US2566888A - Fuel spray producing nozzle - Google Patents

Description

Sept. 4, IQSLQ A. HOLT ET AL 2,566,888

FUEL. SPRAY PRODUCING NOZZLE Filed Feb. 25, 1947 B wouza 042 M v wait-4...

Allorney Patented Sept, 4, 1951 FUEL SPRAY PRODUCING NOZZLE George Allen Holt, Shoreham-by-Sea, and Kenneth Brook, Eastcote, England, assignors, by mane assignments, to Ricardo & Co. Engineers (1927) Limited, London, England, a company of Great Britain Application February 25,1947, Serial No. 730,768 g In GreatBritain August 28, 1946 nular port formed between the pintle and the,

delivery opening, from the casing or body of the nozzle wherein the pintle lies-there are provided one or more holes through the pintle or the body around it thefuelflowthrough these holes being controlled .by the valve formation behind the pintle. It is stated that with this known construction the distribution of injected-fuel in any predetermined proportion, both to the annular port and to the addition'holes issubstantially independent of the fuel pressure. Further it is said that by arranging the inner ends of the additional holes nearer the source of fuel supply than the annular port the fuel discharge from I 1 2 Claims. Cl.299- -107.5)

' main fuel jet can issue, said passage'terminating the holes will precede that from the annular port at the commencement" of thefdelivery stroke of the pump. Lifting of the valve permitsfuel to flow equally to the holes and to the annular port.

It is also said that in this construction the crosssections of the additional. injection ports are larger than the cross-section of the annular port.

In the known construction there is a passageway for the fuel through the annular port at all times even when the valve o'f'the nozzle is on its seat. I

The object of the presentinventionis to provide a fuel injection nozzle in which the fuel is delivered through at least two separate orifices so arranged that with increase in the rate of fuel supply the flow of fuel through one of these orifices will increase while thesfiow through the other orifice or orifices will decrease.

According to this invention'in the improved nozzle in addition to a central delivery orifice in the casing of the nozzle there is at least one livery port and allow the free new offuel through it to begin. r

The improved construction comprises in combination a casing in which is a conical seat for a valve and beyond it at the end of the casing a central opening or passage through which the at one end in an orifice withingthe casing and at the other end in an open central outlet orifice, a needle valve of the pintle type comprising a body with a conical valve formation thereon adapted to engage the said seating in the casing and at its end a pintle which extends beyond the valve and can enter and has a part which then closely fits the central delivery opening, the part of the pintle which fits in the opening being of such lengththat the needle must be withdrawn a substantial distance after the valve is raised off its seat before the pintle end opens or discloses the port constituted by the central opening and permits any free fiow of fuel through this port which then constitutes the main fuel delivery orifice, and at least one hole through the wall at the end of the nozzle casing and spaced radially outwards from the central or maindeliveryorifice, each such hole constituting a passageway through which fuel can fiow as soon as the needle valve hasjbeen moved sufficiently to take the valve oh its seat and before fiow through the main port or orifice can begin. When the needle valve is seated and the pintle closes the central delivery opening there is formed in the nozzle casing an annular chamber around the pintle which extends in the axial direction hetween the valve on its seat and the pintle in the central opening and each hole or passageway at the side of the central delivery opening runs from this annular chamber to the end of the nozzle casing. Fuelcan enter this chamber directly the needle is moved sufilciently to take the valve off 'its seat, but it can at first fiow thence only through the'lateral passageway or ways until the needle has been moved far enough to withdraw the closely fitting part of the pintle from the 3 nozzle of this type there is contained within the nozzle body or casing a sliding needle carrying a valve which is pressed on to a mitre seat in the passage through which the fuel is ultimately discharged. The valve which engages this seat is formed on a needle body at the end of which is a projection or pintle a part of which is cylindrical and a close sliding fit within the cylindrical delivery passage in the end of the nozzle casing. The outer end portion of the pintle is coned inwards towards its axis for a short, distance and then diverges in an expanding cone for a greater distance, these two cones being for the purpose of determining the angle of the spray delivered.

When fuel is supplied under pressure to such a known nozzle construction the needle with the valve and pintle lifts against the spring acting thereon owing to the provision of a differential area behind the mitre seat and between it and the diameter of the main part of the needle body. The .movement of the needle against the spring pressure thereon liftsthe valve from its seat and permits the fuel under pressure to enter an annular chamber formed within the nozzle casing between the lower edge of the valve seat and the orifice at the end of the cylindrical passage in which the pintle moves. Owing to the closeness with which the cylindrical portion of, the pintle fits the cylindrical passage in the nozzle casing fuel cannot then be discharged except by unintentional leakage and the needle valve continues to lift.

