US3371610A - Auxiliary filling means for fuel injection pumps - Google Patents

Description

March 5, 1968 3,371,610

FOR FUEL INJECTION PUMPS F. DE LUCA ET AL AUXILIARY FILLING MEANS 5 Sheets-Sheet 1 Filed Feb. 16, 1966 Flcz.

INVENTORS FRANK DE LUCA THEODORE S. CHMURA ATTYS- March 5, 1968 F. DE LUCA ET AL 3,371,610

AUXILIARY FILLING MEANS FOR FUEL INJECTION PUMPS Filed Feb. 16, 1966 3 Sheets-Sheet 2 FIGB.

INVENTORSi FRANK DE LUCA BY THEODORE S. CHMURA ATTYS.

March 5, 1968 F. DE LUCA ET AL AUXILIARY FILLING MEANS FOR FUEL INJECTION PUMPS Filed Feb. 16, 1966 5 Sheets-Sheet (5 INVENTORS FRANK DE LUCA THEODORE S. CHMURA BMW ATTYS.

United States Patent Office 3,371,610 Patented Mar. 5, 1968 3,371,610 AUXILIARY FILLING MEANS FOR FUEL INJECTION PUMPS Frank De Luca, Thompsonville, Conn., and Theodore S.

Chmura, Chicopee, Mass, assignors to American Bosch Arma Corporation, Springfield, Mass., a corporation of New York Filed Feb. 16, 1966, Ser. No. 527,885 11 Claims. (Cl. 103-2) ABSTRACT on THE DISCLOSURE Auxiliary filling means for single plunger distributor type fuel injection pumps comprising in a preferred form one or more axial grooves in the bore of the control sleeve adapted to provide communication between the sump and a spill port of the plunger and hence the fuel distribution chamber during the suction stroke of the plunger. In another form, the auxiliary filling means comprises at least one fill port in the plunger connected with the plunger bore and axially spaced above the spill ports, the fill port being adapted to communicate with the sump during a portion of the plunger suction stroke.

The present invention relates generally to fuel injection pumps of the single plunger distributor type and relates more particularly to a novel auxiliary filling arrangement for the fuel distributor chamber of such pumps.

A fuel injection pump of the single plunger type for which the present invention was developed is shown in US. Patent No. 2,518,473, issued Aug. 15, 1950, and assigned with the present application to a common assignee. In this type of pump, a reciprocating and rotating plunger pumps fuel from a fuel distribution chamber, sequentially to the cylinders of the fuel injection engine-on which it is mounted, each stroke of the plunger supplying an injection of fuel to an engine cylinder. Fuel is supplied to the fuel distribution chamber 'by a fuel supply pump, the fuel entering the chamber through supply passages which are fully opened tothe chamber only at the bottom of the plunger stroke. The amount of fuel pumped to the engine is controlled by means of an axial bore in the plunger which, in conjunction with radial spill ports, connects the fuel distribution chamber with a sump in which fuel is maintained at the fuel supply pressure. An adjustably positioned control sleeve on the plunger in the sum covers the spill ports during the pumping portion of the plunger stroke. When the spill ports clear the sleeve, the fuel distribution chamber pressure is reduced to the supply pressure, causing a check valve to close and terminate the fuel injection.

Difiiculties have been experienced with this type of pump at high speeds in maintaining the full discharged capacity of the pump. This is due to the failure of the fuel distribution chamber to fill with the necessary volume of fuel, even at increased fuel supply pressures. A further problem with this type of pump has resulted from the vacuum condition caused during the return stroke of the plunger after the spill ports have been reclosed and before the fuel supply passages have been opened, the chamber pressure during this period dropping below the vapor pressure of the fuel. The repeated collapse of the vecuum and transformation of fuel from the vapor to the liquid phase causes cavitation erosion of the fuel supply ports and fuel distribution chamber.

In the preferred form of the invention, the auxiliary filling means employed to correct these difiiculties comprises one or more axial grooves in the bore of the control sleeve adapted to communicate with a spill port of the plunger and hence the fuel distribution chamber during the return stroke of the plunger. Since the sump fuel is maintained at the fuel supply pressure, filling of the fuel distribution chamber continues during the entire suction stroke of the plunger and vaporization of the fuel in the chamber is prevented.

