US2665167A - Fuel injection nozzle - Google Patents

Description

Jan. 5, 1954 c. F. HIGH 2,665,167

FUEL INJECTION NOZZLE Filed July 6, 1951 Patented Jan. 5, 1954 so EZ'S PAT oFFice v r 2,665,163?" FUEL ,I NJECTION QOZ ZLE- cane; ni h, Detroit; Mich; Application Jinye, 1951; Serial No. 235,409:

commie. (01. 299-1073) The present invention relates to -fuel injection apparatus and more particularly to an improved fuel-"injection nozzle designed Ion use in intermittently introducingtimedigmetered charges of liquid fuel undenpressure and in the form of: a jet-'01 spray --to the cylinders of an internal combustion engine for combustionpurposes.

' The improved nozzleyconstruction. comprising theapresent invention is designed-as an improve-V ment qover-the -jspray nozzle: construction shown and described in :my prior Patent l No: 2,294,029; dated: August: 25,- 1942',v for; a: Fuel):Injector. and

Fuel Jet Construction and-the general objects of" the present invention are to provide-an improved nozzle construction .which-is sensitiveato low op eratingvpressures and :which will; inu'esponse' to such-low operating pressures, accurately control the beginning-andzending;of the fuel discharge cycle and spreventzdribhling or bleeding ofv the fuel at such times, thus .protectingsthe valve :seat from. erosion to. provide alnozzlei having-y associated therewith valve-mechanismqwhich despite such low operating.;pressures;i will open and. close sharply when'ithe propenyoperating pressure; is attained or, relieved; and. to produce an'improved valve zmechanismsfor spray; nozzles ofthe type shown, hitheaabove mentionedflpatent which will attainthesame results-as my earlier valve mechanism but .with improved .iperformance over aprolonged periodof-tim e :A more-ispecifi -nbiectx,ofv t inv t w provide .a nozzlevconstruction for use i Connemq tion with fuel inlection systems;having associatedztherewith avalveme h s 0r1contro11ins ovexallflarea pfitlie pressure operating surfaces of th m vab e" valve; el me t pr pe maybe in:

creasedjjrelative; to thegsizeof thebore of the n zzle casing; thereby producing; a valve media nism' which "is extremely; sensitive to p'ressure differentials.

I Another elatedg object of the invention ,jSftO provide a nozzle construction" of this character in-which 'the 'valve opetatingfspring is widely re-' moved from thevalve orifice oropenin'gg-thus relieving thisaopening from obstruction when fuel is passing therethrough,- and thereby; permitting a maximum flow of fuel through the opening whenrequired;

,the';.fiowi;of l u d u l thr uehvthe li m the nozzle inletto the :nozzle outlet and; include A-= further object .of. the a nozzle construction of J greatlycsimplifieddesign in which 1 thetnozzle :casing itself I constitutes ;one elementlo'f. thelvalve construction, thus eliminate ing:.. the. necessity of employing the; accurately.

machined heat treated or; chrome plated:valve.-

sleeve ordinarily l associated withsuch valve 'StIllGr tures; l

Yet anothenobiect ofthe. invention, is tojlpro vide a=nozzleconstructi0n having avalvemechganism associated therewith: in which. 7 the. a movable evalvez member proper. is ofsimplified construction in=that,certain Offihfifllfil conducting; passages formerly provided therein, particularlyin the head portion thereof, have been eliminated and placed, in the nozzle casing assembly in such a-manner. as to attain equally eflicient lres ults' while, at thesame time precludingthe necessityv of resorting toexpensive machiningoperations in manufacturing the valve-member. .A similar-and related object, in a nozzle construction ofl this character is to provide a valvemechanism: include inga movable valve memberproper in whichthe,

head: po 'tiomthercof is solid and. completely devoid of viiuid passages thus simplifying the manufacturing problems in making the valve member. 7 The provision of a iuei-injeeuonmzzie which is extremelysimple in itsconstruction'; onewhich is. comprised? of .a-minimum number offmovin'g parts and which. thereforeis unlikely. to get .out'.

ofjorder; one which is rugged andQdurableiand thereforewismpossessed .of a l comparatively lon life; one,which vmay ,be vmanufactured at a; relati-velylow cost, and one which otherwiseisfwell adapted to perform the services requirediof iit, aretfurther desideratathat have been borne in mind [in the, production and development .of the present'invention; H v a In the accompanying single sheet iof,draw ing's' forming a. pa1',t, of this specification one embodi= ment of theinvention has been'shown;

In these drawings Figure l a"longitudinalsectional view' t'aken v substantially centrally through a *fuel' inj ectiono l a l fim v v v ed em'r a w ththe principles of the present invention'and showd'uring a-pericd of fiie l 1m ectiqn,

new. 7, assembly shown in-Fig. 1.

ingthe parts in the positions which they assume Figs- 3 is-asection'al VieW takensubstantially along the line 3-'-3-'oi Fig. 1 and v I Fig-.- :4 is a sectional view similar showing theparts in their normal positions.

