US3443760A - Fail-safe fuel injection nozzle - Google Patents

Description

May 13, 1969 H. c. SIMMONS 3,443,760

FAIL-SAFE FUEL INJECTION NOZZLE Filed April ze, 1967 sheet of 2 N60 un 90 o INVENTOR HAROLD C S/MMOA/.S

May 13, 1969 H. c. S|MMONS INVENT OR HAROLD C. S/MMO/VS ATTORNEYS United States Patent O U.S. Cl. 239-410 13 Claims ABSTRACT F THE DISCLOSURE A fuel injection nozzle having primary and secondary flow passages leading to primary and secondary discharge orifices. A pressure responsive valve controls the flow through the secondary discharge orifice in accordance with the inlet pressure except when the valve stem or other such valve part fails and the valve engages a shutoff plate in the secondary flow passage closing off an opening therethrough which precludes further secondary flow.

Background of the invention The present invention relates generally, as indicated, to a fail safe fuel injection nozzle and more particularly to a dual orifice fuel injection nozzle having means for blocking the flow through the secondary discharge orifice in the event of breakage or failure of the secondary flow control valve stern, valve biasing spring, or retainer therefor.

`Dual orifice nozzles, as the name implies, are usually provided with two separate nozzles; a primary nozzle having a primary discharge orifice through which fuel is discharged at low fuel pressures for low fuel flow; and a secondary nozzle having a secondary discharge orifice through which fuel is additionally discharged at higher fuel pressures for greater rates of fuel flow. There are, of course, many dual orifice nozzle designs which have been developed for controlling the cut-in point of the secondary nozzle and providing the desired sensitivity of flow to pressure with proper atomization of the fuel throughout the useful flow range of the nozzle under normal operating conditions, but heretofore no provision has been made to check the flow through the secondary nozzle when due to breakage of the secondary flow control valve stem or failure of the valve biasing spring or other such part the secondary nozzle is not roperating properly. Under these circumstances, the secondary valve ordinarily remains fully open even at low fuel pressures whereby the total fuel flow through the nozzle is much higher than desired and the fuel is not suitably broken up into fine droplets for eflicient combustion.

Summary of the invention With the dual orifice nozzle of the present invention, the secondary flow is completely shut off by the head of the secondary flow control valve in the case of breakage or failure of the valve stem or other associated parts to prevent such overflow and improper atomization of the fuel. These and other objects of the present invention are achieved by providing a shutoff plate in the nozzle body having a central aperture in fluid communication with the secondary flow passage which is closed by engagement of the head of the secondary flow control valve with the plate when such breakage or failure occurs.

Another object is to provide such a nozzle with a novel adaptor for supporting the shutoff plate in the nozzle body and including separate passages communicating with the primary and secondary orifices `of the nozzle.

Other objects and advantages of the present invention will become apparent as the following description proceeds.

To the accomplishment of the foregoing and related ends, the invention, then, comprises the features hereinafter fully described and particularly pointed out in the claims, the following description and the annexed drawing setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the various ways in which the principles of the invention may be employed.

Brief description of the drawing In such annexed drawing:

FIG. 1 is a side elevation view of one form of fuel injection nozzle constructed in accordance with this invention;

FIG. 2 is an enlarged central longitudinal section through the nozzle of FIG. 1 in which the secondary flow control valve is shown in phantom lines in both the normal full open position and flow blocking position seated against the secondary nozzle shutoff plate;

FIG. 3 is an enlarged central longitudinal section similar to FIG. 2 but of another form of nozzle in accordance with this invention; and

FIG. 4 is a transverse section through the nozzle of FIG. 3 taken on the plane of the line 4 4 thereof.

Description of the preferred embodiments Referring now to t-he details of the various forms of fuel injection nozzles shown by way of example in the drawing and first of all to the FIGS. l and 2 form, such fuel injection nozzle is generally indicated at 1 and cornprises a body member 2 in which there is received a primary nozzle 3 having a primary plug 4 partially threaded into the primary nozzle 3 from the rear. The forward end of the primary plug 4 is of reduced diameter and cha-mferred at 6 for establishing fluid tight engagement with the correspondingly tapered wall 7 `of a spin chamber 8 located forward of the primary plug 4. Fluid is supplied to the spin chamber 8 for discharge from the primary discharge orifice 9 through angularly disposed swirl slots 11 in the forward end wall 12 of the primary plug 4i which impart a swirling motion to the fuel in known manner for better atomization.