Accordingly, it is a first object of the present invention to provide auxiliary filling means to insure filling of the fuel distribution chamber during the entire suction stroke of the plunger.

Another object of the invention is to provide a filling arrangement which prevents the vaporization of fuel in the fuel distribution chamber and the resultant cavitation erosion of the chamber and fuel supply passages.

A still further object is to provide auxiliary filling means which permits efl-lcient high speed pump operation with normal fuel supply pressures.

An additional object is to provide auxiliary fuel filling means which will allow normal operation of the engine in its designed rotational direction but will prevent the engine from operating in a reverse rotational direction.

For a better understanding of these and other features and advantages of the present invention, reference is made to the following detailed description and the accompanying drawings in which:

FIG. 1 is a side elevational view, partially in section, of a fuel injection pump embodying one form of the fuel distribution chamber auxiliary filling means in accordance with present invention;

FIG. 2 is an enlarged sectional side elevational view of the fuel distribution arrangement of the fuel injection pump of FIG. 1;

FIG. 3 is a fragmentary sectional view taken along line 3-3 of FIG. 1;

FIG. 4 is an enlarged fragmentary sectional view of the plunger, fuel distribution chamber and sum similar to FIG. 2, showing the plunger at the bottom of its suction stroke;

, FIG. 5 is an enlarged fragmentary sectional view similar to FIG. 4 showing the plunger at the top of its compression stroke;

FIG. 6 is a sectional view taken along line 66 of FIG. 4;

FIG. 7 is a sectional view taken along line 77 of FIG. 5;

FIG. 8 is a perspective View of the fuel pump control sleeve;

FIG. 9 is a fragmentary sectional view of a modified form of control sleeve;

FIG. 10 is a graph relating the pumping sequence to the plunger movement through its cycle of operation;

FIG. 11 is a sectional view similar to FIG. 6 showing an alternate form of the control sleeve and plunger;

FIG. 12 is a sectional view similar to FIG. 11 showing another form of the control sleeve and plunger;

FIG. 13 is a sectional view similar to FIG. 11 showing still another form of the control sleeve and plunger;

FIG. 14 is an enlarged fragmentary sectional view similar to FIG. 4 illustrating an alternative embodiment of the plunger and control sleeve with the plunger shown at the bottom of its suction stroke;

FIG. 15 is an enlarged fragmentary sectional view similar to FIG. 14 showing the plunger at the top of its compression stroke; and

FIG. 16 is a sectional view taken along line 16-16 of FIG. 14.

Referring to the drawings and particularly FIGS. 1 and 3, a fuel injection pump, generally designated 10, of the general type illustrated in the above-mentioned Patent 2,518,473 is shown including a hydraulic pump head 12 on a main housing 14. A governor housing 15 con nected with the main housing contains the governor 16.

The hydraulic pump head 12 includes a central vertical bore 18 within which a plunger 20 is slidably disposed, the plunger in conjunction with the bore plug 21 defining a fuel distribution chamber 22 in the upper end of the bore. Near its lower end, the plunger passes through a sump or spill chamber 23 in the pump head formed by a transverse passage in the bend. The plunger is rotatably and reciprocally driven for delivering fuel to cylinders of an internal combustion engine (not shown) in a manner to be presently described.

The pump is driven by the engine through a coupling to cam shaft 24, which is journaled in main housing 14 by suitable bearings. A cam 26 on the cam shaft having a plurality of cam lobes 28 co-acts with roller 30 of tappet 32, and in conjunction with helical return springs 34 and 36, effects a reciprocating vertical stroke of the plunger.

A drive gear 38 On cam shaft 24 meshes with gear 40 on the lower end of vertical shaft 42, causing rotation of shaft 42 and the additional gear 44 on the upper end thereof. Gear 44 in turn drives a gear 46 slidably keyed to the plunger 20. Rotation of the cam shaft thus causes both reciprocation and rotation of the plunger.

