US 2313264 A
Description (OCR text may contain errors)
March 9, -1943.
F. c. REGGIO FUEL SUPPLY SYSTEM Filed Oct. 2l, 1938 2 Sheets-Sheel v March 9, 1943. F, c. REGGIO 2,313,264
FUEL SUPPLY SYS TEM Patented Man 9, 1943 UNITED STATES PATENT OFFICE FUEL SUPPLY srsrmr Ferdinando Carlo Reggio, Buffalo, N. Y. Application October 2l, 1938, Serial No. 236,249
This invention relates to a fuel supply system for an internal combustion engine and in particular to mechanisms for supplying' liquid fuel under pressure and in measured quantity to an internal combustion engine. The invention is particularly applicable for the control of the quantity.` of fuel supplied and for the control of the timing adjustment of the intermittent fuel discharge.
One object of the invention is a fuel pump in which the quantity of fuel supplied at high pressure by the pump is controlled by adjusting the variable and relatively low pressureat which fuel is` delivered to said pump.-
Another object is to provide a hydraulically -controlled engine fuel injection system.
A further object of the invention is to provide means for the accurate determination of the either ilxed or controllable timing of the intermittent fuel supply.
A still further object is to provide means for hydraulically controlling the fuel delivery of the' engine inJection pump and using the hydraulic medium to cool said pump.
Another object of the invention is a fuel pum vented or scavenged with a quantity of fuel increasing or decreasing with an increase or decrease respectively of the quantity of fuel supvice such as a governor whereby the pressure of the uid delivered to the pump and in turn the quantity of fuel supplied by the pump can be controlled.
'I'he above and other objects of the invention will be apparent as the description proceeds;
and while I have illustrated and describedthe preferred embodiments of the invention as they now appear to me, it will be understood that such changes may be made as fall within thescope of the appended claims. In the following .description and in the claims various details will be identified by specific names for convenience, but they are intended to be as generic in the application as the art will permit.
The accompanying drawings show an example of application of the invention to a plunger pump comprising, enclosed in one unit assembly, a spring loaded spray nozzle valve. Delivery of fuel through the loaded valve occurs during the middle portion only of the discharge stroke of the plunger, the beginning and the ending of the plunger stroke being made ineffective by the plied by the pump, and in which a cushion chamber is provided to reduce the periodical pressure surges in the low pressure fuel delivered to the Dump.'
Another object is to combine an injector valve and spray nozzle with a fuel pump in one unit assembly, vented so it can operate at any angle -with the verticalline as it may be required in aircraft engines of the radial type.
Another object is to provide speed regulating or governing means including fluid pressure actuated engine fuel control means and a valve for controlling the latter, wherein the valve is actuated by the centrifugal force transmitted thereto from a flyball mechanism and by a variable iluid pressure load exerted thereon.
A further object of the invention is to provide in the fuel pump unit hydraulically operated means for controlling the timing of the fuel discharge.
Still another object of the invention is to provide a fuel pump of the type described in the first object mentioned above, transfer means for delivering fuel or other suitable fluid such for example as lubricating oil at variable and relatively low pressure to the pump, and control opening of a p ort controlled by the pump plunger. The pump plunger is provided with at least one helical control edge whereby the quantity of fuel delivered may be varied by a. turning ad- Justment of the plunger, eiected through a rack engaging a pinion loosely splined on' the plunger and wherein the plunger can reciprocate.- The rack is connected with the movable wall of a bellows included in the pump unit and urged in opposite directions by a spring and by a suitable fluld which in the example shown is the fuel delivered to the pump through the low pressure fuel line by fuel transfer means whose output is in excess of the pump requirements. The excess fuel ilows continuously through a spring loaded relief and pressure regulating valve connected with the low pressure line.
Pressure variations in this line will expand or contract the bellows and thereby rotate the plunger. Manually operable control means, or automatic means such as governors, or both, are provided to control the lo'ad ofthe relief valve spring whereby the pressure of the fuel in 'the low pressure line and in turn the quantity of fuel supplied by the pump can be controlled.
The usual linkage operatively connecting the governor with the pump, and in multicylinder engines interconnecting the pumps, to control the fuel supply, can therefore be eliminated. It will further be appreciated that, since the governor' has not to overcome the friction resistance opposed by the pumps and by the control linkage,
but it has only to operate the relief valve, its energy and in turn its dimensions can be comparatively very small.
It is further to be noted that should, while a multicylinder engine is operating, a pump plunger seize in its cylinder, the plunger would remain inoperative at the end of its discharge stroke, its spring being unable to lift the plunger, while the other pumps would keep on supplying fuel to' the engine. In conventional fuel supply systems in which the means for turning the pump plungers are positively interconnected, the seized plunger, might prevent the control means from adjustingthe delivery of the remaining pumps and thereby put the engine out of control. Obviously. such hazard is eliminated by the hydraulically operated means forming part of this invention, with which the seized pump cannot prevent the remaining pumps from being controlled by the adjustable pressure of the fuel in the low pressure line.