Fig. 5 is a. fragmentary-sectionaleviewtaken" substantially centrally through at slightly modiinventionlis tozprovide;

"n: end-elevational view of the some to Fig. i

fled form of fuel injection nozzle assembly, similar to the nozzle assembly of Fig. 1, in the forward or discharge region thereof.

While the invention is susceptible of various modifications and alternative constructions, there is shown in the drawing and will herein be described in detail the preferred embodiments but it is to be understood that it is not thereby intended to limit the invention to the forms disclosed, but it is intended to cover all modifications and alternative constructions falling within the spirit and scope of the invention as expressed in the appended claims.

Referring now to the drawings in detail, the improved nozzle assembly comprising the present invention involves in its general organization a nozzle casing l having external threads l2 by means of which the nozzle assembly may be secured in position within the intake opening of an engine cylinder (not shown). The casing I0 is in the form of a tubular member having a central bore I 4 extending therethrough the inlet end of which is enlarged and internally threaded as at [6 for threaded attachment to one end of a fuel conduit (not shown) which may constitute a part of a fuel injection apparatus or which may be suitably connected to a union I 8 when the nozzle assembly is remotely associated with a fuel injector. The union I8 is adapted to be connected by means of the fuel conduit to a source of fuel supply that is intermittently subjected to pressure. During periods of injection, fuel admitted to the bore I4 is permitted to flow from the bore at the outlet end of the casing under the control of a normally closed valve member in a manner that will be made clear presently when the nature of the invention is better understood. A fuel strainer or screen 22 may be positioned at the entrance to the bore [4 and retained in position by means of a snap spring 24.

The valve member 20 is axially movable within the bore l4 and is in the form of a cylindrical tubular member having an open rear end 26 and a solid head 28 which serves to close the forward end thereof. The bore [4 is provided with an enlarged portion or counterbore 30 at the forward region thereof in which the head portion 28 of the valve member 20 is movable upon reciprocation of the valve. The forward limit of movement of the valve member 20 is determined by the provision of a plug-like jet fixture 32 having a rearwardly extending bosslike protuberance 34 formed thereon and which constitutes an abutment or limit stop designed for engagement with the forward end of the valve member 20. The diameter of the head portion 28 of the valve member 20'is substantially equal to the diameter of the protuberance 34, and a coil spring 36 is centered around both of these members and serves to normally urge the valve member 20 rearwardly within the bore I4 toward the position it assumes in Fig. 4.

The jet fixture 32 is formed with a body portion 38 which bears on one side against the extreme forward end or rim of the nozzle casing l0 and on the other side against a circular disklike member 40 having a discharge jet opening or spray orifice 42 formed centrally therein. A nozzle tip 44 is threadedly received on the forward threaded end of the nozzle casing Ill and is provided with an inwardly extending retaining flange 46 providing a central opening 48 in register with the jet opening 42.

The fuel jet fixture 32 is thus tightly clamped in position at the end of the nozzle casing l0 and is provided with suitable fuel passages leading to the discharge jet opening 42. These passages consist of a central passage 50 extending longitudinally of the fixture a slight distance and communicating with a series of tangentially disposed passages 52 (Figs. 1 and 3), of which four have been provided in the present instance, The tangential passages 52 communicate through respective longitudinally? extending ,V-p'assages 53 with the forward end of the annulars'pace 54 existing between the enlarged counterbore 30 in the nozzle casing l0 and the cylindrical surfaces of the valve head 28 and protuberance 34, the space 54 serving as a passageway for conducting fuel to the discharge jet opening 42.

The valve member 20 is provided with a plurality of radial ports 56, of which there may be four, in the cylindrical wall thereof immediately rearwardly of the head 28 and the plane of demarcation between the bore l4 and counterbore 30 provides a shoulder 58 which determines the cut-off position of the valve ports 56. Normally, when no fuel is being supplied under pressure to the bore M, i. e. when the fuel in the bore is insuflicient to overcome the compressional force of the spring 36, the valve member 20 is maintained by the spring in the position shown in Fig. 4 wherein the ports 56 are out of register with the space 54 within the counterbore 30. However, when pressure is built up in the bore M by the application of fuel thereto from the fuel injection device, the valve member 20 will move forwardly in the bore l4 in response to such pressure, thereby uncovering the ports 56 as shown in Fig. 4 and allowing fuel to flow from the screen or strainer 22, through the bore l4, the interior of the tubular valve member 20, ports 56, annular space 54, and passages 53, 52 and 50 to the discharge jet opening 42.

