US2301407A - Fuel injection pump - Google Patents

Description

NOV 10, 1942- J. E. HousER ErrAl. 2,301,407

' FUEL INJECTION PUMP Filed June 22, 1940 4 sheets-sheet 1 FI E11 Nov. 10, 1942. J, E HOUSER ET AL 2,301,407

FUEL INJECTION PUMP v Filed June 22, 1940 4 shee'ts-sheet 5 f /14 IEr-. '7 FIB-.B 5/ //3 T 7 :A 5 42 l y 43 Z7 V is @-954 ,so 57` 58 45 548. Y

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Fmg a "39 Nov. 10, 1942.V J. E. HousR ETAL 2,301,407v

` FUEL INJEAGTVION PUMP Filed June 22, 1940 4l sheets-sheet 4 FI E115 FIB-.14

FIL-'.115 i RIS E Patented Nov. 10, 1942 FUEL mmc'rroN PUMP Jesse E. Houser, William A. Hancock, and Lewis T. Rowe, Dayton, Ohi'o, assignors to The Dayton Liquid Meter Company,r Dayton, Ohio,` a

corporation of Ohio Application June 22 1940, Serial No. 341,840

(Cl. 10S-44) 12 Claims.

The present invention relates to automotive structures, and more particularly to fuel injection pumps for measuring the charges of fuel taken by a gasoline or Diesel engine.

In the case of high power, high speed automotive engines, more particularly those employed in connection with aircraft, there has arisen a marked necessity for, devices which will inject fuel of all kinds 'directly into the respective cylinders of the engine, or into the intake manifold, with a high degree of accuracy of measurement. These injectors are usually employed as a substitute for the ordinary forms of carburetion, leaving to the injection pump the very important function of accurately measuring the amount of fuel in the successive charges.

For this purpose it has been customary to employ a plunger attached to a 'fuel suction line which reciprocates in a cylinder carrying a spray nozzle. This nozzle is sometimes introduced directly into the respective cylinders of the engine,

and in other cases it is inserted in the intake manifold. In order to lubricate this fast moving plunger, passageways which extend from the interior of the cylinder, and a source of lubricating oil are employed. However, it has been found that this oil which thus accumulates on the periphery of the plunger tends to dilute the fuel; particularlyA as the engine runs hot,'thinning the oil. Moreover, the sediment, and other foreign material which Amay be of an abrasive character and contained in the fuel, tends to nd its way into the lubricating system, thus causing excessive wear on the reciprocating parts.

The primary object of the invention is to `provide an improved fuel injector, and more particularly a\device of this character in which the fuel passing=` through the injector pump is maintained entirely;l separate from the lubricating system so as to eliminate any transfer of oil into the fuel "system, land also preventing foreign matter from moving between the fuel system and the lubricating system. This object is attained, in brief, by dividing the fuel injector pump into two compartments, separated by a flexible member, one of the compartments containing the fuel to be injected into the engine and the other compartment containing a plunger and a liquid, preferably oil, so that pressure may be built up in the liquid by the plunger, causing the diaphragm toV flex and thereby ejecting fuel from the fuel side of the compartment. It has been found that when the oil content of the plunger compartment forms part of a closed circulatory system, and due to the rapid reciprocations of the plunger which has returned to the plunger compartment,

through the closed circulatory system is entirely devoid of gas bubbles which might reduce the accuracy with which theimproved injector meters the fuel. This object is attained, in brief, by inserting in the oil circulatory system a filter composed of chamois which serves to strain out the non-condensables while the oil is being recirculated. In attaining this object we therefore provide an extremely accurate measuring device for controlling the injection of fuel into automotive engines.

Anotherv important feature of our invention concerns the after-drip from the nozzle of the injector pump. These nozzles are ordinarily formed of a casing having an annular opening at one end, and adapted to be connected to the discharge port of the injector pump at the other end. This annular opening is normally closed by a spring-tensioned cap, which is'forced from its seat when fuel under pressure is passing through the nozzle. The design of the ordinary form of hydraulically operated nozzle is such that it takes a lower pressure to close the nozzle than to open the same. The result is that when the nozzle is closing and the pressure Within the nozzle still remains high, dripping may take place and these drops of fuel arenot translated into power at the engine because the presence of this fuel is not in proper timed relation or condition with respect to the operating cycle of the engine. Moreover, this fuel dripping represents waste which might readily become an important item in the case of engines having large numbers of cylinders necessitating an equal number of nozzles, and operating at fast speeds.

In our improved injector pump we prevent all dripping from the nozzle by permitting the column of incompressible fuel to be moved bodily into the casing of the injector pump a distance necessary to accommodate the seating of the ca; at the nozzle. Thus there is less pressure within: the column of fuel after the cap has seated thai: before, and all dripping from the nozzle is thereby avoided.

In general, the objects of the present invention are to provide an extremely accurate measuring device ffor controlling the injection of fuel into automotive engines, to provide an injector pump in which the fuel about to be injected is entirely separate from theinjecting apparatus, 'and in' which the energy of injection is obtained through hydraulicpressure; to provide a pump of this character in which the injection of the fuel is caused byv hydraulic pressure exerted on the diaphragm, and the pressure iluldis freed` from nonlector', pump for controlling the flow of fuel to, the respective cylinders.

