US2989957A - Positive displacement metering pump - Google Patents

Description

D. A. MEANS June 27, 1961 A TTOR P/EYS June 27, 1961 D. A. MEANS 2,989,957

POSITIVE DISPLACEMENT METERING PUMP Filed Aug. 5, 1959 2 Sheets-Sheet 2 INVENTOR. DAVID A. MEANS A7' TORNEYS United States Patent 2,989,957 POSITIVE DISPLACEMENT METERING PUMP David A. Means, 162 Topeka, Apt. 4, San Jose, Calif. Filed Aug. "5, 1959, Ser. No. 831,900 4 Claims.. (Cl. 12S-'139) This invention relates to pump mechanisms yfor use with fuel injectors, and, more particularly, to positive displacement metering pumps for fuel injector system utilizing volatile fuels.

The advantages of fuel injection systems for gasoline engines, such as increased peak power, development of peak torque at a lower r.p.m., increased gas mileage, decrease in octane rating of fuel requirement, `and elimination of carburetor icing and vapor lock, have been recognized by the art. The injection of gasoline may be made directly into the combustion chamber of each engine cylinder or into the manifold adjacent the intake port with equal effectiveness up to about 5,000 rpm.

Fuel injector nozzles used for diesel engines cannot -be directly applied to gasoline engine use. The fuel metering requirements of gasoline engines cannot be satisiied with the diesel injector nozzles. Additionally, gasoline has no lubricating attributes kand a nozzle pumping the gasoline will be subject to high frictional wear and rapid failure.

While some metering pumps, such -as the pumps set forth in pages 88-93 of the March 1957 issue of Popular Science, can satisfy the fuel metering requirements of gasoline engines, none satisfy such requirements with the requisite economy of initial cost, economy of maintenance, operational reliability, and ease of maintenance.

It is, therefore, one object of my invention to provide lan improved variable displacement metering pump for metering `of gasoline to an internal combusion engine which pump is economical to install and maintain.

It is a further object of my invention to provide a metering pump for supplying la controllably variable quantity of fuel to injector nozzles which can be fabricated economically.

It is a further object of my invention to provide a variable displacement metering pump in which the component parts in contact with the fuel are not subject to frictional wear by relative movements therebetween.

lt is a further object of my invention to provide a positive displacement metering pump of economical manufacture suitable for retroiitting of present gasoline internal combustion engines.

It is a further object of this invention to provide an improved variable displacement metering pump having separate means for control of displacement, one displacement controller being responsive to laccelerator movement, the other displacement controller -being responsive to ambient conditions such as manifold vacuum for acceleration and deceleration fuel enrichment and cut-off respectively, atmospheric pressure, idle enrichment, and starting and warm-up temperature Variations.

Other objects and advantages of my invention will be pointed out hereinafter.

In yaccordance with these objects I have provided in a preferred embodiment of this invention a plurality of pressure exchangers equally spaced circumferentially yabout a pump body. Each pressure exchanger comprises a exible diaphragm separating the pressure exchanger into a fuel chamber and an oil chamber. Each fuel chamber is coupled to an injector nozzle positioned to inject fuel into the manifold adjacent a respective cylinder when the diaphragm is deflected. In order to deiiect the diaphragm and thus pump fuel to the nozzle from the fuel chamber, there is provided a plurality of cylinders, each of said cylinders being hydraulically coupled to the 2,989,957 Patented June 27, 1961 ice oil chamber in -a pressure exchanger. A piston is movably mounted within each cylinder in sealing engagement so that piston movement will be reflected in diaphragm deflection through the hydraulic coupling. Each piston engages an annular flexible ribbon cam. A shaft driven roller traverses the ribbon cam in deilecting engagement therewith. The roller drive shaft is coupled to the engine so that it is synchronously rotated therewith. Means `are provided to move the roller axially to vary the cam deection, the displacement of the piston and lthus, the quantity. of the fuel delivered to the respective injector in response to operator control and to suit operating conditions of the gasoline internal combustion engine. A dashpot may be provided to damp axial movement of the roller. Means are provided to supply fresh fuel to the fuel chamber and fresh oil to the oil chamber. Means are provided to vent air from the pressure exchanger chambers.

