US3390639A

US3390639A - Fuel injection pump

Info

Publication number: US3390639A
Application number: US558501A
Authority: US
Inventors: Hideg Laszlo
Original assignee: Ford Motor Co
Current assignee: Ford Motor Co
Priority date: 1966-06-17
Filing date: 1966-06-17
Publication date: 1968-07-02
Anticipated expiration: 1985-07-02

Description

July 2, 1968 L. HIDEG 3,390,639

7 FUEL INJECTION PUMP Filed June 17, 1966 2 Sheets-Sheet 1 LASZL O H/DEG INVENTOR BYQWW W Z WW A TTORNEYS 2 Sheets-Sheet 2 Filed June 17, 1966 LASZLO H/DEG /NVENTOR ATTORNEKS United States Patent 3,390,639 FUEL INJECTION PUMP Laszlo Hideg, Dearborn Heights, Mich., assignor to Ford Motor Company, Dearborn, Mich., a corporation of Delaware Filed June 17, 1966, Ser. No. 558,501 20 Claims. (Cl. 103-5) ABSTRACT OF THE DISCLOSURE A pump having a central distributing valve and a conical cam drive plate moving.free-floating plungers in a fuel pressurizing and injection direction, a fuel chamber between the plunger and injector controlling the return travel of the plunger towards the cam plate by the amount of fuel remaining therein; the central valve being axially and rotatably movable to control the duration of injection as a function of speed and operator throttle pedal setting.

This invention, in general, relates to a liquid fuel injection pump for use with an internal combustion engine. More particularly, it relates to a fuel injection pump particularly suitable for use with an internal combustion engine utilizing a Stratified charge combustion process.

One of the objects of the invention is to provide a liquid fuel injection pump construction that distributes liquid fuel at the required pressure to individual fuel injection nozzles of a multi-cylinder internal combustion engine in such a manner that the quantity and duration of fuel delivery to the individual nozzles is substantially equal, the quantity is adjustable and is a function of duration of injection, and the timing of delivery ending varies as a function of the load and speed.

The pump of the invention, in general, includes a drive shaft operably connected to an engine crankshaft, and having, first, a cylindrical cam surface for oscillating the plungers of a multi-plunger fuel transfer pump. The latter pump draws fuel from a tank or reservoir and delivers it via a filter system to the pump injection plunger barrels or chambers associated with each of the fuel nozzle lines. The drive shaft, secondly, includes a concentrically mounted cam having a conical surface that directly engages the bottom face of each of a number of angled free-floating pump plungers, for the sequential flow of scheduled quantities of fuel into the fuel injection lines. The drive shaft, thirdly, drives a rotary fuel flow control valve, which, in general, is so located and constructed as to variably control the supply of fuel to and the drain or spill of fuel from the various pump injection plunger chambers to thus control the quantity of fuel flow and duration of injection into the individual nozzle lines by controlling the linear return travel of the plungers towards the conical drive surface.

The rotary flow control valve is movable axially by a plunger operatively connected to the engine throttle control linkage so as to vary the quantity and duration of injection as a function of the vehicle load and engine speed.

In one embodiment, the plunger also is a fuel metering valve that rotates, as it is moved axially, to progressively vary the quantity of fuel flow to the rotary valve inlet port. In a second embodiment, the plunger merely has a linear movement, and a separate idle speed needle valve control assembly is provided to variably restrict the supply of fuel to the rotary valve as a function of engine speed and load.

The above construction applies suctionless throttling of the fuel supply for part-load fuel delivery regulation. It,

also permits connection of the fuel supply to individual 3,390,639 Patented July 2, 1968 ice fuel injection lines in a progressive and sequential manner without overlap.

It is another object of the invention, therefore, to provide a liquid fuel injection pump having a conical cam drive surface for driving a plurality of circumferentially spaced fuel injection pump plungers, each of which has a longitudinal axis essentially at right angles to the drive surface for a direct engagement with it.

It is another object of the invention to provide a fuel injection pump having free-floating pump plungers that are moved in one direction by a conical cam drive surface, and are returned a variable distance towards their initial position by the quantity of fuel delivered to the pump plunger chambers.

It is a still further object of the invention to provide a fuel injection pump applying suctionless throttling of the fuel supply for part-load fuel delivery regulation.

Another object of the invention is to provide a fuel injection pump with a rotary fuel supply and drain control valve, and fuel supply metering means, to vary the quantity of fuel to and duration of injection of fuel through the various fuel injection lines.

It is a still further object of the invention to provide a fuel injection pump that eliminates the need for an idle speed governor mechanism.

It is also an object of the invention to provide a fuel injection pump that provides a sequential and individual delivery of fuel to and a control of the drain of fuel from the various pump plunger chambers associated with a multicylinder engine.

