US3399627A - In-the-line fuel pump - Google Patents

Description

A p 3, 1 968 c. w. JEEP, JR.. ETAL. 3,399,627

IN-THE-LINE FUEL PUMP Filed June 28, 1966 F I G. 2.

FIG.6.

INVENTORS CHARLES W. JEEP. JR.

EDGAR W. NIEMEYER BY "PW/56W ATTORNEY United States Patent C 3,39,627 IN-THE-LINE FUEL PUMP Charles William Jeep, Jr., and Edgar W. Niemeyer, St. Louis, Mo., assignors to ACF Industries, Incorporated, New York, N.Y., a corporation of New Jersey Filed June 28, 1966, Ser. No. 561,183 8 Claims. (Cl. 103118) ABSTRACT OF THE DISCLOSURE An in-the-line pump for an automotive fuel system is of the vaned rotor type having an electric motor drive. The motor is sealed to the pump housing and pressurized fuel is admitted to the motor chamber for cooling. A pressure regulator between the motor chamber and the pump inlet not only insures that fuel for cooling is present but also aids in vapor handling characteristics of the pump.

This invention relates to a pump and more particularly to a motor driven positive displacement pump for use in automotive fuel systems.

The motor driven pump to be hereinafter described in detail forming the invention finds utility primarily in a fuel system particularly for automotive use in which a volatile fuel is conducted from a remote supply to the engine carburetor. Normally, automotive fuel systems include a fuel tank located remote from the engine such as at the rear of the car, having the engine located at the front. Thus, in conducting fuel to the engine carburetor, as a result of excessive engine heat or the hot ambient, there is a tendency toward fuel vaporizing to lock or partially lock the entire fuel system. As the temperature decreases below the fuel condensation point, the vapors will condense and unlock the system.

Many devices and systems have attempted with varying degrees of success to overcome the problem of fuel vapor lock. This has been attained in one form or other by avoiding excessive vaporization within the fuel system. However, these systems achieve only limited practical acceptance since they tend to remain substantially inoperative so long as the fuel pump is unable to displace the fuel vapor. In the instance of a diaphragm type fuel pump, for example, to overcome a vapor locked condition it is generally necessary to permit the pump to cool. The problem becomes particularly acute when an engine has been running in a relatively hot ambient and is suddenly stopped. The subsequent hot soak period generally causes rapid vaporization of fuel in both the fuel system including the pump and also in the carburetor bowl. Any attempt to start the engine under such conditions will be futile since the pump will be unable to move fuel vapor either upstream or downstream thereof.

The only feasible solution in such an instance is to either wait for the vapors to condense or to vent the vapor to the atmosphere. While the latter affords a stop gap solution, it is by no means desirable. For one thing, the venting practice is both wasteful and insuflicient. Secondly, passing of the vapor to the atmosphere tends to aggravate smog promoting conditions. The latter of course, finds disfavor both with fuel system engineers and with municipalities which are susceptible to smog.

The present invention discloses a means to overcome the vapor locking problem by providing a positive displacement pump for use in a fuel line of a fuel system and driven by an electric motor. The positive displacement pump is compact, yet designed to readily handle a capacity in excess of the carburetor or the engine maximum requirements. Thus, passage means is provided in the fuel pump body for continuously circulating fuel into an enclosure or casing surrounding the drive motor to cool "ice parts of the latter. At least one valved passage is provided to permit a unidirectional fuel flow to the motor casing and return cooling fluid to the pump suction. To permit ready recirculation of liquid, the pump suction is provided with an enlarged, intermediate passage or filter compartment. This passage is so positioned to surround a major portion of the pumping chamber and is communicated with the latter. Fuel is thereby permitted to accumulate in the filter compartment to a relatively large volume before being passed to the pump chamber.

It is therefore an object of the invention to provide an improved fluid pump embodying simple construction for automotive fuel systems. A further object is to provide a liquid cooled, motor driven fuel pump having means for circulating pumped fuel into contact with heated motor parts. Still another object of the invention is to provide a positive displacement in-the-line fuel pump for rapidly overcoming a vapor locked fuel system for delivering fuel from a source to the engine carburetor. A still further object of the invention is to provide a novel fuel system for a vaporizable fuel, being adapted to furnish a continuous fuel stream to a carburetor or engine, and exhibiting favorable requirements under hot ambient conditions. These objects together with others not specifically mentioned will become clear to those skilled in the art from the following description.

In the drawings, FIGURE 1 represents an automotive fuel system of the type herein contemplated including a fuel pump connected in a line communicating the fuel supply with the engine carburetor.

