US3714936A

US3714936A - Multiple plunger fuel control linkage

Info

Publication number: US3714936A
Application number: US00181094A
Authority: US
Inventors: A Dreisin
Original assignee: Allis Chalmers Corp
Current assignee: Deutz Allis Corp
Priority date: 1971-09-16
Filing date: 1971-09-16
Publication date: 1973-02-06
Anticipated expiration: 1990-02-06
Also published as: CA961359A

Abstract

A fuel control linkage having a centrally pivoted lever with a drive arm receiving a driving force from the governor and a timing arm, a quantity control arm, and a fuel programing arm connected to a control rod to control fuel delivery for a multiple plunger fuel injection pump.

Description

United States Patent Dreisin 51 Feb. 6, 1973 MULTIPLE PLUNGER FUEL CONTROL 3,673,996 7 1972 Dreisin ..123 139 AP LINKAGE 3,358,664 12/1967 Thompson... ..123/139 R Inventor: Alexander Dreisin, y p F elds, 2,813,523 11/1957 Bischoff ..123/l39 AP 111. Primary ExaminerLaurence M. Goodridge [73] Assignee: Allis-Chalmers Corporation, Mil- Asst-Stan, Examiner-Con Flint Waukee AIt0rney-Arthur L. Nelson [22] Filed: Sept. 16, 1971 21 Appl. No.: 181,094 [57] ABSTRACT A fuel control linkage having a centrally pivoted lever [52] US. Cl. .....l23/l40 R, 123/139 AP, 123/139 R,

with a drive arm receiving a driving force from the 123/139 AB governor and a timing arm, a quantity control arm, [51 Int. Cl ..F02m 59/00 and a fuel programing arm connected to a control rod [58] Field of Search ..123/140, 139

to control fuel delivery for a multiple plunger fuel in- [56 1 References Cited 18cm" pump UNITED STATES PATENTS 10 Claims, 10 Drawing Figures 3,667,437 6/1972 Dreisin ..l23/l40 R 70 l I T 2 I? g 50 v .7 ,1 l m J! l 41 1% a i um l\ O 7! I;,(76 g 4/ 5 56 J I A/ 75 46 4 56 Z, 41 I 4? 445 ,1! 7 4'" 5f I ll 7 9 l a (mi 1X I! Q 6- 3 1.9 6 55 66 7 If 7 0 6 tffi w X II 1- 111 M PATENTEDFEB' s 1913 3.714.936

snm 10F a I FIGI o l k INVENTOR ALEXANDER DREISIN ATTORNEY SHEET 2 GF PATENTEI] FEB 8 I973 INVENTOR v ALEXANDER DREISIN ATTORNEY l MULTIPLE PLUNGER FUEL CONTROL LINKAGE This invention relates to a multiple plunger fuel injection pump and more particularly to a pivotal linkage driven by a speed responsive device and having a fuel timing, a fuel quantity, and a fuel programing arm connected to the control rod operating control sleeves to provide fuel delivery to satisfy the load requirements of the engine.

A multiple plunger fuel injection pump which has a direct drive from the engine without the dephasing mechanism does not provide satisfactory operation at all speeds. Conventional dephasing mechanisms between the engine and the multiple plunger fuel injection pump are usually bulky and rather complicated because the entire pump driving torque has been transmitted through the driving mechanism. In addition to its bulkiness and complexity which results in low reliability, the dephasing mechanism requires an additional installation link between the pump drive shaft and the pump itself. This space is very costly on engines and sometimes, especially in smaller models, his space is just not available. With diesel engines of increasing engine speed, which is the modern trend of diesel engines, it becomes more and more necessary to dephase the fuel injection pump and to control the beginning of injection with relation to the engine in order to obtain the best starting properties and combustion efficiency throughout the engine speed range.

Accordingly, if the dephasing mechanism is built into the pump, and not in the drive mechanism, these problems can be overcome. A governor driven in direct apportion to the engine speed provides a means for controlling a timing and quantity control mechanism and with a control rod connected to each of the plurality of control sleeves it provides a means for dephasing the fuel injection pump relative to the engine.

Accordingly, this invention provides such a control linkage in a compact multiple plunger fuel injection pump connected between the governor and the control rod for dephasing the pump.

It is an object of this invention to provide a control linkage between the governor and the control rod in the multiple plunger fuel injection pump for controlling timing, quantity, and programing of fuel delivery.