A preferred embodiment of this invention is illustrated in the accompanying drawings of which:

FIGURE l is a cross-sectional View of the variable displacement metering pump in accordance with this invention.

FIGURE 2 is a sectional view along lines 2 2 in FlGURE l; and

FIGURE 3 is an enlarged diagrammatic view of a portion of the apparatus shown in FIGURE l.

Referring to the figures there is shown a metering pump 10 having a plurality of pressure exchangers 12 equally spaced circumferentially about the pump body 14. The output port 16 of each pressure exchanger is coupled to an injector nozzle 18 through fuel lines 20 and iitting 22. Each fuel injector is positioned to discharge within a manifold 24 nea-r the intake port of the respective cylinder. Alternatively, the injector nozzle may be positioned to discharge directly into a respective combustion chamber of each engine cylinder.

While injection directly into the combustion chambers has the advantage of being operable over a higher engine speed range, the pressure requirements are higher and the injector nozzle expense is higher. Injection into the combustion chamber requires a working pressure of approximately 400 p.s.i. at the nozzles. Injection into the manifold, suitable for most applications since such injection operates properly up to about 5,000 r.p.m., requires only -9() p.s.i. at the nozzles. Also the nozzle design is less critical since the nozzle is cooked by the air stream and the fuel is not subject to the pressure and temperature extremes of the combustion chambers. In either case the fuel line connections 20 `between the respective nozzle and output port is made in such manner that the engine cylinders receive fuel in a sequence corresponding to the firing order. In order to stabilize fuel movement to the nozzle at high operating speeds, a high frequency oscillation trap 26 may be inserted within each output line.

Each pressure exchanger comprises a exible incompressible diaphragm 28 which separates the pressure exchanger into a fuel chamber 30 and an oil-filled pressure chamber 32. The diaphragm may preferably be fabricated of stainless steel laminates. In addition to being impervious to the passage of oil or fuel, the diaphragm should be substantially incompressible to prevent absorption of pressure pulsation by the diaphragm.

The diaphragm periphery extends between the fuel chamber housing 34 and the oil chamber housing 35. Bolts 36 clamp the oil and fuel chamber housings together and in friction engagement with the diaphragm. O rings 38 and 40 are positioned astraddle the diaphragm so that the peripheral portion of the diaphragm extends in sealing relationship between the oil and fuel chamber housings.

.A l Y, 3

The diaphragm is provided with a pressure plate 42 secured thereto by the binding screw 44 and the binding nut 46. The pressure plate distributes the load imposed by the return spring 48 urging the diaphragm into contact with the diaphragm return stop 50.

The diaphragm is undulated to force the fuel contained within chamber 30 through the output line 20 to the injector nozzle to charge the associated cylinder with fuel. The injector nozzle comprises a pressure movable valve 52 biased into a closed position by spring 54. Under surge pressure `above a predetermined value the valve will open to yallow fuel to be injected in a mist 56 suitable for quick evaporation into a combustible mixture. At the termination of a diaphragm pulsation in a fuel displacement stroke, the diaphragm return spring will return the diaphragm into engagement with the stop 50. To prevent sucking fuel from the output lines 20 during the return stroke of the diaphragm a check valve comprising ball 60 is provided in the fitting 22. The ball 60 is urged into sealing relationship with the seat 58 by spring 62 to provide for unidirectional flow of fuel through the output lines. The fuel supply in the fuel chamber is replenished through line 64 in manner which will be discussed in greater detail in a subsequent portion of the specification.

In order to pulsate the diaphragm, oil contained within oil chamber 32 is pressure-pulsated in a predetermined sequence. Oil pressure pulsation is provided by operation of pistons 66 operably movable within cylinders 68 spaced circumferentially about the axis of body 14. The piston is provided with a ball socket 72 on the base thereof and return spring 74 biases the piston with the ball 72 in engagement with socket 76. A scraper type neoprene ring 78 is mounted on each piston to prevent oil contained within the cylinder from seeping past the piston skirt. The cylinder is hydraulically coupled to the oil chamber of the pressure exchanger by passage S0. The pressure exchanger is mounted to the body by a pressure plate 82 secured to the body by bolts 84. A seal 86 is provided to ensure that the oil chamber 32 is hydraulically coupled in sealing relationship to the cylinder 68.