A governor shaft 50 is integral with cam shaft 24 to rotate therewith. The governor shaft supports the flyweight assembly 52, the centrifugal action of which through spring loaded linkage 54 governs the position of fulcrum lever 56 pivotally connected thereto. The fulcrum lever is further controlled by the operating lever 57 connected to the engine throttle linkage. The fulcrum lever 56 includes a cam 58 which engages stop plate 60 at full engine speed and/ or full load.

The governor fulcrum lever 56 is connected by a linkage to a fuel control sleeve 62 slidably mounted on the plunger 20 in the sump 23. This linkage 70 includes a control rod 72 extending from the fulcrum lever 56 to a connecting link 74 which in turn is connected to rotatable stub shaft 76 mounted in hydraulic pump head 12, as shown in FIG. 3. Stub shaft 76 has a pin 78 eccentrically mounted as an extension of the shaft at its terminal end to engage a slot 80 in the control sleeve, as shown in FIGS. 3, 6 and 8. Rotation of the stub shaft by the linkage 70 provides a sliding movement of the control sleeve by co-action of the eccentric pin 78 and slot 80. The position of the control sleeve on the plunger is thus determined by the position of the fulcrumlever 56 which is controlled by the governor mechanism and the engine throttle.

Lubrication of the plunger is provided by the fiow of lubricating oil from the cam shaft region through passage 84, filter 86, and passage 88 as shown in FIG. 2. The gear 46 is also lubricated by a flow of oil from passage 88 through the passage 90. A lapped fit is provided between plunger 20 and bore 18 to reduce to a minimum leakage of fuel from the sump 23 into the lower portion of bore 18 and seepage of oil from the lower portion of the bore upwardly into the sump.

The hydraulic pump head 12, as shown in FIG. 3, has inlet ports 91 and 92 to which fuel under pressure is supplied by a suitable fuel supply pump (not shown). Inlet ports 91 and 92 communicate respectively with fuel supply passages 93 and 94 which open into fuel distribution chamber 22, and with passages 95 and 96 respectively which open into sump 23. The pressurized fuel passes from passages 93 and 94 into the fuel distribution chamber when the plunger exposes the passages to the chamber and is pumped sequentially to the cylinders of the engine by the upward strokes of the plunger, the fuel in the chamber being forced through fuel delivery check valve 100, as shown in FIG. 2. Fuel flowing through the check valve passes around the valve plunger 101 and through passages 102 and 104 in closing plug 106 to an annulus 108 of the plug. The fuel flows from annulus 108 through passage 110 in the pump head into annulus 112 of the plunger and then into plunger groove 114, which sequentially communicates with spaced distributor passages 116 in the pump head during rotation of the plunger. Each distributor passage 116 communicates with an outlet passage 118 from which fuel is discharged through suitable connecting tubing 120 to one of the cylinders of the fuel injection engine. The rotation of the plunger is timed to sequentially position the plunger groove in alignment with the distributor passages for delivery of fuel to the cylinders in the proper phase relation to the engine cycle.

The amount of fuel delivered by the pump is regulated by the position of the control sleeve 62 on the plunger in the following manner. The plunger includes an axial bore 122 which extends from the upper end of the plunger to the radial spill ports 124 communicating with the sump as shown in FIGS. 3, 4, 5 and 6. When the spill ports are covered by the control sleeve, fuel cannot pass from the fuel distribution chamber through bore 122 to the sump. However, when the spill ports clear the sleeve toward the end of the plunger pumping stroke, the pressure in the distribution chamber is reduced to the sump pressure, permitting the check valve 100 to close and stopping further fuel delivery. By adjustment of the sleeve position, the duration of the pumping action and hence the amount of fuel delivered may be accurately controlled.

The fuel pump structure and operation as described so far are conventional and are similar to that of the above-mentioned US. Patent No. 2,518,473. It can be understood from the above that during the return or suction stroke of the plunger, a period exists during which both the spill ports and the fuel supply passages are respectively closed by the control sleeve and the plunger. This period is especially pronounced when the control sleeve is at an elevated position in the sump such as at maximum fuel delivery. In order to prevent a vacuum condition in the fuel distribution chamber during this period and consequent cavitation erosion of the chamber and fuel passages, and further to insure the filling of the fuel distribution chamber over a full range of engine speeds with a normal fuel supply pressure, an auxiliary fuel distribution chamber filling means is provided as described below.

