US2145260A - Fuel pump - Google Patents

Description

C. F. HIGH FUEL PUMP Jam. 31, W39.

2 Sheets-Sheet 1 Filed April 22, 1937 Jam. 31 393%, Q R G 2,B45,26

FUEL PUMP Filed April 22, 1937 2 Sheets-Sheet 2 atented Jan. 31, 1939 UNITED STATES PATENT orrlc 11 @laims.

The invention relates generally to fuel pumps for internal combustion engines and more particularly to the control means associated with such pumps for governing the ultimate fuel-air I ratio of the mixture supplied to the engine.

When a fuel pump is employed to feed small, accurately measured charges of fuel for the individual cylinders of an internal combustion engine, the relative proportioning of the fuel and air J supply becomes an important consideration in obtaining efllcient engine performance at all speeds, and it is customary, therefore, to provide a common inter-related control means for varying the fuel charge and air supply in an efiicient relation throughout the range of engine speeds. In attaining an emcient fuel-air ratio, such a common inter-related control means establishes a definite relationship between the actuation or movement of the fuel volume control and the air volume l control throughout therange of engine speeds,

and it is found that variations in air pressure incident to altitude changes of an aircraft engine result in a detrimental fuel-air unbalance.

An important object, therefore, of the present invention is to-provide a fuel pump for internal combustion engines embodying a new and improved control means whereby an efflciently proportioned air and fuel supply may be provided for atmospheric conditions encountered at any altitude of engine operation.

Another object is to provide such a device wherein a new and improved coordinated mechanism of a simple character for varying the fuel and air supply to the engine may be adjusted i manually to providefor changes in atmospheric and barometric conditions, and eiilcient fuel-air ratio throughout the range of engine speed.

A further object is to provide a single throttle connection for regulating valves controlling both fuel and air supplies to an engine which comprises a common, lever connection between the valves and an adjustment separately operated for varying the effective length of the lever arm connection to alter the extent of the opening of one with i respect to the other so as to change the ratio of fuel 'to. air supplied to the engine as a result of normal throttling.

More specifically, the present invention has for its object the provision of new and improved fuel I and air control mechanism of this character embodying means whereby the pilot may, when different atmospheric conditions are encountered during flight, adjust the mechanism to deliver throughout the range of enginespeeds, a properly coordinated supply of fuel and air.

.Justed position.

Figs. 4 and 5 are sectional views taken along the line fl-t of Fig. 3 and illustrating a part of the control means in different positions of adjustment.

For purposes if disclosure, I have illustrated in the drawings and-will hereinafter describe in detail the preferred embodiment of the invention, with the understanding that I do not intend to limit my invention to the particular construction and arrangement shown, it being contemplated that various changes may be made by those skilled in the art without departing from the spirit and scope of the appended claims.

In the form chosen for disclosure herein, the invention is intended and adapted for use with the internal combustion engine of an aircraft, and is embodied in a fuel and air supply system wherein a variable output fuel pump it and an air intake manifold ll provide an emciently coordinated, adjustable supply of fuel and air for the engine under the control of a common accelerator connection l2.

The fuel pump l0, as illustrated herein, is of the suction metering type having a generally cylindrical casing I8 with a plurality of individual pumping units, disposed concentrically of its axis in the lower end of the casing, and actuated by a rotatable cam plate l4 housed in a chamber ii in the upper portion of the casing. In the lower portion of the casing l3, and in the space within the annular row of pumping units, a relatively large fuel chamber I6 is provided to supply fuel for all of the pumping units.

