US2202510A - Nozzle - Google Patents

Description

2 sheetssheet 1 c. R. ALDEN Nozzmi original Filed nay 11, 1932 May 2s, l1940.

Patented May 128, 1:940 v PATENT OFFICE NozzLE Carroll R. Alden, Detroit, Mich., assignorv to Ex-Cell-O'Corporation, a corporation of Michig all Original application May 11, 1932, Serial No.

610,612. Divided and this application March 19, 1937, Serial N0. 131,771

Claims. (C'l. 299-1075 The present invention relates to improvements in nozzles adapted for fuel admission. or injection systems for internal combustion engines.

In compression ignition engines of the liquid 5 fuel injection type, the fuel is injected into a highly compressed charge of air in the combustion space over a predetermined period bearing a definite phase relation to the movement of the piston. This phase relation is-subject to adjustment, and usually is such that injection is started shortly in advance of the end of the compression stroke of the piston, and is cut off during the initial part of the expansion stroke.

Upon ignition of the fuel, a rapid pressure rise of substantial extent above the compression pressure occurs in the combustion space. Various important objects of the invention reside inthe provision of a nozzle which will limit or control the peak pressure so as toprevent overstressing t, of the mechanical parts, andk further will limit or control the rate of'pressure rise so as to pre-` vent objectionable detonation or combustion knock with attendant evils, such as extreme noise, shock, vibration, rough o-peration and failure of the mechanical parts through fatigue.

The desired control of the rate and extent of the pressure rise following ignition is obtained through the utilization of a plurality of injection valves for each cylinder that are adapted to be opened successively at predetermined points in the engine cycle so as to provide a graduated rateor curve of fuel injection. Thus,'the beginning of injection may be made to occur at a time when. the compressionI temperature is most propitious for ignition with a minimum ignition lag. The rate at which the first fuel is introduced may be low so that only a minimum amount of heat will be required to bring the fuel to the ignition temperature. Moreover, the first fuel 'to be introduced may be injected at full pressure through orices of such small size that it will be finely atomized and distributed, and hence will have a large surface area exposed to the compression temperature. Preliminary ignition of an initial charge of fuel under the foregoing conditions .serves to prepare conditions in the combustion space for the subsequent ignition of a main charge of fuel substantially at the rate at which it is injected. The control afforded by a plurality of. valves permits of injection of fuel at the most advantageous rate at yeach instant of the injection period.

Another important object of the invention re- .sides in the arrangement of a plurality of fuel injection valves for a cylinder in parallel relation with respectto the source of fuel so that none of the valves is dependent for connection to such source upon the operation of another valve.

A further object is to provide a plurality of fuel injection valves for asingle cylinder which are operable hydraulically and from pressure impulses common to all.

Further objects and advantages will become apparent as the description proceeds.

Figure 1 is a longitudinal sectional view of a multiple valve nozzle and holder embodying the features of my invention.

Fig. 2 is a transverse sectional view taken along line 2-2 of Fig. l.

Fig. 3 isa fragmentary side view of the nozzle holder.

Fig. 4-is an axial sectional view on an enlarged scale of the multiple valve nozzle.

Fig. 5 is a sectional view of the -nozzle taken 'i along broken line 5 5 of Fig. 4.

Fig. l6 is an axial sectional line 6-6 of Fig. 5.

Fig, '7 is a time chart illustrating the timed relation of the opening of the respective valves for each cylinder to the crank shaft rotation.

Fig. 8 is a polar diagram comprising/curves illustrating the graduated rate of fuel injection and the rate of pressure variation obtainable byl progressive opening of the nozzle valve.

While the invention is susceptible of various modifications and alternative constructions, I have shown in the drawings and will herein describe in detail the preferred embodiment, but it is to be understood that I do not thereby intend view taken along to limit the invention to the specific form disclosed, but intend to cover all modifications and alternative constructions falling within the spirit and scope of the inventionvas expressed in the appended claims. y

The present application is a division of my copending application Serial No. 610,612, filed May l1, 1932, Patent No. 2,145,640 in which a complete fuel injection system, including the mu1tirate nozzle, is disclosed.

