US2375492A - Nozzle for fuel injection systems - Google Patents

Description

' y 8, 1945. E. M. PURDY E"I'AL 2,375,492 V I E F0 FUEL; INJECTION SY I Filed June ll, 1941 3 Sheets-Sheet l nun M y 8, 1945- v -E. 'M. PURDY ETAL A 2,375,492

NOZZLE FOR FUEL INJECTION SYSTEMS Filed June 11, 1941 I I5 Sheets-Shet 2 iNVENTfiRS. W

ATTORNEYS WWW ya, 1945. E. M. PURDY ETAL 2,375,492

NOZ ZLE FOR FUEL INJECTION SYSTEMS Fi'led June 11, 1941 s Sheets-Shet s 44X. ,i ZZ

INVENTORS an internal combustion engine.

The inventionhas for its object generally an I Patented M1178, 1945 NOZZLE Fon 2,375,492 FUEL INJECTION SYSTEMS Everett M. ma and Warner I. Tabb, Brooklyn,

N. Y., assi gnors; by mesne assignments, to Re construction Finance Corporation,

New York,

N. n, a corporation of the United States Application June '11, 1341, Serial No. 397,592

This invention relates to a nozzle jection' systemaand more particularly to a, nozzle unit adapted for injecting fuel into a cylinder of improved construction and arrangement of parts for injecting fuel and achieving a positive and definite opening movement of the nozzle valve to an extent substantially proportional to the pressure of the fuel to be injccte -More speciflcally,jan objectis to provide improved fuel injecting nozzle of the general charac-,

ter disclosed in U. S. Letters Patent No. 2,192,803, patented March 5, 1940, in the names of Purdy and W. T, Tabb, whereby a helical spring is employed as the resilient element 'controlling cautionary elements such as additional cushion- I 11 Claims. (cl. 251-145) for fuel 111-- e'conomical manufacture and assembly of precision in adjustment and operation, conservation of space and the possible elimination of preing springs, etc.

Other objectsof the invention will in part be obvious and will in part appear hereinafter.

Theinvention accordingly comprises the features. of construction, combination of elements,

and arrangement of .parts, which will be exemplifled in the construction hereinafter set forth and the scope of the invention will be indicated in the claims.

valve stem movement and effects precise displacement of the stem at all times in a manner pljoportional to the fuel pressure applied.

Another object is to provide an improved nozzle unit of the character indicated in which provision is made for effecting independently but precisely a desired adjustment of the total travel of the valve stem and of the pressure of the I fuel at which opening movement takes place. t v

Another object is to provide a nozzle unit of the character indicated with a helical spring device or rigging for controlling valve stem movement,

engine:

For a fuller understanding of the nature and objects of the invention reference should be had to the'following detailed description taken in connection with the wall which may 2 is an enlarged vertical sectional view of the nozzle unit, shown mainly in elevation in,Fig. 1, showing details of the construction employed;

. Figs. 3 and 4 are enlarged perspective views re-.

together with means for effecting centering or self-alignment of the spring and stem therewith.

Another object is to provide 'aconvenient assembly of nut elements for adjusting travel and.

pressure response for a valve stem in a nozzle unit of the character indicated, whereby a Vernier adjustment may be had and the element locked in place.

Still another object is to provide an assembly of adjusting elements in 'a. nozzle unit of the character indicated with means for sealing the parts in adjusted relation in a manner preventing tampering or accidental change inadjustment.

Afurther object of the invention is the provision in such nozzle structure of seating arrangements for helical spring stem controlling rigging which serve to balance the thrust at all circumambient points relative to the stem ing tendency of-latter to bend or cock.

An additional object of the invention is the provision of simple cushioning means for limiting outward travel of the stem which. in addition to being readily and easily altered to change valve stem travel may provide an hydraulic cushioning spectively of the outside and of inside adjusting nuts which are disposed on the shank-of the valve 7 stem inaccordance with the invention;

thereby avoideffect combined if desired'with a mechanical cushioning action to avoid injurious shock to and fatigue failure, deformation and. destruction of stem and spring rigg ng, parts. thereof, travel stopping means, etc. v v

A still further object is the provision of such a gedness and simplicity of construction making for nozzle mechanism which is characterized by 1118- Figs. ;5 and 6 are enlarged top plan views of the same outside and inside valve stem nuts;

Fig. 7 is an elevational view of the spring-like element employed-to lock the outside and inside nuts in a desired relative adjustment;

Fig. 8 is a fragmentary view similar to Fig. 2 showing amodification; and

Fig. 9 is an enlarged fragmentary sectional view showing another modified form of the invention.