It is another object of this invention to provide a control linkage for a multiple plunger fuel injection pump having a centrally pivoted lever for automatic control of fuel timing, fuel quantity, and torque control for a diesel engine.

It is a further object of this invention to provide a control linkage for a multiple plunger fuel injection pump with a centrally pivoted lever having a drive arm integral with three control arms with each control arm providing a separate function of fuel delivery timing, fuel quantity control, and fuel programing throughout the engine speed range to satisfy torque need of the engine as required by the applied load on the engine.

The objects of this invention are accomplished in a multiple plunger fuel injection pump having a camshaft driving a plurality of plungers operating to pressurize fuel for transmission through delivery valves to a plurality of combustion chambers. A plurality of control sleeves are connected to a single control rod which can reciprocate and rotate the sleeves to vary initiation and termination of fuel injection. A governor driven in direct proportion to the speed of the engine operates a drive arm on a centrally pivoted lever. The centrally pivoted lever has a timing arm, a quantity control arm, and a program control arm with suitable links connected between said arms and the control rod to provide the timing, quantity, and programing of fuel delivery. Also a throttle linkage is connected between the quantity control arm and control rod which varies' the quantity of fuel injected in response to movement of the throttle linkage. Accordingly, the centrally pivoted lever operates the fuel injection pump in response to engine speed, and a manual control for providing the proper torque requirements in accordance with the load applied to the engine.

Referring to the drawings, the preferred embodiment of this invention is illustrated.

FIG. 1 illustrates a side view with a section taken on the plunger and governor center lines of the fuel injection pump and another section showing the control linkage between the governor and the control rod;

FIG. 2 is a cross section view taken on line IIII of FIG. 1;

FIG. 3 is a cross section view taken on line llIIII of FIG. 1;

FIG. 4 is a cross section view taken on line lV-IV of FIG. 1;

FIG. 5 is an enlarged view of the plunger and control sleeve for each of the plurality pumping assemblies of the multiple plunger fuel injection pump;

FIG. 6 is a cross section view taken on line VI-VI of FIG, 5;

FIG. 7 is a schematic illustration of a speed-torque curve for the engine;

FIG. 8 is a cross section view taken on line VIIIVIII of FIG. 1;

FIG. 9 is a cross section view taken on line IX-IX of FIG. 1; and

FIG. 10 is a cross section view taken on line X-X of FIG. 1.

Referring to the drawings, a fuel injection pump is mounted within the housing 3 to which a side plate 4 is fastened. A fore and aft end plate 1 and 2 are also fastened to the housing 3. A fuel supply pump 60 is mounted within the fore plate 1 which includes a gear 5 which is centered on the drive end of the camshaft 11 and is driven by means of a dowel 6. The drive gear 5 engages the pinion gear 7. These two gears are fitted into pockets on the cover 1 and are enclosed by the plate 8 which is fastened by a plurality of screws 61. Ports are arranged inside the cover in communication with the pockets on both sides of the gear mesh of gears 5 and 7. These gears cooperating with the ports 63 and 65 constitute a supply pump which is used to draw fuel from a reservoir tank, preferably through a primary filter and to deliver it to theinterior of the pump housing by the port 9, either directly or through a secondary filter. The oil seal 10 is positioned around the camshaft in the plate 8. The fuel is supplied through the conduit 67 connected to the outlet passage 64 and the port 9. The camshaft 11 forms passages 12 and 13, connected through the space between the gears 5 and the front camshaft journal by a passage 14 with the inlet port 15. This arrangement allows a continuous flow of fuel from cavity 68 in the interior of the pump housing around the outside of the surfaces of the camshaft bearingjournals, and from there to the intake port to the supply pump 60 assuring positive lubrication of the journal bearings and a cooling flow of the lubricant. The cavity 68 within the housing of the multiple plunger fuel pump being filled with fuel of a pressure of approximately 5-10 pounds per square inch supplies fuel to the injection pump.

The supply pump gears are utilized to drive the governor 69. The ratio of the gears 5 and 7 is 4:l, as shown in the drawings. The injection pump is driven at one-half engine speed, resulting in the governor speed being double that of the engine speed. This allows for a very compact small governor weight assembly. The governor drive pinion has a shaft extension 17 with an axial slot 18 as shown in FIG. 8. The weight assembly is driven through a clock-type spring 19 having a natural frequency lower than any torsion frequency induced either by the engine or the injection pump itself. The inner tang of the clock spring 19 is shown penetrated in a radially inner slot arranged in the governor spindle 20 thus rotation of the pinion shaft 17 causes the governor spindle 20 to rotate with it.

