US2602005A - Fuel injection nozzle - Google Patents

Description

July l 1952 R. K. WELDY 2,602,005

FUEL INJECTION NOZZLE Filed Feb. 23, 1944 3? T4 Jg] y Patented July l, 17,952 y .Y

Robert' K: weldy, Detroit, Mich.,- assignor, by `mesn'e' assignments, to American Bosch Corporation, York n f Application February 23,19`4firerial *A f A l Y '1 Claim. (Cl. 299-107-6) j" The present invention relates to improvements in nozzles adapted particularlyfor vdelivering timed metered injections of liquid fuel in connection with' the`ope'ration of internal combustion engines. One of the objects of the invention is to provide a novel fuel injection nozzle which is eflcient in operation over the entire'speed and load range of the engine, and which in particular will inject a fuel spray `having adequate penetration.

Another object is to provide a new and improved fuel injection nozzle 'which has good fuel spray characteristics, and which will retain such characteristics when subjectedin use to heat and carbon.

A further object is to provide anovel fuel injection nozzle which `has a highv discharge velocity, which is substantiallyfree from the formation of carbon and in -Whichthere is a freevow of the fuel to the injection orifice.

Another object is to providea new and improved fuel injection nozzle of the outwardly opening pintle type in which the discharge -bore and the pintle are correlated -in shapes and proportions to obtain and maintain desired fuel pen--` etration. Y 1

A further object is to provide a fuel injection nozzle havingva novel adapterwhich may be used or omitted to -facilitate mounting the nozzle interchangeably in different types of existing holders.

Another object-is to provide -ay new and improved fuel injection nozzle havng an oil filter of simple and inexpensive construction.

Furtherl objects' vand advantages will .become apparent as the descriptionproceeds."`

In the accompanying drawings.;

yFigure v1 vis a'longitudinal axial sectional view of a fuel injection nozzle andjlter embodying the features of my inventiom j Fig, 2 is a fragmentary end view ofthe nozzle showingA thedischarge orice. j

Fig. 3 is 'a5 fragmentary axial sectionalview of the nozzleA tipon an enlarged scale.v l

Fig. 4 isa, fragmentary perspective view of a valve member forming part of the-nozzle.

Fig. 5 is a transverse sectional view taken along line 5 5 of Fig. 3.

Fig. 6 is a fragmentary end of the nozzle. f

While the invention is susceptible of various modifications and alternative constructions, I have shown in the drawings and 4'will' herein view of the mounting describe inidetail the preferred embodiment, butv it is to -be linderstoodthat I do not thereby intend to limit the inventon'to the 'SpCC form' diS- springuelaMass.,acorporationrofgnew Ai ',:r' f y closedfbut intendto' cover 'all modifications and alternative constructions falling within thespirit and `scope 'of theinvention ajs' expressed-in- "the appended claims..y j I Y, Referring lmore particularly to thejfdrawings the fuel injection nozzle constituting the" exemplary embodiment of my invention of'the'general type disclosed in a copendi'ng "application by James-F. Hoiier, Serial No. 259,088, led March 1, 1939, Patent No. 2,351,965, having Van outwardly opening valve vadapted to openand close` with a popping action,l

