US3215079A

US3215079A - Fuel pump

Info

Publication number: US3215079A
Application number: US222577A
Authority: US
Inventors: Vernon D Roosa
Original assignee: HARTFORD MACHINE SCREW CO
Current assignee: HARTFORD MACHINE SCREW CO
Priority date: 1962-09-10
Filing date: 1962-09-10
Publication date: 1965-11-02
Anticipated expiration: 1982-11-02
Also published as: ES291506A1; FR1368612A; SE303639B; GB1061763A

Description

Nov. 2, 1965 v. D. ROOSA 3,215,079

FUEL PUMP Filed Sept. 10, 1962 2 Sheets-Sheet 1 INVENTOR.

VERNON D. ROOSA BYM7. Wad n M ATTORNEYS V. D. ROOSA Nov. 2, 1965 FUEL PUMP 2 Sheets-Sheet 2 Filed Sept. 10, 1962 FIG. 2

INVENTOR.

VERNON D. ROOSA WW ATTO R NEYS United States Patent 3,215,079 FUEL PUMP Vernon D. Roosa, Hartford Machine Screw (10., Box 1440, West Hartford, Conn. Filed Sept. 10, 1962, Ser. No. 222,577 8 Claims. (Cl. 103-2) The present invention relates to fuel pumps for delivering uniform and consistent measured charges of fuel to each of the cylinders of an internal combustion engine and more particularly to such fuel pumps of reduced size and weight and which are capable of operating at high speeds.

Accordingly, an object of this invention is to provide an improved fuel pump which is of reduced size and Weight for a given output capacity.

Another object of this invention is to provide an improved fuel pump incorporating a design in which the wearing surfaces are minimized and is especially suited for operation with a high-speed engine.

A further object of this invention is to provide an improved injection pump having a two-piece rotor which is simple in construction and is designed to accommodate manufacturing variations without the sacrifice in quality and performance.

Other objects will be in part obvious and in part pointed out more in detail hereinafter.

The invention accordingly consists in the features of construction, combination of elements and arrangement of parts which will be exemplified in the construction hereafter set forth and the scope of the application which will be indicated in the appended claims.

In the drawings:

FIG. 1 is a cross-sectional view, partly broken away, of a fuel pump embodying the present invention;

FIG. 2 is an enlarged left-end view of the fuel pump of FIG. 1 with the end plate thereof removed;

FIG. 3 is a still further enlarged fragmentary crosssectional view taken along lines 3-3 of FIG. 2;

FIG. 4 is an enlarged cross-sectional view of the fuel pump in FIG. 1 taken along the lines 44 of FIG. 1;

FIG. 5 is an enlarged fragmentary cross-sectional view taken along the lines 5-5 of FIG. 1;

FIG. 6 is an enlarged fragmentary cross-sectional view of the metering valve of the fuel pump of FIG. 1; and

FIG. 7 is a fragmentary plan view of the right end of the rotor of FIG. 1 showing a modification of one aspect of this invention.

Referring to FIG. 1 of the drawing, there is shown an exemplary fuel pump having a generally cylindrical pump casing or stator 10 having a relatively large axial opening or bore 12. The left end of the casing, as viewed in FIG. 1, is provided with an enlarged counterbore 22 which is closed by an end plate 24 fastened to the end of the pump casing 10 by any suitable means such as the threaded engagement shown at 26. End plate 24 is provided with a tapered end portion which is sealed to the pump casing 10 by an O ring 28. The right end of the casing 10, as viewed in FIG. 1, is also provided with an enlarged counterbore which is closed by an end plate 32 which engages the end of the bore 30 with a rabbet fit as indicated at 34, and is sealed thereto by O ring 36. End plate 32 may be secured to the casing 10 by any suitable means (not shown).

Disposed within the central bore 12 and rotatably mounted therein is a cylindrical fuel distributing rotor having a fuel pickup or transfer pump 42 on one end thereof and a charge or injection pump 44 on the other end thereof.

A fuel inlet to the transfer pump 42 is supplied through the fitting 58 which is connected to a supply of fuel, not shown, and communicates with the transfer pump by a passageway 60 disposed in the casing 10 as indicated by the arrows. The transfer pump increases the pressure on the fuel in proportion to the speed of the rotor and discharges it into passageway 62 which communicates with an annular channel 66 surrounding the fuel distributing rotor 40. A spring-biased pressure regulating valve 68 is interposed between annular channel 66 and the inlet 60 of the transfer pump 42 to regulate the outlet pressure of the fuel being discharged by the transfer pump to provide a pressure-speed curve of the desired characteristics for the particular application.