, Referring now to the drawings, and particularly to Figs. 1 and 2, l0 denotes a tip member which has a flange I I about its upper end by which it is held in a retainer nut'lZ of a. holder member N.

This latter is arranged to pass through and be secured in an opening in a wall (not shown) of a combustion chamber by suitable means, such as v a clamp I 5, which has an opening it for engaging with the top surface of the holding member I 3 the clamp being provided with openings iifor the reception of screws, or the like, for securing the clamp to the wall. of the internal combustion chamber, The retainer nut l2 and the holder member is are here shown in threaded engagement, but any convenient means for securing the same in assembled relation may be employed.

. Theholder member is here provided with a central bore It by which fuel is supplied from a suit- -able-source (not shown) and pumped under adesider pressure. Bore I6 leads into an enlargement accompanying-drawings, in .which: j Fig. I is a view, partly in section and partlyin elevation, showing a fuel inJection nozzle of the 2 present invention in place .in a suitable holder adapted for supporting the nozzle structure in a be that of an internal combustion and other reasons.

or chamber l! which houses the upper portion of nozzle mechanism, as hereinafter explained. Tip member In and holder member l3 together constitute a nozzle body which need not be made of separate \parts assembled together in the manne'r shown.

The tip member is shown in section in Fig. 2, where it is seen to have a central bore 20 in which reciprocates a valve stem 2 I, the lower portion 22 of which is enlarged and fits snugly into a counterbored portion 2|) which forms a shoulder 20* on which seats a conical valve portion 23 that (preferably the latter), films or small bodies .of fuel are present therebetween during intervals between impacts by the stop member or nut 26 by virtue of the location of the stack of shim members in the fuel chamber 11.

member or nut 26 violently impacts against the stack of shim members at least portions of the intervening bodies of fuel are squeezed out, against opposing forces, that may be due'to capillary action and/ or adhesion'between the intervening films of fuel and the surfaces of the shim members or fluid friction, thereby providing an hydraulic cushioning effect, with which may cooperate. certain mechanical resiliency indicated above, tending to avoid hammering of the metal shim members and the stop member or nut, de-

struction or distortion of threads on the nuts and stem, and damaging shock to the stem and rem lated parts. It is understood of course that when counterbore, as shown at 20 for manufacturing When the nozzle tip I0 is thus bored and counterbored and the valve stem 2| slipped in place ithrough the lower end, the conical portion 23. seats on the shoulder 21] and closes the passage. The other end of the stem projects beyond the top ;of the tip and has disposed about it a spring 1 rig ing in accordance with the invention in order to control the movement of the stem, the arrangement being such that the opening movement is Z substantially proportional to the pressure differj ence between that of the fuel in the chamber l1 1 and that of the fluid into which the fuel is bein 1 injected, such as that in" the cylinder of the 1 engine.

Accordingly, a helical spring member is provided and disposed about the projecting end of 1 the valve stem 2| and arranged toseat at 3| on i the upper end of tip Ill. The upper end of spring 1 member 30 reacts-against a dual member or nut j assembly comprising an outer member 25-and an inner member 26, the latter preferably but, not 1 necessarily being in threaded engagement with the projecting end of the shank of the stem.

On the valve stem shank, below the inner mem- 3 ber or nut 26, is slidably disposed a collar 21 that I has one or more radiallydisposed passages 28 1 for passing fuel from chamber l1 intothe fluted.