To deiiect the piston in a variable stroke synchronously with engine rotation to supply fuel to the injector nozzles `at the proper time, there is provided an annular ribbon cam 88. The ribbon cam is a flat, annular ribbon of suitable alloy spring steel suitable for the service life desired. The annular ribbon cam is deflectibly mounted within guides delined by the annular ribbon cam inner support 90 secured to the body by bolts 92 and an annular outer support 94 secured tothe body by the co-action of the ange 96 on the plate 98 which is secured to the body by bolts 100. The inner cam support serves both as a seat and a guide for the deectible ribbon cam. The outer support 94 serves as a seat only.

To deflect the ribbon cam, rollers 102 and 104 are provided for driving along the ribbon cam surface in deflecting engagement therewith. The rollers `are preferably ball bearings. Therollers are driven along the annular ribbon cam at a rate synchronized with the rotation of the internal combustion engine to thereby synchronize fuel injection with engine rotation. It will be noted that only a single roller need be employed for such ribbon deflection.v However, since the inner roller 102 travels a shorter distance over the cam surface for each rotation than does the outer roller 104, two separate rollers lessens skidding wear upon the surface of the ribbon cam.

In order to 4move the rollers 102 and 104 in a path traversing the annular cam in synchronization with engine rotation, there is provided a housing assembly comprising an upper main shaft housing 106 and a lower main shaft housing 108 iixedlycoupled by bolts 110. The main shaft housing is rotatably mounted within the body and is supported by bearings 112 `and 114. Bearing 114 is an angular contact bearing rotatably mounting the main shaft housing assembly and supporting the housing assembly by co-action of the shoulder 116 thereon with the inner ring. The outer ring co-acts with the shoulder 118 inthe cover plate 98. Similarly, bearing 112 is an angular contact bea-ring, the inner ring of which is clamped between the shoulder 120 on the housing assembly and nut 122 threadably engaging the housing assembly. Suitable preload is applied to the outer ring of bearing 112 by the shoulder 124 of the cover plate 126 axed to the body 14 by bolts 128.

The main shaft housing assembly is rotatably driven by rotation of shaft by the splined connection 132 therebetween. The shaft 130 may, for example, be the camshaft of the engine or an extension thereof contained within the covering housing 134 and suitably supported by bearing 136. Alternately, shaft 130 may be synchronously rotated with engine rotation by being dn'ven by a transmission coupling the shaft to the engine camshaft. The latter arrangement may preferably be employed if the metering pump is used to -retrot existing gasoline engines in -automobiles to yan injector type system. In such cases, the shaft 130 may be mounted adjacent a cam shaft with rotative power derived therefrom.

'I'he lower main shaft housing 108 is cut away to carry the rollers 102, 104 within a cradle assembly 138. The cradle assembly 138 is provided with a tubular insert 140 secured therein by bolt 142. Bearings 102 and 104 are mounted on the insert with a press t. The cradle assembly is pivotably mounted on pins 144 in a cradle fork 146 so that the rollers may track the ribbon cam in their orbital traversement thereof. In order to change the ribbon cam deflection the bearings 102 and 104 must be moved axially. To provide for this movement the cradle fork 146 is pivotably mounted upon pins 148 integral with bolts 150 having a threaded portion to threadably engage the -ange 152 on the lower shaft assembly 108. The cradle fork assembly terminates in a bifurcated yoke 154 which rests upon the surface 156 of the thrust bearing 158. For manufacturing purposes the cradle fork is fabricated from two mirror sections joined by bolts and locating pins 162A.