Other objects, features and advantages of the invention will become apparent upon reference to the succeeding, detailed description thereof, and to the drawings illustrating the preferred embodiments thereof; wherein,

FIGURE 1 shows a cross-sectional view of one embodiment of a fuel injection pump constructed according to the invention; and

FIGURE 2 shows another embodiment of the invention.

FIGURE 1 shows a liquid fuel injection pump enclosed by a one-piece cast housing 10. The housing has a central stepped diameter bore 11, the lower larger portion 12 of which rotatably receives a drive shaft 14. The drive shaft is radially and axially located by annular bearing

portions

16 and 18. This portion of drive shaft 14 is pressure lubricated, by means not shown, through suitable passages 20, and is sealed from the upper section, to be described, by a rubber or other suitable annular seal member 22. A reduced diameter lower portion 24 of drive shaft 14 extends through the open end of housing 10, and would be connected, by means not shown, to an engine crankshaft to be driven thereby at a desired relationship.

The upper end of drive shaft 14 is machined to provide a cylindrical cam surface 26 that is eccentrically mounted with respect to the longitudinal axis of drive shaft 14. Cam surface 26 bears against the bottom or inner end portions 28 of a number (only one shown) of fuel transfer pump plungers 30. Preferably, there would be two or three transfer pump plungers installed in equally circumferentially-spaced radial bores in housing10, to achieve low fluctuation of the fuel supply. The plungers could be made of cast iron, forged steel, or sintered metal, for example.

Each transfer pump plunger 30 is reciprocably mounted in a side bore 32 in housing 10, the bore 'being closed at its outer end by a cap 34. Each plunger consists, essentially, of a cup-shaped piston 36 having circumferentially-spaced, axially-extending slotted wall portions 38, the reduced diameter land 28, and a plurality of circumferentially-spaced ports 40 connected to a central bore 42. Ports 40 connect bore 42 to the drive shaft central 3 cavity fluid chamber 44 defined by the annular space between the walls of bores 12 and 32 and drive shaft 14 and plunger piston portion 36 and 28. Chamber 44 n turn has an opening 46 connected to a fuel tank reservoir passage 47.

The outer end of each pump transfer plunger central bore 42 is closed by a known type of one-Way inlet valve 48 that is press fitted, for example, to plunger 30. The plunger is biased against cylindrical cam surface 26 by a spring 50 that is seated between cap 34 and the plunger piston 36.

The inward or rightward in-stroke movement of the transfer pump plunger 30, upon suitable rotation of drive shaft 14, develops a suction causing fuel to be drawn from reservoir passage 47 into the drive shaft central cavity 44 and through ports 40 and bore 42 past inlet valve 48 into the transfer pump cavity 51 to fill the cavity and a fuel line 52. Line 52 is closed at this time. During the out-stroke of plunger 30, the rise in pressure of the fuel in transfer pump cavity 51 closes inlet valve 43 and the trapped fuel is displaced through line 52, which opens in timed relationship, in a manner to be described.

The upper part of drive shaft 14 includes a cam 54, which, in its simplest form, is a circular cone with an axis parallel to and offset from the axis of drive shaft 14. The conical surface of cam 54 cooperates with a number of circumferentially spaced fuel injection plungers 56 (only one shown) each slidably movable in a separate bore 58 in housing 10. Each bore is connected at one end to the drive shaft central cavity 44, and at its opposite end to a fuel injection line 60. The number of bores, of course, will correspond to the number of cylinders in the engine with which the injection pump is to be used.

The longitudinal axis of each of the plunger bores 58 is perpendicular to the generatrix of the drive surface of cone 54 so that the flat bottom 59 of the pump plunger is tangential to the cam surface 62 to provide full and direct contact of the entire bottom surface area of the plunger with the cam surface. Although not shown, each plunger bore center line 63 is offset from the longitudinal axis of rotation of drive shaft 14, opposite to the direction of turning, indicated by the arrow, to insure efiicient utilization of the contact surfaces during up-stroke. While not shown, the plunger bores are all equally spaced circumferentially to permit the individual supply of fuel to each bore without overlap, in a manner to be described later.

Pump plungers 56 are free floating; that is, they are moved upwardly in a fuel pressurizing direction by the cam 54 and remain in their outermost positions until an additional quantity of fuel flowing into the chamber moves the plunger back towards the cam surface. This mode of operation permits variation in duration and quantity of injection of fuel supplied to the plunger chamber so as to vary the distance of its return movement toward the cam drive surface. The frictional resistance to movement of the plunger 56 is negligible.