In the preferred form of the invention, the auxiliary filling means is characterized by axial grooves 126 along the plunger bore 128 of the control sleeve as shown in FIGS. 4, 5, 6 and 7. The engine of the illustrated pump being an eight cylinder engine, one groove is provided in the control sleeve bore for each cylinder of the engine although a lesser number could be used in view of the multiple spill ports as discussed below. As the plunger is rotated one eighth turn for each reciprocation, each of the spill ports is aligned with a groove during suction strokes of the plunger as shown in FIG. 6, so that the fuel distribution chamber receives fuel from the sump through the grooves after the spill ports are closed and before the fuel supply passages are opened during the suction strokes. As the plunger moves upwardly on its pumping stroke, the rotating plunger moves the spill ports out of alignment with the grooves, as shown in FIG. 7. The grooves thus serve as auxiliary filling means to insure a filling of the fuel distribution chamber during the entire suction stroke of the plunger, supplementing the fuel supply passages 93 and 94 during the terminal portion of the stroke.

Considering the operation of the pump in detail, as the plunger moves downwardly exposing fuel supply passages 93 and 94, fuel flows into distribution chamber 22, as shown in FIG. 4. At the same time the spill Ports of the plunger are aligned with axial grooves of the control sleeve so that the chamber is supplied with fuel by both the fuel supply passages and the sump. As the plunger moves upwardly during the pumping stroke, as shown in FIGS. 5 and 7, the spill ports 124 are rotated out of communication with the grooves so that the fuel is trapped in the fuel distribution chamber when the fuel supply passages are closed by the plunger. When the pressure of fuel in the chamber is sufficient to open the fuel delivery check valve 100, fuel is discharged to one of the cylinders. The fuel discharge is terminated when spill ports 124 are uncovered as they move above control sleeve 62 as shown in FIG. 5, the spill ports dropping the pressure of the fuel remaining in the fuel distribution chamber to the sump fuel supply pressure and thus allowing the check valve 100 to close.

As the plunger begins downward movement, the spill ports move into the control sleeve. At the same time, the spill ports are rotated into communication with the axial grooves of the control sleeve so that fuel passes from the pressurized sump through the grooves, spill ports and plunger bore to the fuel distribution chamber. Upon the subsequent opening of the fuel supply passages, fuel is supplied to the fuel distribution chamber from the fuel supply passages as well as through the plunger. This arrangement insures a continuous inflow of fuel to the fuel distribution chamber during the suction strokes of the plunger, thereby preventing vaporization of fuel in the chamber and the consequent cavitation erosion of the chamber and fuel passages. Furthermore, the additional fuel passage in the plunger insures passage of an adequate volume of fuel to the chamber over the full range of engine speeds.

The sleeve grooves may be semi-circular as shown in FIG, 7, triangular as shown in the modified control sleeve of FIG. 9, rectangular or any other suitable shape.

Rotational movement of the control sleeve relative to the plunger must of course be prevented so that the proper timing sequence is maintained in opening the sleeve grooves to the fuel distribution chamber. For this purpose in the present instance sump 23 is rectangular in cross section as shown in FIG. 6 and the control sleeve is square in cross section but of slightly smaller dimensions than the shorter sides of the rectangle so that two opposite sides of the control sleeve fit closely adjacent two opposite sides of the sump. The square sleeve in the rectangular sump effectively prevents sleeve rotation which, for best efi'iciency of the pump, should be limited to one degree or less.

Should the engine reverse itself, the spill ports 124 of the plunger and the grooves 126 of the control sleeve will be out of phase with one another so that fuel will be spilled from the fuel distribution chamber through the plunger bore, spill ports and grooves, on the upward or compression stroke of the plunger, thereby preventing the normal discharge of fuel from the fuel distribution chamber. In this manner, the auxiliary fuel filling means provided by the grooves serves a further function in allowing normal operation of the pump in its intended rotational direction while preventing the pump and hence the engine from running backward.