The fuel flows from annular channel 66 to longitudinal passageway 64, into radial passageway 72, past a metering valve generally indicated at 76, and into passageways 74 and 75 which communicate with an annular groove 78 provided in the bore 12. Annular groove 78 is axially aligned with inlet port 80 of the fuel distributing rotor 40 so as to continuously communicate with the annular passage 78 as the fuel distributing member is rotated. Inlet port 80 communicates with axial rotor passageway 86 to deliver fuel to charge pump 44.

High pressure fuel discharged from charge pump 44 enters axial passageways 88 and 90 which terminate in ports on the cylindrical surface of the fuel distributing rotor 40. These ports lie in the same radial plane in bore 12 as the ports of the diagonal passageways 92 of the casing 10 which are positioned about the periphery of the bore 12 to communicate in sequence with the outlet ports of the passageway 90 of the fuel distributing rotor 40 as the rotor is rotated. Each of diagonal passageways 92 are respectively connected to the several cylinders (not shown) of the engine to which fuel is being pumped by means of axial passageways 95 and external tubes 97. While only one diagonal passageway 92 is shown in FIG. 1, it will be apparent that one such passageway will be provided for each cylinder of the associated engine and the respective ports thereof are uniformly spaced about the bore 12 so as to be in registry with ports of passageways 90 as the rotor is rotated in timed relation with the engine.

In the illustrated embodiment, the transverse rotor passageway 90 is shown as having two discharge ports positioned at diametrically opposed points on the periphery of the fuel distributing rotor 40. It will be apparent that the use of these two ports will result in communication between the passageway 90 and each of the outlet passageways 92 twice during each revolution of the fuel distributing rotor 40. Thus, it is only necessary to rotate the fuel distributing rotor 40 at one-half the speed required if only one such port were utilized.

A nipple 108 is provided for the installation of a hand priming pump (not shown) which is used to provide fuel for injection into the cylinders of the associated engine during the starting of the engine.

In order to provide a unidirectional flow of the inlet fuel to the charge pump, there is provided a check valve 110. As shown, the check valve 110 comprises a ball which is mounted in the rotor 40 to engage a tapered valve seat 112. In axial alignment with the valve seat is a threaded opening 114 which is adapted to receive an adjustable stop screw 116. The amount of longitudinal movement of the ball 110 with respect to valve seat 112 may be varied by adjusting the clearance of the stop screw 116 and the ball 110.

Referring to FIG. 1, it will be observed that the slot in the head of the stop screw 116 is accessible through the shaft end of the pump when the shaft 48 is removed. Thus, by the use of a screwdriver the stop screw may be turned inwardly until it rests tightly against the ball with the ball in seated position. Using the slot in the top of the screw as an indicator, the stop screw 116 may be unscrewed, say, one-half turn to obtain a very precise adjustment of the distance the ball may move from seat 112.

To lock the stop screw 116 in place, a quantity of initially flowable, settable material 118, such as an epoxy resin, is placed in the threaded opening. A second screw 120 is then threaded into the opening and acts as a hydraulic press to force the resin in between the threads 'of stop screw 116. Since the threaded portion of the locking screw 120 is shorter than the distance from the end of the locking screw to the end surface of the rotor 40, it will not engage the end of the locking screw to change its adjustment. The resin 118 thus positioned in the threads sets, or is treated so as to cause it to set, to lock the stop screw 116 in place.

As indicated above, the transfer pump 42 is positioned on one end of the fuel distributing rotor 40. Referring specifically to FIGS. 2 and 3, the transfer pump 42 has a solid cylindrical hub 130 having a pair of radial slots 132 in which are slidably positioned a pair of pump vanes 134. An eccentric liner 136 surrounds the hub 130 and is non-rotatably secured in counterbore 22 by a pin 138 which is positioned in an axial slot 140. Each of the pump vanes 134 is segmented laterally to provide two segments 134a and 134b. The adjacent edges of segments 134a and 134b are provided with aligned bores 142 in which a coil spring 144 is positioned to urge the segments apart and into engagement with the inner peripheral wall of eccentric liner 136.

Referring especially to FIG. 1, it will be observed that the cylindrical hub 130 of the transfer pump is larger in diameter than the bore 12. It will further be observed that the enlarged hub 130 is provided with a generally radially disposed annular shoulder 146 which is adapted to engage a mating annular wall 148 formed by the bottom of counterbore 22. It will be apparent that these mating annular shoulders form a close-running seal to separate the outlet port 62 and the annular channel 66 from the interior of transfer pump 42.