Figure 2 is a sectional view, partly in elevation, of the improved pump together with the additional feature by which dripping at the injector nozzle is prevented.

Figure 3 is a longitudinal sectional view of a iilter in thepressure fluid line for removing noncondensables and other foreign matter from the fluid.

Figures 4, 5 and 6 are views similar to Figure 2, but showing the various operating parts in different positions during an operating cycle.

Figure 7 is a fragmentary sectional view of the improved injector pump, but showing the parts in the iinal position at the end of the operating cycle. This view ,is a continuation of the sequence of operation of the parts which start from their initial position in Figure 2, and pass throughv Figures 4, 5 and 6 to the nal position in Figure 7, to indicate a complete cycle.

Figure 8 is an enlarged fragmentary view of the check valve mechanism shown at the end of the plunger in the preceding views.

Figure 9 is an elevational view looking in the direction of the arrows shown in Figure 8.

Figure 10 is a fragmentary view of a modified form of diaphragm chamber employed in the improved injector pump.

Figure 11 shows the use of a bellows form of diaphragm chamber advantageously used in place of the flat diaphragm for injecting larger quantities of fuel.

Figure 12 is a fragmentary view of a typical form of fuel nozzle which cooperates with certain features of the present invention.

Figure 13 is a diagram of the cam for actuating the pump diaphragm.

Figure 14 illustrates a modined form of lnjector pump in which the check valve at the end of the plunger-has been omitted. This form of pump may be satisfactorily used only under cernumeral vI generally designates a typical form of automotive engine as specically having six cylinders, as indicated by the six spark plugs 2. 'I'he engine block is indicated at 3 and the bed at 4. Only the left-hand cylinder has been shown in detail and this cylinder contains a piston 5. The bed of the engine is provided with a ange 6, and on this flange rests as many injector pumps of the improved type as there axe cylinders, these pumps being preferably secured Vto the engine and positioned directly below the respective cylinders.

The parts of the improved injector pumps are contained within a casing 1, which may be of a general cylindrical form. and from the upper portions of each casing there is a fuel intake line 8 which connects through a common pipe 9 to a fuel tank (not shown). There are fuel discharge pipes I0 taken from the upper end of the casing 1 and terminating at each cylinder just above the uppermost position of the pistons 5. There is also' a pair of pipes secured to the side of each casing 1, the upper pipe II serving-as an oil inlet pipe and the lower pipe I2 serving as an oil outlet pipe, the circuit being completed through a combined oil reservoir and lter I3, the construction of which is shown in Figure 3. I'he details oi the improved injector pump are illustrated in Figure 2. It will be noted that the casing 1 is actually constituted of two members, joined together by screws I4. The upper casing I6 is provided with multi-shoulderedY portions I1, I8, the latter terminating in a. screw threaded member I9, to which the pipe I0 is secured by any suitable form of coupling 20. There is a cylindrical opening 2| passing down through the casing I6 and in line with the opening in theA discharge pipe I0.

This opening 2| has the same diameter down as far as the`shoulder 22 (Figure 16), and the opening emerges into another opening of smaller diameter, as indicated at 23. At the lower partv of the openingr 2| and resting on the shoulder 22 there is a hollow thimble member 24 (Figure 16) which has a transverse portion 25 containing two diagonally directed openings 26. A pin 21 projects downwardly from the transverse portion or web 25, this pin being in line with a ball 28 which in cooperation with opening 29 at the bottom of the thimble constitutes a check valve. It will be apparent that the pin 21 merely serves to limit the upward movement of the ball when pressure is applied to the fuel passing through the thimble 24; The upper casing I6 is also provided with a transversely extending opening 30,

which contains a sleeve 3| having -a centrally aligned aperture 32. The ball 33, forming part of a second check valvel is urged by the spring 34 against the left-hand end (Figure 16) of the opening 32. There is a projection at 35 extending to the right (Figure 2) of the casing I6, this pro- `jection being threaded to receive a coupling 36 for securing the fuel inlet pipe 8 to the casing in line with the opening 30. The casing I6 is provided at its lower endV with a countersunk conically shapedA opening 31, this opening being adapted to receive a diaphragm 38, preferably of a steel composition which resists corrosion by all of the known types of fuel. This diaphragm may have any desired thickness, but we have found that it performs particularly well when having a thickness less than 1%000 of an inch'. The diaphragm is seated between an annular rim portion formed on the casing I6 and the upper surface of a lower casing 39 of the fuel injector pump, which together contain the main parts of the injector pump.

The lo` er casing '39 is provided with a central opening hich receives a sleeve or cylinder 4I, having a bore 42 in which reciprocates a plunger 43. The bore which receives the cylinder 4I is provided with an annular groove 44, which is in communication with the bore 42 through a radial opening 45. This opening communicates with an opening 46 extending radially outward from the annular groove 44 through the casing 39 to anopening 41, which receives the pressure fluid inlet pipe II (Figure l). Directly below the annular groove 44 there is a similar groove 48 which communicates through a radial opening 43 with another opening 50 for receiving the pressure iluid outlet pipe I2. The plunger 43 is provided with an axial opening which terminates in a larger opening for receiving a screw-headed plug 52. The lowermost portion of the plunger is enlarged so as to more readily accommodate the screw shank of the plug 52, the head of the latter projecting beyond the lower surface of the plunger and terminating in an arcuate portion indicated at 53. At the junction between the opening 5I and the larger opening which receives the plug 52 there is a radially extending opening 56, the purpose of which will be explained hereinafter. The upper end of the plug 52 terminates in a small diameter portion 55 which receives a compression spring 56 for urging the ball 51 against the under side of the opening 5I (Figure 8).