Referring to FIG. 10, the pumping sequence is graphically illustrated with respect to the plunger movement with points A of the graph curve indicating the topof the pumping strokes and points B the bottom of the suction strokes. Thus, filling of the fuel distribution chamber occurs during the plunger movement from point A to point B. During the initial portion of the suction stroke with a typical sleeve position, the spill ports return into the control sleeve at point C and without the sleeve grooves would serve only briefly to pass fuel into the fuel distribution chamber. The Spill ports, however, communicate with the grooves from point D to point E to provide filling of the fuel distribution chamber, the interval of communication of the spill ports and grooves being indicated by the time X. The fuel supply passages are opened by the plunger for filling of the fuel distribution chamber at point P and they are closed by the plunger at point G. Heretofore, the fuel in the fuel distribution chamber became vaporized in the expanding sealed fuel distribution chamber during the time interval Y between points C and F. With the present invention, the fuel distribution chamber is continuously connected with the fuel supply during the suction stroke and vaporization of the fuel is eliminated.

Fuel discharge from the fuel distribution chamber occurs from points G to H during the interval Z, the discharge of fuel being completed at point H when the spill ports move above the control sleeve.

The number of spill ports in the plunger communicating with the plunger bore may vary depending on the demands of the engine to be driven by the pump. The spill function and additional filling function performed by the plunger ports could, of course, be performed by only one spill port. With the eight axial grooves shown in the bore of the control sleeve, there are a number of spill port arrangements that could be employed. For example, a single spill port, two diametrically opposed spill ports, two perpendicularly oriented ports or the illustrated four spill ports spaced at 90 could be employed with the eight groove control sleeve shown in FIG. 7.

When the fuel injection pump is to be operated with a six cylinder engine, six equally spaced axial grooves in the control sleeve might conveniently be employed as shown in FIG. 11. Although six spaced spill ports are shown in this arrangement, the plunger could be provided with a single spill port, two diametrically opposed spill ports or three symmetrically spaced spill ports to operate the pump in accordance with the invention.

With a four cylinder engine, four equally spaced axial grooves could be used along the bore of the control sleeve. In this arrangement the plunger could be provided with one radial spill port, a pair of diametrically opposed spill ports, or four perpendicularly oriented spill ports as shown in FIG. 12 to operate the pump.

Similarly, with a three cylinder engine, three equally spaced axial grooves could be provided along the bore of the control sleeve. The plunger could be provided with a single port or three symmetrically spaced spill ports as shown in FIG. 13, to operate the pump. Although the number of sleeve grooves is conveniently equal to the number of engine cylinders, with a plurality of spill ports in the plunger, a smaller number of grooves would suffice.

FIGS. 14, 15 and 16 illustrate an alternative form of the auxiliary fuel filling means for providing flow of fuel from the sump to the fuel distribution chamber. The hydraulic pump head of this embodiment is similar to that shown in FIGS. 4 and 5 and similar parts are identified by the same number designators with the addition of primes thereto. The primary difference in structure lies in the plunger 20 and bore 152 of control sleeve 62. As can be seen in FIG. 16, bore 152 of the control sleeve does not have axial grooves. In this embodiment, the plunger is provided with a set of upper ports 154 communicating with. the plunger bore and axially spaced a distance above spill ports 124'. The upper ports 154 move from a position in the sump above control sleeve 62' on the termination of the suction stroke of the plunger, as shown in FIG. 14, to a position within central vertical bore 18 of the pump head as shown in FIG. 15. Upper ports 154 in the plunger provide a fuel flow path with the plunger bore for filling the fuel distribution chamber in conjunction with the fuel supply passages 93' and 94'. The axial spacing between spill ports 12-4 and upper ports 154 may be selected so that the upper ports 154 communicate with the sump for a longer or shorter interval of the plunger cycle as desired. The upper ports should be disposed on the plunger so as to be covered by the pump head during the pumping portion of the plunger stroke.