FIGURE 2 is a cross-sectional elevation view of the fuel pump shown in FIGURE 1,

FIGURE 3 is a bottom view of the pump shown in FIGURE 2, having portions removed to reveal the interior mechanism.

FIGURE 4 is a se mentary view on an enlarged scale of a portion of the fuel pump shown in FIGURE 3 illustrating details of the pump rotor,

FIGURE 5 is a segmentary view on an enlarged scale and in cross-section taken along section AA in FIG- URE 4; and,

FIGURE 6 is an enlarged view of the rotor vane actuating spring.

In brief, the novel fuel system contemplates an arrangement whereby an internal combustion engine provided with a carburetor, is supplied with pumped fuel under adverse operating conditions. The above noted fuel pump is powered by a direct current source and is characterized by a speed factor that varies inversely with the load torque.

Thus, during periods when the fuel system is prone to vapor lock, accumulation of fuel vapors in the pump chamber will cause rapid rotation of the pump rotor. Conversely, pumping of solid fuel will result in a decrease in pumping speed. In either instance liquid or vapor flow will be regulated by a regulator valve disposed in the pump which achieves two functions. Said valve assures a cooling of motor parts. Secondly, it continuously circulates fluid through the pump. Consequently, even under partial or full vapor lock conditions, the pump will respond promptly to an increased fuel demand initiated by the engine.

Referring to FIGURE 1, the pump and fuel system forming the subject matter of the invention are illustrated as connected to an internal combustion engine. This includes an engine 10 mounted to the front end of an automotive chassis shown in dotted lines. The engine comprises an intake manifold 11 connected to the respective engine cylinders and to the carburetor 12. The carburetor, following well-known construction includes a mixing conduit having an inlet to which is fastened an air filter 13. The outlet of the mixing conduit is in turn communicated with the inlet opening of intake manifold 11. The carburetor further includes a fuel inlet connected by a line 14 to a motor driven fuel pump 16 having the pump suction communicated through line 17 to the fuel tank 18 located at the rear of the automobile. Fuel pump 16 is operated by an electric motor preferably of the 6 or 12 volt direct current type actuated by the engine ignition system.

Referring to FIGURE 2, the fuel pump unit shown generally at 16 and includes a lower pump 19 to which is sealably fastened a motor casing 21 thereby forming an enclosure about a drive motor 22.

The drive motor is of the direct current type and includes essentially a central shaft or core 23 carrying a plurality of windings 24. Opposed ends of the shaft are provided with overhung shaft ends 26 and 27, journalled in bearings 28 and 29 respectively. Following normal motor construction core 23 is provided with a commutator 31 at shaft end 27. A brush assembly 32 is electrically connected by conductor 33 to the upper end of motor casing 21. The drive motor is preferably series wound and exhibits a torque characteristic peculiar to such motors. For example, in such a motor, the shaft speed will automatically adjust inversely to load. Since the motor casing forms a substantially fluid tight seal, the casing is provided with an electrical connection 34 including an upstanding threaded stud 36 which is adapted to be electrically connected into the automobile ignition system. The lower end of threaded stud 36 extends to the interior of casing 21 and carries a pair of insulating washers 37 and 38 together with a sealing grommet 39 which form a suitable fluid tight connection through motor casing 21.

Motor casing 21 is preferably cylindrical, of metallic construction, having one end opened and defined by a peripheral rim. The casing other end includes a wall having a bearing well 41 adapted to receive and position bearing 28.

Again referring to FIGURE 2, pump 19 is formed essentially of a body 46 including an opening 47 formed in one end, and separated by a wall 48 into upper and lower portions. The lower portion of the pump body is also open and comprises a plurality of concentrically disposed cavities. Center cavity 49 is defined by a cylindrical opening which may be formed within the pump or which may alternately be provided by a suitably formed insert press-fitted into a corresponding aperture within the pump body.

Opening 47 in the pump body 46 is defined by an external peripheral rim 52 which receives and supports the open end of casing 21. The latter casing is deformed over rim 52 after assembly to provide a peripheral fluid tight seal between the pump and the motor casing.

Pump wall 48 includes a central bore adapted to receive bearing 29. As shown particularly in FIGURES 2 and 3, the outer surface of bearings 28 and 29 are generally spherical, thus permitting self-centering as the respective shaft ends 26 and 27 register in the bearing bores. Pump rotor 52 including peripherally spaced vanes 53, is generally cylindrical in configuration. A center opening at the upper end includes a slotted groove 56 adapted to receive a corresponding tongue 42 at shaft end 27. An end plate 54 is received in central cavity 49 and includes a center opening through which shaft end 27 extends to engage slot 56 of the rotor center opening. Plate 54 together with the oppositely positioned end plate 57, function as bearing surfaces against which rotor 52 is guided. Plates 54 and 57 are of course in sliding contact with the respective ends of the rotor 52 to provide a satisfactory fluid tight seal during rotation of the rotor.