Since the cradle assembly is mounted on pins 148 the axis of which is displaced from the axis of pins 144, movement of yoke 154 will elevate or lower the bearings 102 and 104 in variably deilecting engagement with the ribbon cam 88. Thus, as the roller traverses the ribbon cam 88, the cam 88 will be deflected in amounts dependent upon the position of fork 154 deecting the pistons 66 represented schematically in FIGURE 3. Tilting of the cam is taken up by rotation of socket 76 about ball 72 to deflect the piston axially without cooking. Piston deflection will result in diaphragm deflection since the oil chamber of the pressure exchanger is coupled hydraulically to the respective cylinder 68. Thus, fuel will be pumped to the respective injector nozzles at predetermined times synchronized with engine rotation 'and in predetermined quantities determined by the deflection of the ribbon cam.

In conventional four-cycle engines, rotation of the cradle assembly will be at the camshaft speed. In a twocycle engine rotation of the cradle assembly will be at crankshaft speed to properly co-ordinate fuel injection with the cylinder inhalation. It will be noted that the respective pistons will ybe moved by deflection of the annular cam. Thus, the deflection will occur prior to arrival of the roller under the piston dependent upon the stiffness of the annular cam and the piston return spring. By suitable adjustment of the respective spring constants, the fuel may be injected over a period corresponding to the valve timing of the engine to which the pump is applied.

For use with internal combustion engines in automobiles fuel delivered must be variable in accordance with operator control and variation in operating conditions. Co-ordinated variation in fuel and air supplied to the engine must be controllable by the driver. Mixture control, such as acceleration enrichment, must be controllable independently of air control.

To reflect throttle movement in a controlled variation of cam deiiection there is provided a main metering lever 162 coupled to both the throttle and -to the manifold buttery valve through conventional linkages (not shown). The lever 162 is pivotally mounted on journal 164 and is connected to the metering rod drive lug 168 through strap 170 pivotally connected to the metering lever by pin 172 and to the drive lug by pin 174A. A second strap is similarly coupled between the drive lug and the metering lever on the other side of the drive lug. The straps 170 provide a linkage to drive the drive lug 168 vertically even though the pin 172 deviates from a vertical path as lever 162 is rotated. The drive lug 168 threadably engages a metering control rod 174 and is locked thereto by the action of lock nut 176. The control rod is axially movable Within the lower bushing 178 and the upper bushing 180. The upper bushing threadably engages the covering plate 126 and the lower bushing is frictionally engaged within the lower main shaft assembly 108.

A shoulder 182 on the control rod supports the thrust bearing 158. Thus, as the main shaft assembly 108 is rotated the thrust bearing 158 separates the rotating yoke from frictional engagement with the shoulder 182, but provides for axial movement of the yoke with movement of the shoulder 182.

Thus, there is provided means for controlling the fuel quantities delivered to the engine and for simultaneously varying the air supplied in related manner.

To provide means for mixture control, there is provided a mixture compensation lever 184 rotatably mounted on journal 185. The lever 184 carries journal 164 as an integral part thereof. The axis of journal 164 is eccentric to the axis of journal 185 (in the figure the eccentricity is exaggerated for clarity). Thus, as compensation lever 184` is rotated about its shaft 185 the pivot point of lever 162 is moved, changing the amount of fuel delivered to the engine.

The mixture compensation lever is rotated in accordance with engine operating conditions, such as manifold vacuum, or atmospheric conditions, such as change in altitude, to control the mixture by changing the amount of fuel supplied to the engine without corresponding variation in air supplied by movement of the butterfly valve. The compensation lever may be rotated by sensors responsive to engine and atmospheric conditions in manner known to the art to provide for load enrichment (including acceleration loads), idle enrichment, and deceleration fuel cut-off.

Thus, it can be seen that there is provided rotatable deecting rollers in deilecting engagement with an annular ribbon cam. Deection of the ribbon cam will cause deflection of a piston within a cylinder and, thus, deilection of the pressure exchanger diaphragm through hydraulic coupling of the cylinder and pressure exchanger to meter a selectably variable quantity of fuel to each of a plurality of injector nozzles at a time synchronized with engine rotation. The fuel, lacking lubricating qualities, is pumped by a deflectible diaphragm. Thus the fuel pump components in contact with the fuel do not frictionally engage other parts. Such parts may then be fabricated with only normal manufacturing tolerances and have long operating lifetime.