Resilient storing means. shown in the drawings as air cushion chambers. are provided to reduce the periodic pressure surges caused in the low pressure line when the port leading to the pumping chamber is uncovered and covered by thel plunger. In those of the pump units designed for discharging at any angle with the vertical line chambers for air cushioning are located in different points within the unit housing and surround the port, and. suitable venting means together with a return conduit are provided to eliminate from the pump air or gas in excess of the amount required to secure cushioning in order to reduce the danger of air or gas bubbles being admitted through the port to the been proposed, in which an accidental decrease plunger pumping space. Such venting means consistl of conveniently located apertures vof small area connecting the low pressure line with the return conduit through which such bubbles together with a certain amount of fuel are led back to the fuel tank or to the low pressure fuel line. The volume flowing through an orifice under a certain difference of pressure being for the air or a gas several times greater than for a liquid, the areas' of the apertures can be made such that under the existing difference of pressure between low pressure line and return conduit all air or gas in excess of that required for cushioning can be eliminated while only a re1a` tively small volume of liquid fuel escapes through the vents. p
Vents can also be suitably arranged in the plunger pumping chamber. such vents consisting of small apertures connected with the return conduit through a duct having a port controlled by a control edge formed on the pump plunger whereby flow through the vents is established during the dwell"` period provided by the "dwell" portion of the cam between the end of the plunger suction stroke and the beginning of its discharge stroke. In that preferred embodiment of the invention which is illustrated in the drawings, the angles of the helical edges of the plunger are such that, at an increase of pressure in the low pressure system or line correspond an increase of fuel delivery, so that also the ilow through the vents is increased or decreased as the fuel suppliedA by the pump is increased or decreased respectively, whereby the possibility of eliminating all air or gas bubbles from the pump unit with the minimum flow of fuel is increased. A further advantage of said preferred embodiment is that, if the fuel pressure in the low pressure system should accidentally drop, as it might be due for lof pressure of the actuating fuel or other fluid determines an increase of fuel supply and thereby an increase of engine speed which may attain unsafe proportions.
By employing a well known type of hydraulic valve lifter as shown in Fig. 7, or other suitable hydraulic or mechanical slack adjusting device, in combination with a suitable fuel/ pump unit, the timing adjustment of the pump or of the nozzle discharge may be controlled. in a manner to be later described.
In the drawings:
Figure 1 is a'sectional elevation of a combined fuel pump and injection nozzle mounted -vertif cally ln the cylinder head of an internal combus-A tion engine to inject downwardly.
Figure 2 is a section on line 2-2 of Fig. 1
showing the hydraulically operated means for angular adjustment of the plunger.
Figure 3 shows a fuel pump and'nozzle unit having means for venting the low pressure pump system independently of the direction relative to the vertical line in which direction the pump discharges.
Figure 4 is a section on line 4-4 of Fig. 3.
Figure 5 shows the means for venting the plunger pumping chamber of a pump-nozzle unit discharging downwardly.
Figure 6 shows a fuel pump and nozzle unit as in Fig. 3 including means for ventingl the plunger pumping chamber. h
Figure 7 shows partly in section and partly in elevation a pump unit, means for operating the pump and means for hydraulically adjusting the timing of the pump discharge.
-Figure 8 schematically shows a pump. a transfer pump and means for manually controlling the quantity of fuel supplied by the pump and the timing of the pump delivery.
Figure 9 shows a scheme similar to Fig. 8 in-I cluding automatically operated control means.
Figure l0 schematically'shows two pump units connected with the means for controlling their fuel supply and the timing of their periodic delivery.
In the example of application of the invention which is illustrated in the drawings the fluid medium employed for the hydraulic control of 1ttle 1uel delivery of the injection pump is the fuel In all the drawings the pump plunger is shown at the end of its suction stroke and at the beginning of its discharge stroke.
A pump plunger l reciprocates in a cylinder 2 mounted in a housing 3. At its inner end, beyond an annular groove l, the plunger has edges 5, i and a duct 'I which limit the surface of plunger contacting the bore of cylinder 2. Between cylinder 2 and housing 3 there are provided annular chambers or reservoirs 8, 8 communicating by means of openings I0. A port Il connects the housing 3. Fuel at relatively low pressure reaches the chamber I4 through the low pressure line I5.
the pinion while it is capable cf axial displacement therein. The pinion I8 may be angularly turned for adjustment of the duration of the injection by -a rack I8 slidably mounted in a groove 28 formed in the housing 3. One end of the rack I8 is connected with a pressure responsive device, such for example as a piston or plunger slidable in a cylinder or, as shown in the drawings, the movable wall of a'bellows 2| mounted inthe chamber I4 and surrounded by the fuel supplied through the low pressure line I5. A spring 22 may be provided inside the bellows 2| to balance it against collapse.