1 channels at; 24. The collar also preferably has a group of superposed washer or shim members 29,

" preferably formed from spring steel or phosphor- 1 bronze, slidably disposed on the stemshank; the 1 number of" such shim members being less'than enough to fill the space between the innernut 26 e 3 and the top of the collar 21. A clearance space 3 thus remains, which determines the limitof I downward movement of the stem 2| and its memher or nut '26. The shim members 29 may be slightly dished or otherwise shaped or arranged to have a cushioning effect when engaged by the member ornut 26 for stopping the'downward stem movement. The shim members 29 and backingv collar 211 are thus seen to serve as an emcient stop which may have mechanical resiliency-. for deterthe amplitude of stem movement, and to i require a minimum of space while'making fori ease'in assembling the nozzle parts and simplicity f l of manufacture.

fuel injection operation of the device vi (which in'the case of internal combustion engines j 1 is characterized by high frequency reciprocation of the valve stem) with theshim members 29 1 '1 slightly dished, distorted or substantially flat locked in position. To this end, traverse slots 26 (see Figs. 4 and 6.) are formed in the nut 26 effect. Such structure avoids necessity of using a secondary spring which may be subject to hammering damage, shock and fatigue failure.

It will be understood that the above described arrangement makes possible the ready attainment 'of any desired amplitude of valve stem opening movement, by altering'the number of shim members 29 on the stem shank, and/or by.

the adjustment of inner nut 26 on the'stem shank. Nut 26 when properly adjusted ispreferably in order to accommodate the ends of a locking pin 32. For'the reception and engagement of this pin, the upper end of stem 2i is perforated transversely. In consequence, ltis seen that the adjustment of stem movementprovided is independent of any other adjustment and may be achieved with precision at the time of assembly.

The inner stop member or nut 26 is threaded externally and it is the first member. of the assembly to be put in place. The lower-end of stop member or nut 26 is also advantageously thickened, as shown,,in order to impart stiffness inner member or nut 26 is threaded upon the thereto when functioning as a stop. When the valve stem shank and the; pin 32 inserted for holding it in adjusted position, spring iii may; be slipped into place thereover and outerv mom ber or-nut 25 then suitably positioned oil-threaded. 3 upon inner member or nut 26't0 hold theassembiy together.

member or nut 26, and is provided with a laterally extending flange 33..which provides a-reacting abutmentand seat for, the upper end of spring .29. By this arrangement it is seen that outer member or nut 26 may be turned-into a position on inner member or nut 26 so as to compress spring-20 to any desired degree, i. e., cause spring I0 to-giveany desired reacting pressure. Any

desired opening pressure for the valve stem may When'the desired adjustments have been thus provided, the inner and outer, member or nut assembly is preferably locked in place. To this.

When stop The outer member or nut 2I, 'as shownin 'Y end, a plurality of slots or grooves 35 are preferably formedlongitudinally across the internal threads of outer nut 25, which slots or grooves are'adapted to be in register with similar slots or grooves 36 formed longitudinally across the external threads of member or nut 26. To give a Vernier adjustment between the members or nuts, the number of slots or grooves in the respective members or nuts is not the same; for example, five slots or grooves 35 may be providedon the inside of nut 25, while six slots or grooves 38 may be provided on the outside of member or nut 26. The displacement angle of one with respect to the other between adjacent adjustment positions. determined by opposed grooves in the two members or nuts'will be 360 divided by the product of the numbers of grooves in the two. With a reasonably fine thread and a reasonably large number of. grooves in the members or nuts a fraction of a turn when adjusting them relatively to bring a pair of slots or grooves into register for locking, may give a very close adjustment of the reacting spring pressure. For

example, it has been found that with the provision of thirty-two screw threads per inch on the two members or nuts, five longitudinal grooves in the outer member or nut and six longitudinal grooves on the inner member or nut, adjustments in the axial direction of approximately .001" may be positively and accurately attained.