Each pumping unit preferably comprises a piston II reciprocable and oscillatable in a cylindrical bore I8 formed in the wall of the casing It at the side of the chamber It, all of the bores being closed at their lower ends by-plugs l9 held in to place by a bottom plate l9, and all of the bores terminating at their upper ends in a chamber l5 formed in the casing below and partially separated from the chamber I5. The pistons H extend upward beyond the termination of the bores .55

into the upper chamber l5 to provide for operative association of the pistons I1 with the actuating cam plate l4. At a point above its closed lower end, there is an inlet to each cylinder l8 from a radial duct 20 located each in its respective arm 45 of a spider-like internal frame. Spaced circumferentially at approximately from the inlet is anoutlet duct from the cylinder, positioned so that it is invisible in the views of the device here presented. From the lower end of each piston H a central bore 2| extends upwardly to a lateral extension or port 22 opening through the side of the piston l'l so that the clearance space of each cylindrical bore may communicate first with the inlet duct 20 to receive a charge of fuel and then with the outlet to discharge the fluid as the piston is periodically reciprocated and oscillated.

As shown in Fig. 1, each piston I! has a cam shoe 23 engaging therewith at the upper end through the agency of a ball and socket joint 24. An expansive spring 25, surrounding the piston within the chamber I5 and acting between the casing and a flange 26 at the upper end of the piston, maybe operable to urge the cam shoe 23 into bearing relation with an actuating cam surface 21 on the cam plate i4. Thus in rotation of the cam plate about the axis of the casing I3, the pistons are reciprocated in succession, a stop plate 28 being employed, if desired, to accurately gage the end of the upward or suction stroke. Another purpose of the cam plate I4 is to impart timed oscillation to the pistons H. A cam finger or follower 3|] is accordingly provided which projects rigidly from the piston i1 through a suitable radial slot (not shown) in the cam shoe 23, and upward into a cam groove 3| in the lower fact of the cam plate Id. The follower track thus formed by the groove is distant from the axis of rotation by a variable amount, so proportioned that a periodic sequence of rotation is given to the piston. Details of this portion of the structure are more clearly set forth in my Patent No. 2,060,076, issued November 10, 1936. The cam surface 21 'and the cam groove 3| are so formed and related that the port 22 registers with the inlet duct during the suction stroke and with the outlet duct during the discharge stroke of the piston.

Cam plate I4 is preferably journa'led in the casing i3 by an axially hollow shaft i4 formed integrally with the plate i4 and extending upwardly therefrom into an upwardly projecting axial bearing hub 32 formed at the top of the casing. A friction bearing 33 and a combined radial and thrust bearing 34 in the bearing hub 32 serve to support the ifiiper and lower portions respectively of the hollow shaft i4. The inner race of the bearing 34 is supported on a shoulder I4" of the hollow shaft l4, while the outer race is clamped between the casing l3 and an annular internally flanged ring 34' secured to the casing by bolts 34" preferably concealed by an annular plate I3. Extending through and journaled in the hollow shaft I4 is a drive shaft 35 which drives the cam plate l4, in a forward direction only, through a single-position, one-way clutch 36. This one-way clutch is described in greater detail and is claimed in my copending application Serial No. 124,063, filed February 4, 1937. Outside of the bearing hub 32, the drive shaft 35 has a fixed flange 31 riding against the end of the bearing 33, while at its lower or inner end an expansive spring 38 surrounds the drive shaft and acts between a collar 38 fixed on the shaft and the cam plate H to hold the plate H in the vertical position determined by the bearing 34.

In the form illustrated herein, fuel is drawn from a fuel supply tank 40 and fed to the chamber ill by a fuel feed pump 4| which is preferably mounted within the pump casing l3 so as to be actuated by the drive shaft 35. Thus the feed pump 4| has its casing 4| fixed axially of the casing I3 below and in alinement with the shaft 35 so that its rotor 4|" may be driven from the shaft 35 by a coupling 42. The casing 4| extends through the top wall 43 of the chamber I6, and has its outlet I6 discharging into the chamber l6, while its intake 44 is formed through an enlarged or thickened portion (not shown) of the wall 43 as a continuation of a pipe leading from the fuel tank 40. Particulars of the feed pump 4| and its relationship to the other elements of the device are shown and described in detail in my copending application Serial No. 90,056, filed July 11, 1936. Beneath the pump 4| and in the supply chamber I6 lies the spider-like distributing member 46 containing the inlet duct 20 previously referred to, which has a central distributing chamber 41 at the hub from which ducts 48 radiate to communicate with the inlet ducts 20 leading to the several pump cylinders. Threaded upwardly into the hub of member 46 is a plug 49 formed with a vertical metering passage 50 communicating at its upper end with the chamber 41 and at its lower end with. the supply chamber l6 so as to pass fuel from the source of supply to the radiating ducts 48.

