US2967520A

US2967520A - Reciprocatory fuel injection pumps

Info

Publication number: US2967520A
Application number: US692909A
Authority: US
Inventors: Morris John Neville; Gerald J Mccaul
Original assignee: SU Carburetter Co Ltd; Simmonds Precision Products Inc
Current assignee: SU Carburetter Co Ltd; Simmonds Precision Products Inc
Priority date: 1957-10-28
Filing date: 1957-10-28
Publication date: 1961-01-10
Anticipated expiration: 1978-01-10

Description

Jan. 10, 1961 J. N. MORRIS El'AL 2,967,520

RECIPROCATORY FUEL INJECTION PUMPS Filed Oct. 28, 1957 4 Sheets-Sheet 1 INVENTORS JOHN NEVILLE MORRIS GERALD J. MCCAUL ATTO RN EYS.

Jan. 10, 1961 J. N. MORRIS ETAL RECIPROCATORY FUEL INJECTION PUMPS 4 Sheets-Sheet 2 Filed Oct. 28, 1957 N DI 1N ENTORS JOHN NEVILLE MORHS GERALD J. MCCAUL 69148, 7 M, daand ATTORNEYS.

1961 J. N. MORRIS EI'ALY 2,967,520

RECIPROCATORY FUEL INJECTION PUMPS 4 Sheets-Sheet 3 Filed Oct. 28, 1957 INVENTORS. JOHN NEVILLE MORRIS GERALD J. MCCAUL 2 1, MWM r ATTORNEYS.

Jan. 10, 1961 J. N. MORRIS EI'AL RECIPROCATORY FUEL INJECTION PUMPS 4 Sheets-Sheet 4 Filed Oct. 28, 1957 ATTORNEYS.

Unified States PatentO RECIPROCATORY FUEL INJECTION PUMPS John Neville Morris, Birmingham, England, and Gerald J. McCaul, Scarsdale, N.Y., assignors of one-half to The S.U. Carburetter Co. Ltd., Erdington, England, a British company, and one-half to Simmonds Precision Products, Inc., a corporation of New York Filed Oct. 28, 1957, Ser. No. 692,909

14 Claims. (Cl. 123-140) mission of fuel to the respective pump chambers and its delivery therefrom in a desired sequence to individual discharge outlets either equal to or greater than the number of pump chambers, and in particular, the invention involves novel and improved structure and meansfor cutting off delivery of fuel to the engine without having to cut off the ignition.

Discharge pumps of the kind in question (constructed in accordance with-US. Patent No. 2,329,912) have been used quite extensively as fuel-injection pumps for aircraft and land vehicle engines. Undoubtedly, their success is mainly attributable to the hypotrochoid motion (also referred herein as epicyclic motion) imparted continuously to the distributing valve during operation. As a result, a lapping action takes place between the valve and its cooperating stationary facings, which minimizes any scoring of the rubbing surfaces that may arise and ensures the maintenance of an extremely accurate planar contact between those surfaces, with consequent avoidance of leakages at the ports controlled by the valve.

In the existing design of pump, the distributing valve has a ring of gear teeth meshing with a surrounding stationary toothed annulus. It also has ports of arcuate or kidney shape and, as will be appreciated, each of these ports follows a hypotrochoid path during rotation of the valve. The latter is driven by an eccentric, and the pumping plungers are operated by an adjustable wobble-plate driven by a skew shaft which is so phased with respect to the eccentric that, when each plunger is in its outer dead-centre position, the corresponding pump chamber is isolated from the inlet zone and simultaneously placed in communication with a delivery port.

For some applications, notably when it is employed as a fuel-injection pump in aircraft and military land vehicles, the pump has to incorporate provision by which its delivery to the power unit can be positively shut off, in order to stop the engine or engines without having to cut theignition. Various means for achieving this have been adopted in the past, none of them having proved wholly satisfactory. The present invention, however, affords a simple but thoroughly reliable mechanism for meeting that requirement and, at the same time, offers a very convenient means of achieving an automatic cutoff of the fuel supply during overrunning" in the case of a motor vehicle with a fuel-injection engine. This g 7 2,967,520 Patented Jan. 10, 1961 ice all fuel injection systems of the general type referred to herein.

Accordingly it is the principal object of the present invention to provide an improved fuel injection pump for internal combustion engines ada'ptcdto afford simple, thoroughly reliable and effective means for cutting off the delivery of fuel to the engine power unit without having to cut the engine ignition.

It is a further object of the invention to provide an improved fuel injection pump of the general type referrcd to herein employing novel means for cutting off the delivery of fuel to the engine power unit when desired by the engine operator or otherwise automatically without having to cut off engine ignition and which fuel injection pump system is readily adaptable for use in aircraft or land vehicle installations.

In accordance with the invention, a reciprocatory pump, of the kind specified above, incorporates means operable to effect temporary reorientation or rotational displacement of the epicyclic distributing valve, about its own centre of rotation, into a position such that all the fuel discharged from the pump chambers is conducted to spill outlets communicating with the inlet zone of the pump.

The temporary reorientation or displacement of the distributing valve may be achieved by making provision for the cooperating toothed annulus, mentioned earlier, to be partially rotatable instead of being permanently stationary, as has hitherto been the case. A convenient Way of effecting the requisite angular displacement of the distributing valve is to provide the outer periphery of the internally-toothed annulus with a toothed sector, this cooperating with a pinion or toothed quadrant on a control spindle projecting through the main casting of the pump and operable by any convenient means, either manual or automatic. An advantageous feature of this arrangement is that it is only necessary to seal the control spindle against the small difference of pressure obtaining between the inlet zone (which is constituted by the cresent-shaped space left between the epicyclic distributing valve and its surrounding annulus) and atmosphere. A further notable virtue of the arrangement in question is that, provided the pump is operating, if only at very low speed, no static friction between. the distributing valve and its contacting facings has to be overcome, and hence the forces involved in actuating the control mechanism are relatively light. A stop device may be provided to limit the range of rotation of the toothed annulus.