There is a sleeve 58 provided preferably with screw threads on its periphery and positioned within the annular space between the plunger 43 and the opening in the casing 39. Threads of corresponding shape are cut in the casing to receive the sleeve 58. The sleeve 58 is adapted to be rotated on its threads in a manner to be described presently, and While being thus rotated vits longitudinal position with respect to the plunger 83 and the casing 39 is accordingly changed. There is an annular opening 58 cut' into the upper surface of the sleeve 58. For rotating the sleeve we have provided a gear 59, which is journalled at 6I) in a projection 6I extending from the casing 39. The gear is keyed to a shaft 62, and the latter is adapted to be rotated by means of a handoperated throttle lever 63. The teeth of the gear 59 mesh with teeth formed at the lower end of the sleeve 58. Consequently, by rotating the lever 63. the sleeve 58 is rotated at a corresponding rate and is moved upwardly or downwardly, depending on the direction in which the lever 63 is moved.

There is a plate 64 screwed to the under side of thev projection member 6I and the casing 39, this plate having depending therefrom a cylinder 65 which terminates in a flange portion 66. The latter is secured to a portion 61 of the engine frame directli,1 above a cam shaft 66. The latter may .be any one of the cam shafts of the engine and has secured thereto a' cam 69, the general contour of which is shown in Figure 13. The cylinder 65 is hollow and has a shouldered compartmentin which is rigidly secured a sleeve 18. In the sleeve there is a solid cylindrical member 1I adapted to reciprocate within the sleeve, and carrying at its lower end a shaft 'I2 on which is mounted a cam follower 13, preferably of circular conilguration as shown in Figure 13. The upper portion of the cylinder 1I is countersunk toreceive the lower or enlarged portion of the plunger 43, and the latter is secured to the cylinder 1I by a `nut 14 which fits about the upper side of the enlarged portion. There is a compression spring contained within the annular space between the sleeve 10 and the interior oi' the cylinder 65, the

lower end oi' the spring surrounding a sleeve-like spring holder 15 which is secured to the sleeve 10. It is apparent that as the shaft $8 is rotated the cam 69 will cause the follower 13 to move upwardly and downwardly, and thereby causing recprocations oi' the cylinder 1I and the plunger 3.

It was pointed out in connection with Figure 1 that the pressure iluid lines II and I2 communicate with an oil filter or strainer I3. This strainer will now be described. As seen in Figure 3, there is a cylinder 16 which would usually be made of metal but for observation purposes might be made of glass, and contained between a pair of metal discs 11. 'I'he lower disc is provided with an upstandlng centrally positioned rod 18, which has larger diameter portionsV 19 at each end apertured along the entire length, as indicated at 80. The upper disc 'I1 is provided with a central opening to receive the uppermost' shoulder portion 8| of the rod 18, to which it is secured by a nut 82. There is an opening 68 extending radially outwardly from the longitudinal opening 86, the purpose of which will be explained presently. There is a minute opening 88 provided in the upper disc 11. The longitudinal opening or bore 86 is closed at its upper end by a screw member 85, which has a small opening 86 passing through the center thereof.

Surrounding the portions 19 and secured thereto in any suitable manner, `for example by means of spring metal rings 81, there is a cylinder 88 of lter material such as chamois, heavy and closely woven muslin or any other material which will strain non-condensables such Aas air or vapor bubbles, or solids such as gum from the worked oil passing through the filter. The opening 80 communicates at its lower end with the pipe I2 (see Figure l) through any suitable form of coupling 89. The annular space between the filter material 88 and the cylinder 16 communicates with the pipe II through a coupling 96 and an opening 9| in the bottom disc 11, as will be explained in greater detail when the operation of the improved injector pump is described.

Emulsied oil from which air or vapor bubbles have been driven out of solution within the injector pump is caused to pass through the pipe I2,l up through the opening 80, then out through the opening 83 where it collects between the chamois cylinder 88 and the rod 18. This oil then passes through the filter material, however leaving behind the separated air or vapor or other non-condensable materials, so that the cil which collects in the space between the filter 88 and the cylinder 16 represents perfectly pure oil and such air or vapor as is completely dissolved in the oil. The opening 86 serves as a vent for preventing the building up of excessive pressures inside of the iilter, while the opening 64 permits small quantities of air to enter at tion 93 projectingI from one side and screw threaded yto receive a coupling 94 for securing the pipel to the projection 99; The projection 93 contains a bore 95 which communicates with a bore 98 within the cylinder 92.