The governor weights 16 are shown arranged in the conventional manner on the weight carrier 21. The outer shoulder of the weight carrier abuts against thrust plate 22. An anti-friction bearing 23 is shown interposed between thrust plate 22 and the spacer 24.

Centrifugal force of the weights 16 is transmitted by the finger 25 to the thrust bearing 26 and to the shifter 27. This centrifugal force is counterbalanced by springs 28 and 29 which abuts against the spindle cover 30 positioned in the rear cover 2 and secured by lock nut 31. a

A multiple plunger fuel injection pump as shown includes six in-line fuel injection pumps. Each of the pumps is operated by a cam on the camshaft 11. Since all of the pumps operate off the camshaft in the same manner, the pump 70 will be described. The cam lobe 71 causes the cam follower 72 to rise and fall as the camshaft 11 is rotated. The cam follower 11 includes a cam sleeve 73 carrying a pin 74 supporting a bearing assembly 75 and embraced by a roller 76. The roller runs on the cam lobe 71. The follower plate 176 causes the plunger 77 to reciprocate within the barrel 78 which together with the plunger forms a pressurizing chamber 79. A delivery valve assembly 80 is in communication with the pressurizing chamber 79 and permits flow of fuel through the valve to the fitting 81 which is connected to a nozzle injecting into a combustion chamber of the engine.

A plunger 77 reciprocates within the control sleeve 33 which is carried by a retainer sleeve 41. The movement of the control sleeve 33 is controlled by the control rod 38 and the control linkage operating in response to the throttle lever 50 and the governor control. Three main functions which are accomplished for the control of fuel injection is the automatic timing, the delivery of quantity control, and the delivery programing which generates the desired speed torque curve of the engine throughout its operating range.

The start of injection occurs when the lower edge of the metering helix 32 on the plunger registers with the lower edge of the control sleeve 33. When it is desirable to advance the beginning of injection as the engine speed increases this is accomplished by lowering the control sleeve. The retardation of fuel injection or timing of fuel injection is accomplished by raising the sleeve 33 relative to the plunger 77. Timing advance and retardation is a function of engine speed and is transmitted from the governor through the control linkage to the control rod which moves the control sleeve axially relative to the plunger.

The quantity control of fuel injection is responsive to the speed of the engine and also responsive to -a manually controlled throttle. These two changing functions are fed into the control linkage which are then transferred to the control rod to reciprocate the control rod in a manner to rotate the control sleeve 33 clockwise or counterclockwise relative to the plunger 77. Termination of fuel injection is effected when'the helical slot 32 registers with the spill port 83 in the control sleeve 33. Duration of fuel injection is controlled by rotating the sleeve 33 so that the helical slot 32 comes into register with the port slot earlier or later depending upon the speed of the engine and the setting of the throttle control.

The control linkage operates in response to the governor and the throttle control which regulates delivery of the fuel injection pump throughout the operating engine speed range depending on a number of parameters which vary, depending on the characteristics of the engine itself, or depending on the nature of the load driven by the engine. In other words, the fuel delivery must be programed to provide the proper speed torque characteristic throughout the engine operating range. This is accomplished by a control member such as shifter 27 on the governor operation X-lever 85 which is centrally fulcrumed on the pin 34 which is fastened to the governor cover 4. The drive arm 86 of the X-lever 85 carries a pin 35 which is positioned between the cheeks of the shifter 27.

FIG. 1 illustrates the governor in the standstill position. Rotation of the weights will cause outward movement and subsequent movement of the shifter 27 towards the right compressing the springs 28 and 29. This will cause the X-lever 85 to rotate in a counterclockwise direction when viewed in FIG. 1. The timing arm 87 of lever 85 will move upwardly. The timing arm 87 is connected through the timing link 36 with the timing screw 37 which is arranged crosswise in the control rod 38. As the pump speed increases, the timing arm 87 of the X-lever 85 moves upward thereby transmitting this movement through the link 36. The spherical portion 39 of the timing screw 37 is moved upward causing the control rod 38 to rotate clockwise, as viewed in FIGS. 2, 3 and 4. A control finger 40 is attached to the retainer sleeve 41 to control the control sleeve 33 in a manner described previously. its outer spherical portion engages the hole 42 arranged radially in the control rod 38. Counterclockwise rotation of the control rod 38 lowers finger 40 and with it the retainer sleeve 41 and control sleeve 33 thereby advancing fuel injection. Conversely with a decrease in speed of the engine, the governor flyweights move radially inward thereby causing sequence of motion through the linkageand control rod 38 to raise the control sleeve 33 and thereby retard fuel injection.