FIG. 14. As the plunger continues to descend, the upper ports 154 are exposed in the sump, providing an additional fuel path for filling the fuel distribution chamber in conjunction with the fuel supply passages. During the major portion of the suction stroke the spill ports 124' are within sleeve 62 so fuel flow therethrough is prevented. As the plunger moves upwardly in its pumping stroke, upper ports 154 are moved within bore 18 in the pump head and the fuel supply passages are, at approximately the same time, closed by the plunger so that the fuel in fuel distribution chamber 22' is pumped through fuel delivery check valve 100'. Termination of the fuel discharge occurs when spill ports 124' are uncovered as they move above the control sleeve, dropping the fuel distribution chamber pressure to the fuel supply pressure.

In some instances, it may be advantageous to have the top of the plunger close the fuel supply passages 93' and 94' prior to the closing of the upper ports 154 as they are moved within bore 18. In such a case, upper ports 154 should be positioned closer to the spill ports 124' than shown in FIG. 11. Such an arrangement would result in less leakage of fuel from the fuel distribution chamber back into the fuel supply passages. The upper ports 154 will open during the plunger suction stroke before the fuel supply passages are exposed, thereby serving to minimize vaporization of fuel in the fuel distribution chamber.

It will be observed that the auxiliary fuel filling means of the present invention provides advantages over conventional pump constructions in that filling of the fuel distribution chamber is insured for optimum operation of the pump at high speeds. Moreover, it will be seen that the desired fuel discharge from the pump can be obtained at high speeds with normal fuel supply pressures of the fuel supply pump, which may be on the order of 30 pounds per square inch.

Furthermore, the use of the grooved sleeve arrangement provides a means for continuously filling the fuel distribution chamber during the suction stroke of the plunger to prevent vaporization of the fuel in the chamber and the resultant cavitation erosion of the fuel supply ports.

While the invention has been described with particular reference to the specific embodiments thereof, it should be understood that it may be embodied in a wide variety of forms different from the ones specifically described Without departing from the scope and spirit of the invention as defined by the appended claims.

We claim:

1 In a fuel injection pump including a hydraulic head having a bore therein, a pumping and distributing plunger rotatably and slidably disposed within the bore, the bore end above the plunger comprising a fuel distribution chamher, a sump spaced from the chamber surrounding the plunger, fuel supply means for delivering fuel to the fuel distribution chamber and the sump, said means for delivering fuel to the fuel distribution chamber comprising a fuel supply passage opening into the bore and adapted to communicate with the fuel distribution chamber when uncovered by the plunger during a portion of the plunger cycle, fuel delivery means operable to deliver fuel sequentially from the fuel distribution chamber to cylinders of an engine in a predetermined order during compression strokes of the plunger, passage means in the plunger connecting the fuel distribution chamber and the sump, and an adjustable control sleeve slidably mounted on the plunger in the sump which may be selectively positioned to open said passage means in the plunger during the plunger compression stroke to control the amount of fuel discharged from the fuel distribution chamber to the engine, the improvement comprising auxiliary filling means associated with the plunger for providing a fuel flow path from the sump to the fuel distribution chamber to supplement the fuel supply passages during a portion of the plunger stroke.

2. The fuel injection pump of claim 1 wherein the auxiliary filling means includes at least one port in the plunger communicating with the plunger passage means and opening into the sump during a portion of the plunger stroke, the port being axially spaced from the opening of the passage means into the sump.

3. The fuel injection pump of claim 2 wherein the port is opened into the sump by movement of the port from a position in the bore to a position in the sump.

4. In a fuel injection pump including a hydraulic head having a bore therein, a pumping and distributing plunger rotatably and slidably disposed within the bore, the bore end above the plunger comprising a fuel distribution chamber, a sump spaced from the chamber surrounding the plunger, fuel supply means for delivering fuel to the fuel distribution chamber and the sump, fuel delivery means .operable to deliver fuel sequentially from the fuel distribution chamber to cylinders of an engine in a predetermined order during compression strokes of the plunger, passage means in the plunger connecting the fuel distribution chamber and the sump, and an adjustable control sleeve slidably mounted on the plunger in the sump which may be selectively positioned to open said passage means in the plunger during the plunger compression stroke to control the amount of fuel discharged from the fuel distribution chamber to the engine, the improvement comprising auxiliary filling means associated with the plunger for providing a fuel flow path from the sump to the fuel distribution chamber during a portion of the suction stroke of the plunger, said auxiliary filling means comprising means defining at least one groove in the sleeve, the passage means of the plunger opening into the sump being adapted to communicate with at least one groove in the sleeve during each suction stroke of the plunger to permit fuel flow into the passages means from the sump for filling the fuel distribution chamber and preventing cavitation erosion in the chamber.