The moving parts of the pump are immersed in oil. Thus, friction between moving parts is reduced. Also, since the diaphragm deection is caused by pumping of ail, the piston may be economically fabricated. The viscosity of the oil permits use of a neoprene O ring seal with relatively loose fabrication tolerances.

In order to supply fuel to each of the fuel chambers 30, there is provided an` annular fuel reservoir 186 communicating with the fuel chamber through apertures 64.

The annular fuel chamber is defined by an annular housing 188 and a cover 190 `aiiixed thereto by bolts 192. Annular seals 194 and 195 such as neoprene O rings are positioned in sealing relationship between the housing 188 and the cover 190. The reservoir is secured to the Ihousing 34 by fittings 196. An annular O ring 198 is secured in sealing engagement between the housing 34 and the reservoir 188. The fitting 196 is provided with a valve seat 200 which co-acts With ball 202 urged into engagement therewith by spring 204 to provide for unidirectional ow of fuel from the reservoir into the fuel chamber 30. The reservoir is supplied with fuel from line 206 from the fuel pump of the engine. The line is suitably connected to the reservoir through fitting 208 and -nut 210 in conventional fashion. Suitable fuel filters may be provided in line 206 as necessary.

Since the fuel chamber 30 of the pressure exchanger must remain completely full of fuel for proper system operation and since in automotive use, it is anticipated that occasionally the operator will allow the fuel tank to become depleted, means must be provided for elimination of air from the metering pump when the tank is refilled.

For this purpose there is provided a return line 212 from the fuel reservoir to the fuel tank. The return line is coupled to the annular reservoir by fitting 214 and nut 216 in conventional fashion. Inter-posed between the fitting 214 and the annular reservoir is a constrictor Ivalve 217 comprising a ball 218 movably mounted and closely tted within passage 220. The ball engages the perforated stop 222 under influence of the urging of spring 223. The constrictor v-alve is essentially a narrow opening constricting ow of uid therethrough to a small quantity and thus maintaining pressure within the annular reservoir. The spring biased ball is employed to prevent clogging of the restrictor valve construction assembly in a conventional fashion.

Should the fuel tank become depleted, air will be admitted to the annular reservoir and to the fuel chamber 30. As soon as air enters the chamber 30, pulsations of the diaphragm 28 will be absorbed by the compressibility of air and fuel ow to the injector nozzles will cease. Cessation of fuel flow to the injector nozzles will occur before the fuel reservoir 30 has become depleted sutiiciently to introduce air in the outward lines 20. When the tank is refilled and the fuel pump activated, such as, for example, by pressing a starter button in an automobile, fuel will again flow into the annular reserfvoir and air will be vented therefrom through the constrictor valve 217. As soon as the reservoir is full of fuel, pressure will build up and fuel will be introduced into'the chamber 30. Fuel flow into the chamber will deect the ball 202 allowing air entrapped within the chamber to pass through aperture 224 and pass into the reservoir for venting into the fuel tank. In such venting, of course, minor amounts of fuels will be returned to the Ifuel tank. The return of fuel and/ or air tto the fuel tank will be automatically vented through the atmosphere through the vent plugs in the automotive gas tank.

It will be noted that, in theory, even if the output lines 20 have air entrapped therein, the continued operation of the fuel pump will fill the lines with fuel forcing air entrapped therein through the injector nozzles 18. However, to prevent restriction of the placement of the fuel lines 20 as they are passed through the injector nozzles to prevent entrapment of air in a bend therein and to facilitate installation, it is usually preferable to manually vent the air through the lines. Once the lines are full, they will remain full under all operating conditions and only air entrapment within the chamber 30 need be compensated for.

In similar `fashion the oil chamber 32 must be lled with oil and must remain full of oil toV hydaulically couple piston movement to the oil chamber. At installation, the sump 226, the oil chamber 32, the cylinder 68 chamber 32 with oil, a vent plug 228 is provided which Y Vcan be removed to allow air escape from the chamber.