The nozzle comprises-a bodyiji; ladalzite'dto conf tain all of the operatingpartsljandto beremovably mounted. as`a rep laceabl e unitin a suitable holder 2 partially shown yin dotted'outline '(Fig. 1) Preferably; the .body i' is in, the form of a tubular shell or. casing having an external periph? eral mountingfilange A3.on theibase fend., @To secure thenozzle unitendwise againstthe holder 2, a nut 4 is threadedjon the latter, and has an internal flange 5 e engaging overfv the ,mounting ange 3. It will be understood that the holder and nozzle assembly is adapted tofbe clamped or otherwise 4secured v to lan Ainternal combustion engine (not shown) with thenozzletp positioned to discharge a jet orspray offuelintothe-combustion chamber.` ijf The nozzle tipfbody-i 'is made preferably in an integral or one-piece construction, and is -formed in the ba'seend with la stepped bore 6 constitutiing an inner chamber, and in the outer end with an axial discharge passage orV bore 1' opening to the exteriorl The bore 64 comprises sections of varying diameters",l including an linner 'section serving as a spring pilot, an i-nterme'diate'section 6b of slightly Iarger'diameter, and'vanvouter 'sec= tion lc of still larger diameter 'serving la's 'ya' guide', as hereinafter more fullydescribed Formed in the bore E intermediate'the sections'b and 6 is an internal peripheral groove B; 'one side of which defines an outwardly-'facing vannular shoulder 9. A counterbore Gd of comparatively`- large diam'- eter is formed in thebase end ofthe vbody I, y t Fuelunder pressure is adapted to besupplied from'a suitable source Vgnot shown) through the holder 2 to the inner chamberof the nozzle body I. During periodsof injection, the fuel is permitted to now from the chamber 6 through and under the `control. ofga normallyy spring.; seated valve, ill.l I nfthepresent instance, the valvell'comprises'an inlet passage Il connecting vthe chamberv AQ to the discharger'bore .51, wand formed at its outer end with a lstationary annular valve seat I2. A movable valve member I3 is reciprocable axially of the discharge bore 1, and is formed with an annular valve face I4 adapted for engagement with the seat I2.

The valve member I3 has an axial stem or shank i5 which extends in free peripherallyspaced relation through the val-ve passage II to define therewith an annular path of fuel flow, and then inwardly into the bore or chamber 6. Suitable spring means, such as a coil compression spring I6, acts on the inner end of the stem I5 in a direction to urge the valve member |3 inwardly toward or in closedrposition witha predetermined force. V

The spring I6 encircles the valve stem I5, and impinges at one end against the inner end face of the bore section 6a which serves as a pilot for this end of the spring. The other end of the spring I6 impinges against a movable hanger I1 removably anchored to a head I8 on the inner end of the valve stem I5. More particularly, the hanger I1 consists of an elongated guide sleeve slidable in the bore section 6, and having intermediate its ends an inner transverse wall I9 formed with a slot 20 in interlocking engagement with the head I8.

The valve I0 has an effective opening pressure area which is exposed to the pressure of the fuel within the chamber '6, and which is substantially equal to the area circumscribed by the stationary annular valve seat I2. When the valve I0 is in closed position, the iiow of fuel to the discharge bore 1 for injection is blocked, and the hanger sleeve I1 is spaced inwardly from the annular shoulder 3. When .the'pressure of the fuel acting on the opening pressure area is sufficient to overcome the closing force of the spring |6, the valve member I3 is lifted outwardly from the seat |2 to open thev valve I0 and start injection. The maximum height of rise of the valve member I3 is limited by engagement ofthe hanger sleeve I1 with the fixed stop shoulder 9.

A spray control pintle 2| is formed integral with and projects outwardly from the valve member I3. The pintle 2| extends slidably through the discharge bore 1, and coacts with the outer end thereof to define an annular discharge orifice 22. By selective choice and variation in the form of the bore 1 and the pintle 2|, fuel sprays of different characteristics are obtainable. in the present instance, the discharge bore 1 is formed with a narrow inner cylindrical land area 23, conveniently termed a body land, at the extreme outer end, and with an inclined peripheral undercut 24, defining a conical bore section tapering outwardly to the body land. Thus, the undercut converges symmetrically with respect to the axis ofthe discharge bore 'I toward and merges into the body land 23. At the inner end of the inclined body undercut 24, the bore 1 is formed with an annuiarrib 25 for guiding the pintle 2|, andinwardly of the rib, the bore is formed with a cylindrical undercut 2S to permit flow of fuel past the valve member i3 while the valve member is unseated. The pintle 2| is formed with a narrow cylindrical land area 21, conveniently termed a pintle land, of full pintle diameter, at the extreme outer end, and a control cone 28 tapering inwardly therefrom. When the valve IIl is closed, the pintle 2| is fully retracted, and the pintle land 21 is located within the body land 23. Upon opening movement of the valve I0, the pintle 2| is projected out of the body I, and the control cone 28, in moving across the outer peripheral edge of the body land 23.

provides an injection oriiice 22 of progressively increasing area.