- Thequantity of fuel supplied to the pumping units is controlled by a manually actuated tapered valve or metering pin 5| disposed in the metering passage 50. The metering pin 5| is preferably supported on a piston 5| slidably vertically within a sleeve-like downward extension 49' of the plug 49. Above the upper level of the piston 5| transverse ports 53 in the plug 49 provide for communication between the passage 50 and the fuel supply chamber l6. An inverted cup-shaped member 45' may be secured between the hub and a shoulder on the plug 49 with the skirt portion thereof extending over but spaced from the ports 53. To provide for longitudinal movement of the pin for varying the quantity of fuel metered thereby, a spring 54 surrounds the extension 49 and acts against a bottom flange 5|" of the piston 5| to maintain the lower end of the piston in contact with an actuating control cam 56. Preferably the cam '56 is carried within the chamber IS on a hollow horizontal shaft 51 so that by rotation of the cam, the valve or metering pin 5| may be opened or closed as desired. On the projecting outer end of the shaft 51 an arm 58 is mounted, the arm 58 being connected by means of an angle fitting 16 to a link 59 pivoted upon an actuating arm 60 of an air control valve 6| which controls the air intake manifold M. The arm 60 is connected to and actuated by the manually operable accelerator connection l2, so that the fuel metering pin and the air control valve are opened or closed in unison.

In maintaining the most efficient quantity relationship between the fuel and air throughout the range of adjustment of the fuel and air valve means, the valves of the present embodiment are relatively simple in form and the requisite variation in relative movement of the several parts is obtained through the conformation of the effective cam surface of the cam 56 which is for this reason termed the fuel-air cam" of the mechanism.

- 2,145,260 To secure accurate suction metering of the fuel past the needle valve or metering pin 5|, the feed pump 4| is constructed so as to feed fuel in excess of the total requirements of the fuel pumping units, and a uniform pressure is maintained in the chamber It by a constant pressure relief valve G2'located in a by-pass line 63 leading from the chamber l6 to the fuel tank .40. As shown in Fig. 1, the b -pass line 63 is connected to a valve chamber 64 formed by an upwardly extending vertical bore in the side wall of the casing I 3, there being a valve port 65 axially located in the upper end of the bore and communicating with the chamber It so as to be adapted to be opened and closed by vertical movement of a valve 62 in its chamber 64. Thus the pressure of the fuel in the supply chamber it acts on the exposed upper end of the valve 52 with 'a tendency to unseat or open the same, this valve opening action being controlled by a spring 55 located in the chamber 64 and acting between the valve 62 and a plug which extend through the bottom plate l5 and is threaded into the lower end of the chamber 55.

Since the air valve'5l and, the fuel metering valve 5i are actuated in unison, it is found that in the operation of the engine in an aircraft, the changes in air pressure incident to changes in altitude cause variation in the amount of air fed for a particular positioning of the two valves, with the result that an unbalance of the fuelair ratio causes inefllcient engine operation. The present invention contemplates and provides means whereby the pilot may, at any time during flight and in accordance with the altitude, correct or adjust the relative operative relationship of the fuel and air valves so that throughout their range of movement by the accelerator t2, the proper proportion of fuel and air will be supplied to the engine. Such corrective adjust ment is, in the present embodiment, obtained through manually effected variation of the operating connection between the accelerator l2 and the fuel valve 5i, so that for any given movement of the air valve M, the corresponding movement of the fuel valve 5! may be adjusted. Preferably such adjustment is effected by varying the effective length of the control arm 58 of the fuel pump ill, and in order that required adjustment may be made during flight, and without interference with the normal operativeness of the accelerator and the operating connections therefrom, the adjusting means is actuated by an element Hi (Fig. 4) which is shiftable axially of the cam shaft 51 by means of a Bowden cable Ill. The Bowden cable II may,-of course, have its other end connected to a reciprocable operating knob (not shown) located conveniently and in a conventional position on the instrument panel so as to be accessible and operable in accordance with principles familiar to most pilots.