Quantity control of fuel injection is accomplished through the quantity control arm 90 of the X-lever 85 which carries pin 43. Pin 43 is engaged in the slot in the lower end of the torque link 44. Its upper end is ful crumed around the pin 45 which is positioned in the upper end of the throttle link 46. The lower end of the throttle 46 is fulcrumed on the pin 47 of the throttle crank 48. The throttle shaft 49 extends through the side cover 4 and is fixed on its outer end to he throttle lever 50. Movement of the throttle lever will move the crank 48.

Referring to FIG. I the crank movement in the counterclockwise direction will move the pin 47 to the left which will cause the link 46 and pin 45 to move to the left. The inner extension of pin 45 is engaged in slot 51 of the control rod 38. The movement-of the pin 45 to the left will move control rod 38 in the same direction causing the control sleeves 33 to rotate in a counterclockwise direction when viewed from above, thereby increasing fuel delivery. Spring 52 is arranged around the assembly of the torque link 44 and the throttle link 46 in such a way as to normally press torque link 44 towards the pin 47. For a given position of the throttle crank 48, an increase in engine speed causes the pin 43 to move to the left, as viewed in FIG. 1. This causes the link assemblies 44 and 46 to fulcrum around the pin 47 in a clockwise direction moving the pin 45 to the right rotating control sleeves in a clockwise direction, as viewed from above, thereby reducing pump delivery quantity.

The maximum fuel pump delivery at any speed is limited when the edge 53 of the torque link 44 contacts the outside diameter of the torque screw 54. The torque screw 54 is positioned in the upper end of the program link 55. The lower end of the program link is fulcrumed on the pin 56 positioned in the program arm 92 of the X-lever 85. Spring 57 forces program link 55 against the maximum delivery screw 58 which is adjustable from the outside of the pump assembly.

The programing in the fuel delivery is more clearly illustrated in FIG. 7 of the speed torque curve. From rated speed, the point 150 on the curve, the torque decreases above rated speed and increases below rated speed to maintain the stability of the engine. If the engine speed falls below that corresponding to the maximum torque point 151, it is desirable that the value of torque decrease. Then the operation of the engine will be unstable and the engine will stall unless the operator shifts gears. This condition is desirable because otherwise, if the engine is lugged down below the maximum torque speed at wide open throttle, some engine parts such as bearings might be severely damaged.

However, if the torque continues to decrease all the way down to the cranking speed there may not be enough fuel delivered at cranking speed to start the engine after a shutdown. Therefore, the programing should be able to provide an additional fuel at cranking speed as shown at point 152 resulting in another torque peak on the curve.

The operation of the control linkage in the multiple plunger fuel injection pump will be described in the following paragraphs.

Referring to the speed torque curve, the various changes in fuel delivery are generally indicated as the speed of the engine increases or decreases.

When the manual throttle 50 is in the wide open position, the throttle crank 48 is in the position shown as in FIG. 1. The governor weights 16 are in their outer position and the governor springs 28 and 29 are fully compressed. The X-lever 85 has moved all the way in a counterclockwise direction and the torque link 44 contacts pin 47 while edge 53 is in contact with torque 5 screw 54. At this point pin 56 is in its lowest position and the outside diameter of torque screw 54 is contacting the edge 53 at its lowest point. When the centrifugal force of the governor weights diminishes, the governor springs move the shifter 27 to the left causing the X- lever 85 to rotate in a clockwise direction. The torque link 44 now pivots around the contact point between the edge 53 and the torque screw 54. The pin 45 moves left causing the control rod 38 to move towards an increase in pump delivery. At the same time the pin 56 is moving upward causing the contact point between edge 53 and the outside diameter of the torque screw 54 to move upward. At a certain intermediate engine speed desired to correspond to the desired maximum torque output of the engine, protruding nose on the edge 53 overrides the outside diameter of torque screw 54 causing the torque link assembly and the control rod to move to the right decreasing pump delivery and therefore engine torque. This point is shown as maximum torque in the curve shown in FIG. 7. At lower speeds the operation of the engine is unstable and with an increasing load the speed of the engine rapidly falls off and may stall unless the load is removed.