Beyond the pinion I8 a washer 23 provides a seat for a spring 24. The outer end of the plunger is formed with a head 25 and a seating collar 28 for the spring 24, and is enclosed by a cover 21 which reciprocates in the pocket 28 of the housing 3 under the influence of any suitable driving means such as the rocking lever 28 shown in Fig. 7, for the pressure stroke of the plunger, the spring 24 effecting the return or suction stroke of the plunger. A small, screw 55 through the housing 3 engages a slot 5'6 in the cover 21 retaining thec over over the plunger and its spring but permitting its reciprocating movement.
Between the cylinder 2 and the cap 38 which screws into the housing 3, a-valve seat piece 3| and an intermediate piece 32 are provided, tightly clamped together and against the cylinder 2 when the cap 38 is screwed. A gasket 33 of ductile or resilient material prevents leakage of fuel between the housing 3 and the cap 38, and between the cap 38 and valve seat piece 3|. Ducts 34, 38 through the-pieces 32 and 3| lead the fuel from the pumping chamber 48 to a chamber 4I in the piece 3l. In this chamber 4| is a seating for aninjection valve 42 which has an area formed by a shoulder 43 whereby it is lifted by the pressure of the fuel in the chamber 4| to permit the ow of fuel to suitable spray holes 44. The lifting of the valve 42 is resisted by a spring 48 in the chamber 41 whose load determines the minimum injection pressure. A drain hole 48 may be provided in order to maintain in the chamber 41 the same pressure as in the annular chamber 58 which latter, through holes 52, communicates with the reservoir 8.
The complete assembly constitutes a unit fuel pump and injection nozzle which may be mounted in a suitable bore 58 through the cylinder head of an internal combustion engine. A gasket 88 is provided to prevent gas leakage from the combustion chamber, and against said gasket 88 the unit is held by two studs 82 (Fig. 2). In operation, fuel at variable and adjustable pressure is supplied through the low pressure line I to the chamber I4 where it surrounds the bellows 2| whose interior communicates with the surrounding pressure through the clearance between rod I8 and slot 28. Through the duct I2 the fuel fills the reservoir 8. In the position shown in the drawings the plunger I is at the end of its suction stroke and has uncovered the port' II allowing fuel to ow into the pumping space 48. As the plunger descends. the edge 8 covers the port II. The pressure rises rapidly in the pumping space 48 and in the chamber 4| containing the spring loaded valve 42 until the pressure is suillcient to lift the valve off its seat, and the fuel is injected into the engine vcylinder through the spray holes 44. The injection continues until the edge 8 uncovers the port I I which now functions as a pressure relief port through which the remainingfuel displaced by the plunger \is bypassed into the reservoir 8.
Air or gas separating out from the fuel in the reservoir 8 fills the chamber 8, and excess air or sas may flow back through the duct I2 to the bellows chamber I4. The air cushion chamber 8 'reduces the periodic pressure surges in reservoir 8 and in chamber I4 which surges accompany the opening and closing ofthe port I I. In operation.
- pressure variations in the bellows chamber I4 obtained by changing the pressure of the fuel in the low pressure line I8 in a manner to be later described, result in contraction or expansion of the bellows 2|, in axial displacement of the rack I8 and rotation of plunger I, whereby, owing to the helical edges Sand 8 controlling the port |-I, the volume of fuel injected by the pump unit may be controlled.
Excess of air or gas can be eliminated from the reservoir 8 of the pump shown in Fig. l through the duct I2 only when the axis ofthe pump is substantially vertical, the spray nozzle discharging downwardly,lor when the axis of the pump is horizontal and the duct i2 emerging from the uppermost part of the reservoir 8, or for positions of the pump intermediate between the two positions described. In the pump unit shown in 3 the air and gas bubbles in excess ofthe amount necessary for air cushioning can be eliminated from the reservoir 82 whatever the orientation of the unit in the space; relative to the vertical line, may be. The circular flanges 1I, 12 of the pump cylinder expanding and coling into contact with the bore of the housing 3, have openings 14, 18 through which the reservoir 82, receiving fuel from the duct I2, communicates with the chambers 83 and 84. Annular grooves 18, 11 are provided in the anges 1I and 12 respectively, which grooves communicate, throughradially drilled ducts 18, 18, with ducts 88 com- `municating with circular grooves 81, 88. The
spring chamber 41 communicates through a duct with the groove 81, while the groove 88 communicates through 4a small chamber 82 and a pipe union 83 with the fuel return pipe 8|. That portion of the outer cylindrical surface of the flange 1I which is comprised ybetween the groove 18 and the chamber 83 fits tightly into the bore of the housing 3 and prevents any direct leakage between the chamber 83 and the groove 16, while the cylindrical surface between the groove 18 and the reservoir 82 ilts loosely in said bore. Similarly, ange 12 ts tightly into the bore of housing 3 between the chamber 84 and the groove 11, while it fits loosely between this groove and the reservoir 82. Since, as it will be seen later, the fuel pressure in the return pipe 8| is lower than in the reservoir 82, a steady ilow` will be maintained from the reservoir 82 to the grooves 18 and 11 and from these grooves to the return pipe from the reservoir 82, while only a comparatively small amount of liquid fuel can escape. Whatever position, relative to the vertical line, the
pump unit may assume, air or gas cannot be entirely eliminated from at least one of the cushion l An air cushioning chamber 92 may be provided between the groove 88 and the return pipe 9|. Since the pipe union connecting the pipe 9| with the housing. 3 projects with its free end 93 toward the center of chamber 92, here too, whatever the orientation of the pump may be, some air or gas will always be contained, in order to reduce the periodic fluctuations of the pressure in the'return pipe 9|.