Referring to FIGURE 3, central cavity 49 is provided with a suction inlet 58 for directing fuel into the pump chamber 51. Similarly, the high pressure or discharge side of pump chamber 51 is provided with a discharge passage 59 in boss 61. Discharge passage 59 may be threaded internally to provide means for connection into line 14 in the fuel system or to a similar connection for conducting a pressurized fuel flow toward the engine carburetor. Pump body 19 is further provided with inlet passage 63 for connection to fuel tank 18 in the fuel system. Inlet boss 62 is formed on an outer wall of the pump and includes an inlet passage 63 which is likewise threaded or otherwise adapted to receive the end of line 17.

Inlet passage 63 is communicated with suction inlet 58 and with pump chamber 51 by way of an intermediate chamber 64 formed in the pump body and taking a generally arcuate configuration. Chamber 69 substantially surrounds central cavity 49 and is formed between adjacent walls defining a groove Within the pump body.

Intermediate chamber 64 as shown, is discontinued at the discharge side of the pump thereby forming an intermediate section into which discharge passage 59 is formed in communication with pump chamber 51.

As shown in FIGURES 2 and 3, intermediate chamber 64 comprises a relatively large volume in contrast to the volume of pumping chamber 51. A plurality of spacers 66 disposed discretely along adjacent walls of chamber 64, provide a guide and centering means for filter element 67. Filter element 67 extends substantially the entire height of intermediate chamber 64 and from one peripheral extremity to the other. Element 67 in elfect divides the intermediate chamber into spaced apart compartments 91 and 92, the outer of which receives unfiltered fuel, and the inner of which is communicated with passage 58 for conducting filtered fuel to pump chamber 51.

Referring to FIGURE 2, the outer end of pump body 19 is provided with a center apertured gasket 68 forming a substantial closure across the open side of the intermediate chamber 64. A cover 60 is carried on the outer surface of pump body 19 and includes a peripheral rim 71 received in a mating groove formed in the surface of pump body 19. Cover 60 as shown in FIGURE 3 is fixedly located by a plurality of fastening screws 72 to provide a fluid tight seal at the pump end.

Again referring to FIGURE 2, pump body 46 is pro vided with an opening 73 formed in wall 48. Said opening provides communication between discharge passage 59 and chamber 47 for passing a pressurized liquid upwardly into the compartment defined by opening 47 and motor casing 21, to circulate in contact with the motor parts which would otherwise become heated as a result of normal running.

Wall 48 is further provided with an upstanding boss 74 having a central bore which terminates in a peripheral shoulder 77. The bore is communicated with passage 78 which intersects suction inlet 63. Said bore receives a housing 79 enclosing a valve regulator element 81 which is normally biased against a peripheral shoulder 80 in housing 79 by a spring 83, to form a displaceable closure to the interior of casing 21. A screen 84 is carried on th inlet end of housing 79 to achieve two purposes. First; for filtering fuel, and secondly to furnish a flash 'arrestor in the event of the ignition of fuel Vapors within the pump casing. A similar screen or flash arrestor 86 is likewise carried on opening 73 forming the inlet to compartment 47 within the pump body.

Regulator element 81 comprises a central column having a dished retainer 93 fixed to one end thereof, a resilient seal member 87 is carried on the column and located by a washer 94. The edge of member 87 overhangs annular shoulder 80 to form a displaceable sealing joint. Spring 83 carried on column 85 bears against retainer 93 and the upper side of shoulder 80 to normally urge sealing member 87 into engagement with said shoulder.

operationally, the constant of spring 83 is designed to yield under a predetermined pressure in chamber 47. The magnitude of yield will of course determine the peripheral opening communicating chamber 47 with passage 78. Thus, fluid flow through the regulator 81 will be directly contingent on the pressure within chamber 47. Consequently the -regulator 81 functions to regulate pressure fluctuations occurring in the motor cooling circuit of the fuel system. This in turn assures rapid response of the pump to a demand for fuel at the carburetor under vapor lock or partial vapor lock conditions.