It is a further object of the instant invention to provide a fuel injection pump affording cutoff operation wherein an eccentrically mounted fuel distributing valvehaving suitably disposed ports undergoes hypotrochoid movement as its ring of outer teeth meshes with the toothed gear ring such that the metering chambers of the pump are individually interconnected in a desired sequence alternately with the fuel supply and then one and then the other of pump discharge lines leading to respective engine cylinders. The pump includes means for rotationally displacing said gear ring through a predetermined angular; distance from one position to another and then backjto' ,gpemao its initial position thereby effecting corresponding shift to the valve such that pump operation alternates from normal fuel distribution operation to fuel cutoff operation respectively.

It is understood that the pumps contemplated herein are particularly suitable to effect delivery of fuel as a function of intake manifold air density of the engine. It is, therefore, a further object of the instant invention-to employ an effective and simple structure for temporarily repositioning said gear ring, which structure includes: a pinion mounted on a turnable spindle and a pawl member also mounted on said spindle to turn therewith, wherein turning of the pinion, spindle and pawl member assembly is regulated by a pressure sensitive device. The pressure sensitive device is coupled to the engine intake air manifold such that upon decrease of air manifold pressure to'a preselected value, the pressure-sensitive device responds by movement in one direction. Such movement is transmitted by a mechanical linkage to pivot the pawl member in a direction to turn the pinion and thus the meshing gear ring. The amount of turning is preselected so that gear ring is oriented a predetermined angular distance to cause corresponding valve movement whereby the pump assumes fuel cutoff operation. Upon increase of manifold air pressure above the preselected value, the pressure sensitive device returns to its initial position which results in transmittal of corresponding movement to the pinion to rotate same back to its initial position and likewise rotates the gear ring and the valve correspondingly to return the pump to normal fuel distribution operation.

It is a further object of the instant invention to employ a suitable mechanical linkage controlled by the motor vehicle operator or a solenoid which may be energized by the motor vehicle operator-and which last-mentioned linkage or solenoid finishes reversible; movement in order t P vo th pa rec ite vt eff c tt t l v m vem n of the gear ring from oneto the other of'its'two' positions as described hereinbefore so that pump operation may-be alternated from normal operation to fuel cutoff operation respectively by the motor vehicle operator or in response to the pressure sensitive device, each not in any way interfering with the other.

Further objects and advantages will become apparent from the following description of the invention takenjin conjunction with the figures, in which,

Fig. l"is a longitudinal viewiin sectionillustrating the invention as applied to afuel injection pump adapted for an internal combustion engine; 7 v i Fig. 2 is a viewof the pump takenalong line 22.,of Fig. l and alsoillustrates the pump acting means partially in section. The figure also illustratesa trace-of an arcua'te slot with respect to a metering chamber, its correlated discharge ports and spill passage for a pump operating to. effect normal fuel distribution;

Fig. 3 corresponds to the view of Fig. 2 and is also taken along line 22 of Fig. l but shows the relationship of the above noted components when the pump is set for fuel cutofi operation; I

Fig. 4 also illustrates a structure for a six cylinder pump but in this instance the spill passages are disposed somewhat differently in the plunger face than the foregoing illustration and is a plan view of the valve looking toward the distributor block and illustrates the trace of an arcuate slot with respect to a metering chamber, its correlated discharge ports and spill slots wherein the pump is set for normal distribution;-and I i Fig. 5 corresponds to Fig. 4 except that it shows the relationship of the above noted components wherein the pump is set for fuel cutoff operation,

As shown in the'figures, a pump housing 50- includes a stationary plunger block portion 1 in which are formed, or

suitably arranged, a plurality of metering pump chambers 2. Metering pump chambers 2 are disposed with their axes equidistantly around a common central axis.

Each chamber 2 contains a reciprocatory plunger Q,

which is movable in the outward direction by a spring 4. Movement of the plungers 3 in the opposite direction is effected by a wobble plate 5 acting on the outer ends of all the plungers. The wobble plate 5 has the form of a part of a sphere and is supported in an oscillatory manner on a complementary concave surface 6 in a hollow stationary portion of housing end cover 7 enclosing the outer ends of the plungers 3 and the adjacent end of the plunger block 1. An axial bore 8 is formed in wobble plate 5 and this is provided at or near one end with an annular recess 9. The surface of recess 9 is sphericalshapedand has its geometricalcenter situated at any convenient distance from that of the spherical surface of wobble plate 5.

An ohliquesleeve 10, also referred to herein as a skew shaft, extends through bore8 in wobble plate 5. Skew shaft 10 is suitably mounted upon a drive shaft 11 for axial movement therealong. Skew shaft 10 is also keyed to driveshaft 11 for driven rotation therewith. Accordingly, it will be understood that sleeve 10 is rotatable with and capable of sliding movement along drive shaft 11. The exterior end of drive shaft 11, extending from housing 50, is suitably interconnected with the engine (not shown) in a well-known manner so as to be driven by suchengine. A complementary ring 12 is freely supported in the recess 9 and closely surrounds sleeve 10. When driving shaft 11 rotates, the axis of sleeve 10 generates a conical surface. By moving sleeve 10 axially to .vary the distance between the center of ring 12 and the apex of the conical surface generated by the axis of sleeve 12, the amplitude of motion of the wobble plate 5 can be adjusted, and this causes the strokes of the-plungers 3 to be varied. Axialmovement of the sleeve 10 is effected by a crank lever 13 pivoted to thehousing 50.