Below the plate is at the bottom of the casing a hollow cap I9 is attached which is recessed for reception of the cam 56 and the contacting end of the piston 5|. As illustrated in Figs. 4. and 5, the cam shaft 51 is tubular in form and is journaled in the cap l9 by a sleeve hearing it, and the adjusting element. 15 takes the form of a rod slidably mounted in the tubular cam shaft. On the projecting end of the cam shaft 51!, a supporting or mounting member 13 is fixed, said member having a mounting sleeve portion l4 surrounding and secured to the shaft 511 and a second sleeve portion 15 integrally formed at one side of and disposed at right angles to the mounting sleeve portion 04 so as to form a slldeway in which the arm 58 may' be moved longitudinally in a direction transverse to the axis of the cam shaft 51. At one end of the arm 58 the angle fitting 16 is pivoted by a pin 11, and one end' 18 of the link 59 is screw threaded into the angle fitting. Thus by sliding the arm 58 longitudinally within the sleeve 15, the effective length of the arm (that is, the radial distancebetween the pivot 11 and the axis of the cam shaft 51) may be adjusted. Such adjustment is effected by longitudinal movement of the axially slidable rod 75, and to this end the rod i is connected by means of a link 80 to the other end of the arm 55.

In order that the link 80 may, in one position of the slide rod, stand parallel and adjacent to the arm 58, the end of the link 80 which is connected to the arm 58 is formed with a right angle extension ill through which a pin 52 extends to pivot the link 80 and the arm 55 together. From its pivotal connection 52, the link extends past one side of the sleeve l5, and at its other end is connected by a pivot pin 55 to a ing 85 which extends from a head 55 fixed to the end of the slide rod ill. The Bowden cable H is in the present instance attached to the head 55 by a swivel joint 85. As best seen in Figs. 4 and 5, the joint is formed by a member 55' at one end threadedly connected to the Bowdencable and reduced at the other end to be received in a recess in the head 55. The reduced portion and the recess are formed with complementary grooves 55" in which pins 55" are inserted in well known manner.

Preferably, the withdrawal of the adjusting or slide rod ill by means of the Bowden cable i! isopposed by a yieldingmeans forming a part of the adjustable assembly carried by the cam shaft 51. In the present instance, this means comprises an expansive coil spring 8? surrounding the arm 55 between the bearing sleeve l and a flange formed on the arm 55 adjacent to the pivot pin 52. ,The spring 55 may actually serve to return the arm 58t0 its shortened relation of Fig.3 when the. cable M is released, or

it may, as in the present instance, be of such a strength as to act in the nature of a counterbalance to facilitate a return movement actually initiated by force applied through the cable.

When the slide rod "i5 is in the position shown in Figs. 3 and 4, the toggle link 55 is positioned parallel to the arm 55'and the arm is, therefore, in its fully retracted or shortened position wherein the arm has its minimum effective length. Hence the movement of the accelerator M to open fully the air valve 5| will operate also to open the needle valve to its fully retracted position with the result that the maximum pump output will be fed to the engine. This adjustment adapts the fuel feeding system for operation of the engine at substantially sea level conditions wherein the maximum atmospheric pressure feeds air into the intake at the maximum rate. I

As the engine is carried by a plane to a higher eifective length of the arm 58 (shown in Figs. 1'

altitude, there is a notable decrease in air pres- I and 5, and indicated by dotted outline in Fig. 3), the maximum opening of the air valve 6| produces only slightly over half the movement of the cam 56. Therefore, the amount of fuel fed to the engine is reduced to correspond to the reduced air supply, and similar adjustments may be made to produce the correct relationship of the fuel and air valve movements for any intermediate altitude.