The upper end of each pump plunger bore is machined to slightly larger diameters to provide a fuel charging chamber or cavity 64, containing a delivery valve assembly 65, and to receive a seal 66, the end of injection line 60, and a sleeve 68. More specifically, the delivery valve assembly 65 includes a hat-shaped delivery valve holder 70 having a reduced diameter closed lower portion 72 and apertured side walls 74. The holder supports a tubular, rubber-like delivery valve 76 having a central aperture or passage 78 open at the bottom to the space 79 between it and the holder, and at the top to a passage 80 through seal 66. The seal clamps over the end of the delivery valve and nests within the flared end 82 of fuel injection line 60. The delivery valve, holder, seal, and the end of line 60 are maintained in place by the sleeve 68, which is urged downwardly by a essentially star-shaped spring 84. The spring is locked in position against housing by a central nut 86.

The delivery valve 76 operates as follows. When the residual pressure of the fuel in line and bore 78 is greater than the'fuel pressure in chamber 64 acting through apertures 87 in holder 74 on valve 76, the rubberlike material of the valve expands radially outwardly to seal off flow at both the top and bottom portions of the valve. It should be noted that this radial outward expansion of the delivery valve provides the retraction volume for injection line 60 necessary to lower the residual pressure sufiiciently below the opening pressure of the injection nozzle, not shown, in a known manner, to prevent after-dribbling, secondary injection, etc. On the other hand, during the pumping cycle, when the pressure in plunger chamber 64 increases above the level of the residual pressure in injection line 60, the delivery valve 76 is compressed, permitting flow past the bottom and top diameters of the valve into central bore 78 and injection line 60. Thus, fuel will be injected into the engine cylinder.

The control of flow of fuel to and from the pump plunger injection chamber 64, as well as the control of the supply of fuel from the transfer pump discharge line 52. to chamber 64, is controlled, essentially, by a rotary valve 88. This latter valve is axially aligned with drive shaft 14, and is slidably and rotatably mounted in the upper reduced diameter portion 90 of housing bore 11. The valve is of the spool type, and has an axially-slotted lower portion 92 that is slidably pinned to drive shaft 14 to rotate with it. A spring 93, contained in a recess in the upper end of drive shaft 14, biases the valve 88 towards its uppermost position.

Valve 88 has a pair of spaced lands 94 and 96 interconnected by a reduced diameter neck portion 98 that defines an annular fuel chamber 100 between the neck portion and the wall of bore 90. The outer cylindrical surface 101 of land 96 has an axial groove 102 of narrow circumferential extent that opens inwardly into an annular passage 104. This latter passage is connected through chamber 100 to a passage 106 leading to a fuel filter 107.

The cylindrical outer surface 101 of land 96 normally blocks flow from transfer pump plunger line 52 through valve 88 into fuel filter inlet line 106 until the valve axial groove 102 becomes aligned with line 52 during rotation of drive shaft 14.

Upper valve land 94 contains two axially-extending grooves 108 and 110 in the surface of the valve, groove 108 being a fuel inlet or pump plunger injection chamber charging groove, while groove 110 is a fuel drain or spill port. Groove 108 has a substantially constant crosssectional area along its length, and is open continuously at its upper end to the top of land 94. At its lower end, gr ove 108 is of an axial extent to permit alignment at times with a plunger injection chamber charging or supply passage 112. Passage 112 intersects the pump plunger chamber bore to provide fuel to fill plunger chamber 64, and is closed at its outer end by a suitable plug 113.

Drain groove 110, on the other hand, tapers circumferentially along its axial length, as shown, to vary in crosssectional area to thereby vary the duration of injection of fuel as a function of the axial position of the rotary valve. Groove 110 is open at all times at its lower end to chamber 100 connected to fuel filter inlet line 106.

Fuel is supplied to rotary valve charging groove 108 from a fuel filter outlet line 114. The flow of fuel between line 114 and charging groove 108 in turn is controlled by a normally stationary, but movable, plunger 116. The plunger is axially slidably and rotatably received within housing bore 90. It has a cylindrical surface 117 that sealingly engages the Walls of bore 90 and would normally block flow from line 114 to charging groove 108. The plunger surface, however, is machined with an axially-extending groove 118 that varies in radial depth along its circumferential width. Thus, in eflect, it constitutes a metering orifice that varies in cross-sectional area as a function of its rotary position with respect to supply line 114. Plunger 116 also has a button-like end 120 that abuts the rotary valve land 94 to provide a communication chamber 121 between line 114 and charging groove 108.

Plunger 116 is rotated and moved axially by an engine throttle pedal actuated lever 122. More specifically the upper stem end of plunger 116 is formed with a large pitch external thread 124 that cooperates with the threaded interior of a normally stationary, but rotatably adjustable, maximum fuel quantity adjusting sleeve 126. The sleeve is threaded into an upper portion of housing 10, as shown, and is axially located by a jam nut 127. The fuel control lever 122 is rotatably mounted below the jam nut, and is reversely bent to form an upper portion 128 that is non-rotatably fixed to the uppermost end of the stem of plunger 116.