5. The fuel injection pump of claim 4 in which means is provided to prevent rotational movement of the control sleeve relative to the plunger.

6. The fuel injection pump of claim 4 in which a groove is provided in the control sleeve for each of the cylinders of the engine, the grooves being symmetrically spaced around the sleeve bore.

7. In a fuel injection pump including a hydraulic head having a bore therein, a pumping and distributing plunger rotatably and slidably disposed within the bore, the bore end above the plunger comprising a fuel distribution chamber, a sump spaced from the chamber surrounding the plunger, fuel supply mean for delivering fuel to the fuel ditribution chamber and the sump, fuel delivery means operable to deliver fuel sequentially from the fuel distribution chamber to cylinders of an engine in a predetermined order during compression strokes of the plunger, the plunger having an axial bore extending from the fuel distribution chamber to the sump, at least one spill port connecting the plunger bore with the sump, and an adjustable control sleeve movably supported in the sump and having a bore through which the plunger extends and being adapted to coact with the spill port for selectively controlling the amount of fuel discharged from the fuel distribution chamber to the engine, the improvement comprising means defining at least one groove along the bore of the control sleeve adapted to provide a flow path with at least one spill port between the sump and the fuel distribution chamber during each suction stroke of the plunger for filling the fuel distribution chamber in conjunction with the fuel supply means and for preventing cavitation erosion in the fuel distribution chamber.

8. The fuel injection pump of claim 7 in which the number of spill ports in the plunger and the number of grooves in the control sleeve are such that at least one port of the plunger communicates with one of the grooves during each suction stroke of the plunger.

9. The fuel injection pump of claim 8 in which means is provided to prevent rotational movement of the control sleeve relative to the plunger.

10. The fuel injection pump of claim 9 in which the means for preventing rotational movement of the control sleeve comprises a non-circular form of the control sleeve and a cooperating non-circular form of the sump.

11. In a fuel injection pump including a hydraulic head having a bore therein, a pumping and distributing plunger rotatably and slidably disposed within the bore, the bore end above the plunger comprising a fuel distribution chamber, a sump spaced from the chamber surrounding the plunger, fuel supply means for delivering fuel to the fuel distribution chamber and the sump, said means for delivering fuel to the fuel distribution chamber comprising a fuel supply passage opening into the bore and adapted to communicate with the fuel distribution chamber when uncovered by the plunger during a portion of the plunger cycle, fuel delivery means operable to deliver fuel sequentially from the fuel distribution chamher to cylinders of an engine in a predetermined order during compression strokes of the plunger, the plunger having an axial bore extending from the fuel distribution chamber to the sump, at least one spill port connecting the plunger bore with the sump, and an adjustable control sleeve slidably mounted on the plunger in the sump and adapted to coact with the spill port for selectively controlling the amount of fuel discharged from the fuel distribution chamber to the engine, the improvement comprising at least one fill port communicating with the plunger bore and axially spaced from the spill port, the fill port being adapted to communicate with the sump during a portion of the plunger stroke to provide a fuel flow path into the plunger bore supplementing the fuel supply passage to fill the fuel distribution chamber.

References Cited UNITED STATES PATENTS 2,518,473 8/1950 Hogeman et a1. 103-2 2,746,443 5/1956 Meyer 103--2 2,980,092 4/1961 Dreisin et al. 1032 3,011,490 12/1961 Biscoif 10341 3,138,103 6/1964 Dreisin et al 103-2 3,186,396 6/1965 Nystrom et al. 103-2 DONLEY J. STOCKING, Primary Examiner. W. KRAUSS, Assistant Examiner.

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