Air or gas may separate from liquid fuel in the pumping chamber 40 where it might interfere with the correct operation of the pump. Means for venting said chamber are shown in Fig. 5. An annular groove 98 is provided in the plunger I. Between the grooves 99 and 4 the diameter of the plunger is such that a certain clearance 83, larger than in other portions of the plunger, is left between the plunger and the cylinder bore. A duct 91 is drilled through the cylinder 2 connecting the groove 39 with that portion of the cylinder bore which is contiguous with the groove 96 when the plunger is at the top end after its suction stroke and before its discharge stroke during the dwell period provided by the "dwell" portion of asians?.
tending to dilow upwardly, will be eliminated* through the aperture 93. or I 00, or. both. Bubbles from the cavity |85 will also flow either to the groove 4 through the drills |08, or to the pumping chamber 40, or both. and will be eliminated therefrom. To reduce the danger that bubbles be drawn into the duct 34 leading tothe nozzle 4|, the duct 34, drilled in a central extension |03 of the intermediate piece 32, has its inlet opening about in the center of the pumping chamber 40.
In the above disclosed example of embodiment of 'the invention engine fuel is employed as the fluid medium serving to actuate the pressure responsive bellows 2|. It is however to be clearly understood that according to the present invention any other suitable fluid, for instance lubricating oil, may be used as medium for actuating the bellows 2| to control the fuel delivery.
While the pump units above described may be actuated by any suitable reciprocating mechanism, a preferred embodiment is shown in Fig. '7. wherein the timing adjustment is controlled by hydraulic means. In the pump unit a stop mem- 'ber |20 having a cylindrical portion adapted to slide axially on the boss |1 of the pinion I6 is provided to limit the outward displacement of the plunger I. The lower portion of the member is externally threaded to engage a companion the cam. During this period the port II is open and the fuel pressure in the pumping chamber 40 equals the pressure of the low pressure line, while, owing to the fact that the area of the ducts between the groove 9S and the pipe 9| is considerably larger than that of the aperture 98, the pressure in the groove 98 is substantially the same as inthe return pipe 9|. rAn upward scavenge flow, whose volume increases with an increase of pressure in the low pressure fuel line, will therefore be established during the "dwell" period, from the port I to the groove 4 and, through the aperture 93, to the return pipe 9|, and the air or gas bubbles, tending to ow upwardly in groove 4, are eliminated from the pump. Obviously the unit as shown in Fig. 5 is designed to operate with its axis substantially vertical, the nozzle discharging signed to assure venting of the pumping chamber 49 whatever the orientation of the pump unit in the space, relative to the vertical line, may be. In addition to the groove 81 shown in Fig. 3, a second concentric groove 99 is provided in the lower terminal face of the cylinder 2. An annular clearance space |00 establishes between the pumping chamber 40 and the groove 99 an aperture of the groove 99 is also maintained substantially at the pressure of the return pipe 9|. and an additional scavenge flow from the port to the groove 99 will be established. A cavity |05 having its end connected with the groove 4 through several drills |08 is provided at the inner end of the plunger l I. According to the orientation of the Dump relative to the vertical line, the air or gas bubbles. 7s
helical thread formed in the bore of pinion |25. A thrust washer |26 solidly fastened to the housing 3 by screws |21, serves as a seat for the spring 24 and prevents pinions |25 and I6 from axial displacement. The end of one at least of the screws |21 extends into an axial groove |28 of the stop member |20 to prevent it from rotating. Annuler displacement of pinion |25 will therefore displace axially the stop member |20 and thereby alter the outer position that the plunger I, urged outwardly by the spring 124, may assume. Various means, obviously, may be provided to rotate the pinion. In the preferred embodiment illustrated in Fig. 7, rotation of the pinion |25 is controlled, in a way similar. to that already described in detail for the pinion I6, by a rack formed in a rod |30 connected with the movable wall of a bellows I3| balanced against collapse by an inner spring |32 and contained in a housing |33 fixed by small screws to the housing 3.' A duct |35, extending to the center of the chamber 92 communicating with the groove 88, leads the fuel and the air and gas bubbles eliminated from the pump to the space comprised between the housing |33 and the bellows |3|. The pipe |39 is the return line. Axial adjustment of the stop member |20 can thus be obtained by varying the pressure in the fuel return pipe.