The lever 122 rotates counterclockwise in a horizontal plane from right to left, as seen in FIGURE 1, in response to depression of the conventional engine accelerator pedal (not shown) so as to cause a downward rotary movement of screw 124 and plunger 116. This results in presenting a greater cross-sectional area of groove 118 to inlet line 114, and, therefore, a lessening of the resistance to flow through the groove, and a greater quantity of fuel flow to rotary valve charging groove 108. Simultaneously, the downward movement of plunger 116 moves rotary valve 88 downwardly, which results in a quicker alignment of spill groove 110 with the pump plunger charging passage 112 for any one revolution of the rotary valve, and for a longer duration due to the increased cross-sectional area of the spill port. The duration of injection at any speed of rotation, therefore, is shorter due to the drain groove leftward opening edge 128 now being closer to inlet groove 108. Since the rightward drain groove edge 130, however, remains a fixed distance from the closing right edge of groove 108, a fixed injection ending position and timing is provided. Therefore, it will be seen that depression of the vehicle accelerator pedal not only varies the quantity of fuel injection, but also the duration of injection. The range of the axial movement of plunger 116 can, of course, be set at different heighths by turning the fuel delivery .adjusting sleeve 126 upon loosening jam nut 127.

Filter 107 includes an annular filter element 132, cooperating rubber seals, and a cover 136, that are held against the side of pump housing by a suitable bolt 138. The filter has annular inlet passages 140 connected to inlet line 106, and a branch line 141 intersecting a passage 142 connected to the fuel reservoir or tank, not shown. In this particular instance, the transfer pump plungers 30 always supply an excess of fuel to the fuel filter so that no starving of the injection pump plunger chambers 64 will occur at any time. Accordingly, line 142 contains a ball check type valve 143 for spilling excess fuel back to the tank. The ball check valve also is used to maintain a constant pressure in the filter chamber, and the fuel pressure, of course, will be determined by choice of the spring load on the ball check valve. The fuel passes inwardly through filter element 132 and then into the supply line 114.

In over-all operation, rotation of drive shaft 14 first causes an inward movement of the transfer pump plungers 30 to draw fuel into the central drive shaft cavity 44 from tank passage 46. The fuel passes through the plunger inlet valve 48 and fills the transfer pump plunger cavity 51. During this in-stroke of plunger 36, the outlet from passage 52 is sealed by the cylindrical surface 101 of rotary valve land 96. During the out-stroke of plunger 30, groove 102 in rotary valve land 96 now has rotated to a position aligning it with passage 52. Thus, fuel in passage 52 now connects with filter inlet passage 106, resulting in a transfer of the fuel into the fuel filter cavity. The excess fuel in this line, together with any vapor and air collected in the upper portion of the filter cavity, enters into filter inlet branch passage 141 and line 142, opens check valve 143, and returns to the fuel tank.

The amount of fuel that eventually is distributed to the injection nozzle lines 60 then passes through filter element 132 and enters main fuel supply passage 114. As described previously, the upper end of this passage, cooperating with throttle valve plunger 116, serves as an adjustable orifice system. At full load, with throttle lever 122 rotated fully, the largest cross-sectional area of groove 118 is aligned with passage 114, thereby permitting the largest quantity of fuel flow to the upper end of the rotary valve and to charging groove 108 in rotary valve land 94.

When drive shaft 14 rotates valve 88 to align one of the plunger injection chamber charging passages 112 With charging groove 108, fuel then flows into one of the chambers 64. As stated previously, charging groove 108 is designed so that it aligns with only one charging passage 112 at a time. The alignment starts, for example, when the conical surface of the drive cam 54 arrives at, say 10 to 40 before bottom dead center position relative to injection plunger 56.

In this instance, plunger 56 is still in the position to which it was moved by the conical cam, since there is no spring force acting on it to cause it to follow the cam as the cam recedes from its top dead center position, and fuel drained from chamber 64 When spill port 110 aligned with passage 112. During the alignment of charging groove 108 and one charging passage 112, however, the fuel entering chamber 64 now pushes the plunger 56 downwardly, charging the chamber for the next injection.

The quantity of the charging fuel flowing in during this time, of course, is a function of the flow resistance existing between the filter cavity and the injection plunger cavity. The fiow resistance will be changed by adjusting the position of the throttle plunger 116 by moving fuel control lever 122. At full load and full speed, therefore, metering groove 118 of valve 116 is fully open; the flow resistance, therefore, is low, and a fast downward rovement of the pump injection plunger 56 occurs. The system is so designed, however, that the plunger bottom 59 contacts the cam surface 62 before charging groove 108 moves away from alignment with passage 112, and after the cam 54 starts to push the plunger 56 upwardly.