By a suitable mechanicallinkage, lever 13.may. be inte sq e s t .prs s l q s sitiv de (no shown herein)'. whi ch device1 is adapted torespond to pressure variations and also temperature variations, if desired,.in the intake manifold. to cause lever 13 to pivot in one or the other oftheopposed directions indicated by the arrow 51. This movement serves as a metering signal which is substantially a function of the intake manifold air density of the engine to cause corresponding repositioning of skew shaft 10 axially along drive shaft 11 in order to suitably adjust thestroke of plungers 3.

The ends .of thepu mp chambers 2 remote from the wobble. plate 5 open into-a planesurface14 of the plunger block 1 at right angles to the common axis around which the chambers-are arranged,-and this surface forms one of the boundaries of a chamber or cavity 15. A stationary end cover encloses the adjacent end of plunger block 1 which cover is an integral extension ofthe distributor block portion 16 of the pump. As seen in the figures, cavity 15, in elfect, separates the plunger block portion of the pump from its distributor block.

It is desirable that the pump above described shall be operated atengine speed, and therefore the number of metering chambers 2 provided in the plunger block 1 is one-half the number of cylinders in the engine, it being assumed that the later operates on the usual fourstroke cycle. That is to say, in the case of a pump required to supply a twelve-cylinder engine, six pump chambers 2 and plungers 3 are provided for supplying liquid fuel through twelve delivery pipe connections or passages as 17 to the corresponding enginecylinders. It follows from this condition that the contents ofeach metering chamber 2 mustbe discharged to each in turn of two operativelyassociated delivery pipe connections or discharge passages 17. For controlling the supply and discharge of liquid to and from the pump chambers Zin a desired sequence, we employ a rotary disc valve 19 which is situated inthe above mentioned chamber or cavity 15. Preferably, and as shown, discharge passages 17 are provided in the distributor block portion 16 of swa l wi g-5 T sqss fl a faces .99.19

of valve 19 are designed to abut and lap against the bearing surfaces 14 and 21 of plunger block and distributor block portions 1 and 16 respectively. Said distributor block is also provided with ports 22 interconnecting the bearing surface 21 thereof with respective ones of the discharge passages 17. In order to distinguish one discharge port 22 from the other for the pair operatively associated with each metering chamber 2, one port sometimes will be depicted as 22 while the other is 22.

To enable both faces of valve 19 to maintain proper contact with their seating surfaces 14, 21, the valve 19 is made from two coaxially arranged annular parts 19A, 19B, and interposed compressed springs 20 located between these parts to press them against the seating surfaces. Springs 20 are located in respective recesses 23 formed in the adjacent sides of the valve parts 19A, 19B, and in the same recesses are arranged sealing bushes 24 which surround each spring. Recesses 23 serve to establish communication between

ports

25, 26 in the valve parts 19A, 198 respectively and the sealing bushes 24 serve to prevent escape of liquid from between the valve parts. Preferably and as shown bushes 24 are provided with rubber or like sealing rings 27 which extend into the recesses 23 and between the valve parts 19A, 19B.

The valve 19 is actuated by an eccentric 28 formed or secured on drive shaft 11 which passes coaxially through the plunger block 1. Eccentric 28 (which may conveniently consist of a pair of spaced parts as shown) is situated within and adapted to fit the inner peripheries of the annular valve parts 19A, 193. Moreover, the

outer periphery of valve 19 or of one of its two parts 19A',"19B,'is formed with a ring of gear teeth 29 adapted to engage the internally toothed annulus 30 of a gear ring 52. Gear ring 52 is also disposed between bearing surfaces 14, 21 for rotation through a preselected angular distance, and is provided with a toothed annulus 31 on its outer periphery for the purpose of imparting such angular displacement thereto with respect to the longitudinal axis of drive shaft 11 in a manner described hereinafter. At the moment, it will be assumed that gear ring 52 remains stationary.

Upon rotation of drive shaft 11 and keyed eccentric 28, hypotrochoid motion is imparted to valve 19 as said valve revolves with respect to the drive shaft axis. Upon selecting a suitable ratio of pitch circle diameters for the meshing gear ring teeth and valve teeth such as 9:8, valve 19 will revolve with respect to drive shaft axis in a backwards sense, that is to say, in a direction opposite to the direction of turning of drive shaft 11 as valve 19 experiences a traveling toothed engagement with gear ring teeth 30. Due to the foregoing 9:8 gearing, valve 19 creeps backwards one-eighth of a revolution for each revolution of turning of drive shaft 11 in the other direction.

Valve cavity 15 in the example shown serves also as a chamber to which liquid fuel under pressure is supplied through an intake port 18 from a fuel source or storage tank (not shown), and from which the liquid fuel can pass into the open ends of metering chambers 2 in bearing surface 14. The diameter of valve 19 is made such that its outer periphery can control the flow of liquid from valve chamber 15 to each of the pump chambers 2, the eccentric motion of the valve causes said metering chambers to open and close in a desired sequence. A cresent shaped area 53 is formed by the fact that the diameter of valve 19 is less than the diameter of toothed annulus 30, which area is developed as valve 19 undergoes hypotrochoid movement to bring about exposure of the respective pump chambers in sequence as noted hereinbefore.