When the slots or grooves in the two members or nuts and 26 are in register, a locking pin 3 preferably made of spring wire and bent as shown in Fig. 7, is inserted, thereby locking the assembly in place. While substantially any convenient shape of pin 34 may be used, that shown comprises one having leg portions for insertion into the, registering slots and two arms 34' and 34" which meet to form a V-shaped portion which may be made to engage resiliently with the inside threads of the outer member or nut 25, as shown in Fig. 2. These arms are seen to provide a portion that may be readily engaged by a tool from without for the insertion or removal of the locking pin. When the pin 34 has been properly inserted in place to secure a desired adjustment in the factory assembly, the top of the bore of the outer member or nut through which the pin tained at all times.

figuration. In Fig. 2, the inside edge ll of thetop flange H is ground to provide a. conical surface. The end of the helical spring 10 is similarly ground in orderv to conform therewith and to seat thereon without tendency to shift laterally. The two ends of spring 30, however, are not alike. The lower end. of the spring is conically ground on the outside to fit the upwardly facing conical surface 3| of flange II, and the upper end is conically ground on the inside to lit the downwardly facing conical surface ll of flange 33.1

The resulting conical or centering arrangement due to cooperating conical or tapered surfaces ii on tip member i0, 4! on nut 25 and both-ends of spring 30 is seen to cooperate with the reactingpressure not only to keep the spring 30 properly centered and concentric with ,the valve stem 2|. butoperates to balance the thrust at any circumambient point with that at substantially diametrically opposed points, Thisbalancing of rejusted at the factory or in the field to have any desiredamount of valve stem displacement and to respond to any desired opening pressure of the fuel; the adjustments of which' are had independently. By the seating arrangement for. spring 30, alignment of spring and stem is main- When the pressureof the fuel in' chamber l1 (relative to the pressure of fluid into whichfuel is to be injected) rises to opening value, for example, to 2000 lbs. per square inch, the force on the upper end-of stem 2| causes it to move downwardly. until the lower end of nut 26 engages Withthe stack of shim mem- 34 was introduced is preferably closedand sealed to prevent unauthorized tampering with or accidental displacement of the adjustments. To this end, a suitable sealing cap (see Fig.2) is introduced. Such cap may be of metal, wax, or other suitable material.

' It is believed to be obvious that suitable means other than the locking key piece 34 could be used in lieu thereof for locking the members or nuts 25 and 26 together in desired adjusted position;

rooves 35 and 36 could .be used in'accordance with the invention, the diflerences in numbers of slots and relative angular relations of coursebe:

ing provided to assure attainment of the desired end.

. In the assembly of the nozzle umt, as'shown in Fig. 2, the helical spring 30 is retained in balanced relation with the valve stem. To effect such retainment, the tip, the spring and the stem, to.-

gether with its associated nuts, are formed to have suitable centering seating means for the spring 30 whereby this is tip l0 and outside nut 25 by grinding the parts F bers 29. The stem movement is thus stopped at a desired point and fuel issues from the bore of the nozzle. When the pressure falls again, the spring 30 which has been compressed now expands and retracts the stem until the conical por-' tion 23 on stem 2| again seats on the shoulder 20 thereby. cutting oil the passage of fuel. The

- effect of the valve 'stem on fuel control is discussed more fully in our United States Patent No. 2,263,197 of November 18, 1941.

A modified form of the inventionis shown in Fig. 9, in which a swivel seating means is providedzlorv the spring 30. Here a swivel plate 43 has an opening of a diameter adapted to be passed e and that indexing means other than the slots or insured. Such-seating means is readily provided on the spring 30, the

Hence it is seen that the loosely over the skirt of the nut 25. The upper edge of this opening is beveled, as shownv at 42', in order to provide a surface, preferably conical, adapted to ride on and be tangent to a surface 33', preferably spherical, provided on the lower outside edge of the flange 33 of the nut 25. The upper end of spring" seats on swivel plate 43'. a plate 43, riding on the spherical surface 33, is free to take a position i of least strssiin seating the spring 30 against the reaction of the nut 25.

A swivel plate 44 for the lower or outwardend of spring 30 similarly has a spherical surface as-T- sociatedwith it so that it is free totake a position of=least stress. The spherical spriace is here a surface 45, preferably conical as shown, on the upper inside edge of flange II on the nozzle tip l0. The top surface of this plate, as shown at 4G, is adapted to serve as the seat for the lower end of spring 30.