'I'he bore 98 is reduced to a small bore indicated at 91. which receives an arcuate headed pin 98. The upper surface of the head 99 of the pin seats against the lowermost surface of an enlarged portion |00 of the cylinder 92. The latter is threaded, as indicated at I0|, into a threaded opening formed in the cylinder head |02. The pin 98 has four or more longitudinal grooves |03 extending along its length, and communicating at one end with the bore or opening 98 and at the other end with an annular opening |04 formed at the lower end of the enlarged cylinder portion I 00. The pin 98 has a threaded opening |05 in its upper end which receives the threaded shank of a rod |08 contained within thevopening or bore 88. This rod is provided with an enlarged head |01 which normally bears against a cap |08 threaded to the exterior surface of the cylinder 92. 'I'here is a tension spring |09 which loosely surrounds the rod |06 and bears at its upper end against the head |01, and `rests at the opposite en d on |00 around the pin 98. The purpose of this spring is to resiliently hold the head 99 of the pin 98 against its seat, thereby preventing fuel from flowing beyond the annular space |04 except when the fuel is under high pressure.

Operation of those parts of the injector pump described up to this point Referring first to Figure 2, which represents the starting position of the various parts of the pump, let us assume that fuel has been drawn in from the pipe 8 through the openings 30, 32, past the check valve 33 and into the space directly above the diaphragm 38. The cam 69 is in its lowermost position, causing the plunger 43 to be also withdrawn to its lowest position. Under these circumstances a partial vacuum will be formed within the bore 42 directly above the plunger, causing oil to be Withdrawn from the outer annular space of the filter |3, through the pipe openings 4i, 46 and 45. Thus the bore 42 is completely filled with oil or vother relatively incompressible pressure uid.

As the cam 69 rotates the plunger 43 is caused to be elevated, closing oil the opening 45 and finally placing the trapped oil under pressure. Reference to Figures 13 and 15 will show that the upward movement of the plunger 43 is extremely rapid because the translation from the small `di ameter portion of the cam 69 marked a to the large diameter portion of the cam marked b takes place over a relatively few degrees of angular motion. The steepness of the portion c of the graph shown in Figure 15 also indicates this rapid rise of elevation of the plunger. The increased pressure produced by the plunger on the trapped oil serves to flex the diaphragm 38, as shown in Figure 16, causing a reduction in the volume of the space directly above the diaphragm. This, in turn, produces a large increase in pressure on the fuel trapped above the diaphragm, causing the lball 33 to be rmly seated against its sleeve 3|,

thereby closing oi the inlet passage 32 and also forcing the ball 28 in the discharge passageway to be moved away from the opening'29. Fuel un- 75 asomo? predetermined amount. The preferred form of nozzle is illustrated in Figure 12, and consists of a h'ollow cylinder 92 having a rounded por.

der pressure is therefore caused to pass upwardly rthrough the passageways 20, 29, through the diagonal passageways 20, into the respective pipes' ,annular space |04, forcing the head 99 to beV moved downwardly (as seen in the figure) away from its seat, and permitting the fuel under high pressure to be ejected as a spray of circular configuration about the entire under side of the head i9 9, into the cylinder of the engine.

It'will be understood that there are as many cams 09 and fuel injection pumps as there are cylinders, as indicated in Figure 1, and the cams are sopositioned with respect to the cam shaft 88 (Figure 2) as to cause the circular spray to leave the respective nozzles in proper timed relation, depending on the firing order of the engine cylinders. As the plunger 43 (Figure 2) continues to rise, due to the actuation by the cam 89, fuel is ejected at the nozzle until the fluid4 pressure within the plunger bore 42 is released. This pressure releasing function is obtained by the upward movement of the radial opening 55, which as soon as it uncovers the annular opening 58', permits the oil under pressure in the bore 42 to pass through the longitudinal opening 5| and to unseat the check valve 51 against its spring 86, thereby allowing the oil to pass through the radial opening 54 in the plunger and through the annular opening l58'. This annular opening communicates with the openings 48, 48 and 50. thus permitting the oil to move through the pipe i2, into the longitudinal opening of the filter I3. As explained hereinbefore, the oil then passes through the chamois cylinder 88, where the disassociated vapor and air bubbles or other form of non-condensables are strained.

It is apparent that one oi the main purposes of ltering these non-condensables before the oil is returned to the injector pump is to assure the maintenance of one hundred per cent. non-compressible fluid introduced into the bore 82, so that the upward travel of the plunger 83 is translated directly and accurately into changes of pressure in the oil, which in turn, cause accurate fiexing of the diaphragm 3B and an accurate measurement of the fuel expelled at the nozzle. The smallest amount of a compressible medium such as air or vapor in the oil, and particularly when this air or vapor appears as bubbles disassociated from the body of the oil, i. e. outl of solution, may cause, for a given travel of the plunger, a disproportionate movement or exing of the diaphragm, thus introducing slight errors in the amount of fuel ejected at the nozzle. These air or vapor bubbles may be driven out of the oil solution by the extreme agitation produced in the oil when the pressure in the latter is released by permitting the oil to flow through the openings 5|, past the check valve 81 and through the passageway 54, into the filter.

