said pumping chamber, ad:

: in said second bore in response to a manifold vacuurn actuated control. control mechanism, and biasing means disposed between said piston means and adjustable stop pin means for limiting the movement of said piston means tothereby control the volume of fuel distributed to said outlet means.

mg: I p

(1) a pump housing formed with a fuel inlet and'a plurality of fuel outlet means; v (2) means defining first and second bore means in said housing; I p f (3) means defining a pumping chamber formed in said housing at one end ofsaid firs-t bore means; i a t V (4) a fuel pumping and distribution plunger disposed t in said first bore means; I

(5), means for reciprocating said plunger in bore for pumping fuel; a

' (6) means in said plunger including valve means providing fluid communication between said inlet and outlet means; 7

(7) means for rotating said plunger for distributing said fuel to said plurality of outlet means;

"(8) means in said housing defining a fuel supply reservoir for supplying fuel under pressure to said pump ing chamber; I

(9) means defining a fill valve disposed between said reservoir and said pumping chamber;

(10) means including a flexible diaphragm for maintaining a substantially constant pressure within said reservoir when said fill valve opens; V

7 (11) and fuel metering mean in fluid communication with said pumping chamber for metering the amount of fuel pumped to said outlet means, said fuel metering means comprising a piston disposed in said second bore in direct communicationwith said pumpsaid first ing chamber and adapted to be displaced by fluid (6) means in said plunger including valve nieans jpro justable stop pin means adapted to be moved axially '5. In a fuel injection system the combination conlpris- V i vacuum activated control mechanism, and biasing means disposed between said piston means and adjustable stop pin means for limiting the movement of said piston means to thereby control the volume of fuel distributed to said outlet means and fuel leakage passage means in communication with said second bore to prevent a build-up of pressure behind said piston.

204,747 Maxim June 11, 1878 1,076,915 Setz Oct. 28, 1913 1 1,116,494 Setz Nov. 10, 1914 1,135,476 Watts Apr. 13, 1915 1,799,704 Riley 2. Apr. 7, 1931 1,993,369 Goldberg Mar. 5, 1935 2,055,578 Hurst Sept. 29, 1936 2,102,117 Goldberg Dec. 14, 1937 2,237,347 Grannan Apr. 8, 1941 2,267,479 Sturm Dec. 23, 1941 2,297,942 Collins Oct. 6, 1942 2,301,435 Mercier Nov. 10, 1942 10 Tabb May 4, 1943 Brown Mar. 6, 1951 Kraft Apr. 15, 1952 Johnson July 15, 1952 Paterson Dec. 2, 1952 Gibbs June 28, 1955 Cooper Dec. 27, 1955 Voit Mar. 27, 1956 Herbrich Feb. 5, 1957 Burman June 4, 1957 Froelich Oct. 22, 1957 Aldinger Oct. 22, 1957 Evans May 6, 1958 Shallenbeng Tune 24, 1958 Foltz Aug. 12, 1958 Dahl et a1 Sept. 9, 1958 Thompson Dec. 22, 1959 Nystrom Jan. 26, 1960 Aldinger Mar. 15, 1960 Bischofi Sept. 19, 1961 FOREIGN PATENTS Great Britain June 6, 1912

Claims

1. IN A FUEL INJECTION PUMP FOR AN INTERNAL COMBUSTION ENGINE, THE COMBINATION OF A CASING FORMED WITH A LONGITUDINAL BORE AND A PLURALITY OF FUEL DELIVERY PORTS OPENING INTO SAID BORE, A COMBINED PUMPING AND DISTRIBUTING PLUNGER DISPOSED WITHIN SAID BORE, FILL VALVE MEANS FOR SUPPLYING FUEL TO SAID BORE, MEANS FOR RECIPROCATING SAID PLUNGER TO COMPRESS FUEL WITHIN SAID BORE AND ROTATING SAID PLUNGER TO DISTRIBUTE FUEL THROUGH SAID PORTS, METERING MEANS COMPRISING A SPRING LOADED PISTON IN DIRECT COMMUNICATION WITH SAID BORE AND ADAPTED TO BE DISPLACED A LIMITED AMOUNT BY FLUID PRESSURE DEVELOPED IN SAID BORE WITH EACH STROKE OF SAID PLUNGER AND INCLUDING CONTROL MEANS FOR LIMITING THE STROKE OF SAID PISTON IN ACCORDANCE WITH ENGINE DEMAND, WHEREBY METERED CHARGES OF FUEL ARE FORMED AND DISTRIBUTED BY SAID PLUNGER THROUGH EACH OF SAID PORTS.