The outer wall 13 of the primary nozzle 3 is concentrically located in spaced relation from the inner wall 14 of the body member 2 by an outwardly directed flange 15 on the rear end of the primary nozzle 3 closely slidably received in a counterbore 16. Such outer and inner walls 13, 14 extend forwardly in a longitudinal direction and then taper inwardly to define therebetween a secondary nozzle 17 comprising a secondary spin chamber 19 and secondary discharge orifice 20 surrounding the primary discharge orice 9. Moreover, 'both such discharge orifices 9 and 20 communicate with :a common exit orifice 21 in the body member 2. A shroud 23 may be provided on the body member 2 outwardly of the exit orifice 21 and secured thereto in suitable manner, as by welding at 24 or the like.

The primary plug 4 extends rearwardly beyond the primary nozzle flange 15 and has threaded thereon an adaptor 26 whose forward end face 27 is flush against the back face 28 of such flange to provide a fluid seal therewith. A generally cylindrical strainer support 29 having threaded engagement with the rearward end of the body member 2 surrounds the adapter 26 in spaced relation to define therebetween an annular flow passage 30 which communicates with the interior 31 of the primary plug 4 via one -or more radial passages 32 in the adapter 26 and an internally threaded central recess 33 in the adapter into which the primary plug 4 is threadedly received. Accordingly, fuel entering the fuel injection nozzle 1 through the cylindrical strainer 34 surrounding the strainer support 29 and apertures 35 in the strainer support will provide uninterrupted flow from the primary discharge orifice 9 via passages 30, 32, recess 33, swirl slots 12 and spin chamber 8. A ring 37 having tabs 38 for receipt in axial slots 39 in the rear end of the body member 2 may be crimped radially inwardly into circumferentially spaced recesses 40 in the outer surface of the strainer support 29 to lock these two members together.

For controlling the flow of fuel to the secondary discharge orifice there is provided rearwardly of the adapter 26 a pntle valve 44 having a stem 45 telescopically received in the bore 46 of a sleeve 47. The forward end or head 48 of the pintle valve 45 is tapered outwardly to permit engagement with a seat 49 on the sleeve 47, and there is a piston 50 on the valve stem 45 adjacent the rear end thereof which is closely slidably received in a liner 51 surrounding the sleeve 47 for guiding the valve 44 during its movement toward and away from the seat 49. A helical groove 52 in the outer surface of the piston 50 permits the escape of stagnant fuel which may become trapped behind the piston.

The piston 50 may be retained on the valve stem 45 by a C-washer 53 received in a peripheral groove 54 on the valve stem 45 and a retaining cap 55 which fits over the C-washer 53 and is held in place by a cotter pin 56 inserted through a transverse bore in the stem 45.

A spacer element 60 and spring support washer 61 may be disposed between the rearward end of the liner 51 and bottom wall 62 of the strainer support 29 for maintaining the adaptor 26, primary nozzle flange 15, and body member 2 in firm sealing engagement with each other. An end cap 65 slidably received on an extension 66 of the strainer support 29 and held in place by a retaining ring 67 engaged in a groove 68 in such extension has a forwardly directed flange 69 which overlies one end of the cylindrical strainer 34 to hold the same in place.

The sleeve 47 has a rearwardly facing shoulder 70 which is engaged by a washer 71, and there is a compression spring 72 disposed between the washer 71 and piston 50 for yieldably maintaining the valve head 48 in seating engagement with the seat 49. Shims 73 of different thicknesses may be interposed between the piston 50 and C-washer 53 to vary the compressive force exerted by the spring 72 on the pntle valve 44.