Inwardly of the tapered control cone 28, the pintle 2| is generally cylindrical in form, and in guiding engagement with the rib 25. Suitable iiats 29 arel formed in the sides of the cylindrical portion rofthe pintle 2|, yfour such iiats being shown, to' provide passages for the l. free ow of fuel from the valve I0 past the rib 25 to the injection orifice 22. Y The eilciency of operation, and the characteristics of the fuel spray issuing from the nozzle areinfluenced by certain critical factors involving the relative shapes, angles and dimensional proportions of the discharge bore 1 and the pintle 2|. y

The four 4flats 29 which define the downflow passages along the pintle 2|, as compared to a lesser number, tend to prevent or minimize division of the fuel spray into separate jets, the fuel recommingling morefreadily in the region of the control cone 28.

The width of the pintle land 21 has a direct effect on the form of the spray. In general, a comparatively narrow land results in a soit spray, and a relatively wide land in increased penetration. The width of the land; 21 may be varied in practice depending on the spray characteristics desired, but such variation is cone iined within certain practical limits for best results. If the land is too narrow. dimculties may be encountered in obtaining the desired popping action of the valve IB in itsaccelerated opening and closing movements. As more fully explained in the aforesaid application, this popping action is obtained because ythe' eifective transverse area of the pintle 2|, exposed to the pressure of the fuel when the valve I0 is open, is larger than the valve opening pressure area. If the pintle land 21 is too wide, the valve opening may be accelerated to such an extent that the pintle is subjected to undue stress. and an excessive dash-pot action may result on valve closing. Satisfactory results are obtainable if the width of the pintle land 21 is conned to a range of from .001 to .015 inch. When a soft or low penetrating spray is desired, a width of pintle land within a range of from .002 to .005 inch maybe advantageously used. For a high penetrating spray, a land having a width within a range of from .008 to .015 inch may be advantageously used.

The distance of the inclined body undercut 24 from the outer end face of the body determines the width of the body land 23. and influences the extent to which thespray penetration characteru istics are retained in continued use. This land circumscribes the pintle ,land 21 when the valve I0 is closed or nearly closed, and coacts with the pintle 2| to edect a smooth flow of fuel to the outlet of the 'discharge or injection orifice 22. If the body land 23 is considerably wider than the pintle land 21, carbon tends to form thereon and interfere with the smooth flow of fuel. If the body land 23 is increased to an excessive width, the fuel spray will be unduly soft and lack the desired degree of penetration. Satisfactory results are obtainable if the width of the body land 23 is conned within arange of frozn .005 to .030 inch. VThe preferred vwidth of the body land 23 is approximately .013 inch, which imparts a smooth flow to the fuel and gives excellent penetration, and which, being only slightly greater, ii' greater at all, than the-width is an important factorv in obtaining a penetrating spray, andv the length, depth and angle .toi the nozzle 'axis all have, a controlling infiuence.. 'The converging surface of theundercut 24, in cooperation with the diverging surface of the control cone 28, serves to direct the vfuel smoothly and fat progressively increasing'fvelocity to the discharge orifice 22. The included angle between the bottom surface of the undercut 24 and the axis of the pintle 2| should be between 5 and 25 for satisfactory results. The preferred angle is 11, so that the undercut will have ample length without undue depth.

The maximum depth of the undercut 24 is also confined between preferred limits. If the depth is too great, the undercut is deprived of effectiveness. If, for a given included angle, the depth is too shallow. the undercut will not be of suicient length to influence the spray properly for best penetration. Satisfactory results are obtainable if the radial depth of undercut is confined within a range of from .001 to .010 inch. Preferably, an undercut 24 having a maximum depth of .0045 inch isemployed. If the undercut 24 is inclined at an angle and provided with a suitably selected depth, respectively within the ranges therefor specified herein, it will also have ample length to infiuence the characteristics of the fuel spray in the manner and to the extent desired.

The penetration of the fuel spray is also infiuenced by the cone angle and the degree of lift of the pintle 2|. For maximum penetration, a cone angle of from 7 to 10 is employed.