A rocker lever 29 actuating the plunger is operated. through a rod ||0 and a lifter III capable of reciprocating inside the guide II2, by a cam ||3 carried by the engine camshaft. Oil under pressure from the lubricating system of the engine is supplied through a conduit ||5 to an oil chamber |I5 and, through a duct Ill, to a piston chamber II8. A check valve |I9 prevents the oil in chamber ||8 from returning to chamber |I8. When the lifter rests on the base circle or dwell portion of the cam II 3, and the pump plunger is maintained by the spring 24 in its outer top position against the stop member |20, the piston spring |2| lifts the piston |22, the intermediate piece |23 and the push rod ||0 so that all clearances between rod I0, rocking lever 29, cover 21 and plunger disappear. As the piston |22 moves outwardly, increasing the volume of the piston chamber I I8, the check valve I I9 moves oil its seat and'the chamber I |'3 is filled with oil the chamber I3. As the camshaft rotates. after the dwell" period the cam ||3 pushes the lifter body upwardly, tending to decrease the volume of chamber ||3 and forcing the valve III onto its seat, whereupon further rotation of the camshaft lifts the piston |22 and operates the fuel pump. So long as the plunger I is out of contact with the stop member |20, the load is carried by this column of oil in the chamber III. During this period a predetermined slight leakage of oil occurs, so that the volume of chamber ||3 -is reduced, `and space is provided for a new amount of oil to lill the chamber ||8 and thus maintain the adjustment during the next cycle, as soon as the plunger I contacts the stop member |20 again. The hydraulic lifter above described is well known in the art, particularly in connection with valve lifting mechanisms of internal combustion engines. Any other suitable type of hydraulic or mechanical slack adjusting device may obviously be substituted therefor.
For a given angular adjustment of plungerl relative to the cylinder 2, and for a given cam profile, the beginning of the eifective delivery stroke of plunger I depends on the distance between the outermost position of plunger I, as determined by the stop member |20, and the position of the same plunger I in which the port is being covered by the plunger. Variation of the beginning `of the injection may therefore be obtained by axially displacing the stop member |20 relative to 'cylinder 2 and in turn by changing the fuel pressure in the return pipe |33.
Obviously, mechanical instead of hydraulically actuated devices may be employed for altering the axial adjustment of the stop member |20 to vary the injection timing. In particular, if in the above described mechanism the stop member |20 has a xed position relative'to the cylinder 2, the hydraulic lifting deviceinstead `of being axially adjustable will automatically maintain a constant timing adjustment of 'the pump discharge, independently of thermic dilatation of different parts, changes in the thickness of the gasket 60 and so forth. 4
An arrangement of fuel supply system for internal combustion engine according to the invention is diagrammatically shown in Fig. 8, in which a fuel transfer pump |40, shown as a gear pump ,driven through an extension |4| of the engine camshaft, draws fuel from a tank, not shown in the dra'wing, through a suction pipe |42 contain.
ing a non-return valve |43 to prevent the fuel system from emptying when the engine is stopped,
and delivers fuel under pressure to the pipes |31 and I5 and to thefbellows housing 34 of pump 3. The volume of fuel delivered by the transfer pump |40 is considerably in excess of the maximum volume of fuel that can ow through the pump or pumps 3 whereby, despite the action of the air'cushioning chambers which may be included in the low pressure system, the pressure of fuel therein can rapidly be changed by a relief or pressure regulating valve |45 comprising a slidably mounted valve plunger |46 loaded by a spring |41, and a return pipe |43 leading to the fuel tank or to the suction pipe |42. Obviously, the` fuel pressure in the low pressure system and in the bellows housing 34 is controlled by the load Y of the spring |41. A control lever |50 is provided to adjust the load of the'spring |41 and thereby to control the quantity of fuel supplied by the pump 3.
The housing |33 of the pump 3 containing the from through pipes |34 and |33 to a relief or pressure regulating valve |5| similar to valve |45 and including a valve plunger loaded by a spring |52 whose load can be adjusted by a control lever |53, and a return pipe |54 leading. as the pipe |43, to
` the fuel tank or to' the suction pipe |42. Fuel pressure in the pipes |34. |33 and in the bellows housing |33 and in turn the timing adjustment of the periodic discharge of the pump unit 3 can therefore be controlled by the lever |53.
In order to avoid that pressure changes in the bellows housings 34 and |33 interfere with the correct scavenging and venting of the pump 3, design and operation of the relief valves |45 and |5| shall be such that the fuel pressure will always be substantially higher in the housing. 34
connected with the low pressure line than in the housing |33 connected with the return pipe.