Assuming the plunger block 1 to be provided with three metering chambers 2, the end face of the valve part 19A (which laps against the surface 14 of the plunger block) is formed with eight ports-25. Ports 25 are of arcuate or kidney-shaped form, andare situated around a circle concentric with the center of valve 19 with their'adjacent ends suitably spaced apart. Also the end face of the other valve part 19B (which laps against the surface 21 of the distributor block) is formed with eight ports 26 and these are of circular form in cross section, and being situated around a circle concentric with the center of the" valve. Moreover the ports 26 are disposed in pairs, the

, ports of each pair being respectively situated opposite or nearly opposite to the adjacent ends of the corresponding arcuate or kidney-shaped ports 25 and the pairs of ports 26 being separated by considerable distances as shown in Fig. 2. In other words, valve ports 26 are disposed substantially in axial alignment with alternate adjacent ends of arcuate slots 26, such that ports 26 of each pair are spaced closely together and the spacings between each pair are relatively large. Each port 25 is interconnected with a respective port 26 by a respective recess 23 to effect communication between metering chambers 2 and with one and then the other of respective ones of the operatively associated ports 22, 22' leading to delivery pipe discharge passages 17. Discharge passages 17, which passages are suitably arranged in distributor block portion 16 of pump housing 50, are connected to respective ones of the engine cylinders by fuel supply lines not shown herein in a manner well known in the art.

The embodiment of the fuel pump illustrated herein contemplates use with a six cylinder engine. Hence, each metering chamber 2 of the three will be operatively associated with -a respective pair of six discharge passages or delivery pipe connections 17, as they are also referred to herein, suitably disposed in a convenient manner in distributor block 16 and wherein six ports 22 leading to respective discharge. passages 17 are suitably grouped in pairs to connect each chamber with its operatively associated passages 17. v

The mode of operation will be described with respect to the sequence of operation associated with only one of the metering chambers 2. It should be understood that the same operation applies to all the metering chambers. In one position of the valve 19, the outer periphery of its part 19A exposes an ample area of the adjacent end of the pump chamber 2, and liquid fuel flows into that chamber from the valve chamber 15 while the corresponding plunger 3- is performing its suction stroke. Meanwhile the adjacent arcuate ports 25 are closed. By the rotation of the valve 19, the end of the pump chamber 2 is gradually closed, and when the plunger 3 is about to commence its delivery stroke the pump chamber is fully closed. Continued rotation of the valve 19 now causes one of the arcuate ports 25 to overrun the end of the pump chamber 2. In consequence, said chamber is put into communication with one of the ports 26, and simultaneously (or just previously) the port 26 concerned has been brought into communication with one of the ports 22 which leads to one of the discharge outlets 17.

As rotation of the valve 19 continues, the arcuate port 25 moves clear of the pump chamber 2 which, simultaneously, is again opened, by the outer periphery of the valve part 19A, to the valve chamber 15. Simultaneously with, or shortl yafte'r these events, the port 26 moves clear of the port 22. This takes place during one rotation of drive shaft 11 and valve 19. During the next rotation, the cycle is repeated, but in this cycle the next of the arcuate ports 25 comes into action and, during the delivery stroke, causes the contents of the pump chamber 2 to be discharged to the other of the outlets 17 associated with the metering chamber concerned. Consequently, this particular pump chamber supplies fuel alternately to each of one pair of the engine cylinders. It will be appreciated, however, that, during each rotation, the valve 19 opens and closes each pump chamber 2 in turn-and causes fuel to be supplied to threelof the three cylinders being supplied in the course of the next rotation of the valve.

The present invention, as has already been indicated above, makes it possible to effect temporaryreorientation of the epicyclic distributing valve 19, about its own center of rotation, into a position such that all the liquid discharged from the pump chambers 2 is conducted to spill outlets communicating with the inlet zone 15 of the pump. Porting of fuel to the inlet zone 53 is effected by spillway passages42 constituted by ports or grooves in plunger block surface 14. Each spillway passage is suitably situated alongsidea respective metering chamher 2 so as to receive fuel therefrom during the fuel cutoff phase of operation. Said passages extend a sufiicient distance outwardly so that the outer ends of said passages are adapted to register with crescent shaped area 53 when said areais developedthereat. On the other hand, the position of passages 42 in bearing surface 14 is such that said spill passages avoid register with metering chambers 2 by lying outside the path of travel of arcuate slots 25 for the foregoing described operation with the result that during normal pump operation (as illustrated by the phantom trace in Fig. 2) passages 42 do not interfere by registering with the metering chambers 2. Cut-off operation is effected by suitably orienting gear ring 52. This in turn correspondingly shifts valve 19 to cause arcuate slots thereof to register with passages 42 while said slots 25 encounter metering chambers 2. The passages 42 in this instance are overlapped by the extremity of arcuate slots 25 -of-the moving valve 19 and this condition .will persist throughout -the delivery stroke of the relevant meteringcharnber. In this way the entire output of the metering chamber is b-y-passed to the adjacentspill passage and returned to the inlet zone 53 -of the pump. Ihisis shown by the phantom trace depictedin Fig. 3.

During operation as exemplified by Fig. ,2 gear -ring 52 is held stationary by being flocked in position by locking means to be described hereinafter. The pump is switched to fuel cutoff phase of operation by angularly shifting or displacinggear ring.52 a suitable amount so that a suitable valve shift is effected to cause its slots 25 to overlap passages 42 as noted hereinbefore. Gear ring 52 is maintained inthis latter position-as long as fuel cutofiphase of operation is desired.