It will be understood that it is assumed that the nozzle is being fed with fuel, for example, by an injection pump such as those in which the plunger is lifted by acam or other device to deliver a predetermined quantity of fuel to the nozzle.

The pressure continues to build up in the annular chamber below the valve seat under the continued delivery of fuel by the pump plunger until the cylindrical portion of the pintle is Just about to leave the end of the cylindrical passage in the nose of the nozzle casing. The valve continues to lift under the continued supply of fuel, and discharge of fuel takes place through the annulus formed by the two spray determining cones formed on the nose of the pintle which lie more or less within the cylindrical passage in the nose of the nozzle casing depending on the degree of lift of the valve.

The pressure in the space below the moving valve seat quickly builds upto a high value until the instant is reached in the lift of the valve against the spring when the cylindrical part of the pintle is about to withdraw from the cylindrical passage in the nozzle casing. This build up of pressure-occurs owing to the fact that although the valve is lifting against the spring, the relatively long closely-fitting portion of the pintle is still obstructing the cylindrical passage in the nozzle casing thus preventing any substantial discharge of fuel until that point is reached when the cylindrical portion of the pintle is about to withdraw from the cylindrical passage.

The accompanying drawings illustrate by way of example a nozzle of the delay-action type constructed according to this invention. In these drawings,

Figure 1 is a somewhat diagrammatic longitudinal sectional elevation of the improved noz- 4 zle on an enlarged scale showing the needle valve seated when no fuel flow is taking place.

Figure 2 is'a similar view but showing the needle valve lifted to permit free fuel flow.

In its main features the construction follows known practice as indicated above. .Within the casing A is a conical seating B for a. valve and beyond this seat is a central opening and passage-.

way C constituting the main. fuel delivery passage and whence issues the fuel'jet. The valve seat B is arranged between the delivery opening C and an annular chamberD formed in the casing A around the needle valve and into which the fuel is delivered under pressure in the usual way. The needle valve comprises a body E with a conical valve F formed on it and adapted to engage the seating B. Extending from the body E beyond the valve F is the pintle G having a cylindrical part G which as seen in Figure 1 can enter and closely fit the delivery jpassage C, with the end portion formed with cones G and G in a known way. It will, be seen in Figure 1 that when the needle is positioned with the valve F on the seat B there is formed around the pintle G and beyond the valve an annular chamber H. From this chamber at least one passageway J runs as a plain hole through the casing A at one side of the'central delivery passage C.

The needle valve E is acted on invthe usual way by a spring, not shown, and this spring tends to keep the valve F on the seating B. When fuel is supplied under pressure into the chamber D the whole needle lifts and when the valve F fuel pump a good well-sustained discharge of fuel will take place through each hole or passage such as J -well in advance of the main discharge through the pintle-controlled'passage C owing to the fact that pressure rapidly builds win the chamber H and causes a suitable discharge through the passage J during the period of'pressure build up which occurs while the pintle G is still obstructing the passage 0. As soon as the closely-fitting cylindrical portion G of the pintle withdraws from the orifice at the inner end of the cylindrical passage C, discharge of fuel begins through that passage and the discharge through the plain hole or holes J falls off. This is due to the fact that the resistance of the plain hole J progressively becomes rela-- tively greater than the resistance to flow through the open central outlet orifice at the outer end of the cylindrical passage C as the pintle is progressively withdrawn back from the orifice at the inner end of the passage C by the continued lifting of the needle E against its spring by the action of the continued delivery of fuel by the pump.

The resistance to fuel flow through the cylindrical passage 0 is determined by the position of the end of the cylindrical portion G of the pintle in relation to the orifice at the inner end of the passage 0 and not by an annular clearance between these parts. The converging-diverging cones G'-G at the end of the pintle determine the angle of the spray delivered. If

plain hole J which vary supply to the injector. The characteristic is such that at low rates of supply, i. e.,wlth the fuel pump running slowly, the quantity of fuel discharged through a plain single hole J may be of the order of 6 times the quantity of fuel discharged by way of the pintle controlled passage C, while the same nozzle when the rate of fuel supply is substantially increased, i. e. with the fuel pump running faster but with the same delivery of fuel per stroke of the pump, gives a discharge through the pintle controlled passage C which is of the order of 4 times the discharge through the plain hole J. The nozzle on which this observation was made had only one plain hole J as shown in the drawings.

In another example in which a single plain hole was employed and tested under the same conditions, the characteristic was such that at a low rate of fuel supply the flow through the pintle controlled passage C was substantially zero, the whole of the fuel supplied being delivered through the plain hole J, while at a higher rate of fuel supply, the flow through the pintle orifice C was three times the flow through the plain hole J.