As pump plunger 56 is moved upwardly, it displaces fuel'from plunger cavity 64 back into charging passage 112 and charging groove108, groove 118 and into supply line 114, since charging groove 108 is still partially aligned with charging passage 112. Injection will start the instant charging groove 108 moves out of alignment with charging passage 112. From this point on, the cylindrical surface of the rotary valve blocks charging passage 112, and, therefore, prevents a back flow of the fuel. This, of course, causes a rise in the pressure in the plunger injection chamber 64 sufficient to compress delivery valve 76 and flow fuel into injection line 60. The beginning of injection is set, for example, at, say, 30 to 50 after bottom dead center position of the surface of conical cam 54 relative to the injection plunger 56.

Fuel delivery continues during the up-stroke of plunger 56 until valve 88 has rotated to a position where the spill groove or drain port 110 arrives at the edge of charging passage 112. This immediately permits the fuel to flow through spill port 110, down into chamber between rotary valve lands 94 and 96, and out into fuel filter inlet passage 106. This reduces the pressure in the pump plunger chamber 64 to allow a closure or expansion of the delivery valve 76 and an end to injection. Since there is no spring acting to return plunger 56 to engagement with the cam surface 62, the plunger will remain in the highest position attained.

The rotary valve spill or drain groove is designed so that injection ends, for example, at say, 80 to before top dead center position of the cam surface 62 relative to plunger 56. Continued rotation of the rotary valve closes charging passage 112 again, at say, to after top dead center position of the cam surface.

Maximum delivery, of course, is determined by the displacement of pump plunger 56 during the time the closing edge of charging groove 108 and the Opening edge of spill groove 110 closes and opens, respectively, charging passage 112. The maximum delivery can be adjusted by rotating the sleeve 126 while simultaneously holding the fuel control lever 122 stationary against a maximum delivery stop, not shown. Rotation of sleeve 126 axially moves rotary valve 88 in the same direction, and, therefore, presents more or less cross-sectional area of spill groove 110 to charging passage 112, sooner or later than with the previous axial setting. Since the closing edge of charging groove 108 and the opening edge of spill groove 110 enclose a different angle with the center line of rotary valve 88, the duration of injection is varied, and the quantity of the maximum fuel delivery is changed.

At part-load fuel delivery, the throttle valve controlled lever 122 will be in a position whereby plunger 116 is rotated so that it is only partially aligned with inlet line 114; therefore, the restrictive orifice system is now such that the flow resistance between the filter cavity and charging groove 108 is elevated. During this time, therefore, the plunger injection chamber 64 will be only partially charged up during the time charging groove 108 aligns with charging passage 112, since the fuel quantity has now been reduced. When charging groove 108 closes, therefore, the injection pump plunger 56 has been depressed downwardly only a portion of the total distance from its highest position, and its bottom face 59 still is a distance away from cam surface 62. At this particular time, therefore, fuel delivery starts only when cam surface 62 makes contact with the bottom 59 of the injection pump plunger 56. It will be clear, therefore, that a smaller quantity of fuel will be injected into injection line 60 at this time, and that the amount will vary progressively with the progressive restriction caused by the variable position of plunger 116.

Delivery of fuel ends as the opening edge of spill groove 110 arrives at the opening to charging passage 112. The amount of part-load charging, therefore, is determined not only by the flow resistance, as set by the position of plunger 116, but by the time available for charging during the alignment of the charging groove 108 with the charging passage 112. Since this time changes with the speed of drive shaft 14, the delivery is a function of the pump speed, meaning a decrease in fuel delivery at increased speeds. This peculiarity of the delivery characteristic eliminates the necessity of an idle speed fuel control governor.

It will be seen, therefore, that with the construction described, constant injection endings at very engine speed, and gradually advanced endings towards higher loads, are provided by proper shaping of the rotary valve spill groove opening edge 128. It will also be seen that the construction provides an injection duration varying as a function of the load, since lower speeds resulting from higher loads provides more time for the fuel to enter charging groove 108 and charging passage 112, and the more open positions of groove 118 in throttle plunger 116 lowers the resistance to flow.

FIGURE 2 shows a modified form of the fuel injection pump as described and shown in FIGURE 1. The FIGURE 2 pump, for example, incorporates a two-piece cast iron, die cast aluminum, or other suitable housing 10', a slightly modified rotary valve 88', a slidable but non-rotatable rotary valve actuating plunger 116', and a separate throttle lever actuated needle valve assembly for controlling idle speed operation of the pump. Since the details of construction and assembly and operation of drive shaft 14, the transfer pump plungers the filter 108, and the pump fuel injection plungers 56' and delivery valves 76' are substantially the same as already 8 shown and described in connection with FIGURE 1, they are not repeated.