Fuel passing through the strainer 34, strainer support 29 and radial openings 73' in the liner 51 enters the sleeve bore 46 in which the pntle valve 44 is disposed through radial apertures 74 in the sleeve 47 and through the open rear end of the sleeve. However, at low fuel pressures the pintle valve 44 will remain closed and the flow will only be through the primary nozzle 3. Then, as the fuel pressure acting on the valve head 48 increases to a predetermined level, the bias of the spring 72 will be overcome and the pntle valve 44 will move away from its seat 49 to provide for additional fuel flow through the secondary discharge orifice 20 via a` central recess 75 in the adaptor 26 into which the pntle valve 44 projects, a generally axially extending passage 76 in the adaptor 26 communicating with an annular chamber 77 in the forward end face 27 of such adaptor, and holes 78 in the primary nozzle flange 15 which may be angularly disposed to provide a swirling motion to the fuel as it enters the secondary spin chamber 19.

As the fuel pressure increases, the valve head 48 will be lifted progressively away from its seat 49 for additional secondary fuel flow which varies automatically with changes in fuel pressure and may be as much as ten times the primary fuel flow. However, should the valve stem 45 break or the spring 72 or retainer cap 55 fail or become disengaged from the valve stem, even at low fuel pressures the pntle valve 44 would remain wide open resulting in uncontrolled ow through the secondary discharge orifice 20 and improper atomization of the fuel except for the shutoff plate 80 which is disposed in the recess 75 in the adaptor 26. As clearly shown in FIG. 2,

the shutoff plate has an annular side wall 81 terminating in an outturned fiange 82 which extends between the adjacent ends of the adaptor 26 and sleeve 47 to provide a fluid seal precluding primary fuel in the annular passage 30 from entering the recess 75. The length of the side wall 81 is such that the shutoff plate 80 is located a sufficient distance from the adjacent end face of the sleeve 45 to provide the necessary clearance for movement of the pntle valve from the fully closed position shown in solid lines t-o the intermediate or normal full open position indicated in phantom lines at 48 without restricting the flow around the valve head 48 and through the central opening 83 in the shutoff plate. Preferably, the distance between the rear face 84 of the shutoff plate 80 and the flat front face 85 of the valve head 48 when in the fully closed position is slightly more than twice the distance that the valve moves between the fully closed and fully open positions.

With the plate 80 in the position shown, should the valve stem 45 break or the spring 72 fail, the fuel acting on the valve head 48 will force the same into engagement with the plate as illustrated in phantom lines at 48 thereby closing off the central opening 83 in the plate and completely eliminating secondary fuel flow. Thus, in effect the shutoff plate 80 acts as a valve seat for the pntle valve 45 which is engaged by the fiat front face 85 of the valve when it comes into Contact with the shutoff plate 80 because of a broken valve stem or the like.

In FIGS. 3 and 4 there is shown another form of fuel injection nozzle which like the fuel injection nozzle 1 of FIGS. 1 and 2 has a body member 91 in which there is concentn'cally disposed a primary nozzle 92 having a spin chamber 93 therein and a primary discharge orifice 94 communicating with the exit orifice 95 of the body member 91. Also like the nozzle 1, the nozzle 90 has a secondary nozzle 96 surrounding the primary nozzle 92 which comprises a secondary spin chamber 97 defined between the inner and outer walls 98 and 99 of the body member 91 and primary nozzle 92, respectively, communicating with a secondary discharge orifice 100 which continues into the exit orifice 95.

Similarly, there is a shutoff plate 101 interposed between the primary nozzle 92 and valve housing 102 having a central opening 103 therethrough which is closed off by engagement of the head 104 of the pntle valve 105 with the plate 101 as seen in phantom lines at 104" to halt secondary flow to the secondary discharge orifice 100 via radial passages 106 and longitudinal bore 107 in the valve housing 102 in which the valve 105 is disposed and angularly disposed slots 108 in the outturned flange 109 of the primary nozzle 92 in the event of failure of the valve stem 110, valve biasing spring 111, or spring retainer 112. A C-washer 113 received in a groove 114 in the rear end of the valve stem. 110 holds the spring retainer 112 in place, and shims 120 may be interposed between the spring 111 and spring retainer 112 for varying the compressive force exerted by the spring on the pintle valve. However, the adaptor 26 of the nozzle 1 has been eliminated and instead the shutoff plate 101 has an outer sleeve portion 115 which extends axially beyond both faces of the shutoff plate 101 to establish a fluid seal with the adjacent faces of the primary nozzle 92 and valve housing 102 and provide the necessary spacing between the shutoff plate and valve head 104 when in the full open position (104') for unrestricted fiow through the central aperture 103 and secondary discharge orifice 101. A plug 116 adjacent the rear end of the primary spin chamber 93 precludes the secondary flow from entering the primary nozzle 92.