Fig. 3 illustrates the pathof travel traced ;out i n phantom by one of the arcuate-slots25 with respect to a single metering chamber 2, the associated

discharge ports

22, 22 of the

correlateddischarge passages

17, 17 and its adjacent spillwaypassage (depicted as 42a) as drive shaft 11 undergoesone revolution of turning in the direction indicated by arrow 57. As arcuate slot 25 passes through-a sector corresponding to a, b and cof the phantom trace, valve 19 has receded from gearring 52 to expose metering chamber 2 to crescent shaped area 53 at which time chamber plunger 3 is undergoing its intake stroke to cause said chamber to fill with fuel. Upon further turning of shaft 11, it will be noted that spillway passage 42a communicates with the arcuate slot prior to and during a period of timesaid arcuate slot registers with metering chamber 2. By the time chamber 2 registers with the arcuate slotit has ceased communication with crescent shaped area 53 andthe plunger thereof is experiencing a discharge stroke to relieve chamber 2 of fuel. The fuel flowing from metering chamber 2 re turns to crescent shaped area 53 via spillway passage 42a. Area 53 is still in register with the outer end of spillway passage 42a although long before this occurrence area 53 has ceased toregister with metering chamber 2 by reason of the fact that-the outerend of spillway passage 42a is suitably spaced from metering chamber 2. It will be assumed for the particular illustration, that port-26 is opposite the left-hand end of the slot 25 in which caseportz fi does not -register with-discharge passage port 22 as slot 25- traces1-o ut aforesaid path of travel. However, if port 26 were in register with discharge passage port 22, fuel will still portback to the fuel input supply 18 rather than to the engine cylinder via the discharge passage 17 for the reason to be explained hereinafter. Further rotation of valve 19 sweeps slot 25 through a sector during which time metering chamber 2 is again exposed to area 53 to receive fuel from supply 18. As seen from Fig. 3, the discharge port 22' does not interfere with the aforesaid operation. Said port 22' does not come into register with slot 25 via port 26 thereof until after said slot has receded from chamber 2.

Upon the next cycle of revolution of drive shaft 11, the next slot 25in the sequence is brought into register with metering chamber 2, but in this instance the port 26 thereof is opposite the right-hand end of the slot. As before, the innerend of passage 42a registers with slot 25 prior to and during a period of time metering chamber 2 is in register with said slot. During the latter portion of the aforesaid travel, the outer end of passage 42a communicates with crescent area 53 as the metering chamber 2 releases the fuel trapped therein. During the aforesaid sector of travel there exists a period during which port 25, now opposite therighthand side of the slot 25 in register with chamber 2, also registers with discharge port 22. Fuel continues to port into spillway passage 42a by reason of the;fact-that the back pressure existing in the fuel supply line leading from the coupled discharge passage ,17 and-to the engine cylinder connected therewith is much greater than the backpressure in the fuel input zone 53. Consequently fuel returns to fuel input supply 18in the manner described hereinbefore. With furtherrotation of valve 19, metering chamber 2 is again exposed to crescent ,shaped-area53 toreceive fuel for the, next revolution of operation.

,Although not;sl1 ownin,-Fig.;3 it will be understood that the other chambers also experience a similar operational relationship with respect to arcuate slots 25 in valve 19, withthe result that upon successive revolutions of drive shaft 11, each metering chamber is individually interconnected alternately with the fuel supply intake line 18 and then with its correlated spillway passage 42, to effect fuel cutoff operation. Consequently as long as gear ring 52 is held stationary in the position depicted in Fig. 3, a preselected distance from its initial position corresponding to normal pump operation, fuel, instead of being released to respective engine cylinders, is returned to the fuel sup ply line 18. The fuel pump is returned tonormal operation by-again orienting gear ring 52 but this time in an opposite direction in respect to the direction that it was initially oriented so that gear ring is returned to its initial position. This will, in turn, reposition the valve so that it again assumes the time phase it experienced prior to the first orientation with the result that the pump is returned to normal fuel distribution operation.

Angular displacement of gear ring 52 is brought about by a pinion or toothed quadrant 32 meshing with the toothed sector '31 on the outer periphery of gear ring 52. Pinion 32 is suitably recessed in housing 50 and is mounted and keyed to a control spindle 34 supported for rotation. An advantageous feature of this arrangement is that it is only necessary to seal'the control spindle 34, as indicated at 34A, against the small difference of pressure obtaining between the inlet zone (which is constituted by the crescent-shaped space left between the epicyclic distributing valve 19 and its surrounding-annulus 30) and atmosphere. A further notable virtue of the arrangement in question is-that, provided the pump is operating, if only at very low speed,-no static friction between the distributing valve 19 and its contacting facings 14, 21 has to be overcome, and hence the forces involved in actuating the control mechanism are extremely light. A stop device 35 is pro- .vided to limit the range of rotation of the gear ring 52. A two-armed pawl member 41 is mounted on the end of control sp ndle .34 exteriorl y ofhousing 50 and keyed thereto also to turn therewith. Said pinion, control spindle 34 and pawl member 41 are designed to pivot or oscillate from one to another of two positions about the axis of control spindle 34. Simultaneously, gear ring 52 meshing with pinion 32 undergoes corresponding orientation. A pressure sensitive device 36 mounted exteriorly of pump housing 50 is made up of a suitably sealed chamber 54 having a deflectible wall 38 formed by a diaphragm member resting centrally against a ferrule 55. Chamber 54 is adapted to sense intake manifold air pressure by means of a convenient interconnection 37 leading to the inlet manifold, not shown herein.