When the engine is at standstill the governor mechanism is in the position shown in FIG. 1. The operator has put the manual throttle in a wide open position. As the starter revolves the engine at low speed (approximately l50-250 rpm) the relative position of the links remains essentially the same. The upper portion of the edge 53, which now contacts the torque screw 54, is recessed in respect to the rest of the edge of the profile allowing the control rod to move farther to the left corresponding to an excess fuel quantity.

As the engine starts firing, the engine speed begins to increase and the shifter 27 moves to the right, pin 56 is pulled down and the outside diameter of the torque screw 54 climbs over the nose of the edge 53 setting the pump delivery to a desirable lower level.

Thus to program the pump delivery in wide open throttle to any desirable shape, we can change the profile of the ram 53. Adjusting the torque screw 54 up or down and the link 55 will vary the specific engine speeds at which the separate events in the torque program are initiated. Adjustment of the maximum stop screw 58 permits a variation in the maximum delivery of'the pump at rated engine speed without initially changing the shape of the program.

The preferred embodiment of this invention for the fuel delivery control of the multiple plunger fuel injection pump has been illustrated and described. The centrally pivoted X-lever 85 receives a driving force from the governor, and together with a manual input from the throttle changes and fulcrum point of the torque link whereby the timing and quantity control of the fuel is regulated. All three of the control arms; timing, quantity and programing of X-lever 85 serve in a combined way to provide the control of the fuel injection pump.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A multiple plunger fuel injection pump for an internal combustion engine comprising, a pump housing means defining a plurality of bores, a plunger received in each of said bores and defining a fuel injection pumping chamber and a fuel supply chamber ineach of said bores, one delivery valve in communication with each one of said fuel injection pumping chambers for delivering fuel to a combustion chamber, each of said plungers defining passage means selectively communicating between said supply chamber and said injection pumping chamber for supplying fuel to said injection pumping chamber, a control sleeve mounted for reciprocal and rotational movement about each of said plungers and defining port means with said plunger for controlling the closing and opening of said passage means in said plunger between the supply chamber and the fuel injection pumping chamber, means sequentially reciprocating each of said plungers for discharge of fuel from said fuel injection pumping chamber through said delivery valve, a speed responsive device adapted for connection to an engine including a control member moving in response to engine speed, a centrally pivoted lever defining a drive arm, a timing arm, a quantity control arm, and a programing arm,- means connecting said drive arm to said control member of said speed responsive device, a control rod connected to each of said control sleeves providing rotational or reciprocating movement of said control sleeves, a timgram arm and defining a shiftable fulcrum point for said quantity control linkage to program the fuel delivery rate of said fuel injection pump, said centrally pivoted lever thereby controlling the quantity, timing, and programing of fuel delivery for said fuel injection pump in response to speed and throttle control.

2. A multiple plunger fuel injection pump for an internal combustion engine as set forth in claim 1 wherein said throttle control includes a rotatable throttle shaft adapted for connection to a throttle lever, a throttle crank on said throttle shaft, a throttle link pivotally connected between said throttle crank and said control rod to thereby vary quantity control of said fuel injection pump in response to rotation of said throttle shaft.

3. A multiple plunger fuel injection pump for an internal combustion engine as set forth in claim 1 wherein said quantity control linkage includes a torque link pivotally connected to said quantity control arm and connected to said control rod to thereby provide a reciprocating motion of said control rod for quantity fuel delivery of said fuel injection pump.

4. A multiple plunger fuel injection pump for an inpoint for said quantity control linkage to thereby modiy the reciprocating movement of said quantity control rod for programing fuel delivery.

5. A multiple plunger fuel injection pump for an internal combustion engine as set forth in claim 1 wherein said centrally pivoting lever defines an X- shaped lever, and means pivoting said X-shaped lever at its central portion.

6. A multiple plunger fuel injection pump for an internal combustion engine as set forth in claim I including a program link pivotally connected to said program arm of said lever, a maximum fuel delivery screw mounted on said housing means pivotally engaging said program link to thereby provide supplemental adjustment of the fulcrum point of said quantity control linkage.