In FIGURE 2, the restrictive orifice assembly 114, 116 of FIGURE 1 is replaced in part by a simple, axially movable throttle lever actuated plunger 116, a variable cross-sectional area rotary valve charging groove 108, an idle speed control needle valve assembly 144, and a multiple throttle lever control linkage 122. More specifically, the plunger injection chamber charging passage 112, in this instance, has an inlet at right angles to the cylindrical surface of rotary valve 88'. The rotary valve charging groove 108 again is open at all times to the top of rotary valve land 94', like in FIGURE 1. However, groove 108 varies in cross-sectional area along its axial length, and extends essentially diagonally with respect to the axis of rotation of valve 88'. It will be clear, therefore, that axial movement of rotary valve 88' not only will change the quantity of but duration of fuel injection by changing the point of beginning and ending of injection for each revolution. The shape and location of spill groove 110', in this instance, remains essentially the same as shown in FIGURE 1.

The control linkage 122' includes a primary fuel control lever 146, a secondary fuel control lever 148, and a thermostatic idle speed control cam 150. Both the primary and

secondary levers

146 and 148 are mounted about a stationary pivot shaft 152 provided on a linkage support bracket 1-53 secured to housing 10. The upper end of primary lever 146 would be suitably connected, by means not shown, to the vehicle accelerator pedal. The two fuel control levers have essentially rightangled push prongs 154 and 156 each adapted to cooperate with the other lever in a manner to be described. Lever 148 also carries a secondary idle speed control adjusting screw 158 that cooperates with the surface of the idle speed control cam 150. Secondary lever 148 further carries a ball contact member 160 for engagement with the plunger 116.

The primary fuel control lever 146 is fixed to a short lever 162 that threadedly receives an idle speed adjusting screw 164. This latter screw bears against the end of an idle speed control needle valve 144 that is slidably and sealingly mounted in the pump housing so as to project in a flow controlling manner into the main fuel inlet passage 114'. The needle valve is spring-biased in a direction out of line 114' and against the adjusting screw 164. It will be clear, of course, that the needle valve will be adjusted by adjusting screw 164, to provide the desired idle speed operation.

The lower portion of charging groove 108 is narrow so that at the idle speed load range the charging groove aligns with only one of the charging passages 110' at a time. In this range, the amount of fuel that charges up the injection pump plunger cavity 64' is a function of the fuel pressure in the filter cavity, the flow resistance of the passages between the filter cavity and the plunger cavity, and the time of alignment of the idling portion of the charging groove 108' with the charging passage 112. The pressure and the flow resistance of the passages are selected so that without throttling by needle valve 144, even at the higher speeds of rotation of rotary valve 88', when the alignment time is shortest, the fuel is able to push the injection pump plunger 56' down against the cam surface 62' during alignment.

When throttling is not applied, the delivery is determined by the opening and closing edges of the charging and spill grooves 108 and 110 on rotary valve 88' in the same manner as at normal operation.

However, by adjusting screw 164, throttling is applied to the supply line. The flow resistance between the filter cavity and the plunger cavity 64' is increased to a value such that the pressure can transfer only enough fuel during the alignment of the charging groove 108' and passage 112' to partially charge the plungers. The plunger 56 is then moved down less than the distance necessary to contact the cam surface during the alignment of the charging groove and passage. Delivery then begins only when the cam reaches the plunger bottom and moves it upward. Delivery ends, of course, when the opening edge of spill groove 110 uncovers passage 112'.

By throttling, the fuel delivery is decreased to provide say a 500 r.p.-m. engine idle speed. Under this condition, the delivery of the pump is speed sensitive; e.g., if the operating speed increases for some reason, the length of time of the alignment between charging groove 108 and passage 112 decreases. Since the pressure and the flow resistance of the supply line are now constant, the charging of the plungers 56, therefore, decreases, which lowers the speed to the desired level. Thus, the pump automatically counteracts for changes in the engine friction; therefore, hunting is prevented and stable engine idle operation is assumed.

The maximum fuel delivery can be adjusted by a screw (not shown) to limit the travel of the fuel control levers 146 and 148 toward the left side portion of FIGURE 2.

The upper end of secondary fuel control lever 148 would be connected to an ignition timing regulator (not shown) to achieve regulation in the function of fuel delivery.

The temperature sensitive element of the idle control system is the thermostatic idle control cam 150. The cam would be operated by a thermostatic coil. Depending upon the engine temperature, the cam would set the idle position of the fuel control levers 146 and 148 and the idle control valve 144 to higher or lower delivery positions.

In operation of this embodiment, the primary and secondary control levers 146 and 148, and needle valve 144, are located in the positions shown for idle speed operation. The secondary fuel control lever 148 is located against the control cam 150, thereby locating the primary control lever against the push prong 156. This locates the small lever 162 and needle valve 144 in the position desired to maintain the idle speed r.p.m. chosen. As can be seen by the position of charging groove 108' at this time, only the lower portion of the charging groove will register with charging passage 112, and only for a short duration before charging passage 112 is connected to spill groove 110'.