Itis desired that diaphragm 38 respond to a drop in manifold air pressure below a preselected valve by inward movement in the direction of arrow 56. This is achieved by spring biasing diaphragm 38 with a spring 39 fastened between diaphragm 38 and a rest plate 58. Rest plate 58 is supported at one end of a shank 59 extending through the wall of pressure sensitive device 36. The force imparted to diaphragm 38 by spring 39 will determine the pressure level at which said diaphragm moves inwardly against spring 39. The spring force may be regulated by axially adjusting the position of shank 59 by means of a threaded locking nut 60 on the exterior wall of device 36 so as to reposition rest plate 58 in chamber 54.

The motion of diaphragm 38 in the direction of arrow 56 is transferred to pawl member 41 by means of a

twoarmed link

61, 62, interconnected at their joined ends by a bendable knee 63. One arm 61 is fixed to diaphragm 38 and extends through the ferrule bore outwardly from the housing of pressure sensitive device 36. By this arrangement arm 61 is capable of reversible axial movement in response to diaphragm movement. The other arm 62 is slotted at its other end 40 to receive an engaging pawl 64 integral with one arm 41' of pawl member 41 such that upon inward movement of diaphragm 38 in response to a drop in manifold pressure to a preselected value, pawl member 41 is pivoted in the direction of arrow 65. On the other hand, outward movement of diaphragm 38 back to its seat against ferrule 55 causes pawl member 41 to turn in the direction opposite to arrow 65 thereby returning said pawl member to its original position. Return movement of pawl 41 is the response to an increase of manifold pressure above the preselected value.

From the foregoing it will be seen that when diaphragm 38 is held in one position under the force exerted thereon by spring 39, for example, the position shown in Fig. 2, quadrant 32 and thus gear ring 52 are set for normal fuel distribution operation. On the other hand, upon inward movement of diaphragm 38, pawl member 41 pivots in the direction of arrow 65 which causes corresponding angular shift of gear ring 52. The gearing and dimensions of the mechanical structure are preselected so that when quadrant 32 comes to rest at its second position in response to inward movement of diaphragm 38, valve 19 will have shifted so that its slots 25 register sequentially with the respective spill passages 42as the valve undergoes hypotrochoid movement to effect cutoff pump operation. Thus it is seen as diaphragm 38 moves from one to the other of its opposed positions, such movement is transferred to gear ring 52 which oscillates from one to the other of its two positions and which in turn causes pump operation to alternate correspondingly from normal operation 7 to fuel cutoff operation.

It will be apparent from the foregoing that-the invention is particularly applicable to fuel injection pumps for motor vehicles wherein operation of the pump responds to preselected pressure variations in the intake manifold. In this connection the spring tension is selected such that diaphragm 38 responds by inward movement only to an abnormal high depression existing in the engine induction system during overrunning. For example, during normal idling, the depression of the engine may 10 l when the vehicle is driving the engine at a speed marked-- ly higher than normal idling speed with the throttle closed. Under the latter condition, pressure sensitive device responds and actuates pawl member 41 and the quadrant mechanism so as to cut off temporarily the supply of fuel to the engine. When the depression drops to a normal value diaphragm 38responds by returning to its initial position. a It will be noted also that cutoff operation may be effected directly by the operator of the motor vehicle. The instant embodiment provides for such a feature wherein the other arm 41" of pawl member 41 is coupled to a'. spring loaded and movable plunger 66 of a solenoid 67. The spring loaded plunger 66 is adapted to follow the movement imparted to pawl member 41 as determined by diaphragm 38 so that plunger 66 does not interfere with switching pump to cutoff operation and back to normal' operation pursuant to pressure sensitive device regula tion. Plunger 66 will respond by suitable movement upon energization of solenoid 67 which may be energized, in any suitable manner by the motor vehicle operator and when energized, plunger 66 moves upwardly which in turn pivots pawl member 41 in direction or arrow in the same manner as described hereinbefore. In this instance the slot and

pawl linkage

40, 64 and the bendable knee 63 of interconnecting

linkage

61, 62 follow pawl movement so as not to interfere with the signal imparted to the pump by the motor vehicle operator. Upon deenergization of solenoid 67, the spring biased plunger 66 returns to its initial position thereby returning pawl member 41,to its initial position to effect again normal fuel distribution operation. It will also be understood that any other mechanical linkage under the control of the motor vehicle operator may be used in lieu of the solenoid mechanism shown herein. Although the illustrated embodiment is designed to accommodate a six cylinder engine, it will be understood that the invention is equally applicable to engines of larger or smaller numbered cylinders. The invention can be carried into effect successfully if the following conditrons are fulfilled. First, the number of pumping plungers 3, the disposition of the pump chambers 2 with respect to the arcuate ports 25 of the epicyclic distributing valve 19, and the ratio of the gearing between that valve and its annulus 30 must be so correlated that, in the normal operation of the pump, the arcuate valve ports 25 make their cycloidal approach to, and recession from, the um chamber ports 2 in an identical and symmetrical manner. Secondly, matters must be so arranged that an adequate peripheral length of each of the arcuate valve ports 25 1S ut1l1zed in traversing the respective pump chamber ports 2, since advantage is taken of the possibility of using one extremity of the periphery of each arcuate valve port 25 to overlap the respective pump chamber port 2 in the normal running of the pump, and the opposite extremity to overlap the pump chamber port similarly in the cutoff or by-pass condition. Fig. 4 illustrates in a relatively simple form for the purpose of clarity, a plan view of a six cylinder pump incorporating features of the instant invention wherein disposition of spill passages 42 in plunger bearing face 14 is slightly different than the arrangement illustrated 1n the foregoing Figs. 2 and 3. In this embodiment, each spill passage 42 is situated to extend along a radial line from the common axis and is angularly spaced from a line bisecting its correlated metering chamber 2 by the amount of twenty-three degree depicted as 0 in the figure.