Primary flow is continually supplied to the primary nozzle 92 through an annular passageway 117 surrounding the sleeve portion 115 which communicates with a pair of oppositely disposed chambers 118 between the primary nozzle 92 and valve body '91, and through tangential holes 119 in the primary nozzle ange 109.

Proper sealing engagement between the contacting surfaces of the valve housing 102, sleeve portion 115, primary nozzle ange 109, and body member 91 is established by tightening the valve housing 102 which has threaded engagement with the body member 91. A lock ring 121 having tabs 122 projecting into circumferentially spaced slots 123 in the valve housing 102 may be crimped at circumferentially spaced zones into slots 124 in the body member 91 for locking such valve housing and body member together. The sleeve portion 115 overlies a shoulder 125 on the forward end of the valve housing 102 for concentrically locating the plate 101 with respect to the valve 105.

The operation of the fuel injection nozzle 90- is substantially the same as the nozzle 1. Thus, at low fuel pressures, the flow is only through the primary discharge orifice 94 via the annular passageway 117, chambers 118, holes 119, and spin chamber 93. However, when the fuel pressure acting on the valve head 104 is sufficiently high to overcome the bias of the spring 111, there is additional fuel fiow through the secondary discharge orifice 100 via the central aperture 103 in the shutoff plate 101, slots 108, and spin chamber 97 Which flow automatically varies in accordance with the fuel pressure. Moreover, should the valve stem 110 or other such part of the valve 105 break, the valve head 104 will close off the central aperture 103 much in the same manner that the aperture 83 is closed off by the valve head 48 of the nozzle 1 previously discussed.

I claim:

1. A dual orifice flow nozzle having a fluid inlet passage and primary and secondary flow passages through which fuel from said inlet passage is adapted to flow through the primary and secondary discharge orifices of primary and secondary discharge nozzles, and a pressure actuated valve means in said secondary flow passage effective when closed at low pressures to cut off flow of fluid to said secondary nozzle whereby fiuid fiows only through said primary nozzle at such low pressures, and effective when opened by higher pressures to permit flow of fluid to said secondary nozzle to supplement the flow through said primary nozzle; wherein the improvement comprises providing a shutoff plate, means for supporting said shutoff plate in said secondary ow passage downstream of said valve means, said shutoff plate having an opening through which the secondary fluid ows when said valve means is opened as aforesaid, said valve means when moved beyond full open position due to failure of any part of said valve means being adapted to engage said plate and close off said opening for blocking such secondary fiuid flow, said primary fiow passage bypassing said valve means and shutoff plate and said primary discharge orifice being spaced downstream from said shutoff plate, whereby continued ow will be permitted through said primary passage regardless of the position of said valve means in said secondary flow passage.

2. The dual orifice fiow nozzle of claim 1 wherein the improvement further comprises providing a flat forward end face on said valve means which when brought into engagement with the adjacent fiat face of said shutoff plate blocks such secondary fluid flow as aforesaid.

3. The dual orifice flow nozzle of claim 1 wherein the improvement further comprises a spring means and spring retainer operatively connecting said spring means to said valve means for yieldably maintaining said valve means in closed position, said valve means in the event of failure of said spring means or retainer being adapted to engage said plate and close off said opening therein for blocking such secondary fluid flow as aforesaid.

4. The dual orifice flow nozzle of claim 1 wherein said means for supporting said shutoff plate comprises an adaptor disposed between said discharge nozzles and said shutoff plate, said adaptor having first and second iiow passages therein which constitute a part of said primary and secondary flow passages, respectively, said adaptor also having a recess in the rear face thereof in said secondary flow passage, said shutoff plate being disposed in said recess intermediate the inner and outer ends thereof to provide sufficient clearance between said shutoff plate and both the inner end of said recess and said valve means when in the full open position so as not to restrict the flow through the opening in said shutoff plate and into said second fiow passage.