It is to be understood that the improved n0z zle may be used with a continuous supply of liquid as well as with an intermittent supply. In

the case of a continuous supply the total quantity of liquid discharged by the nozzle is controlled by varying the pressure of the liquid supply.

When the improved nozzle is used with a continuous supply of liquid, the whole of the discharge other than unintentional leakage past the pintle G will at low rates of liquid supply be through the plain hole or holes J. The rate of supply at which intentional delivery of liquid by way of the pintle controlled passage will take place will be determined by the pressure of the liquid supply and the rate or the springer springs loading the valve. When the pintle G is liftedout of the cylindrical passage C flow will commence through that passage and will increase as the pressure of supply increases owing to the end of the cylindrical portion G of the pintle retreating from the orifice at the inner end of the cylindrical passage C, thus decreasing the resistance offered by the pintle. As the pintle lifts with further increase of pressure the rate of flow through the passage C will increase and the rate of flow through the plain hole or holes J will decrease.

It is to be understood that by suitable choice of proportions of the various parts of the improved nozzle or variations in the-rate of the spring or springs controlling the needle valve, it is possible to arrange that the total liquid discharge of the nozzle shall have various flow characteristics including a substantially straight line flow characteristic in relation to the rate of liquid supply to the nozzle or the pressure of the liquid supplied to the nozzle.

What we claim as our invention and desire to secure by Letters Patent is:

1. A fuel spray-producing nozzle comprising incombination a casing for the nozzle, a central main cylindrical delivery passage leading from an orifice within the casing to an open central outlet orifice, a seating for a valve within the casing and set back from the orifice at the inlet end of the main delivery passage, at least one passage through the wall of thecasing and posiwith the rate of fuel tioned laterally with respect to the central main delivery passage, the lateral delivery passage having a substantially smaller cross sectional area than the main delivery passage, a needle valve adapted to seat on said seating and a cylindrical pintle forming an extension beyond the needle valve and adapted to fit closely and slide in the main delivery passage, the length of the cylindrical part of the pintle which closely fits within this passage being such that, whereas for low rates of fuel delivery the valve will open to permit fuel to flow to the lateral passage without the cylindrical part of the pintle being withdrawn from the main delivery passage, at higher rates of fuel delivery the cylindrical part of the pintle will be withdrawn from the main delivery passage to a greater or less distance to open and determine the effective free cross section of this passage and fuel will be delivered through both passages, the mean direction of injection through the lateral passage being different from the main direction of injection through the mean delivery passage, the proportion of the whole fuel delivered which flows through the main delivery passage increasing progressively with increases in the rate of fuel delivery beyond that just sufflcient to withdraw the cylindrical part of the pintle from that passage by reason of the increased withdrawal thus effected.

2. A fuel sprayproducing nozzle comprising in combination a casing for the nozzle, a main central delivery cylindrical passage leading from an orifice within the casing to a central delivery orifice, a seating for a valve within the casing and set back from the orifice at the inner end of the said central delivery passage, at least one passage through the wall of the casing and posi tioned laterally with respect to the said main central delivery passage, this lateral passage running from a place between the said valve seating and the said orifice of the central delivery passage'and being of small cross sectional area compared with the main delivery passage, a needle valve member having a formation constituting a valve and adapted to engage the said seating and beyond this valve a part of less diameter which is at least partly cylindrical and forms a pintle extending beyond the valve for such a distance that when the valve is on the said seating the cylindrical extension will lie and fit closely in the said central delivery passage and there will then be an annular chamber between the said valve on its seat and the orifice at the inner end of the said main central delivery passage, the length of the said cylindrical extension being such that when the valve is off its seat the needle valve member must still more some distance before the cylindrical extension is withdrawn from the orifice so as to permit and control the flow of fuel through the said delivery passage, so thatfor low rates of fuel delivery which the lateral passage can accommodate above the valve will lift but insufficiently to withdraw the cylindrical part of the pintle from the main delivery passage, whereas for higher rates of fuel delivery the cylindrical part will be withdrawn by a greater or less distance from the main delivery passage so that fuel will be delivered through both delivery passages, the mean direction of injection through the lateral passage being different from the mean direction of injection through the main delivery passage, the proportion delivered through the main passage increasing progressively with increases in the rate of delivery above that just sufficient to 8 withdraw the cylindrical part from the main pa's- UNITED ST PAmNTS sage. 1

- Number Name Date GEORGE ALLEN HOLT. 1,833,080. Kenworthy Nov. 24. 193i KENNETH BROOK. 5 2,235,365 Grumbt Mar. 18, 1941 FATE 8 REFERENCES CITED FOREIGN NT I 1 Number Country Date. The following references are of record in the 812,411 France Feb. 1' 1937 file this Patent 10 671,686 Germany Feb. 11, 1938

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