Referring more particularly to the drawings, the nozzle may comprise any desired number of injection valves, two valves, namely a primary valve 9 and a secondary valve I0, being shown in the present instance. These valves 9 and I0 may be mounted in any suitable position to discharge into the combustion space Il, and may be arranged separately, but preferably they are combined in a -unitary structure as shown in the drawings. The provision of a plurality of injection valves affords 'a choice in the arrangechamber such that a uniform and thorough penetration of the combustion space II can be obtained without relying largely on turbulence. In the present instance, the nozzle is mounted in one side of an engine cylinder I2 to inject a plurality of jets of fuel laterally into the combustion space I. With a plurality of jets of fuel, quick, thorough and uniform penetration by the fuel of the combustion space II and ne atomization of the fuel are possible.

Within the broad aspects of the invention, the injection valves 9 and I0 may be provided in various forms. In the present instance, the unitary nozzle structure, of which the two valves form part, comprises a cylindrical body I3 which is adapted to be removably mounted in a holder In the preferredform, the holder I4 comprises an elongated casing I5, preferably cylindrical in shape, which has a sleeve I6 of reduced diameter on its inner end, and which presents an annular peripheral seating shoulder I1 at the juncture with the' sleeve. 'I'he sleeve I6 is snugly disposed in the inner end of a bore I8 opening through a boss I9 on the side of the cylinder I2 into the combustion space .I I. The outer portion of the bore |8 is enlarged as indicated at 20 to snugly gagement by the shoulder I1.

receive the casing |5 and to provide an outwardly facing annular seat 2| adapted for en- A gasket washer 22 may be disposed between the shoulder 'I1 and the seat 2|.

To secure the holder removably in position, the outer portion of the casing I5 is formed with a peripheral flange 23, and is enlarged beyond the flange as indicated at 24. A clamping plate 25, apertured at 26 to receive the outer end 24 of the casing, engages the outer face of the ange 23, and is securely clamped by means of 4bolts 21 threaded into the end of the boss |.9.

r'I'he body I3 of the nozzle unit is mounted in the sleeve I6, and is formed adjacent its inner end' with an annular peripheral seating shoulder 28 in engagement with an inner peripheral ange 29 on the innerend of the sleeve. A `gasket Washer 3|) may be disposed between the shoulder 28 and the flange 29. The outer end of the body I3 projects from the sleeve I6 into the intermediate section of the casing I5 in concentrically spaced relation thereto, and is formed with a peripheral end flange 3| defining a central recess or chamber 32.

The` body |3 is held removably in position by means of a clamping "rod 33 extending axially in the casing I5, and having a head 34 on its inner end engaging the end of the flange 3|. Agasket washer 35 is positioned between the flange 3| and the head 34. A clamp nut 36 is adjustably threaded into the outer end 24 of the casing I5 and has a centering recess 31 engaging the outer end of the rod 33 to'secure the head 34 tightly against the body I3. A gasket washer 38 is disposed between the rod 33 and the bottom of the recess 31. The extreme outer end of the casing I5 is tightly closed by a screw plug 39. It will be evident that bodies I3 with different numbers of valves may be mounted interchangeably in the holder I4.