Referring again to Figure 15, it will be noted that, notwithstanding the fact that the plunger is given a considerable movement upward, as indicated by the diagonal lineA c of the graph, the injection stroke of the plunger normally takes place only over a portion of the entire plunger travel. This has been indicated by the dotted lines appearing in Figure 15 and suitably labeled. Inasmuch as the oil pressure is released at that point in the plunger travel which is determined by the uncovering of the opening 54 by the annular opening 58' in the sleeve 58, it is apparent that by moving the sleeve 58 relative to the plunger the pressure release point may .be changed. 'I'his is conveniently accomplished by simply rotating the throttle lever 63, which causes the sleeve to be rotated through thc gear 59, and in case a later release point isrequired in order to increase the charge of fuel delivered at the nozzle, the lever 53 is moved in such direction as to cause the sleeve 58 to move longitudinally upwardly on its threads. Thus for full throttle position the sleeve 58 is moved upwardly as far as possible, and for low throttle the sleeve is moved to a suitable intermediate position, thereby controlling the amount of fuel in each charge delivered at the nozzle and injected into the respective cylinders.

Figure 4 shows the position of the parts while the oil is being compressed and the diaphragm is flexed, while Figure 5 shows the change taking place in the position of the parts immediately after the hydraulic pressure has been released by uncovering the port 54. It will be noted in this case that the diaphragm 38 is practically returned to its fiat position. When the diaphragm starts to unfiex, due tothe release ofA hydraulic pressure, a partial vacuum is produced in the space directly above the diaphragm, and this causes fuel to be sucked through the pipe 8 from the gas reservoir (not shown), past the check valve 33 which has now become unseated, into the space directly above the diaphragm ready for the next'injection movement of the plunger. The check valve 28 is obviously closed during this suction operation. However, the plunger 63 continues to rise due to the cam action, and this has been clearly indicated in Figures 5 and 6 which show the plunger in different relative positions. There is no pressure exerted on the diaphragm because .the oil finds a ready exit through the release port 5d.

The return movement of the plunger is shown in Figure 'l and is caused by the follower 18 moving over the most extended portion of the cam 58 (Figure 13), permitting the spring, which had previously been compressed, to now force the plunger downwardly. As the plunger moves downwardly a vacuum is produced between the upper edge of the -plunger and the diaphragm, until at the moment the upper edge of the plunger reaches the inlet opening 45 oil is withdrawn from the filter through the pipe i i. It will be noted in Figure 'l that during the first part of the downward travel of the plunger the pressure release opening 54 is in communication with the anular space 58, and inasmuch as a vacuum is being produced at the upper end of the plunger oil would normally tend to pass from the annular opening 58, through the port 54 and through the longitudinal opening 5|, to the upper vend of the cylinder. However, this return flow of oil is prevented by the check valve 51 (Figure 8) whichis seated by the spring and suction effect produced at the upper end of the plunger.

As explained hereinbefore, the non-condensables are thrown out of solution when the fluid pressure is released, causing. the oil to move rapidly and with considerable agitation through the opening 54. Thus the oil remaining in this opening, and also in the annular opening 58' and the space above the latter is of an emulsifled character, i. e. containsv disassociated gas and vapor bubbles, so that it is highly desirable to prevent this oil from reaching the upper side filter. Therefore the check valve 51 serves the useful function of preventing the emulsiiled or contaminated oil from returning to the pressure side of the plunger without having passed through the filter. As the plunger continues to move downwardly it uncovers the oil intake port 85, drawing in oil until it reaches the lowermost point of its travel. lIt will be noted from thev graph (Figure 15) that the return travel of the plunger may take place over approximately 150 degrees, and the plunger remains in its retracted position giving ample time for the check valve 33 to close after the space above the diaphragm has been completely filled with fuel. The plunger is then ready for its injection stroke to complete the operating cycle.

It is obvious that we have disclosed an injector pump which very accurately measures the amount of each charge of fuel, because the diaphragm 38 is forced to seat itself flat during the pressure release portion and the suction portion of the plunger travel, thereby accurately determining the volume of the space directly above the diaphragm. The amount of fuel in each charge is accurately controlled by the position of the pressure release opening 54 in the plunger with respect to the annular space 58 ln the sleeve 58. The latter may be moved with any degree of precision through the gear 55 by simply manipulating the throttle lever 63.

In order to enhance the accuracy with which the oil inlet port B5 is opened and closed by the plunger, also with which the hydraulic pressure is released at the moment port 54 is uncovered. it may be desirable to give the openings 45 and 54 a rectangular configuration. This square shape of port opening tends to give a quicker transition from the open to the closed condition. and vice versa, than in the case of openings of circular configuration. The square shape of the opening 54 has been illustrated in Figure 9, although it will be understood that this opening and the other opening 45 may take on any other desired shape, depending on the results required.

From the foregoing it is evident that in the improved injector pump of this invention the fuel and oil are never allowed to mix. The plunger is being continually bathed in a lubricant which reduces excessive wear, and moreover the plunger never comes into actual contact with the diaphragm, but exerts only a hydraulic pressure on the diaphragm. This insures equal pressure throughout the entire area of the diaphragm, which promotes the operating life of the various parts.