Referring to FIGURES 4 and 5, rotor 52 within pump chamber 51 comprises a cylindrical member having a plurality of outwardly radiating open slots disposed Substantially equally apart and of sufficient width to slidably receive the respective vanes 53 positioned therein. One or more compression springs 88 is compressibly disposed on the underside of each of said vanes 53 and having an enlarged coil 89 retained within a corresponding groove formed at the lower side of the slot. This arrangement simplifies assembly and disassembly of the rotor by permitting removal of the vane without removing the spring.

In accordance with the preferred operation of the pump rotor, the respective vanes 53 are urged outwardly to bring the upper end of the respective vanes into rubbing contact with adjacent walls of pump chamber 51. Thus, fuel in both liquid and or vapor phase, received at the inlet side of the compression chamber 51 from passage 58, is progressed about the periphery of the pump compartment and discharged at a higher pressure into discharge passage 59.

As is generally known, a characteristic inherent to this type of rotor and pump is the ability to achieve a positive displacement of fluid. Thus, whether the pump is compressing liquid, or fluid in the form of vaporized gas, the latter will still be circulated from the inlet side to the discharge side and thereafter passed from the pump.

Operation of the system During normal operation of the disclosed fuel system, and as herein mentioned, the pump is designed with sufiicient capacity and driven at a suflicient speed to provide more fuel than would ordinarily be required for maximum engine load. Thus, the pump provides a substantially constant pressured flow of liquid at the carburetor inlet needle valve regardless of the load imposed upon the internal combustion engine. So long as the pump motor is engaged, there will be a pressurized fuel flow passed through the pump. Whether or not fuel is actually discharged is dependent entirely on the engine load, and controlled by the carburetor float.

Where the engine is operated at light or idle load, and under a minimum fuel demand, fuel pumped from the discharged side of the pump will be urged upwardly through passage 73 and into casing 21 by way of chamber 47 to contact heated motor parts. The regulator valve 81 will permit a maximum accumulation of fuel or vap0r within casing 21 before the valve moveable element is displaced to the open position, thereby permitting fluid to be discharged through the valve opening and reintroduced to suction passage 63 for recirculation.

The pump as presently described is of course most preferably inserted into a fuel line as shown in FIGURE 1, which may be toward the front of the vehicle. However, the unit may likewise be disposed at a point nearer the source of fuel in tank 18. It is therefore largely a matter of engineering design where the pump is physically mounted by means of bracket 94 since the positive displacement characteristic of the pump will permit the latter to overcome fuel vapor lock regardless of where it occurs within the entire fuel system.

It is however preferable that the pump be positioned as near as possible to the fuel source to more rapidly draw liquid into the pump suction. Thus, under full or partial vapor lock conditions, upon engine startup, the pump will immediately commence to move vaporized fuel thereby clearing the line along conduit 17 between fuel tank 18 and the pump suction. Because of the high vapor pumping speed, and the minimum load imposed by the fuel vapors, line 17 will be promptly cleared of vapor thus permitting the fuel to be drawn upwardly along line 17 and into the pump suction.

As previously noted, intermediate chamber 64 within the pump casing, is relatively large to hold a substantial quantity of fuel during hot soak periods or during periods when there will be a tendency for vaporization due to either heat from the engine or due to the ambient. Chamber 64 thereby serves the dual purpose of not only filtering the fuel passed from the pump and into the engine carburetor, but also of providing a reservoir for holding an amount of fuel to assure immediate priming of the pump instantaneous with engine startup.

For example, after the engine is shut off subsequent to a relatively hot run, fuel within the casing 21 will tend to vaporize. The pressure buildup will thus lower the fuel level toward the bottom of the pump casing. Because of the volume of fuel contained in motor casing 21, liquid will be discharged through both the regulator valve, and through opening 73 to enter the pump chamber 51.

At startup therefore, fuel contained within compartment 47, chambers 91 and 92, will permit instantaneous priming of the pump and greatly reduce the time needed for overcoming the locked condition of the system.

At engine start up, the regulator valve will of course be closed due to the static condition of the fuel system. If the carburetor needle valve remains closed, indicating a sufiicient amount of fuel in the carburetor fuel bowl, the regulator valve will open and permit liquid to be circulated through casing 21 to passage 78 and to the pump suction.

At part of full throttle settings, the position of the regulator valve, whether open or closed, will be dependent on the amount of fuel vapor present in the pump and in both lines connected thereto. For example, with a significant amount of vapor in the fuel system to cause full or partial vapor lock, the regulator valve will close. Thus, the pump rotor will move a mixture of both liquid and fuel vapor. The lower density of the mixture, as compared with the density of liquid alone, will permit the drive motor speed to increase. It is clear to those skilled in the art that the present invention provides many advantages in fuel systems particularly for overcoming vapor lock which is otherwise relatively unavoidable. The constant pressure provided at the carburetor as a result of the positive displacement of the variable speed pump permits a more efficient and stable operation of the carburetor during all running conditions of the engine.