The valves 9 and I0 respectively comprisetwo discharge tips 48 and 4| formed on the inner end of the body |3 and having a plurality of jet orifices 42 and 43 opening to the combustion space. The number, arrangement and sizes of the orifices 42 and 43 are subject to considerable ment of the valves and design of the combustion selection, but in the-present instance two orifices 42 and four orifices 43, all of the same size, are shown. Two nozzle passages 44 and 45 respectively are formed in the tips 40 and 4I and communicate with the orifices 42 and 43. The inner ends of the passages 44 and 45 open respectively past conical valve seats 46 and 41 to two fuel chambers 48 and 49 in the body I3. ValveA members 50 and 5I are adapted to coact respectively with the seats 46 and 41 to control the supply of fuel to the orifices 42 and-43. 'f

The valves 58 and 5| are adapted to be opened or lifted by fuel pressure in the chambers 48 and 49, and to this end are carried by pressure responsive members, such as reciprocable pistons or plungers 52 and 53. While within certain broad aspects of the invention, provision may be made for seating or closing the valves 58 and 5I under the infiuence of any desired relative .pressures applied through any suitable medium, pref- One of theA important features of the invention resides in effecting the selective operation of the valve members 58 and 5I so that during injection first the primary-valve 9 alone will inject fuel over an initial period and then both valves 9 and I0 will inject fuel over a final period. The successive opening of the valve members 50 and 5I in a predetermined sequence is accomplished by subjecting theplungers 52 and 53 to unequal lifting pressure differentials. Where equal seating pressures are employed, as illustrated, such'differentials are obtained by exerting unequal net lifting pressures on theA plungers 52 and 53 in the fuel chambers 48 and 49.

Preferably, the valve members 58 and 5| are arranged in parallel, so that the opening of one is not physically dependent on the opening of the other, and are subject to the same fuel pressure.- Thus, the lchambers 48 and 49 are joined by a common fuel inlet passage 54 so as in effect to constitute one fuel chamber, and the plungers 52v and 53 are reciprocable in parallel bores 55 and 56 formed in the body I3 and opening at opposite ends into the pressure and fuel chambers 32 and 48, 49. Since in the present instance both plungers 52 and 53 are subjected in common to one seating fuel pressure and to one lifting fuel pressure, the vunequal lifting pressure differentials are obtained by making the ratio of the lifting pressure area, exposed in the fuel chamber 48, 49, to the :seating pressure area,'

exposed in the pressure chamber 32, for the plunger 52 greater than that for the plunger 53 when the valve members 50 and 5| are seated. The specific area ratios are determined by the design and dimensions of the plungers 52 and 53 and the embraced areas of the valve seats 46 and 41, and maybe obtained in different ways by varying the relationship between the foregoing factors. In the form selected for illustration, the two plungers 52 and 53 are cylindrical and of uniform diameter throughout the length of the bores 55 and 56, and are slightly different in diameter, and the valve seat 46 isv smaller than the valve seat 41.

It will be evident that when the valve members 58'and 5| are lifted, the area ratios will be alike substantially scribed and less t'tan one.

are seated, the lifting. pressure areas will be reduced in `eect by the areas of the valve seats so that the area ratios will be unequal as de- Preferably, the effective cut-off areas `of the valve seats 46 and .41 are twenty andthirty (30) percent. of the associated end faces of the respective plung ers 52 and 53 so thatthe latter have pressure area ratiosof eighty (88) and seventy (7 0) percent. respectively when the valve members 58 and 5I are seated.

To provide means for supplying fuelunder pressure to the fuelchamber 48, 49, the ends f of' thefuelinlet passage 54 intersectl the inner ends of two diametrically opposed longitudinal slots body I3. The outer ends of the slots 51 open to the interior'of the casing I5 about the rod 33.

' -constituting a supply chamber 58.. A

Connected to thecasing through a` port 59 therein to the chamber 58 isa fuel feed conduit 68; The. connection preferably comprises a sleeve 6I which is'snugly"pos itioned on the outer end 24'of the casing -Iii andagainst the plate 25, and which-has a lateral boss 62 formed with anl aperture 63 to receive'thedis' charge end of the-conduit 68. vA 'clamp nut 64-is y threaded into'the aperture 63 against a collar 65 the fuel chamber 48 49, and will open onlyl upon i increasing the fuel lifting pressure relatively' above the fluid seatingpressure, whatever ythe 4latter may .be and however it may be applied,