, The trace illustrating the path of travel of slot 25 with correspond to 20 inches of mercury'whereas the depression may attain a value equivalent to 23 inches of mercury respect to one spill passage 42a, the adjacent and correlated metering chamber 2 and the two discharge ports 22, 22' corresponds substantially to one revolution'of drive shaft 11. As noted hereinbefore, the moving slots 25, as it undergoes 'epicyclic motion,- does not plaeeits adjacent metering chamber 2 in communication with spill 11 passage 42a. It will be understood that this figure depicts; normal fuel distribution operation;

Fig, corresponds to Fig. 4 exepr that it illustrates of travel in which the correlatedmetering chamber 2 is in communication with its adjacent spill'pa'ssage-Ma to return fuel to the fuel inlet zone rather than to theengine cylinders interconnected by

ports

22 and 22. Orientation of gear ring 52 fifteen degrees in the opposite direction returns the pump to normal fuel distribution.

Since many changes could be made in the above con struction and many apparently widely different embodiments of this invention could be made without departing from the scope thereof, it is intended that all matter contained in the above descriptio'fior shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. In a pump for distributing metered qnantities of fuel to an internal combustion engine and employing a pump housing having an internal cavity formed in part by opposed bearing surfaces separating a plunger block portion of said pump housing" fro'rnnadistributor block portion thereof, wherein said' h'oii'sing also includes a plurality of metering chambers arranged about a comm'on axis wherein each chamber has an open end in the bearing surface on the plunger'block side of said cavity, a'reciprocating plunger in each'chaniber, a fuel intake port for supplying fuel under pressure to the metering chambers, a plurality of discharge passages in said distributor block for supplying fuel to a corresponding number of engine cylinders and communicating with the bearing surface on the distributor block side of said housing, the combination comprising, a ported disc shaped valve mounted eccentrically and seated between said opposed bearing surfaces, an annulus of teeth on the outer periphery of said valve, a gear ring having an inner toothed annulus surrounding said valve and meshing with said valve teeth, said gear ring being mounted between said bearing surfaces for rotation about said axis, means imparting hypotrochoid motion to said valve in respect to said axis as the teeth thereof engage said gear ring, and means for releasing said gear ring for rotatable displacement alternately from one to another of two positions and locking said gear ring in such positions, one of said bearing surfaces also having a plurality of spillway passages corresponding to the number of chambers and adapted to register with the fuel intake port, each spillway passage being in spaced relationship with respect to a correlated chamber whereupon said spillway passages lie outside the path of travel of said valve ports when said releasing means holds said gear ring in a first of its'positions and as said chambers are individually interconnected in a desired sequence alternately with the fuel intake port and one and then the other of correlated ones of said discharge'ports during valve movement, repositioning of said gear ring to the second of its positions causes correlated orientation of said valve wherein said spillway passages register sequentially with said valve ports upon interconnection of same with re spective ones of said chambers during the discharge stroke of said bearing surfaces, said valve teeth and meshing gear ring teeth havingan eight to nine gear ratio, displacement of said gear ring through a preselected angular distance from the first of its positions causes corresponding shift to said valve to effect fuel cutoff operation, rotational displacement ofsaid valve in an opposite sense returns said gear ring to its first, position and correspondingly shifts said valve to effect normal pump operation.

3. Apparatus as defined in claim 1 wherein, said spillway passages being in the plunger block bearing surface, said valve teeth and meshing gear ring teeth having an eight to nine gear ratio, displacement of said valve through a preselected angular distance from a first of its r positions causes corresponding shift to said valve to effect cutoff operation, rotational displacement of said gear ring in an opposite sense through said same distance returns said gear ring to its first position and correspondingly shifts said valve to effect normal pump operation.

4. Apparatus as defined in claim 3 wherein, said gear ring having an annulus of teeth on its outer periphery and said releasing means comprising, a pinion engaging said last mentioned annulus of teeth, and means for rotatably displacing said pinion alternately from a first to a second of two positions, movement of said pinion from the first to the second of its two positions correspondingly shifts said gear ring from its first to second position to convert normal pump operation to fuel cutoff operation, and further rotation of said pinion in an opposite sense returns said pinion to the first of its positions to cause corresponding return of said gear ring whereby said pump returns to normal operation.

5. Apparatus as defined in claim 1 wherein, said gear ring having an annulus of teeth on its outer periphery and said releasing means comprising, a pinion engaging said last mentioned annulus of teeth, and means for rotatably displacing said pinion alternately from a first to a second of two positions, movement of said pinion from the first to the second of its positions correspondingly shifts said gear ring from its first to second position to convert normal pump operation to fuel cutoff operation, and further rotation of said pinion to the first of its positions causes corresponding orientation of said gear ring whereby said pump returns to normal operation.

6. Apparatus as defined in claim 1 wherein, said gear ring having an annulus of teeth on its outer periphery and said releasing means comprising, a control spindle mounted for rotation, a pinion engaging the outer peripheral annulus of said gear ring, a pawl member, said pinion and pawl member being mounted on said spindle and turnable therewith, and a solenoid having a movable plunger for rotatably pivoting said pawl member from one to another of two positions, wherein alternate actuation of said solenoid plunger results in correlated pivoting of said pawl member and rotation of theinterconnected gear ring, whereby said pump alternates from normal pump operation to fuel cutoff operation.