The surfaces but not necessarily so. Resultingline contact or at least small area of contact is a desired feature but not absolutely essential to attainment of centering and balancing action, and maybe attainedin the modification shown in Fig. 2' by cooperating surfaces similarly formed. Other cooperat-- 43' and are preferably conical 1 nozzle body, and a hydraulic-cushioning device for limiting valve opening travel of said stemcqmprising a plurality of substantially fiat shim members loosely mounted between said'spaced apart engaging means and having contiguous ing spring seating surfaces for attaining cent'er-- ing and/orbalancing'actioncan be used to advantage in lieu of those shown in various modifications depicted in the drawings. For the pur-' pose of the present application all'such surfaces .wlll be identified generically as tapering surfaces, outwardly facing tapering surfaces indicating such surfaces which face away from the longitudinal axis of the valve stem and inwardly facing tapering surfaces those which face toward such axis. Obviously an inwardly facing tapering surface on the outward end of the spring may cooperate with an outwardly facing tapering surface on the tip member as is the case with j the inward end of the spring seated against the flange 33 of the nut 25 in Fig. 2. Additionally the swivel plate arrangement at either end of the spring as shown in Fig. 9' could be substituted for the seating of either of the corresponding ends of the spring in the Fig. 2 modification.

It is also seen that equalization of pressures about the circumference of a bearing circle for spring 30 may be substantially accomplished by the use of but one swivel plate, i. 'e., either plate 43 or 44 may be used alonewithout using both.

It will be understood that the spring in the modifications shown in both-Figs. 2 and 9 terminates at either or both ends with a bearing having a tapered seating surface, in Fig. 2 the end of the spring itself constituting the bearing having the seating tapered surface and in Fig. 9 the swivel plate at either end engagedby the spring constituting the bearing having the tapered seating surface.

In the specification and claims the term butwardly, when used alone, is used to indicate in the direction axially of the nozzle toward the jetdischarge end of the tip member, while inwardly, when used alone, isused to indicate the reverse direction oraxially of the nozzle away from the jet discharge end of the tip membenf sinse certain changes may be made in the above construction and different embodiments of the invention could be made Without depart- Y ing from the scope thereof, it .is intended that all matter contained in the a bove description or "shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the following claims are intended to' cover all of the generic .and specific features of the invention herein described, and all statements of the scope of U chambers, comprising, combination, a nozzle the invention which, as a matter of language,

might be said'to fall therebetween.

Having described our invention, what we claim as new and. desire to secure by Letters Patent is: 1. A nozzle for injecting fuel into combustion chambers, comprising in combination, a nozzle body having a fuel passage therethrough', a valve stem having a shank portion and a valve'to control flow of fuel in the fuel passage, spring means coupling said stem-to .said nozzle body members loosely mounted in the fuel passage bechambers," comprising, in combination, a nozzle body having a fuel passage therethrough, a valve stem in the passage having a valve to controlflow of fuel and provided with a. shank portion projecting inwardly of saidvalve, spring means coupling said stem to said nozzle body biasing said valve to closed position, spaced apart engaging means on said shank portion and in the fuel passage of said nozzle body inwardly of said valve, and a hydraulic cushioning device for lim- 'iting valve opening travel of said stem comprising a plurality of substantially flat liquid-impervious shim members loosely mounted in the fuel passage between said spaced apart engaging means.