When the accelerator pedal is depressed, the primary fuel control lever 146 rotates counterclockwise gradually, resulting in the gradual termination of the throttling of fuel supply line 114 by valve 144, and a gradual increase in fuel delivery. This provides a smooth transition between idle and normal operation. After a predetermined rotation, the throttling is completely terminated and prong 154 of primary lever 146 contacts the side of secondary lever 148 and pushes it to the left. During this motion, push ball 160 moves down and through push rod 116 lowers the rotary valve 88. This causes an earlier injection beginning than for the idle speed setting, and, as the depression continues, an increasing quantity of fuel fiow, in a manner similar to that provided by the construction shown in FIGURE 1. This increases the fuel delivery to that provided during the normal operating range. The position of the fuel injection plunger 56' relative to the cam surface 62 will be determined by the quantity of fuel flowing into plunger chamber 64', and will determine the distance the plunger will return towards the actuating conical cam surface 62 in the same manner as described in connection with FIGURE 1.

From the foregoing, it will be seen that the invention provides a liquid fuel injection pump that can provide suctionless throttling, a delivery of fuel to individual fuel injection plungers one at a time, the use of free-floating injection pump plungers driven by a conical cam, and the use of a rotary metering valve controlled by a throttle pedal lever linkage assembly.

While the invention has been illustrated in its preferred embodiments in the figures, it will be clear to those skilled in the arts to which the invention pertains that many changes and modifications may be made thereto without departing from the scope of the invention.

I claim:

1. A liquid fuel injection pump comprising, a longitudinally extending rotatable drive shaft having a cam drive surface concentrically mounted thereon and extending circumferentially therearound, a reciprocable freefloating pump plunger having a longitudinal axis perpendicular to the generatrix of said cam surface and having an end drive surface tangential to and engageable at times with said cam surface to be moved thereby in a fuel pumping and pressurizing direction, a bore having one end slidably containing said plunger and having an intermittently opened fuel outlet at the opposite end defining a fuel chamber therebetween, a source of fuel under pressure, conduit means connecting said source to said fuel chamber to act on and move said plunger in a return direction towards said cam surface when said outlet is closed, and fuel flow control means operably controlling the supply of fuel to and drain of fuel from and the pressure build-up in said chamber to control the extent of the return travel of said plunger towards said cam surface.

2. A pump as in claim 1, said control means including fuel flow metering means variably movable to progressively vary the quantity of fuel flow to said chamber whereby said plunger moves progressively towards said cam surface a distance proportionate to the quantity of fuel flow to said chamber.

3. A pump as in claim 1, said control means including a valve rotatable with said drive shaft, said valve having circumferentially spaced fuel supply and drain ports in the surface of said valve and alternately connected to said conduit means upon rotation of said valve for variation of said fuel flow to said chamber as a function of the speed of rotation of said valve.

4. A pump as in claim 3, said drain port extending axially and tapering circumferentially along a portion of its length, said valve being axially slidably movable, and actuating means to slide said valve to thereby vary the duration of and quantity of fuel flow to said chamber for a given speed of rotation of said valve.

5. A pump as in claim 4, said means for sliding said valve comprising a manually operated control.

6. A pump as in claim 4, said valve supply port being open to said source at all times and comprising an axially and circumferentially extending groove in the surface of said valve, said groove varying in cross-sectional area along its axial extent, the sliding of said valve by said manually operated control varying the quantity and duration of fuel flow to said chamber.

7. A pump as in claim 4, said valve supply port having a continuously open fluid inlet, said control means including variable area flow control means movable by said actuating means between a non-restricting fluid flow position and positions variably restricting the flow from said source to said supply port.

8. A pump as in claim 3, said valve supply port having a continuously open fluid inlet and a fuel supply groove extending axially at an angle to the axis of rotation of said valve, means for sliding said groove axially, said groove tapering circumferentially along its length for varying the duration and quantity of fuel supplied to said conduit means as a function of the axial position of said valve and groove.

9. A liquid fuel injection pump comprising, a longitudinally extending rotatable drive shaft having an essentially conical cam drive surface concentrically mounted thereon and extending circumferentially therearound, a plurality of circumferentially spaced reciprocable freefloating pump plungers together surrounding said shaft and each extending at an angle to but in the same general direction as the longitudinal axis of said shaft, each of said plungers having a longitudinal axis perpendicular to the generatrix of said cam surface and having an end drive surface tangential to and engageable at times with said said cam surface to be moved thereby in an out- Ward fuel pumping and pressurizing direction, a bore associated with each plunger having one end slidable containing said plunger and having intermittently opened fuel outlet at the opposite end defining a fuel chamber therebetween, a source of fuel under pressure, a plurality of conduit means surrounding said drive shaft and separately connecting said source to separate ones of said fuel chambers to act on and move each of said plungers progressively in a return direction towards said cam surface a distance proportional to the change in the amount of fuel in the associated chamber when said outlet is closed, and fuel flow control means including means operably connectable to said conduit means controlling the supply of fuel to and drain of fuel from and the pressure build-up in said chambers to determine the extent of return movement of said plungers.