7. Amultiple plunger fuel injection pump for an internal combustion engine as set forth in claim 1 wherein said programing linkage includes a program link pivotally connecting said program arm, a maximum fuel delivery screw adjustably mounted in said housing means and pivotally engaging said program linkage, spring means on said program link and program arm biasing said program link to an engaging position with said maximum fuel delivery screw.

8. A multiple plunger fuel injection pump for an internal combustion engine as set forth in claim 1 wherein said quantity control linkage includes a torque link pivotally connected to said quantity control arm and pivotally connected to said control rod, a throttle shaft integral with a throttle arm, a throttle link pivotally connected to said throttle arm and pivotally connected to said control rod, a spring biasing the torque link and said throttle link together to thereby form a linkage mounted for pivotal movement on said quantity control linkage.

9. A multiple plunger fuel injection pump for an internal combustion engine as set forth in claim 1 wherein said throttle control linkage includes a torque link pivotally connected to said quantity control arm and pivotally connected to said control rod, means defining a pivoting surface on said torque link, a recessed portion of said pivoting surface for programing fuel delivery to desirable lower level with decreased engine speed below a predetermined point.

10. A multiple plunger fuel injection pump for an internal combustion engine as set forth in claim 1 wherein said quantity control linkage includes a torque link pivotally connected to said quantity control arm and said control rod, a torque link defining a predetermined profile for programing the rate of fuel delivery in response to engine speed and load.

Claims

1. A multiple plunger fuel injection pump for an internal combustion engine comprising, a pump housing means defining a plurality of bores, a plunger received in each of said bores and defining a fuel injection pumping chamber and a fuel supply chamber in each of said bores, one delivery valve in communication with each one of said fuel injection pumping chambers for delivering fuel to a combustion chamber, each of said plungers defining passage means selectively communicating between said supply chamber and said injection pumping chamber for supplying fuel to said injection pumping chamber, a control sleeve mounted for reciprocal and rotational movement about each of said plungers and defining port means with said plunger for controlling the closing and opening of said passage means in said plunger between the supply chamber and the fuel injection pumping chamber, means sequentially reciprocating each of said plungers for discharge of fuel from said fuel injection pumping chamber through said delivery valve, a speed responsive device adapted for connection to an engine including a control member moving in response to engine speed, a centrally pivoted lever defining a drive arm, a timing arm, a quantity control arm, and a programing arm, means connecting said drive arm to said control member of said speed responsive device, a control rod connected to each of said control sleeves providing rotational or reciprocating movement of said control sleeves, a timing link connected between said timing arm and said control rod rotating said control rod and reciprocating said control sleeves, a quantity control linkage connected between said quantity control arm and said control rod reciprocating said control rod and rotating said control sleeves, a throttle control pivotally connected to said quantity control linkage to modify movement of said control rod in response to movement of said throttle control, a program linkage connected to said program arm and defining a shiftable fulcrum point for said quantity control linkage to program the fuel delivery rate of said fuel injection pump, said centrally pivoted lever thereby controlling the quantity, timing, and programing of fuel delivery for said fuel injection pump in response to speed and throttle control.

4. A multiple plunger fuel injection pump for an internal combustion engine as set forth in claim 1 wherein said program linkage includes a program link pivotally connected to said program arm, a torque screw on said program link defining a shiftable fulcrum point for said quantity control linkage to thereby modify the reciprocating movement of said quantity control rod for programing fuel delivery.

5. A multiple plunger fuel injection pump for an internal combustion engine as set forth in claim 1 wherein said centrally pivoting lever defines an X-shaped lever, and means pivoting said X-shaped lever at its central portion.

6. A multiple plunger fuel injection pump for an internal combustion engine as set forth in claim 1 including a program link pivotally connected to said program arm of said lever, a maximum fuel delivery screw mounted on said housing means pivotally engaging said program link to thereby provide supplemental adjustment of the fulcrum point of said quantity control linkage.

7. A multiple plunger fuel injection pump for an internal combustion engine as set forth in claim 1 wherein said programing linkage includes a program link pivotally connecting said program arm, a maximum fuel delivery screw adjustably mounted in said housing means and pivotally engaging said program linkage, spring means on said program link and program arm biasing said program link to an engaging position with said maximum fuel delivery screw.