An annular oil reservoir 230 is provided in the body and is dened by the body walls and the annular cover plate 232 a'ixed thereto by bolts 234. Annular O rings 236 and 238 are provided in sealing engagement between the body and the cover plate toprovide ahydraulically sealed annular reservoir. Oil is provided to the annular reser- Voir through tubing 240 which is supplied with oil from the engine under normal oil pressure such as 35 p.s.i. The pipe is secured to the reservoir in conventional manner by fitting 242 and nut 24,9. Communicating between the reservoir 230 and each passage 80 isa passage-way defined by itting 244. Unidirectional ow of oil therethrough is provided by check valve composed of ball 246, seat 248 and spring 250. Thus, any depletion of oil from the cylinder during pumping cycle such as the escape of oil past the piston skirt will be made up by oil introduced under pressure Ifrom the annular reservoir. n

To provide means for venting Iany air that may be entrapped within the oil of the reservoir before it is introduced into the oil chamber 32 air where the compressibility thereof would interfere with pressure exchange, there is provided an oil constrictor valve 251 containing a ball 252 slideably mounted within a bore 254. The ball is normally urged into engagement with the perforated seat 256 by spring 25S. However, the constriction assembly is prevented from clogging by flexibility of ball movement under pressure increase. The diameter of the ball is so dimensioned with respect to the bore as to permit a small quantity of oil to be continuously vented therethrough and enter pipe 260. The oil and vented'air is then direeted into the sump 226 of the pump -through fitting 262 and nut 264 coupling the pipe 260 to the sump. The continuous flow of oil ensures that the sump is always maintained full and allows for some recirculation of oil. Excess of oil from the sump is bled off through channel 266 and returned to the engine crank case through pipe 268 coupled to the channel by fitting 270. The other end of the pipe 268 is coupled through fitting 271 to return oil to the crank case through the annular space between shaft 130 and the annular shaft cover 134. In so doing, the bearing 136 is provided with lubricating oil. It will be noted that any air vented from the oil reservoir 230 is similarly vented to the engine crank casefor safe dissipation,

To aid in control of any reaction force that might be imposed on the control rod 174 during deflection of the ribbon cam, -a dashpot may be provided onV the rod. The dashpot chamber is `comprised of the upper main shaft housing 106 with a piston 274 therein. The piston is mounted on the control rod in threaded engagement therewith and vhas apertures 276 therein for oil movement therethrough. A check valve plate 279 is mounted on and secured to the center hub 278 of the piston by nut 280 and peripherally contacts the piston skirt 232. As the control rod is pulled upwardly, the check valve plate will deflect, oil will pass through apertures 276 to provide little resistance to upward movement. However, when the control rod 174 is moved downwardly, the check valve plate will be moved into peripheral contact with the piston skirt preventing oil flow through apertures 276 and restricting oil flow to the passage between the piston skirt and the walls of the upper mainshaft housing 196. Thus, any high frequency reaction force imposed by the roller will be partially or completely absorbed by the dashpot `and will not be reected in throttle movement to annoy the driver. It will be noted that in many cases since the ribbon cam is relatively mild and since deflection is only of the order of 60 thousandths of an inch that the reaction force may be insignificant and a dashpot can be omitted.

To fill the dashpot with oil and to provide for circulation thereof, there are provided apertures 284 in the wall of the upper main shaft housing. As the main shaft housing is rot-ated, centrifugal Aforce will tend to cause oil flow through the apertures, which flow will vary with the rotational speed of the mainshaft housing. An enclosure plate 286 is provided having an aperture 288 centrally located about the control rod. Thus, the oil flowing out of apertures 284 is replenished by oil ow through aperture 288. An oil seal 290 is provided to prevent the establishment of an oil flow through the associated aperture during such conditions.