Speed responsive means for operating the relief valves |45 and |5| are shown in Fig. 9. From that extension of the engine camshaft |4|1 driving the transfer pump |40, a pairof .gears drive a vertical shaft |53 on which is arranged a governor having flyballs |51 acting on an axially slidable sleeve |53 connected with one end of a lever |33, the other end of which controls, through the spring |41, the relief valve |45. Through la.v sleeve |30 and a thrust bearing |3I. the load of the governor spring |59 may be adjusted by a control lever |62. For a fixed position of said lever, the governor |51 will maintain the engine at a corresponding substantially constant speed. Said speed will however increase or decrease with Aa decrease or increase in the engine load, re-
spectively. In fact the governor must regulate the speed of its engine/in such manner that the speed is lower for full load than for no load. In
yone of the preferred embodiments of the invention, shown as an example in Eig. 9, the engine speed is such that the corresponding centrifugal force applied to the ilyballs |51 balances the resilient load exerted on sleeve |53 by the spring |53 'minus the hydraulic load applied by the fuel pressure to the upper surface of valve plunger |43 and transmitted through lever |33 to said sleeve |58. For a given adjustment of the control lever Aand a downward displacement of valve plunger |43, whereby the fuel pressure in the low pressure system and the engine fuel supplyare reduced. The hydraulic load applied to theupper end of valve plunger |43 andv transmitted to sleeve |53 against the load of spring |53 is thus decreased, and a higher value of the centrifugal force transmitted by the ilyballs |51 to said sleeve |58 is required to maintain the latter in yequilibrium. The engine speed will therefore assume a higher value. Conversely, an increase of engine load causes a'decrease of engine Speed. a downward movement of sleeve |53 and an upward movement of the valve plunger |43 determining an increase of fuel pressure in the low pressure system and an increase of engine fuel supply. The hydraulic load exerted on valve plunger |43 and transmitted to the sleeve |53 against the load of spring |53 increases, whereby the centrifugal load the compression load of the spring |53 and thereby upon the angular adjustment of the speed 6 ,e 'control lever |82. On the same vertical shaft 2,318,204 it is subject are negligible, this spring thus merely I |88 a second governor is arranged. having fiybails 188, a governor spring|88 and a sleeve |81 connected with one end of a lever |88, the other free end of which controls the valve spring |52 of the relief valve |8| and thereby the pressure in pipes |88 and |84 and in the bellows housing |33. The timing of the periodic discharge of the pump unit will therefore vary automatically with the engine speed. Since both the governors |81 and |88 have to control onlfij'a relief valve, their energy can be very small.
'I'he stabilizing and compensating effect obtained by the application of lan axial variable fluid pressure load to the slidable valve |48 of the governor |81 shown in Fig. 9 may more clearly and distinctly be described as follows: As the engine operates under steady load and speed, the valve |48 remains in a corresponding definite axial adjustment. Neglecting the weight of valve |48, the three forces applied thereto by the ilyballs |81, by the spring |59 and by the fluid pressure exerted on the upper end thereof are in equilibrium. If the engine load decreases the engine accelerates and the increased centrifugal force of the ilyballs |81 causes adownwa rd movement of the valve |48 thus determining a pressure drop in the pressure lines |81 and I5 and initiating a movement of the resiliently loaded bellows 2| connected with the control racks I8 in a direction to decrease the engine fuel supply and in turn the speed thereof. As a result the axial fluid pressure load exerted on the upper end of the valve 48 decreases and restrains the-downward movement thereof. Although this restraining action due to the variation of the fluid pressure exerted on the valve |48 is very small as compared to the centrifugal force of the fly-balls |81 and to the load of spring |59, it prevents overtravel of the valve |48 and causes the latter to resume its correct adjustment quickly so that an underspeed condition of the engine does not occur and the danger of hunting is avoided.
performing the function of a connecting element. While in Figures 8 and 9 one pump unit only is shown, inserted between the pipes |81 and |84, it is obvious that such pipes may extend parallelly, and between them several pumps may be inserted, as shown diagrammatically in Fig. 10.
These embodiments of the invention have been shown merely for purpose of illustration and not as a limitation of the scope of the invention. It is, therefore, to be expressly understood that the invention is not limited to the specific embodiments,
shown, but may be used in various -other ways, in connection with other mechanisms and regulators, and various modifications may be made to suit diiferent requirements, and that other changes, modifications, substitutions, additions and omissions may be made in the construction,
arrangement and manner of operation of the parts without departing from the limits or scope of the invention as defined in the following claims.
In interpreting the claims, where they are directed to less than all of the elements -of the complete system disclosed. they are intended to cover possible uses of the recited elements in installations which may/'lack the non-recited elements.
Certain featu es herein disclosed are claimed in my copending applications Serial No. 254,355 led February a, 1939ser1a1 No. 333,529 med May s, 1940, Serial No. 376,170 led January 27, 1941, and Serial No. 466,041 filed November 18, 1942.
What I claim is:
l. In combination, a fuel pump to intermit- .pump may be varied, means responsive to the Conversely when the engine load is increased the engine decelerates and the action of the governor is the reverse of that :lust described. 'Ihe valve |48 is then displaced upwardly by the spring |88 acting against the decreasing centrifugal force of the flyballs |81. This reduces the effective opening of the discharge valve and causes pressure increase in lines |51 and chambers |4 to initiate displacement of the bellows 2| in a direction to increase the engine fuel supply and the engine speed. The axial fluid pressure exerted on the valve |48 increases so as to restrain the upward movementthereof initiated by the change of centrifugal force, thus avoiding overtravel of the valve |48 and overcorrection on the part of the bellows 2 I.