7. Apparatus as defined in claim 1 wherein, said pump is adapted to accommodate an internal combustion engine of the type wherein the fuel to air ratio induced by said engine is proportional to manifold air density, said gear ring having an annulus of teeth on its outer periphery and said releasing means comprising, a pinion engaging the outer peripheral annulus of said gear ring, a control spindle mounted for rotation, a pawl member, said pinion and pawl member being mounted'on said spindle and tu-rnabletherewith, pressure sensitive means for sensing the engine intake manifold air pressure and adapted to undergo alternate movement in response to preselected variations of air manifold pressure, and means operatively interconnecting said pressure sensitive means and said pawl member for alternately pivoting said pawl member and interconnecting pinion from one to another of two limiting positions in response to increase and decrease of air manifold pressure respectively, a drop of manifold pressure to a preselected value causes movement of said pawl member in one direction to cause corresponding shift of said gear ring to effect cutoff pump operation, an increase of air manifold pressure above said preselected value causes said pawl member to return to its initial position to effect corresponding return of said gear ring, whereby pump operation alternates correspondingly from normal operation to fuel cutoff operation.

8. Apparatus as defined in claim 7 wherein, said pressure sensitive means comprising, a sealed chamber having means interconnecting said chamber with the intake manifold, said chamber having a flexible member responding to variations of manifold air pressure by movement in opposite directions, and a spring imparting a force on said movable member and maintaining same stationary, the force exerted by the spring on said member being preselected to release the member for movement in response to a manifold air pressure sensed by such chamber below a preselected value and for returning said member to its initial position in response to a rise of said pressure above said preselected value, said flexible member being operatively connected to said operatively interconnecting means for transmitting flexible member movement to said pawl member.

9. Apparatus as defined in claim 8 further including, a means regulated by the operator of the engine and operatively coupled to said pawl member and being adapted to pivot said pawl member from one to another of its two positions whereby pump operation may be alternated from normal fuel distribution to cutoff phase of operation either by said pressure sensitive means or by the operator of the engine.

10. In a pump for distributing metered quantities of fuel to an internal combustion engine employing a pump housing having opposed bearing surfaces separating a plunger block portion of said pump housing from a distributor block portion thereof, said housing also including a plurality of metering chambers arranged about a common axis and having individual open ends in the plunger block bearing surface, a reciprocating plunger in each chamber, a fuel intake port for supplying fuel to said chambers, a plurality of discharge passages in said distributor block bearing surface for supplying fuel to engine cylinders, the combination comprising, a ported disc-shaped valve mounted eccentrically and seated between said opposed bearing surfaces, means imparting hypotrochoid motion to said valve in respect to said axis,

means for orienting said valve through a preselector angular distance about its own center of rotation to cause the pump to alternate from normal fuel distribution operation to cutoff operation, one of said bearing surfaces also having a plurality of spillway passages adapted to register with the fuel intake port, each spillway passage being in spaced relationship with respect to a correlated chamber, whereupon said passages lie outside the path of travel of said valve ports as said chambers are individually interconnected in a desired sequence alternately with the fuel intake port and one and then the other of correlated ones of said discharge ports during valve movement for normal operation, and whereas orientation of said valve through said preselected distance causes said spillway passages to register sequentially with said valve ports upon interconnection of same with respective ones of said chambers to permit return of fuel to the intake port as said valve undergoes hypotrochoid movement.

11. Apparatus as defined in claim 10 wherein, said spillway passages being in the plunger block bearing surface.

12. Apparatus as defined in claim 10 wherein, said orienting means comprising, a movable member operatively engaging said valve, and means for releasing said member for movement alternately from one to another of two positions and locking said member in such positions, said releasing means holding said member in a first of its positions to cause the pump to undergo normal fuel distribution operation, movement of said member to the second of its positions upon actuation of said releasing means effects correlated orientation of said valve to cause the pump to undergo cutoff operation.

13. Apparatus as defined in claim 12 wherein, said spillway passages being in the plunger block bearing surface.

14. Apparatus as defined in claim 13, wherein said valve having a ring of teeth, said movable member having a ring of gear teeth meshing with the teeth of said member, and a toothed sector adapted for actuation, said movable member having additional teeth meshing with said sector, whereby actuation of said sector results in corresponding movement of said member and correlated orientation of said valve to cause the pump to alternate from normal fuel delivery to cutoff operation.

Beeh Aug. 20, 1946 lsreeli et al. Oct. 11, 1955 Wahlmark Apr. 28, 1942' .i in Ilium in .l of ffff l ll UNITED STATES PATENT OFFICE CERTIFICATION OF CORRECTION Patent No. 2,967 ,520 January 10, 1961 John Neville Morris et al.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 2 line 50 for "-cresent-shaped" read crescentshaped column 3 line 50, for "acting" read actuating column 4, line 60 for later" read latter column 5, line 65, for "cresejnt shaped read crescent-shaped column 6, line 14 for "26", first occurrence, read 25 line 62, for "shortl yafter" read shortly after column 10, line 23 for "or" read of line 67, for ldegree', read degrees same column 10, line 72, for "slots" read slot Signed and sealed this 1st day of August 1961. (SEAL) Attest:

ERNEST W. SWIDER DAVID L. LADD Attesting Officer Commissioner of Patents