As previously stated, a charge pump 44 is positioned on the right end of fuel distributing rotor 40, as viewed in FIG. 1. According to one aspect of this invention, the charge pump comprises an enlarged cylindrical carrier or hub 82 positioned around the end of fuel distributing rotor 40 and is provided with a pair of radial chambers 84 which communicate with transverse passage 86 of rotor 40. The radial chambers 84 of the carrier serve as cylinders in which a pair of pistons 94 are positioned for radial movement. Pistons 94 are actuated inwardly as the fuel distributing rotor 40 is rotated in timed relation with the associated engine and the actuation of the pistons is effected by means of an annular cam 96 through intermediate rollers 98 which are positioned in roller shoes 100. As best shown in FIG. 4, shoes 100 are slidably mounted in radial slots 102 in the carrier 82 and the cam 96 is seated in the annular recess provided by counterbore 30 and is so constructed and arranged that the pair of pistons 94 and the associated rollers 98 and shoes 100 move inwardly and outwardly simultaneously. The relative angular position of cam 96 is controlled by the timing advance mechanism generally indicated at 150 whose lateral position is automatically controlled in accordance with engine speed by means of a passageway 152 (FIG. which provides communication between the transfer pump outlet pressure in passageway 64 and chamber 154 to urge piston 156 axially against the bias of spring 158.

Fixed to the free end of the carrier 82 is an annular flange 46 which is internally splined for connection to a shaft 48 driven by the engine with which the fuel pump is associated. Shaft 48 is provided with annular grooves 50 which are sealed to end plate 32 by annular sealing members 52.

In order to assemble the rotor 40 in the casing 10, the

rotor is inserted into the left end of the bore 12 without the carrier 82 being installed. The carrier and its associated parts are then pressed onto the right-hand end of the rotor 44 with the cylinders 84 is alignment with transverse passageway 86 of the rotor, as shown in FIG. 1. A set or locking screw 41 is then threaded into an aperture of the rotor 40 to fix and index, or locate, the carrier 82 thereon. It will be noted that the end of set screw 41 is tapered at 43 and engages a mating tapered seat 45 on the rotor for closely indexing the carrier thereon.

In order to prevent leakage between the carrier 82 and rotor 40, as well as to aid in providing a driving connection therebetween, the inner bore of carrier 82 is provided with a smaller diameter than the outer diameter of rotor 40. I have found that an interference fit of about 0.l0.2 mils is satisfactory for these purposes.

Referring now particularly to FIG. 7, there is shown the right end of the rotor 40 (as shown in FIG. 1) in which the tapered seat 45 for the set screw 41 is modified to accommodate axial adjustment of the carrier relative to rotor 40 while locking and indexing the carrier precisely in a circumferential direction. This modification involves the provision of an elongated slot having tapered sides for mating the tapered end 43 of set screw 41. It will be apparent that by the use of this modification of FIG. 7, the axial position of the carrier 82 may be adjusted with respect to rotor 40 so that the mating

annular walls

146 and 148 of the transfer pump and its associated counterbore will provide a close-running seal of high quality regardless of the variation in the distance between the

bottom walls

148 and 160 of the casing 10.

From the foregoing, it will be apparent that this invention provides a compact fuel pump incorporating a rotor construction having a diameter at the center which is smaller than the diameter at the ends to decrease the surface speed center portion of the rotor 40 and the bore 12 for a given speed of rotation without reducing the capacity of the transfer and charge pumps. This construction enables the pump to operate at higher speeds and minimizes the wear of the periphery of the rotor so as to reduce leakage at the points where the fuel is transferred from the rotor to the stator thus providing a longer pump life.

In addition, the provision of a two-part rotor construction makes it possible to accommodate dimensional variations which norm-ally result from manufacturing tolerances between the

counterbores

22 and 30 in a construction which enables the provision of a high quality close-running seal which separates the outlet passages of the transfer pump from the interior of the pump.

Finally, by connecting the splined hub 46 directly to the carrier, rather than providing the usual driving connection directly to the rotor 40, this invention reduces the possibility of relative rotation between the carrier 82 and the rotor 40 during use since by far the greatest torsional load of the pump results from the action of the cam ring 96 in urging the pistons 94 toward each other to compress the fuel in the charge pump. This is particularly important in view of the fact that the load imposed by the charge pump does not provide a relatively constant torque but rather is the result of repetitive sharp impulses.

As will be apparent to persons skilled in the art, various modifications and adaptations of the structure above described will become readily apparent without departure from the spirit and scope of the invention, the scope of which is defined in the appended claims.