It is appreciated also by those skilled in the art that the foregoing description and illustrations of the invention are provided for the purpose of disclosing a preferred embodiment of the device. It is further understood however, that certain changes and modifications may be made in the disclosed arrangement without departing from the spirit and scope of the invention as defined in the appended claims.

We claim:

1. In a system for furnishing a substantially constant pressure stream of vaporizable fuel from a source thereof to a charge forming device having a float regulated valve and exhibiting a fluctuating fuel demand, said system being adapted to operate continuously under conditrons conducive to fuel vaporization and embodying first and second integral circuits;

(A) said first circuit including,

( 1) conduit means in communication with said source of fuel,

(2) a positive displacement pump including a drive motor, said pump having a pumping chamber including suction and discharge openings,

(3) a line communicating said pumping chamber discharge opening with said charge forming device valve,

(B) said second circuit including,

(l) a hydraulic casing enclosing said drive motor and communicated with the respective suction and discharge openings in said pumping chamber,

(2) pressure regulating means moveable between open and closed positions, and disposed in said casing, being communicated with said pumping chamber suction opening to control passage of fuel to the latter in response to fluid pressure at said pump chamber discharge opening,

(C) whereby said pressure regulating means when urged by fluid pressure to the open position will permit circulation of fluid through said second circuit in an amount proportional to back pressure in said line in response to fluctuations in fuel demand.

2. In a system as defined in claim 1 wherein said drive motor is characterized by a rotational speed that varies inversely with the motor torque.

3. In a system as defined in claim 1 wherein said pressure regulating means includes, a valve flow passage communicating said casing with said pump chamber suction opening.

4. In a system as defined in claim 1 wherein said pressure regulating means includes, a spring biased member carried in said flow passage, said spring biased member being operable to pass liquid at a predetermined pressure from said casing to said pump chamber suction inlet opening.

5. In a system as defined in claim 1 wherein said pressure regulating means includes a spring biased member carried in said flow passage to permit unidirectional flow therethrough, the downstream side of said pressure regulating means being communicated with said pump chamber suction inlet opening.

6. A motor driven pump for a fuel system comprising, a body having an opening at one end defined by a peripheral rim, means forming a cavity in said body having a circular wall defining a pump chamber including suction inlet and discharge outlet, a rotor journaled in said pump chamber, a drive motor engaging said rotor for rotating the latter in said pump chamber, means forming an intermediate passage in said body adjacent to said pump chamber, a casing sealably enclosing said motor and having one end thereof fixed to said peripheral rim thereby defining a liquid tight closure about said motor, a filter element disposed in said intermediate passage and forming the latter into a plurality of compartments communicated through said filter element, one of said compartments being communicated with said suction inlet, the other of said compartments being communicated with said pump chamber, passage means in said body communicating said discharge outlet with said casing to introduce a pressurized stream of liquid to the latter for contacting heated motor parts, and pressure regulating means in said casing providing communication between said casing enclosure and said suction inlet, for returning cooling liquid to said intermediate passage when pressure in said casing exceeds a predetermined value.

7. In a pump as defined in claim 6 wherein said intermediate passage is formed by a channel extending at least partially about and spaced from said cavity formed in said body, and said filter element includes an elongated screen positioned in said channel to form said plurality of compartments.

8. A motor-pump unit having an integral motor cooling system and adapted to pass a constant pressured flow of liquid from a source thereof to a point of use; a pump including a pump body being open at one end, a wall defining a chamber in said one end, a pumping chamber formed in a side of said wall opposite to said open end, said pumping chamber having a suction inlet and a discharge outlet and having a rotor journaled therein, an intermediate chamber formed into said wall adjacent to said pump chamber, a casing fixed to said pump body at one end and forming a hydraulic enclosure, a drive motor journaled in said enclosure having a shaft coupled to said rotor, a means forming an opening in said wall communicating said discharge opening with said pump chamber, a second opening in said wall communicating with said pump suction, a pressure regulator carried in said wall forming a valved passage intermediate said chamber and said pump suction for regulating passage of liquid from said compartment in response to liquid back pressure applied to said pump suction from said point of use.

References Cited UNITED STATES PATENTS 2,810,348 10/1957 White 103-118 2,885,962 5/ 1959 Campbell 103-1l8 3,126,030 3/ 1964 Stoermer 103118 FRED C. MA'ITERN, 111., Primary Examiner.

WILBUR I. GOODLIN, Assistant Examiner.

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