In the example of embodiment of the invention which is illustrated in Fig. 9 the flyballs |51 are connected with the valve |48 by means of a lever |88 and a spring |47. As stated above the axial duid pressure exerted on valve |48 is very small as compared to the centrifugal force transmitted by the flyballs |51 to the sleeve |88, and accordingly the load on spring |41 isvery` small as compared to that of spring |58. Obviously the rate of deflection of the connecting spring 41 may be so determined as to suit the desired requirements, and
where no appreciable amount of elasticity is desired between lever |88 and valve |48, the spring |41 may be designed sufficiently stiff so that the deflections thereof under the small loads to which 78 fuel pressure in Said conduit and operatively connected with said mechanism, and means for adjusting the fuel pressure in said conduit to control the timing of said intermittent fuel delivery.
2. A fuel pump for intermittently delivering fuel to an internal combustion engine, said pump including fuel inlet me'ans, a reservoir connected with said inlet means, fuel return means, venting means connecting said inletandsaid return means whereby said reservoir is vscavenged and cooled by a continuous now of fuel determined by the difference of pressure between said inlet and said return means, a control mechanism for varying the fuel delivery of said pump. and means responsive to the fuel pressure in said inlet means and operatively connected with said mechanism whereby an increase or decrease of the fuel pressure in-said inlet means determines an increase or decrease respectively of both the fuel delivery of said pump and ow of fuel scavenging and cooling said reservoir.
3. A fuel pump for intermittently delivering fuel to an internal combustion engine, said pump including a cylinder having port means, a plunger reciprocable in saidv cylinder and adapted to cover and uncover said port means. fuel inlet means, fel return means, a pressure chamber in said cylinder at one end of said plunger, venting means controlled `by said plunger for intermittently connecting said chamber with said inlet and said return means whereby said chamberl is scavenged by an intermittent flow of fuel determined by the difference of pressure between said inlet and saidreturn means, a control mechanism for adjusting the fuel delivery of said pump, and means responsive to the fuel pressure in said inlet ofsaid pump and the flow of fuel intermittently scavenging said chamber.
4. A fuel pump as defined in claim 2 said pump including a cylinder having a port in said reservoir, said venting -means including orifices connecting said reservoir with said fuel return means, said orifices surrounding said port whereby at whatever angle said pump may be set relative to the vertical line fuel including any air, gas or vapor bubbles may be vented from said reservoir at a point higher than said port.
5. A fuel pump as denned in claim 3, including an outlet duct for the fuel discharged under pressure from said chamber, the inner end of said duct extending toward the center of said chamber, said venting means including orifices connecting said chamber with said return means, said orifices surrounding said inner end of said duct whereby at whatever angle said pump may be set relative to the vertical line fuel including any air, gas or vapor bubbles may be intermittently vented from said pressure chamber at a point higher than said inner end of said duct.
6. A fuel injection system for internal combus 'tion engines including interchangeable pumps for intermittently discharging fuel under pressure to said engine, conduit means connected with said pumps for supplying the latter with fuel, hydraulically operated control means included in each of said pumps whereby the fuel discharge of each of said pumps is' individually controlled by the pressure of said fuel supplied thereto through said conduit means, a fuel transfer pump for delivering fuel under pressure to said conduit means, and valve means for controlling the fuel presssure in said conduit means and thereby controlling the engine fuel supply.
7. A fuel im'ection system as defined in claim 6 in which said valve means are actuated by govern ing means.
8. In combination with a fuel injection system including pumps for intermittently delivering fuel under pressure to an internal combustion engine and conduit means connected with a source of fuel under pressure and with said pumps for supplying the latter with fuel, means whereby the fuel delivery of said pumps is controlled by the pressure of said fuel supplied to said pumps and decreases or increases with a decrease or increase of the pressure of said fuel respectively, and valve means for regulating the pressure of the fuel supplied to said pumps, the adjustment of said valve means being determined by the loads transmitted there to by resilient means tending to increase the fuel pressure in said conduit means, by means responsive to the speed of said engine and acting against said resilient means, and by a compensating load applied to said valve means by fuel having sub- ,stantially the same pressure as in said conduit means and acting in opposition. to said resilient means, whereby the speed of said engine is higher at no engine load than at full engine load.
9. In combination with a fuel injection system including pumps for delivering fuel under pressure to an internal combustion engine, a source of liquid under pressure, conduit means connected with said source and said pumps. means whereby the 75 fuel delivery per cycle of said pumps is controlled by the pressure of said liquid and increases or decreases with an increase or decrease of said pressure respectively, and valve means for-regulating 5 the pressure of said liquid to control the fuel delivery of said pumps, the adjustment of said valve means being determined by the loads transmitted thereto by resilient means under the control of the operator, by means responsive to the speed of said engine and acting against said resilient means, and by the pressure of said liquid acting against said resilient means, whereby the speed of said engine increases or decreases with a decrease,or an increase of the load of said engine respectively. i
10. A fuel metering pump for intermittently delivering fuel to an internal combustion engine, said pumpincluding a cylinder and a plunger having a reciprocating motion of constant stroke in said cylinder, means for controlling the .fuel delivery per cycle of said pump by angularly adjusting said plunger and means for varying the timing of said` delivery by changing the mean axiai position of said plunger relative to said cylinder, duct means for the fuel niiet, conduit means for the outlet of excess fuel, a fuel flow communication including small aperture means between said duct means and said conduit means whereby the fuel pressure in said duct means and in said conduit means may have different values, pressure responsive means actuating said first mentioned means whereby the fuel delivery of said pump is determined by the fuel pressure-in said duct means, and pressure responsive means con- .35 nected with said second mentioned means whereby the timing of said fuel delivery is dependent on the fuel pressure in said conduit means.