5. The dual orifice nozzle of claim 4 wherein the improvement further comprises a sleeve having a bore in which said valve means is slidably receiver, an apertured liner surrounding said sleeve, and an apertured support member surrounding said liner having threaded engagement with the body of said nozzle, said sleeve having an outwardly extending shoulder interposed between said adaptor and liner, and said support member having an end wall which forces said adaptor and sleeve into sealing contact with each other through said liner upon tightening of said support member to preclude primary fluid flow from entering said secondary fiow passage via said recess in said adaptor.

6. The dual orifice nozzle of claim 5 wherein the improvement further comprises an annular side wall on said shutoff plate which terminates in an outturned ange extending between said adaptor and shoulder on said sleeve for supporting said shutoff plate in said recess.

7. The dual orifice nozzle of claim 4 wherein the improvement further comprises a plug having threaded engagement with both said primary nozzle and said adaptor, and a passage through said plug communicating said primary discharge orifice with said first flow passage in said adaptor.

8. The dual orifice nozzle of claim 1 wherein the improvement further comprises a valve housing having an axial bore in which said valve means is slidably disposed said shutoff plate being located between said primary nozzle and said housing and having an annular sleeve portion extending axially beyond opposite faces of said shutoff plate to provide sufficient clearance of said shutoff plate with said primary discharge nozzle and said valve means when in the full open position so as not to restrict the ow through the opening in said shutoff plate.

9. The dual orifice nozzle of claim 8 wherein the improvement Afurther comprises an annular shoulder on the forward end of said valve housing over which one end of said annular sleeve portion is slidably received for concentrically locating said annular sleeve por-tion and thus said shutoff plate With respect to said valve means, said valve housing having threaded engagement with the body of said dual orifice flow nozzle whereby said valve housing is tightened, the adjacent surfaces of said valve housing, annular sleeve portion, and primary nozzle are held in sealing engagement with each other.

10. The dual orifice nozzle of claim 9 wherein the improvement further comprises an annular passage surrounding said annular sleeve portion and communicating with circumferentially spaced chambers around said primary nozzle, said annular passage and circumferentially spaced chambers constituting part of said primary flow passage.

11. A dual orifice nozzle comprising a body member having a primary nozzle including a primary spin chamber and primary discharge orifice disposed therein and a secondary nozzle including a secondary spin chamber and secondary discharge orifice concentrically disposed about said primary nozzle, a fluid inlet, primary and secondary fiow passages communicating said inlet with said primary and secondary spin chambers, respectively, a pressure actuated valve means in said secondary flow passage effective when closed at low pressures to cut off flow of fiuid to said secondary discharge orifice whereby fiuid flows only through said primary discharge orifice at such low pressures, and effective when opened by higher pressures to permit flow of fluid to said secondary discharge orifice to supplement the flow through said primary discharge orilice, and a shutoi plate in said secondary flow passage downstream of said valve means, said shutolf plate having an opening therein through which the secondary fluid ows when said Valve means is opened as aforesaid, said valve means when moved beyond full open position due to failure of a part of said valve means being adapted to engage said shutoi plate and close off said opening for blocking such secondary fluid flow, said primary ow passage bypassing said valve means and shutoff plate and said primary discharge orice being spaced downstream from said shutoff plate, whereby continued How will be permitted through said primary passage regardless of the position of said valve means in said secondary flow passage.

12. The dual orice nozzle of claim 11 wherein said primary nozzle has an outwardly directed ange adjacent the rear thereof for supporting the forward end of said primary nozzle in spaced relation from the inner wall of said body member to dene therebetween said secondary nozzle, said outturned flange being in sealing engagement with said body member, and there are slots through said flange communicating said secondary flow passage with said secondary spin chamber.

13. The dual orice nozzle of claim 12 further comprising radial holes in said outturned flange communicating said primary flow passage with said primary spin chamber.

References Cited UNITED STATES PATENTS 2,213,928 9/1940 Gold et al 239-406 2,893,647 7/1959 Wortman 239-403 3,095,153 6/1963 ASoth Z39-417.3

EVERETTE W, KIRBY, Primary Examiner.

U.S. Cl, X.R.

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