10. A pump as in claim 9, said control means including fuel flow metering means variably movable to progressively vary the quantity of fuel flow to said chambers and effect a progressive movement of said plungers towards said cam surface a distance proportionate to the said quantity of flow to said chambers.

11. A pump as in claim 1, said control means including a valve rotatable with said drive shaft, said valve having circumferentially spaced fuel supply and drain ports in the surface of said valve alternately connected to said conduit means upon rotation of said valve, the circumferential spacing of said plungers and bores effecting a registry of said ports sequentially and individually with separate ones of said bores and varying the fuel flow to each of said bores as a function of the speed of rotation of said valve.

12. A pump as in claim 10, said control means including a valve axially aligned with and rotatable with said drive shaft and having a pair of circumferentially spaced fuel supply and drain ports in the surface of said valve alternately supplying fuel to and draining fuel from individual ones of said conduit means for varying the fuel flow to each of said conduit means as a function of the speed of rotation of said valve.

13. A pump as in claim 12, said valve being axially slidably mounted to said drive shaft, said drain port varying in cross-sectional area along its axial length, and actuating means to move said valve axially to vary the duration of fuel supply to individual conduit means.

14. A pump as in claim 12, said supply port varying in cross-sectional area along its axial extent whereby axial movement of said valve by said actuating means varies the quantity of fuel flow as a function of the movement of said valve.

15. A pump as in claim 13, said fuel flow control means including fuel flow restricting means in said conduit means variably movable by said actuating means in said conduit means to control the supply quantity of fuel to said supply port.

16. A pump as in claim 13, said actuating means comprising manually operable lever means operably connected to axially movable force applying means, said force applying means bearing against said rotary valve means for axially moving said latter valve means upon movement of said lever means.

17. A pump as in claim 15, said supply port being open to said source of fluid at all times.

18. A pump as in claim 17, said flow restricting means comprising a valve member rotatable by said actuating means and having a fuel flow port varying in cross sectional area along its circumferential extent.

19. A pump as in claim 17, said flow restricting means comprising a needle valve variably movable into said conduit means by said actuating means, and spring means urging said valve out of said conduit means.

20. A liquid fuel injection pump for a throttle lever controlled engine comprising, a pump housing containing an essentially central bore, a longitudinally extending drive shaft rotatably mounted in said housing bore and having a conical cam drive surface extending circumferentially therearound, a plurality of circumferentially spaced reciprocable free-floating pump plungers each having a longitudinal axis offset from and at an angle to the axis of rotation of said drive shaft and perpendicular to the generatrix of said cam surface and having an end drive surface tangential to and engageable at times With said cam surface to be moved thereby in a fuel pumping and pressurizing direction, said housing having a bore associated with each plunger, said plunger bore having one end slidably containing said plunger and having an intermittently opened fuel outlet at the opposite end defining a fuel chamber therebetween, a source of fuel under pressure operably connected to said shaft bore, a plurality of conduit means circumferentially spaced around and each extending transversely of said shaft bore and connecting said source individually to said fuel chambers to act on and move each of said plungers progressively towards said cam surface a distance proportional to the quantity of fuel in the associated chamber when said outlet is closed, rotary valve means rotatable with said drive shaft and axially movable relative thereto and having a pair of circumferentially spaced essentially axially extending fuel supply and drain grooves in the surface of said valve means, means operably connecting said fuel supply grooves at all times to said source, the surface of said valve means, being in registry with said conduit means at all times whereby fuel is supplied thereto and drained therefrom as said grooves are aligned therewith during rotation of said valve means, said drain groove varying in cross-sectional area along its axial extent, axially movable means between said source and rotary valve means engageable with said rotary valve means for moving said valve means axially to vary the duration of injection as a function of the cross-sectional area of said drain groove, and means operably connecting said axially movable means to said throttle lever for movement thereby.

References Cited UNITED STATES PATENTS 1,990,263 2/1935 Benedek 103-37 2,391,174 12/1945 LoWnsbery 103-2 2,405,938 8/1946 Beeh 103-227 X 2,708,880 5/1955 Peterson 103-174 2,709,339 5/1955 Edelman ct al. 103-5 3,050,001 8/1962 Links 103-2 3,095,824 7/1963 Elfes 103-150 3,311,100 3/1967 Maddalozzo 123-140 WILLIAM L. FREEH, Primary Examiner.