While We have described our invention from the standpoint of starting out with a diaphragm Vin its flat position a'nd flexing the same to an arcuate condition, it will be understood that our invention is not limited to a fractional cycle of the diaphragm. Indeed, it may be desirable to employ a diaphragm which under no pressure conditions is flexed to one side of its flat planar position, and when hydraulic pressure is introduced by the plunger the diaphragm is flexed to a position on the opposite side of its flat planar position. This modification is illustrated in Figure 10, andit ia apparent that under these conditions greater quantities of fuel may be ejected at the nozzle during a flexing cycleof the diaphragm.' For practical reasons we believe that a half or fractional cycle of the diaphragm gives greater precision of measurement of the fuel charge.

of the plunger until it has Passed through the 7s Another way of increasing the amount of the fuel charge is shown in Figure 1l, in which the diaphragm takes the form of a completely closed bellows im or sylphon material. The diaphragm preferably surrounds the plunger and the reciprocations of the latter, as explained hereinbefore, cause changes in the hydraulic pressure of the oil contained within the bellows, and in a corresponding manner the bellows forces the fuel which had previously been drawn through the opening 36, into the discharge opening 2i, to the nozzle. Various other forms of diaphragm will occur to those skilled in the art, by which a change in the hydraulic pressure introduced by a reciprocating plunger may be translated into varying quantities of fuel ejected through the discharge opening 2i.

While we have described and shown the use of a check valve 5i (Figure 8) for preventingemulsiiied oil from returning to the pressure chamber above the plunger, it will be understood that when using certain forms of design this check valve may be unnecessary. 1t is apparent that the opening 5d is uncovered only during that portion of the plunger travel when the opening 54 is in communication with the annular opening 58. As the sleeve 58 is moved upwardly the time of intercommunication between these open-v ings becomes less. full throttle conditions and when the opening 5t' has been moved to its innermost position, the time during which the port 5d is in communication with this opening is s`o short as to prevent any appreciable amount oi emulsiied oil from returning to the pressure chamber above the plunger. Certain forms of engines, such as those employed for operating water pumps, etc., are usually run at constant speed under full throttle conditions, so that in this case it may not be altogether necessary to provide the check valve El! for preventing emulsied oil from reaching the pressure chamber above the plunger. Figure 14 shows such an injector, in which the check valve has been omitted. However, it will be understood that the omission of the' check valve is simply a compromise in that at least small quantities of emulsified oil do reach the pressure chamber, and the accuracy with which the fuel is metered from the chamber above the diaphragm depends on the relative quantity of emulsied oil which is permitted to return and the amount of non-condensables or solid materials contained in the emulsified oil.

Another feature of the present invention is an Consequently, in the case of improved non-drip nozzle by which the nozzle completely shuts on the fuel at the termination of the charge provided by the flexed diaphragm.

It has been pointed out that during the flexing of the diaphragm by the oil under pressure, the fuel is 'transmitted under pressure through the pipe i0, into the annular opening |04, from which it is ejected as a spray. of circular configuration. At the moment the pressure exerted on the fuel startsto recede, due to the return of the diaphragm to its unfiexed position, the head 99 is withdrawn upwardly by the spring 109 to snap the nozzle closed. It is apparent from the design of the nozzle structure, particularly from a consideration of the diierential areas involved, that only a relatively small pressure may be permitted to remain vwithin the nozzle structure during the closing period. Ifthe pressure in the fluid is not reduced at a rate -to correspond with the closing snap action, dripping will inevitably take place from the end of the nozzle. This after drip enters the engine cylinder at a time later than the main inJection impulse, and represents waste since it is not withdrawn into the engine cylinder at the suction valve. It will be understood that only a few drippings when multiplied by the number offcylinders, and being repeated many times per minute in the case of high speed engines, may produce considerable waste. In accordance with the present invention we have provided a feature which cooperates extremely satisfactorily with our improved injector pump, and completely eliminates the dripping of iuel.

Referring to Figure 2, the casing i8 is provided with a diagonal opening iii which communicates at one end with the discharge opening 2i and at the other end with an annular opening i i2 formed in' a. small cylindrical plug H3. This plug is provided with a combined diagonally and longitudinally extending opening iid, which communicates at one end with the annular opening H2 and at the other end terminates at the lower surface of the plug. There is a diaphragm H5, preferably of thin flexible metal and non-corrosive with respect to the fuel, secured to the lower surface of the plug. For practical reasons this diaphragm is welded to a sleeve i iii, and the latter is secured to the plug iid. The plug is so positioned within the casing in as to permit a free flexing movement of the diaphragm i le, only in. a half cycle. In order to remove the plug when necessary a downwardly extending hole ill may be provided in the casing, directly in line with the plug, and this hole is closed by a screw iid.

Now assume that the nozzle (Figure 12) is in the act of closing, after having ejected a full charge of fuel into one of the cylinders, so that the head 99 is snapped upwardly. In the unimproved form of nozzle, the back pressure may remain high or fail to reduce suiilciently quickly and cause dripping of fuel. In accordance with our invention, this excess pressure is relieved by the exing of the diaphragm H5 which permits the column of trapped fuel to expand, thereby lowering the pressure and permitting the head 99 to seat promptly. Figure 2 shows the diaphragm H5 in its extended position to prevent dripping of fuel at the nozzle after the diaphragm 38 has started to retract to its initial flat position. in Figure 4 the diaphragm H5 is in its seated position, i. e. unextended, because the main diaphragm 38 is in the act of causing the ejection of fuel at the nozzle, and no back pressure has been built up because the head 99 is maintained in its open position by the pressure in the fuel.