I claim:

1. A fuel pump comprising a casing having inlet and outlet passages, a bore in said casing having enlarged counterbores at each end thereof, a fuel distributing rotor positioned in said bore and having fuel inlet port means adapted to communicate with said inlet passage and out let port means adapted to communicate in sequence during the rotation of said rotor with the outlet passages of said casing to permit alternate admission and discharge of fuel from the interior of said rotor, a transfer pump having a hub of greater diameter than said bore integrally formed on one end of said rotor, and a charge pump having a carrier of greater diameter than said bore on the other end of said rotor, said carrier providing radially aligned passageways forming cylinders in which a pair of pistons are slidably received, said carrier further being apertured and being positioned about an end of said rotor and non-rotata'bly secured thereto with an interference fit.

2. A fuel pump comprising a unitary casing having inlet and outlet passages, a bore in said casing having enlarged counterbores at each end thereof, a fuel distributing rotor positioned in said bore and having fuel inlet port means adapted to communicate with said inlet passage and having outlet port means adapted to communicate in sequence during the rotation of said rotor with the outlet passages of said casing to permit alternate admission and discharge of fuel from the interior of said rotor, a transfer pump having a hub of greater diameter than said bore integrally formed on one end of said rotor, a charge pump having a carrier of greater diameter than said bore on the other end of said rotor, said carrier being apertured and being positioned about an end of said rotor and secured thereto with an interference fit, and means on said carrier for drivingly connecting the rotor to a drive shaft.

3. A fuel pump comprising a casing having inlet and outlet passages, a bore in said casing having enlarged counterbores at each end thereof, a fuel distributing rotor positioned in said bore and having fuel inlet port means adapted to communicate with said inlet passage and having outlet port means adapted to communicate in sequence during the rotation of said rotor with the outlet passages of said casing to permit alternate admission and discharge of fuel from the interior of said rotor, a transfer pump having a hub of greater diameter than said bore integrally formed on one end of said rotor, a charge pump having a carrier of greater diameter than said bore on the other end of said rotor, said carrier having radially aligned passageways forming cylinders in which a pair of pistons are slidably received for movement toward and away from each other, the radially aligned passageways being in selective communication with the fuel inlet port means and the fuel outlet port means of said rotor, a cam ring surrounding said carrier for urging said pistons toward each other to pressurize the fuel in said radially aligned passageways, an annular hub projecting from the outer end of said carrier, said annular hub being splined to engage a splined drive shaft to provide a driving connection to drive the rotor in timed relation to its associated engine, said carrier being apertured and being positioned about an end of said rotor and secured thereto with an interference fit to drive the same.

4. A fuel pump comprising a casing having inlet and outlet passages, a bore in said casing having enlarged counterbores at each end thereof, each of said counterbores providing a generally radial annular shoulder surrounding said bore, a fuel distributing rotor positioned in said bore and having fuel inlet port means adapted to communicate with said inlet passage and having outlet port means adapted to communicate in sequence during the rotation of said rotor with the outlet passages of said casing to permit alternate admission and discharge of fuel from the interior of said rotor, a transfer pump having an enlarged hub integrally formed on one end of said rotor and providing an annular shoulder, a mating annular shoulder in the counterbore in which the transfer pump is positioned, and a charge pump comprising a carrier having a generally radial annular thrust wall for engaging the mating annular wall of the associated counterbore, said carrier being apertured and being positioned around the end of said rotor With an interference fit to provide a driving connection therebetween, said carrier being axially positioned on the rotor to form a close run- 6 ning seal between the annular shoulder of the hub of the transfer pump and the mating annular shoulder of its associated counterbore regardless of variations in the distances between the counterbores resulting from manufacturing tolerances.

5. A fuel pump comprising a casing having inlet and outlet passages, a bore in said casing having enlarged counterbores at each end thereof, a fuel distributing rotor positioned in said bore and having fuel inlet port means adapted to communicate with said inlet passage and outlet port means adapted to communicate in sequence during the rotation of said rotor with the outlet passages of said casing to permit alternate admission and discharge of fuel from the interior of said rotor, a transfer pump having a hub of greater diameter than said bore integrally formed on one end of said rotor, and a charge pump having a carrier of greater diameter than said bore on the other end of said rotor, said :carrier providing radially aligned passageways forming cylinders in which a pair of pistons are slidably received, said carrier further being apertured and being positioned about an end of said rotor and non-rotatably secured thereto with an interference fit of about 0.1-0.2 mils.