In connection with the proportioning and arrangement of the adjustable linkage, it is to be noted that the pivot pin 83, in an adjusting movement while the air and fuel valves are in their idling positions, is shifted along a line which is substantially perpendicular to the longitudinal axis of the link 59. Because of this relationship, the adjustment of the arm 58 does not change the low speed or idling position of the fuel valve, but is effective to produce relatively reduced fuel valve opening only when the accelerator 'is positioned for speeds above the idling speed.

From the foregoing description, it will be apparent that the'present invention provides a fuel and air feeding apparatus capable of adjustment during flight to correct for changes of altitude so as to furnish an efficient proportion of fuel and air. It will also be evident that the adjustment is accomplished by means of a simple and rugged character, and that the manually operated actuating element thereof is adapted for mounting and actuation in accordance with principles familiar to most pilots. I

I claim as my invention:

1. In a fuel and air supply system for an internal combustion engine, the combination of an air intake having a control valve mounted on a rock shaft, a fuel pump for supplying fuel to the engine cylinders and having means for varying the fuel output of the pump including an operating rock shaft, an operating arm on each of said rock shafts, a link pivoted at its opposite ends to said arms, means for shifting said link at one of its ends toward and away from the axis of the adjacent rock shaft to vary the effective length of the arm at said end, and means for actuating said shifting means including an element shiftable axially of said adjacent rock shaft.

'2. In combination with the air intake of an internal combustion engine, a valve for controlling the air intake, a rock shaft mounting said valve, a first operating arm on said rock shaft, a fuel pump for supplying fuel to the engine, means for varying the fuel output of said pump including a second rock shaft through rocking movement of which the output of fuel is varied, a bearing member fixed to said second rock shaft, bearing means on said member providing a slideway extending generally radially with respect to the axis of said second rock shaft, a second operatingarm slidable on said slideway to vary the position of the ends of said second arm with respect to said shaft axis, a link connected between said first operating arm and one end of said second arm, a slide member mounted on said second rock shaft for movement longitudinally thereof, and a linkpivoted at its opposite ends to said slide member and to said second operating arm at a point eccentric to the slide member.

3. In combination with the air intake of an internal combustion engine, a control valve for said intake having an operating arm, a variable output fuel pump connected to supply fuel to the engine and having output control means including an actuating arm, a link pivotally connected at its opposite ends to said arms to efiect simultaneous rocking movement of the arms, and means for varying the effective length of one of said arms with respect to its pivotal connection with said link.

, 4. In combination with the air intake of an internal combustion engine, an air intake valve having an operating arm, a fuel pump having means for varying the fueloutput including a rock shaft, a link pivoted at one end to said valve operating arm, a second operating arm extending transversely of said rock shaft and adjustable to vary its effective length relative to the axis of said shaft, said link being pivoted at its other end to one end of said second arm, an adjusting member mounted on said rock shaft for movement longitudinally thereof, and an operating connection between said adjusting member and said second arm for varying the effective length of said second arm as said adjusting member is shifted longitudinally of the rock shaft.

5. Apparatus of the character described comprising, in combination, an air intake for an internal combustion engine, an air intake valve having an operating arm, a fuel pump having means for varying the fuel output including a rock shaft, a link pivoted at one ,of its ends to said operating arm, means connecting the other end of said link to said rock shaft eccentrically thereof to impart rocking movement to said shaft when said link is actuated, adjusting means for varying the degree of eccentricity of said last mentioned connecting means, an adjusting member mounted on said rock shaft for movement longitudinally thereof and operable in such movement to actuate said adjusting means to vary the eccentricity of said connecting means, and an operating means connected to said adjusting member axially thereof.