It will be. noted that the non-drip feature described immediately above cooperates with the improved injector pump in such a, way as to prevent any dripping from the nozzle after the metered charge of fuel has been ejected at the nozzle due to the flexing of the main diaphragm 38. Consequently, the operation of the latter serves accurately to measure the fuel content or each charge and to cause the full charge to be ejected at the nozzle without any after drip. Our injector pump operates so efilciently in the accurate measurement of the fuel charge, as determined by the setting of the throttle sleeve 58, as to cause every trace of the fuel to be used up in the engine, and there is not the slightest trace of carbon deposits expelled from the vexhaust pipe of the engine. The fuel ejected at the nozzle contains no trace of oil since the oil and the fuel compartments are entirely separated by the main diaphragm.

prehend within our invention such modifications i l. An injector pump for delivering measured quantities of fuel to an engine, said pump comprising an elongated compartment having one end communicating with the cylinder of the engine, and the other closed by a flexible member, a body of oil for flexing said member when placed under pressure, whereby fuel is caused to issue from the open end of said compartment, and means for `maintaining the oil free of air and vapor globules, whereby said member is flexed and fuel is ejected in proportion to pressure applied to the oil, said means comprising a illter which permits oil to pass but restrains air and vapor out of solution.

2. An injector pump for delivering measured quantities of fuel to an engine, said pump comprising an elongated compartment open at one end and closed at the other end'by a flexible member, a cylinder secured to said compartment adjacent said flexible member, fluid in s aid cylinvder and a plunger for applying pressure to said iuid and to said flexible member, means including a pressure release opening communicating with the pressure end of the plunger for controlling the pressure applied to the fluid by the plunger, said pressure release opening being of rectangular shape and adapted to beimmediately opened when the pressure is applied to the fluid.

3. An injector pump for delivering measured quantities of fuel to an engine, said injector comprising' a compartment open at one end and closed by a diaphragm at the other end, a hollow cylinder adjacent said compartment and ccntaining a, fluid plunger adapted to reciprocate Within said cylinder in timed relation with the operation of the engine, whereby the uid is periodically placed under pressure to ex the diaphragm and to cause fuel to be ejected from said compartment, a longitudinal yopening which extends through the plunger from the pressure end and communicates with a radial opening in the plunger, and a pressure release opening in said cylinder in line with said radial opening at that position of the plunger which determines the duration of pressure to be applied by the plunger to the diaphragm, and a barrier adjustable from the exterior of the ypump for controlling the position of the opening in the plunger which is in communication with said pressure releaseopening, and a one way valve positioned at the junction between the longitudinal and radial openings in the plunger to permit uid to flow from the pressure side of the plunger to the pressure release opening, but to prevent flow in the opposite direction. y

4. An injector pump for delivering measured quantities of fuel to an engine, said pump comprising a pair of cylindrical compartments arranged end-to-end and separated by a flexible member, one of said compartments containing fuel to be injected into the engine and the other compartment containing uid adapted to be placed under pressure in order to flex said member, said last-mentioned compartment having a pair of interconnecting circular bores of different diameters, a movable sleeve in the bore of larger diameter, said sleeve having a central opening smaller bore, a pair of apertures extending radially outward from the respective bores, one of said apertures serving to admit fluid into the space above said plunger when the plunger is withdrawn and the other aperture serving to exhaust uid from the space immediately above the sleeve, an opening extending longitudinally of said plunger, and an opening extending radially through said plunger and communicating with the longitudinal opening in the plunger, said last-mentioned radial opening being adapted to register with the exhaust iluid opening whenv the plunger is moved into its pressure-producing position.

5. An injector pump for delivering measured quantities 'of fuel to an engine, said pump comprising a pair of cylindrical compartments arranged end-to-end and separated by a flexible member, one of said compartments containing fuel to be injected into the-engine and the other compartment containing iluid adapted to be placed under pressure in order to ex said member, said last-mentioned compartment having a pair of interconnecting-circular bores of different diameters, a movable sleeve in the bore of larger diameter, said sleeve having a central opening to receive a plungerl which extends into the ,smaller bore, a pair of apertures extending radially outward from the respective bores, one of said apertures serving to admit fluid into the space above said plunger when the plunger is withdrawn and the other aperture serving to exhaust iiuid from the space immediately above the sleeve, an opening extending longitudinally of said plunger, an opening extending radially through said plunger and communicating with the longitudinal opening in the plunger, said last-mentioned radial opening being adapted to register with the exn haust fluid opening when the plunger is moved into its pressure-producing position, and means for moving said sleeve relatively to said plunger whereby the distance through which the plunger must be moved lto cause registry between the radial opening in the plunger and said exhaust uid opening is changed.