It is desirable to confine the lift or height of rise of the pintle 2| between certain limits so as to retain a relatively small orifice area and thereby insure a vhigh velocity of fuel discharge. The height of rise is related to the maximum rate of discharge which in turn is a function of the engine size, speed and duration of the iniection period for a given quantity of fuel. Preferably,

faeoaoou groove33 opening throug'lia bore 3,4`to the counterbore 6d and adaptedfor communication with the fuel supply passage vin the holder; In use, When the adapter 30 is removed, th

mounting flange 3 alone is secured to the holder by means of the nut 4, and fuel is supplied directly to the counterbore 6d and thence.to theV inner chamber 6 of the body For other types of holders, the adapter 30 is inserted in position which may be of laminated construction and the lift or height of rise of the pintle is limited to a distance Within a range `of from,.020 to .050 inch, a rise of .035 inch being suitable in most instances. limited positively in conformity with the maximum rate of fuel delivery required in a given instance, but it is to be understood that the actual height of rise of the pintle may be less than the permissible maximum, and will be selfadjustable to develop the necessary orice flow area for a given rate of fuel delivery required under particular operating conditions, as for example, when the engine speeds and loads are reduced.

The nozzle is provided with an adapter 30 The maximum height of rise is thus which may be used or omitted as required to facilitate mounting the body interchangeably in different types of holders. The adapter consists of a circular plate adapted to be seated against the base end of the body l, and formed on its inner face with a circular projection 3| having a snug press t in the counterbore 6d. Preferably, the circular projection 3| is peripherally undercut, as indicated at 32, thus providing substantially line contact with the inner surface of the counterbore 6d and a degree of flexibility to insure a good press fit. The outer face of the adapter 3| is formed with an annular which is secured at the periphery by a rim 31 rounded at its outer peripheral edge for snug yieldable engagement with the inner peripheral surface of the counterbore 6d.

In operation, fuel under pressure is supplied to the inner chamber 6. The pressure acts on the opening area of the valve I0, and when the force is sufficient to overcome the pressure of the spring I6, the valve will open to start injection. After the initial opening movement, the full diameter of the pintle 2| will be subjected to the fuel pressure, and since the effective pintle area is larger than the valve opening area, the valve will continue to open with an accelerated or popping action. In the opening movement, the pintle 2| is guided by the rib 25. From the valve Il), the fuel passes along the fiats 29 and then is directed by the inclined undercut 24 and the control cone 28 to the injection orifice 22 from which it issues at a high velocity in a narrow penetrating spray.

I claim as my invention:

In a fuel injection nozzle, in combination, a hollow body having a fuel inlet passage in communication with one end and a discharge bore opening axially to the other end, said discharge bore being formed with a narrow inner cylindrical body land at the extreme outer end and with an inclined undercut converging toward said land, a valve controlling communication between said passage. and said bore and comprising an outwardly facing annular valve seat formed in said passage in axial alinemeni'. with said bore, a valve member reciprocable in said bore and having an annular valve face adapted for engagement with said seat, and spring means acting on said valve member in a direction to urge said member toward said seat, a cylindricalundercut in said bore to permit the fiow of fuel about said valve member when said valve is open, an inner peripheral guide rib formed in said bore between said undercuts, a pintle rigid with said valve member and slidably guided in said rib, said pintle coacting with the outer edge of said bore to define an annular discharge orifice having a narrow cylindrical land at the extreme outer end and a symmetrical control cone tapering inwardly from the pintle end, said pintle being formed in the sides and inwardly of said control cone with longitudinal ats defining downiiow passages from said valve past said rib to said inclined undercut.

ROBERT K. WELDY.

(References on following page)l 7 `REFERENCES CITEDy NurnbEr- YThe follwng references are bf record in the 21207344 le of th patent: y UNITED STATES PATENTS Y 5 2,308,504 Number C Name Date 2,348,248 1,537,555 Schenk May 12, 1925 2,351,965 L 1,835,047 Hill ..-1 DBC. 8, 1931 1,996,180' Vincent Apr. 2,1935 1,999,116 V,Sidney Apr. 23, 1935 10 Number Webicke Dec. 12, 1939 v8 Y Name Date Richardson July 16, 1940 Sheppard Aug.l 6,1940 Alden June 2, 1942 'French Jan. .19, 1943 Elliott May 9, 1944 Hoffer June 20, 1944 FOREIGN PATENTS Country Y Date Switzerland Dec.V 16, 1941

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