Immediately upon relief of the pressure of fuel in the bore l4, due to the fact that the fuel injection device has terminated its pressure or dis charge stroke, the spring 36 urges the valve member 20 to the left as viewed in Fig. 4, thus closing the ports 56 and terminating the flow of fuel to the discharge jet orifice or opening 42.

It is to be noted that the momentum of the valve member 20 will be such as to cause the same to move beyond its normal position illustrated in Fig. 4 to a position illustrated in dotted lines in this view. Since at this time the ports 56 are closed during this over-travel of the valve member, a suction will be created in the system between the ports 55 and orifice 42. This suction tends to suck the fuel in and around the discharge jet orifice and thus minimize leakage of fuel through the orifice 42 at the end of the fuel injection cycle.

From the above description it will be noted that the valve member 20 is of the free floating type. This member is closely fitted within the bore I4 and to enhance such a'fit and to minimize wear, the wall of the bore may be heat treated or chrome plated. Alternatively, the outer cylindrical surface of the valve member may be similarly so treated. In any event, the fit between the two surfaces is such as to prevent leakage of fuel around the body of the valve 20.

Due to the fact that the spring 36 is disposed on the discharge side of the valve member 20 in an out-of-the-way position, no obstruction to passage of fuel through the ports 56 is presented and the fuel flowing to the jet opening or spray. orifice 42 completely bypasses the spring and is not obliged to enter the interstices afiorded by the spring convolutions. Furthermore, the valve head 23 is of solid construction and the onli passages provided in the valve member 20 are the radial ports 56 which may easily be machined therein without involving complicated tool processes. Finally, the nozzle construction of the present invention embodies a minimum number of parts, particularly moving parts, and the structure is readily capable of assembly and disassembly for purposes of inspection, cleaning, repair or replacement of parts. i

In Fig. a slightly modified form of nozzle assembly has been shown. In this form of the invention, the various operative parts of the structure are similar in their design to the operative parts of the structure shown in Fig. 1 and, accordingly, similar reference characters have been applied to the corresponding parts in this latter figure.

In this form of the invention, the valve member ml, the jet fixture I32, the circular disc-like member let, the coil spring I35 and other operative parts of the assembly remain the same but the valve casing H0, instead of being provided with a removable nozzle tip such as that shown at 4 3 in Fig. 1, is of integral construction and the disc-like member I4!) is retained in position forwardly of the jet fixture 32 by means of an inturned retaining flange [at which may be formed by crimping the extreme forward end of the nozzle casing llfl inwardly after the various parts have been assembled within the casing. In substantially all other respects, the valve structure of Fig. 5 is identical with that 01 the valve structure of Fig. 1. Similarly, its operation is identical.

I claim as my invention:

1. In a fuel injection nozzle, a casing having a bore formed therein and an enlarged counterbore in communication with said bore at its downstream end, said casing having a fuel inlet in communication with said bore at its upstream end, a cylindrical valve member slidably disposed within said bore and having one end in constant communication with said inlet, said valve member having a fuel port formed in its wall and being movable from a retracted position with said port within said boreand closed. by the wall thereof to an advanced position with said port moved downstream into communication with said counterbore, said valve member having a spring abutment disposed thereon downstream from said port, nozzle means positioned in said counterbore downstream from said valve member, and a compression coil spring disposed downstream from said port and between said abutment and said nozzle means, said nozzle means having an outlet passage therethrough extending from a point in said counterbore outside the coils of said spring so that fuel will flow entirely outside said spring from said port to said outlet passage.

2. In a fuel injection nozzle, a casing having a bore formed therein and an enlarged counterbore in communication with said bore at its downstream end, said casing having a fuel inlet in communication with said bore at its upstream end, a cylindrical valve member slidably disposed within said bore and having one end in constant communication with said inlet, said valve member having a fuel port formed in its wall and being movable from a retracted position with said port within said bore and closed by the wall thereof to an advanced position with said port moved downstream into communication with said counterbore, said valve member having a reduced head extending into said counterbore and forming a spring abutment shoulder disposed downstream from said port, nozzle means positioned in said counterbore downstream from said. valve member, and a compression coil spring closely surrounding said reduced head and extending between said spring abutment shoulder and said nozzle means, said nozzle means having an outlet passage therethrough communicating with said counterbore at a point outside the coils of said spring so that fuel will flow entirely outside said spring from said port to said outlet passage.

CARL F. HIGH.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,693,931 Lowe Dec. 4, 1928 2,090,350 Heinrich Aug. 17, 1937 2,294,029 High Aug. 25, 1942

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