-6. An injector pump for delivering measured quantities of fuel to an engine, said pump comprising a pair of cylindrical compartments arranged end-to-end and separated by a flexible member, .one of said compartments containing fuel to be injected into the engine and the other compartment containing fluid adapted to be placed under pressure in order to flex said member, said last-mentioned compartment having a pair of interconnecting circular bores of diierent diameters, a movable sleeve in the bore of larger diameter, said sleeve having a central opening to receive a plunger which extends into the smaller to receive a plunger which extends into the 75 bore, a pair of apertures extending radially outward from the respective bores, one of said apertures serving to admit fluid into the space above said plunger when the plunger is withdrawn and the other aperture serving to exhaust fluid from the space immediately above the sleeve, an opening extending longitudinally of said plunger, an opening extending radially through said plunger and communicating with the longitudinal opening in the plunger, said last-mentioned radial opening being adapted to register with the exhaust fluid opening when the plunger is moved into its pressure-producing position, means for moving "said sleeve relatively to said plunger whereby the distance through which the plunger must be moved to cause registry between the radial opening in the plunger and said exhaust fluid opening is changed, said means comprising threads which are provided on the exterior surface of said sleeve and meshing with threads provided in said bore of larger size, and means for rotating the sleeve with respect to said larger bore whereby the sleeve is moved longitudinally of said bore.

7. An injector pump for delivering measured quantities oi fuel to an engine, said pump comprising a pair of cylindrical compartments arranged end-to-end and separated by a flexible member, one of said compartments containing fuel to be injected into the engine and the other compartment containing fluid adapted to be placed under pressure in order to flex said member, said last-mentioned compartment having a pair of linterconnecting circular bores of different diameters, a movable sleeve in the bore' of larger diameter, said sleeve having a central opening to receive a plunger whichextends into the smaller bore, a pair of apertures extending radially outward from the respective bores, one of said apertures serving to admit fluid into the space above said plunger when the plunger is withdrawn and the other aperture serving to exhaust fluid from the space immediately above the sleeve, an opening extending longitudinally of said plunger, an opening extending radially through said plunger and communicating with the longitudinal opening in the plunger, said lastmentioned radial opening being adapted to register with the exhaust fluid opening when the plunger is moved into its pressure-producing position, means for moving said sleeve relatively to said plunger whereby the distance through which the plunger must be moved to cause registry between the radial opening in the plunger and said exhaust uid opening is changed, said sleeve being threadedly engaged by the bore of larger, size and being provided with teeth, a gear meshing with said teeth, and a lever for rotating said gear whereby as the gear is rotated by the lever the sleeve is caused to move with respect to the bore of larger size.

8. A fuel injector pump comprising two compartments separated by a diaphragm, one of the compartments being adapted to receive fuel and another of the compartments being adapted to receive pressure fluid. means for circulating the pressure uid through its compartment, said means including a fluid reservoir and outgoing and return uld conduits extending between the reservoir and the uid-containing compartment, said reservoir being so positioned with respect to the pump as to promote the separation of air and vapor bubbles in a free state from the fluid, and means for removing the separated air and vapor bubbles. f

9. A fuel injector pump comprising a pair of compartments separated by a diaphragm, one of said compartments being adapted to receive fuel and another of the compartments being adapted to receive pressure fluid, a reciprocatory plunger for forcing pressure fluid into the fluid-containing compartment, said plunger being supplied with uld through a circulatory conduit system including a reservoir, means for exhausting the pressure fluid through the plunger, and means for preventing fluid from passing from the exhaust side of the plunger to the pressure side thereof until the fluid has passed through the circulatory conduit system and reservoir.

10. A fuel injector pump comprising two compartments separated by a diaphragm, one of said compartments being adapted to receive fuel and another of the compartments being adapted to receive pressure fluid, a reciprocatory plunger for forcing pressure fluid into the fluid-containing compartment, said plunger having a passagewayA extending longitudinallyv thereof from the exhaust side of the plunger to thepressure side thereof, a reservoir for the fluid, an inlet conduit connected between the pressure side of the plunger and the reservoir and a discharge conduit connected between the exhaust side of the plunger and the reservoir, and means cooperating with said plunger passageway for preventing the flow of fluid directly from the exhaust to the pressure side of the plunger.

l1. A fuel injector pump comprising two compartments separated by a diaphragm, one of said compartments being adapted to receive fuel and another of the 'compartments being adapted to receive pressure iluid, a reciprocatory plunger for forcing pressure fluid into the fluid-containing compartment, said plunger having a passageway extending longitudinally thereof from the exhaust side of the plunger to the pressure side thereof, a reservoir-for the fluid, an inlet conduit connected between the pressure side of the plunger and the reservoir and a discharge conduit connected between the exhaust side of the plunger and the reservoir, and means cooperating with said plunger passageway for preventing the flow of uuid directly from the exhaust to the pressure side of the plunger, said means cornprising a check valve spanning the exhaust end of the passageway and spring biased to permit passage only of the fluid which flows from the pressure side of the plunger to the exhaust side and thence to the reservoir.

l2. A fuel injector pump comprising two com-v partments separated by a diaphragm, one of the compartments being adapted to receive fuel and another of the compartments being adapted to contain oil, means including a plunger for applying pressure to the oil in its compartment whereby the diaphragm is flexed to eject fuel from the fuel compartment, means for actuating vsaid plunger, means for exhausting the pressure fluid through the plunger, and a circulatory conduit system including a. r reservoir connected to the `pressure and exhaust sides of the plunger, said reservoir being positioned remote from said plunger-actuating means whereby the oil in said reservoir remains in a relatively stillV condition to promote deaeration of the oil.

JESSE E. HCUSER, WILLIAM A. HANCOCK. LEWIS T. ROWE.

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