In recapitulation, there is thus provided a plurality of pressure exchangers having a fuel chamber dened by a housing and a deflectible diaphragm. The diaphragm and an oil chamber housing defines an oil chamber, so that the diaphragm is positioned in pressure transfer relationship between the oil and the fuel chambers. Hydraulically coupled to each oil Ichamber is a cylinder containing a movable piston. Each of said pistons are mounted to engage a deliectible annular ribbon cam. A roller radially constrained to transverse the ribbon cam is axially deilectible to vary the deflection of the ribbon cam and, thus, to pulsate the pistons at a time related to engine rotation and in an amount controllable by the operator and by engine operating conditions. Piston deection is reflected in diaphragm ydeflection to pump selectible quantities of fuel through a spring lloaded injector nozzle to supply engine fuel at the proper times for combustion within the engine cylinders. Thus, no moving parts are immersed within the fuel, but all moving parts are immersed within oil. For simplicity this oil may be the same as that used in the engine itself. The heavier viscosity of the oil, in addition to its lubricating qualities, allows parts to be fabricated with lower manufacturing tolerances and thus lower manufacturing costs. l

The annular ribbon cam requires little deection since the associated pistons are larger in diameter than conventional piston operated injector pumps. Thus, the total deflection of the ribbon cam at maximum fuel metering would be restricted to approximately 60 thousandths of an inch. Thus, the ribbon cam may be fabricated of suitable alloy steel for long operating life. Since the traveling distortion of the annular ribbon cam is accompanied by movement of the cam, it is -found that the yannular cam rotates slowly during pump operation preventing localized working and possible localized failure of the cam surface.

The roller is rotated `at a rate synchronously related to engine speed to supply the fuel to the respective engine cylinders when the cylinder is inhaling. For a four-cycle Y engine the roller would rotate lat camshaft speed. For a two-cycle engine, the roller would be rotated at crankshaft speed. If desired, a dashpot may be provided to damp out the reaction force imposed by cam deflection. In such applications where a dashpot is uneccessary, it will be noted that the sump need not be lilled with oil but the oil supply for the bearings may be provided in any conventional lfashion such as splash. In such case the sump need only be `filled so that the oil level contacts the lower edge of the deliecting roller.

It will be understood that my invention can be variously modified and embodied within the scope of the subjoined claims.

What is claimed is:

1. A fuel metering pump `for use with -a multicylinder internal combustion engine, comprising an -annular ribbon cam, a roller rotatably mounted -to traverse said cam in detiecting engagement therewith, means for moving said roller axiallyto vary the deflection of said ribbon cam, a metering unit for each of said cylinders, each of said metering units having a pressure chamber, a gasoline fuel chamber, and a flexible diaphragm isolating said pressure and gasoline chambers, and means responsive to cam deflection for moving said diaphragm to supply gasoline to each of said cylinders, said last named means including said pressure chamber.

2. A pump according to claim 1 in which said diaphragm-moving means includes a cylinder having a piston operable therein in response to deection of said ribbon cam and means hydraulically coupling said cylinder to said pressure chamber.

3. A metering pump for supplying variable quantities of gasoline fuel to a plurality of injector nozzles in fuel trans-fer relationship with the cylinders of an engine comprising -a metering unit `for each of said nozzles, each of said metering units comprising a `fuel chamber, a pressure chamber, -a exible diaphragm, said pressure chamber and said -fuel chamber coupled together with said diaphragm in sealing relationship therebetween, means coupling said :fuel chambers to an injector nozzle, an annular deectible cam surface, a ldeecting member rotatably mounted for movement along said cam surface in deecting engagement therewith, and means responsive to cam deection yfor moving said diaphragms, said last named means including said pressure chamber.

4. A metering pump in accordance with claim 3 in 10 which said diaphragm moving means comprises a plurality of cylinders, a piston operable within each of said cylinders, said cylinders mounted adjacent said annular cam |with said pistons in frictional engagement therewith, 4and hydraulic means coupling Ieach of said cylinders to a pressure chamber in pressure transfer relationship.

References Cited in the tile of this patent UNITED STATES PATENTS 2,283,242 Van Der Walt May 19, 1942 2,301,407 Houser et al Nov. 10, 1942 2,395,330 Houser Feb. 19, 1946 2,624,284 Straub Jan. 6, 1953 FOREIGN PATENTS y 350,817 Great Britain June 18, 1931 475,036 Germany Apr. 16, 1929

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