1l. In a fuel pump forintermittently delivering fuel to an internal combustion egine, a plunger having a reciprocating motion of constant stroke,
means for controlling the fuel delivery by a turning adjustment of said plunger and means for varying the timing of said delivery by changing the mean axial position of said plunger in said medium, pressure responsive means connected with said first mentioned means whereby the fuel delivery of said pump is determined by the presl2. A fuel injection system for a multicylinder internal combustion engine including fuel pumps as set forth in claim 1l, first and second duct means connected with said rst and second conduit means of said pumps respectively, valve means for regulating the pressure in said first conduit means to control Vthe fuel delivery of said pumps, and valve means for regulating the pressure in said second conduit means to adjust the timing of the fuel delivery of said pumps.
13. A fuel injection system for internal cornbustion engine including in combination a pump having a cylinder, port means in said cylinder, a plunger having a reciprocating motion in said cylinder and controlling said port means, tappetpump, first and second conduit means for a liquid of said stop means. j
14. In a fuel injection system for multicylinder internal combustion engine including fuel metering units, a source of liquid under pressure, conduit means connected with said source and with said units; means in said units for controlling the fuel delivery thereof; resilient means and diaphragm means in said units operatively connected with said means thereof for varying the fuel delivery of said units in response to changes of pressure of said liquid; and pressure regulating means for adjusting the pressure of said liquid to control the fuel delivery of said units.
l5. In a fuel supply system for multicylinder internal combustion engine, including fuel metering units, a source of fuel and conduit means connected with said source and said units; means in said units for controlling the fuel delivery thereof; resilient means and diaphragm means in said units operatively connected with said means thereof for varying the fuel delivery of said units in response to changes of pressure of said fuel; and pressure regulating means for adjusting the pressure of said fuel to control the fuel delivery of said units.
16. An engine fuel injection pump including means for varying the fuel discharge thereof, fuel containing means, and fuel pressure actu-` ated means operatively connected with said first mentioned means for increasing or decreasing the fuel discharge of said pump upon increase or decrease respectively of the fuel pressure in said containing means. A
17. An engine fuel injection system including, in combination with a source of fluid under pressure, fuel injection pumps having fluid containing means, conduit means connected with said source and said containing means of said pumps, fluid pressure actuated delivery control means in said pumps for increasing or decreasing the fuel delivery of said pumps upon an increase or decrease respectively of the fluid pressure in said containing means, and means for regulating the fluid pressure in said containing means.
18. An engine fuel injection system including a pump having a cylinder, port means in said cylinder, a plunger in said cylinder controlling said port means, tappet means for actuating said plunger from an engine driven cam to effect the discharge stroke of said plunger, resilient means for automatically adjusting the length of`said` tappet means in dependence of the adjustment for causing the suction stroke of said plunger, stop means in said pump for determining the position of said plunger at the end of said suction stroke, and means for automatically adjusting said -tappet means to `render said stop means effective and eliminate backlash. f
19. An engine fuel injection system including a pump having a cylinder, port means in said cylinder, a plunger in said cylinder controlling said port means, cam and tappet means for' effecting the discharge stroke of said plunger, resilient means for causing the return stroke thereof, means in said pump for determining the end of said return stroke, and hydraulic means lfor automatically adjusting the eii'ective length of said t'appet means.
20. An engine fuel injection system including, in combination with a fluid pump, fuel injection pumps, conduit means for connecting said injection pumps with said fluid pump, fluid pressure actuated means in said injection pumps for varying the fuel discharge thereof with changes of fluid pressure in said conduit means, and valve means for regulating the fluid pressure insaid conduit means.
21. In combination, an engine fuel injection pump having a cylinder, port means in said cylinder, a plunger in said cylinder controlling said port means, tappet means to effect the discharge stroke of said plunger from an engine driven cam, resilient means for causing the suction stroke of said plunger, adjustable means for determining the end of said suction' stroke, hydraulically actuated means for varying the adjustment of said adjustable means to change the injection timing ofv said pump, and means for the automatic adjustment of said tappet means.
22. An engine fuel injection system including separately mounted-fuel injection pumps, each of said pumps having fuel delivery control means, fluid containing means and fluid pressure responsive means operatively connected with said control means for varying the fuel delivery of said pumps as a predetermined function of the fluid pressure in said containing means, conduit means for interconnecting said containing means of said pumps whereby the fluid pressure in the latter means is maintained uniform, and means for regulating the pressure in said fluid containing means.
FERDINANDO CARLO REGGIO.