6. A fuel pump comprising a casing having inlet and outlet passages, a bore in said casing having enlarged counterbores at each end thereof, a fuel distributing rotor positioned in said bore and having fuel inlet port means adapted to communicate with said inlet passage and outlet port means adapted to communicate in sequence during the rotation of said rotor with the outlet passages of said casing to permit alternate admission and discharge of fuel from the interior of said rotor, a transfer pump having a hub of greater diameter than said bore integrally formed on one end of said rotor, and a charge pump having a carrier of greater diameter than said bore on the other end of said rotor, said carrier providing radially aligned passageways forming cylinders in which a pair of pistons are slidably received, said carrier further being apertured and being positioned about an end of said rotor and non-rotatably secured thereto with an interference fit, and means on said carrier for engaging said rotor for indexing and locating the carrier thereon.

7. A fuel pump comprising a casing having inlet and outlet passages, a bore in said casing having a counterbore at one end thereof, a fuel distributing rotor positioned in said bore and having fuel inlet port means adapted to communicate with said inlet passage and having outlet port means adapted to communicate in sequence during the rotation of said rotor with the outlet passages of said casing to permit alternate admission and discharge of fuel from the interior of said rotor, a transfer pump positioned on one end of said rotor, a charge pump positioned on other end of said rotor, one of said pumps having a hub of greater diameter than said bore, said charge pump having radially aligned passageways forming cylinders in which a pair of pistons are slidably received for movement toward and away from each other, the radially aligned passageways being in selective communication with the fuel inlet port means and the fuel outlet port means of said rotor, a cam ring surrounding said carrier for urging said pistons toward each other to pressurize the fuel in said radially aligned passageways, an annular splined member projecting from the outer end of said hub for engagement with a splined drive shaft to provide a driving connection to drive the rotor in timed relation with its associated engine, said hub being positioned about the end of said rotor and engaging the same with an interference fit, and means engaging a recess in said rotor for indexing and locating the hub on said rotor.

8. A fuel pump comprising a casing having inlet and outlet passages, a bore in said casing having enlarged counterbores at each end thereof, a fuel distributing rotor positioned in said bore and having fuel inlet port means adapted to communicate with said inlet passage and having outlet port means adapted to communicate in sequence during the rotation of said rotor with the outlet passages of said casing to permit alternate admission and discharge of fuel from the interior of said rotor, a transfer pump having a hub of greater diameter than said bore on one end of said rotor and positioned in one of said counterbores, and a charge pump having a hub of greater diameter than said bore on the other end of said rotor and positioned in the other of said counterbores, the hub of one of said pumps surrounding said rotor and engaging the same to rotate therewith, and means for indexing and securing said one hub to said rotor, said means comprising a set screw engaging an axially e1on gated recess on said rotor.

References Cited by the Examiner UNITED STATES PATENTS 2,641,238 6/53 Roosa 1032 2,883,934 4/59 Roosa 1032 2,946,292 7/60 Chmielecki 1035 3,000,318 9/61 Volossevich 1032 10 3,035,523 5/62 Kemp et a1 1032 RICHARD B. WILKINSON, Primary Examiner.

LAURENCE V. EFNER, Examiner.

Claims

1. A FUEL PUMP COMPRISING A CASING HAVING INLET AND OUTLET PASSAGES, A BORE IN SAID CASING HAVING ENLARGED COUNTERBORES AT EACH END THEREOF, A FUEL DISTRIBUTING ROTOR POSITIONED IN SAID BORE AND HAVING FUEL INLET PORT MEANS ADAPTED TO COMMUNICATE WIHT SAID INLET PASSAGE AND OUTLET PORT MEANS ADAPTED TO COMMUNICATE IN SEQUENCE DURING THE ROTATION OF SAID ROTOR WIHT THE OUTLET PASSAGES OF SAID CASING TO PERMIT ALTERNATE ADMISSION AND DISCHARGE OF FUEL FROM THE INTERIOR OF SAID ROTOR, A TRANSFER PUMP HAVING A HUB OF GREATER DIAMETER THAN SAID BORE INTEGRALLY FORMED ON ONE END OF SAID ROTOR, AND A CHARGE PUMP HAVING A CARRIER OF GREATER DIAMETER THAN SAID BORE ON THE OTHER END OF SAID ROTOR, SAID CARRIER PROVIDING RADIALLY ALIGNED PASSAGEWAYS FORMING CYLINDERS IN WHICH A PAIR OF PISTONS ARE SLIDABLY RECEIVED, SAID CARRIER FURTHER BEING APERTURED AND BEING POSITIONED ABOUT AN END OF SAID ROTOR AND NON-ROTATABLY SECURED THERETO WITH AN INTERFERENCE FIT.