6. In a fuel and air supply system for internal combustion engines, the combination of an air intake having an air control valve movable between idling and wide open positions, a fuel pump for supplying fuel to the engine, fuel control means for varying the fuel output of said pump including a metering valve movable between idling and wide open positions, an operating cam for actuating said metering valve, and means for actuating said cam, a manually operable occelerator means connected to said air valve and said fuel control means for actuating the same to vary the engine speed, and manually actuated adjusting means operable upon a part of said fuel control means to vary the control movement of said metering valve with relation to said air control valve while maintaining the same relationship of the idling positions of said valves.

'7. In a fuel and air supply system for the internal combustion engine of an aircraft, the combination of an air intake having a control valve, a fuel pump for supplying fuel to the engine cylinders and having a fuel valve for varying the fuel output of the pump, an accelerator having operating connections to both of said valves for opening and closing said valves in predetermined relation to vary the engine speed,

- and means for adjusting one of said connections during flight to vary said predetermined relation of the fuel and air valves.

8. In a fuel and air supply system for internal combustion engines, the combination of an air intake having an air control valve mounted on a rock shaft, an operating arm on said rock shaft, a fuel pump for supplying fuel to the engine, fuel control means for varying the fuel output of said pump including a shiftable element, an operating cam foractuating said shiftable element, and a shaft carrying said cam and having an operating arm, a link connecting said arms, a manually operable accelerator connection for actuating said arms to vary the engine speed, and a manually adjustable altitude compensating means including and operable through an element movable longitudinally of said camsupporting shaft to vary the controlling movement of said shiftable element with relation to the movement of said air control valve.

9. In combination with the air intake of an internal combustion engine, an air intake valve having a supporting shaft and an actuating arm, a fuel pump for supplying fuel to the engine cylinders, fuel control means for varying the fuel output of said pump including a shiftable element, a shaft, a cam supported on said shaft for operating said shiftable element, and an arm on said shaft, a link connecting said arms, a manually operable accelerator connection for actuating said link to vary the fuel and air supply in predetermined relation throughout the range of engine speeds, and an altitude compensating mechanism including a manually operable member, a pivoted element operable in its pivoting movement upon a part of said fuel control means to variably adjust the movement of said shiftable element by said fuel control means with relation to the corresponding movement of said air control valve, and a slidable element mounted for movement longitudinally of said cam-supporting shaft and operatively associated with said pivoted element to impart pivotal movement thereto, said slidable element being actuated by said manually operable member.

10. Apparatus of the character described comprising, in combination, an air intake for an internal combustion engine, an air intake valve having a supporting shaft and an actuating arm, a fuel pump for supplying fuel to the engine cylinders, fuel control means for varying the fuel output of said pump including a shiftable element, a shaft, a cam supported on said shaft for operating said shiftable element, and an arm on said shaft, a link connecting said arms and a manually operable accelerator connection for actuating said link to vary the fuel and air supply in predetermined relation throughout the range of engine speeds, and altitude compensating mechanism including a manually operable member, a pivoted element and a slidable element, said pivoted element being connected to said manually operable member for movement about its pivot by said member, and said pivoted element being operable in its movement to impart sliding movement to said slidable element, and means operable upon a part of said control means by said slidable element in its movement to variably adjust the movement of said shiftable element by said fuel control means with relation to the corresponding movement of said air control valve,

11. In combination with theinternal combustion engine, an air intake valve having a supporting shaft and an actuating arm, a fuel pump for supplying fuel to the engine cylinders, fuel control means for varying the fuel output of said pump including a shiftable element, a shaft, a member supported on said shaft for operating said metering valve, and an arm on said shaft, a link connecting said arms, a manually operable accelerator connection for actuating said link to vary the fuel and air supply in predetermined relation throughout the range of engine speeds, and an altitude compensating mechanism including a manually operable member, a 'pivoted element and a slidable element mounted for movement longitudinally of said cam-supporting shaft, one of said elements being connected to said manually operable member for actuation thereby and the other of said elements being actuated by said one element, said other of said elements being operable on a part of said fuel control means to vary the control movement of said shiftable element by said control means with respect to the corresponding movement of the air control valve.

CAR-L F. HIGH.

air intake of an I

Images