threaded onto the conduit`68 to secure the end outer end of the bore 66 opens through an alined axial bore 61 in the nut 36 to.the space 68 between' the nut and the plug 39. A' control conduit 69 connected to the casing I5 in the same manner as the feed conduit 68 opens tothe space 68. The connection for the conduit 69 comprises a 'second' aperture 18 in the boss 62, a collar II threaded onto the discharge end of the conduit,

anda nut` 12 threaded into the aperture against 45' .the cenar' to secure the conduit tightly against .the casing l5 in aliner'nent with a port 13 opening to the space 68.

4Since the area ratios for the valve plungers 52 and 53 are less than' one (l) when the vvalve members 58 and 5I are closed, thevalves 9 and I8 will remainclosed when equalfluid pressures are impressed in 'the pressure chamber 32 and to overcome the ratios." Lifting of the . valve plungers 52 and 53 involves a reversal in l direction of the-pressure differential. In' a broad sense, such reversal may be accomplished in various ways, as for example'by sufllciently increasing the pressure 'in the fuel chamber '48,' 49. Preferably, opening of the valve members 58`and 5I is effected, subsequently to the establishment in the fuel chamber 48, 49 of the pressure, approximately equal toy the normal pressure of the seating fluid, at which the fuelis;

to be injected into the cylinder, by gradually reducing the seating pressure. As a result, no building up of the fuel pressure in the chamber 48, 49, involving a--time consuming flow and a fluctuation in the injectionV pressure, nor creation of pressure surges due to momentum, occur during opening of thelvalves. 0n thecontrary, the full injection pressure is immediately avail- 51 formed 'in the exterior of the nozzle unit I5 and opening able, thus avoiding dribbling and providing a.- quick and sensitive control.

Since their seating area ratios are unequal, the valve members 58 and 5I will open in timed Isequence upon reduction of the seating pressure. The relationship of the control pressure reduction to the sequential opening of thevalve -members 58 and 5I is illustrated inthe time chart shown in Fig. 7 whereiny percentages of control pressure reduction' are plotted along the ordinate. and. time in degrees of crank shaft rotation is plotted along the abscissa, The rate 4of pressure reduction is represented by the curve 4a-b, assuming that percent. represents the normal maximum seating fuel pressure in the chamber 32, and-that the fuel pressure in the chamber 48, 49 is equal thereto when the valve members 58 and 5I are lifted, the drop in pressure starts at degrees of engine crank shaft rotation. After a drop in pressure of twenty (20) percent., the seating area ratio of .8 will have been overcome, and hence the valve member 58 will be lifted at 0 degrees of crank shaft rotation. A further drop of ten (l0) 'percent-in the control pressure results in overcoming the seating area ratioof .7, and the consequent opening of the secondary valve I8 at degrees of crank shaft rotation. i

The multiple rate of fuel injection is illustrated 'diagrammatically in the polar diagram of Fig. 8, in which the degrees of engine crank shaft vrotation are indicatedangularly, and the. rate of injection is plotted along the radii. Upon lifting of the valve member 58 at 0 degrees, i. e. 360-0 before top dead center, fuel is injected through the primary valve 9 at a rateo-d, depending on the injection pressure and the characteristics of fthe valve member 58 and the orifices 42. Subsequent lifting of the valve member 5I at y degrees, i. e..360 before top dead center, causes fuel to be injected also throughthe secondary valve I8 at a rate de, subject to the same factors as the rate c-d, thus injecting fuel at the combined rate c-e. Upon restoring the normal seating pressure in the chamber 32, and reducing the fuel pressure in the chamber 48, 43, as through venting or injection after cut-off, the valve memof injection, particularly at the- 55 start, is graduated kin steps Vc-d and (1 -e, represented approximately .by amean curve c--e,f i' hereinafter referred .to as rate curve.. Ob'

viously, the greater the number'of valves that are provided,-the more closely do the series of incremental steps approach to the rate curve.