3. A. nozzle for injecting fuel into combustion chambers, comprising, in combination, a, .nozzle body includinga tip member and having a fuel passage therethrough, a valvestem in the passage having a valve-in said tip member to control flow of fuel and provided with a shankportion projecting inwardly of said valve, spring means coupling said stem to said nozzle body biasing said valve to-closed position, stopping means comprising a plurality of substantially fiat metallic shim members loosely mounted in the fuel I passage about said shank portion to provide a cushioning stop for said stem and limit valve of said valve to provide a chamber and saidstem being provided with a shank portion projecting into said chamber, spring means coupling said stem to said nozzle body biasing said valve to closed position, stopping means comprising a plurality of substantially flat metallic shim members latter, and engaging means onsald nozzle body and said shank portion in said chamber adapted to engage opposite sides of the stack of shim members in limiting travel of said valve stem. 5. 'Av nozzle for injecting fuel into combustion 'body'having afuel passage therethrough, a valve flow of fuel and provided with a shank portion projecting inwardly of said valve, spring means coupling said stem to said nozzle body biasing said valve to closed position, spaced apart engaging means on said shank portion and in the fuel passage of :said nozzle body inwardly of said valve, and a hydraulic cushioning device for lime iting valve opening travel of said stem comprising a plurality of substantially flat metallic shim loosely mounted in said chamber about saidshank portion to provide a cushioning stop for said stem and limit valve opening travel of the stem in the passage having a valve to control as-races tween said spaced apart engaging means, said shim members having contiguous faces of substantial areabetween which are received films -of fuel acting to absorb shock upon engagement said bore having a valve. tocontrol the flow of fuel and provided with a portion projecting inwardly of said tip member, spring means posi-' tioned inwardly of said tip member for controlling the actuation :of said valve. stopping means comprising a plurality of substantially flat spring shim members having contiguous faces of substantial area disposed at the inward side of said tip member about said stem portion, a nut member adjustably disposed on said stem portion for) engaging with said stopping means and limiting the valve opening travel of said stem, and a sec-' and nut member adiustably disposed over said 'flrst named nut member; for determining the reaction pressure of said spring means and serving as the coupling of said spring means to said valve stem.

'1. A fueliini ction nozzle, comprising; in combination, a nozzle body includinga tip member and having a fuel bore, a valve stem in said-bore; having a valve to control the flow of fuel and provided with a-.portion projecting inwardly of said tip-member, springmeans disposed at the ;-inward-side of said tip member, stopping means at the inward side of said tip member making a desired number of resilient washer-like metallic shim members havingcontigu'oug faces of substantial area disposed about said stem'portion; an inner nut member adjustably disposedon said stem portion for engaging with said stopping means and determining preclsely the amplitude of stem travel-when opening said valve, and an outer nut member adiustably sposed over said first-named nut member for determining the reaction pressure of said spring means and coupling said spring means to said valve stem.

8, a fuel comprising. in combination, a nozzle bod including a tip member andhavingafueipassingboreavalvestemin side a spring disposedon said seat about said stemportimanutadiustablydisposedonsaid stempos-tionfortbetravelofsaid minelnsformgaaid stemTandsaidnut:

and a seecndnut adiustsbly threaded on tbe-outside-of said travel determinieggannt and-having seating means for the other 'blnation, a nozzle body having 0f said springQvsrnier adjusting means be-' a n swmn sing a pl rality of longi and having a shank portion projecting inwardly of said abutment,- an en aging abutment on said said shank portion between said engaging abutments, a spring seating abutment on said shank portion, another spring seating abutment on said nozzle body, a spring having cocking characteristics disposed about said shim members and shank portion between said spring seating abutments, at least one of said spring seating abutments having a tapered seating'surface and said spring terminating at at least one end with a bearing having a tapered surface cooperating with the tapered seating surface of the abutment for attaining balanced spring action.

10. A fuel injection nozzle, comprising, in combination, a nozzle body including a tip member and having a fuel passing bore, a valve-stem in said bore having a valve to control the flow of fuel and provided with a projecting portion free of surface guidance, spring means disposed'at the inward side of said tip member, stopping means contiguous faces of substantial area disposed about said stem portion within said bore, an inner memberthreaded on said stem portion for with said stopping means and determining precisely the amplitude of stem travel when opening said valve, means locking said inner member to said stem an outer member threaded between said'spring means and said stem, vernier adjusting means between said inner and outer 1 members comprising a plurality of indexescir- 'on said innermember and serving. as a coupling:

cumferentially arranged at equally spaced points,

on said outer member and a different number of -indetes circumferentially arranged at equally spaced points on said innermember, and ,a looking member adapted to enga e said inner and outermembersfor locking them together when an index on one is in register with an index on the other. e

11. A fuel injection nozzle, comprising, in coma fuel e theretln-ougnavalvesteminthefml for controlling flow of fuel therethrough and raiity of substantially flat metallic shimmembeis having contiguous faces of substantial'area for inter-positioning films of fuel loosely mountedinthefuelaboutsaidshankportion -havingapro:lectlngshankportionfreeofsurface,

between said spaced apart abutments;

- aspring sating'abutmenton saidshankportion, another-spring seating abutment in the fuel pas-

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