Therate curve of injectionis subject to adjustment so as to approximate a' theoretical ideal, i. e. to admit fuel into theengine cylinder I2 at vthe most advantageous ratev at any moment duringwthe entire period of injection. Such adjustment can be accomplished by a judicious variation in. the rateof seatingpressure drop and/or rise, and/or selection of different seating area ratios for the valve members 58 and 6I, and/or selectionof 'valve's'ha'ving different coefficients of flow, and/or'regulation of ,the relative extent of rise of the alve members. Preferably, the valve members 58 and 5I are opened in a'Hi sluence and closed substantially simultaneously, although they may also be closed in sequence. Ordinarily, the restriction to oW in the control conduit 69, when being exhausted to a lower pressure, is such that a suitable timed pressure drop to produce the desired rate curve is obtained. Varying the rate ,curve by changing the rate of control pressure drop may be effected byy adjusting the restriction to flow in the control conduit 69 selectively in` either or both directions.

The means for supplying the fuel to the conduits 60 and 69 and for effecting the desired pressure fluctuations therein per se forms no part of the present invention, and hence is not disclosed, but reference may be had to said copending application which discloses a suitable means for this purpose.

In general, the extent and rate of combustion pressure rise are limited and controlled to avoid combustion knock and excessive peak pressures, and the attendant faults such as noise, shock and fatigue and failure of the engine parts. Thus, the start of injection is delayed until the compression temperature is most propitious for ignition with a minimum of ignition lag. ,If fuel is injected too far in advance of top dead center, even though the rate be decreased, the temperature and pressure in the combustion space will not have risen sufficiently to insure prompt ignition, and hence there will be a substantial ignition lag resulting in the accumulation of unburned fuel and upon ultimate ignition in an objectionable knock, The shape of the curve rate of injection should be such that at the start only a small amount of fuel is injected so that a minimum of heat is required to effect ignition. Thus, the initial fuel instead of cooling the air in the compression space of the engine cylinder and thereby retarding ignition, burns quickly, thus increasing .the combustion temperature and preparing the combustion space for the ignition of the main part of thel charge practicallyv at the rate at which it is introduced.

The first fuel to be injected, being under the full injection pressure is atomized at least as nely as the main portion of the charge. By reason of the foregoing control, the degree of pressure rise, depending on the amount of fuel burned before top dead center, and .the rate of pressure rise, governed by the amount of fuel introduced before ignition are so regulated that the engine operates smoothly, noiselessly and eillciently.

I claim as my invention:

1. A nozzle comprising, in combination, body means having two discharge means and two fuel chambers for supplying fuel under pressure thereto, said chambers being in intercommunication, two independent valve means for connecting said chambers in parallel respectively to said discharge means, said valve means comprising respectively two valve seats of unequal areas and two pressure responsive valve members for coacting with said seats, said members when seated presenting in said chambers unequal preslsure areas responsive to the fuel pressures therein in a direction to open said valves, and means for effecting seating of said members.

2. A nozzle comprising, in combination, body means having two discharge Umeans and a fuel chamber for supply fuel under pressure thereto, two independent valve means for connecting said chamber in parallel to said discharge means, said valve means comprising respectively two vali a seats of unequal areas and two reciprocabl:

pressure responsive valve members yfor coacting with said seats, the ratio of the full end area of either member in said chamber to the associated valve seat area being different than the corresponding ratio for the other member so that said end areas when seated against said valve seat areas present unequal lifting pressure areas in said chamber responsive to increasing fuel pressure therein to cause said valves to open consecutively, and means for effecting seating of said members.

3. A nozzle comprising, in combination, body means having a fluid pressure chamber and having two discharge passages arranged in parallel, two valvesfor controlling the flow of fuel respectively to said passages, two pressure responsive members for actuating said Valves, said members having lifting pressure areas exposed in said chamber acting in response to fluid pressure therein in a direction'to open said valves and having seating pressure areas adapted to act in response to the application of fluid pressure in a direction to close said Valves, andmeans for directing fluid pressure against said seating pressure areas, said oppositely acting pressure areas ,for each valve member being adapted upon the application of fluid pressure thereon to set up a differential force subject to reversal alternately to open and close the associated valve, and said differential forces being unequal so t at said valves on occasion will be opened consecutively.

4. A nozzle comprising, in combination, body means having .two discharge passages, a fuel chamber for supplying fuel to said passages, and a pressure chamber, two valves for controlling the flow of fuel from said fuel chamber to said passages, each of said valves comprising a valve member having e lifting pressure area exposed in said fuel chamber and a seating pressure area exposed in said pressure chamber, the ratio of said areas for one member being different than the corresponding ratio for the other member so that uponvarying the pressure differential in said chambers'to effect opening of said valves,

said members will lift consecutively.

5. -A nozzle compri. ing, in combination, body means having two discharge passages, two fuel supply chambersfor said passages, and a fluid pressure chamber, and two valves for controlling the flow of fuel from said fuel chambers respectively to said passages and respectively comprising -two valve members, said members being responsive to the fluid pressure inA said pressure chamber in a direction to close said valves, and when seated presenting in said fuel chambers unequal lifting pressure areas. responsive to the fuel pressures in said fuel chambers in a direction to open said valves in sequence against said fluid pressure.

6. A nozzle comprising, in combination, bodyv means having two discharge passages and two fuel chambers for supplying mel under pressure to said passages, and having a fluid pressure chamber, said fuel chambers being in intercommunication, two valves for connecting said fuel chambers in parallel respectively to said pas- Abetween said chambers and. projecting at their opposite ends into said chambers, the ends of said plungers in said fuel chamber carrying said Valve members and therewith presenting lifting pressure areas, the opposite ends of said plungers presenting seating pressure areas in said pressure chamber, the ratio of lifting area to seating area of each plunger being one when the asso' ciated valve is open and less than one when the `associated valve isr closed, said ratios of said -plungers being unequal when said valves are closed, and means for directing fuel under pressure to said chambers to eiect consecutive open,- ing of said valves.

8. A nozzle comprising, in combination, body means having two discharge passages', a fuel chamberv for supplying fuel lto said passages, and a pressure chamber, and two valves for-control'- ling the passage of fuel fromsaid fuel chamber to said passages, each of said valves comprising a valve member having a liftingpressure area exposedv in said fuel chamber and a seating pressure areaexposed in said pressure chamber, the ratio of said areas for one member being different than the corresponding ratio for the other member, whereby a gradual relative increase of,

' pressure in said fuel chamber over that in said pressure chamber will effect consecutive opening of said valves.

9. A nozzle comprising, in combination, a holder having a cylindrical sleeve on one end and a seating flange on said sleeve, a cylindrical nozzle unit removably mounted in said sleeve, said unit having a port of fuel delivery, a fuel chamber vopening to said port, a pressure chamber, a valve member for controlling -said port, said member being movable in opposite directions by the pressures in said chambers, a transversev bore opening to said fuei chamber, and a longitudinal external slot opening from said bore to the interior of said holder, means for directing fuel to the interior of said holder, a clamp member for securing said unit in position, said clamp member hav- 'ing -a passage opening to said pressure chamber,

and means for directing fluid. under pressure to said passage. y

10. A hydraulically operable fuel injection nozzle comprising, in combination, a pressure chamber adapted to receive fluid under pressure, a fuel chamber, and a plurality of discharge -valves adapted to close in response to the pressure in said pressure chamber and constructed. and arranged to open successively in response to the fuel pressure against the action of the pressure in said pressure chamber to permit the discharge ofv fuel from said chamber at an increasing rate.

CARROLL a. ALBEN.

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