US3656464A

US3656464A - Fuel injection nozzle and system

Info

Publication number: US3656464A
Application number: US23572A
Authority: US
Inventors: Stuart G Hilborn
Original assignee: Fuel Injection Engineering Co
Current assignee: Fuel Injection Engineering Co
Priority date: 1970-03-30
Filing date: 1970-03-30
Publication date: 1972-04-18
Anticipated expiration: 1989-04-18
Also published as: CA928179A

Abstract

A fuel injection nozzle having a passage extending therethrough and terminating at one end in an outlet. An atomizing device is positioned in the passage adjacent the outlet. The nozzle is preferably mounted on an intake manifold of an engine at such an angle that it directs the fuel into the manifold in the same direction as the air flowing through the manifold. The nozzle controls the shape of the spray pattern so that the cross sectional configuration of the spray pattern generally conforms to the cross sectional configuration of the manifold.

Description

United States Patent Hilborn [is] 3,656,464 [4 1 Apr. 18, 1972 [54] FUEL INJECTION NOZZLE AND SYSTEM [72] Inventor: Stuart G. Hilborn, Laguna Niguel, Calif. [73] Assigneez' Fuel Injection Engineering Company,

South Laguna, Calif.

[22] Filed: Mar. 30, 1970 [21] Appl. No; 23,572

[52] 11.8. C1. ..123/139 BF, 239/462, 123/139 AW [51]v Int.Cl ..F02m 45/12 [58] Field ofSearch ..-..123/ll9,l39,139.15, 13.9.17,

[56] I References Cited UNITED STATES PATENTS 2,833,260 5/1958 D0128 et ..123/119 2,893,365 7/1959 Haefner ..123/119 3,395,682 4/1968 Jackson ..123/139.18

2,102,476 -12/1937 Mennesson ..123/139.18 X 2,117,380 5/1938 Walters ..l23/139.l7 X 2,865,357 12/1958 Mueller... ..l23/l39.17 2,585,092 2/1952] Conto ....239/366 X 2,665,943 l/l954 Palm ..239/366 1,506,601 8/1924 Nelson 1 23/141 Primary Examiner--Laurence M. Goodridge Attorney-Smyth, Roston & Pavitt 57] ABSTRACT A fuel injection nozzle having a passage extending therethrough and terminating at one end in an outlet. An atomizing device is positioned in the passage adjacent the outlet. The nozzle is preferably mounted on an intake manifold of an engine at such an angle that it directs the fuel into the Y manifold in the same direction as the air flowing through the manifold. The nozzle controls the shape of the spray pattern so that the cross sectional configuration of the spray pattern generally conforms to the cross sectional configuration of the manifold.

19 Claims, 4 Drawing Figures FUEL INJECTION NOZZLE AND SYSTEM BACKGROUND OF THE INVENTION Fuel injection nozzles and systems are used extensively with high performance engines such as in race cars although their use need not be so limited. One fuel injection system includes a fuel pump for supplying fuel under pressure to several fuel injection nozzles. The rate of fuel supply through the nozzles is controlled by a metering valve and one or more fuel bypasses.

One function of the fuel injection nozzle is to atomize the fuel supplied thereto and discharge the atomized fuel into the engine. Improved or finer atomization results in better mixing of the fuel and air, more complete combustion of the fuel, increased fuel economy and a greater cooling effect from the latent heat of vaporization of the fuel. One problem with fuel injection nozzles is how to improve the degree of atomization obtainable therefrom.

SUMMARY OF THE INVENTION The present invention provides a fuel injection nozzle in which fuel atomization is substantially improved. This is accomplished by an atomizing device which includes one or more transversely extending strand-like elements in the path of the fuel stream through the nozzle. Preferably the atomizing device is a screen composed of numerous relatively fine wires. A screen provides optimum atomization and is easier and less expensive to make than an apertured disc. Another advantage of a screen over an apertured disc is that a screen can provide a greater number of impingement surfaces and a greater number oforifices.

The atomizing device is preferably located near the outlet of the nozzle. The fuel is preferably substantially prevented from atomizing upstream of the atomizing device because atomized fuel would be more difficult to force through the nozzle. Accordingly a substantially nonatomized fuel stream impinges against the atomizing device and substantially all atomization occurs at the atomizing device.

The passage through the nozzle has an inlet section, an intermediate section and an outlet section. The inlet section is connected to a supply of fuel under pressure and the outlet section terminates in an outlet which discharges the fuel into the inlet manifold of an engine. The atomizing device is provided in the outlet section adjacent the outlet.

One preferred way for preventing fuel from atomizing upstream of the atomizing device is to maintain the cross sectional area of the outlet section of the passage relatively small. Also, a tube may be provided in the intermediate section spaced from the outlet section by a gap for shooting a stream or needle of fuel across the gap into the outlet section.

When a screen is used as the atomizing device, a number of small orifices are provided through which the fuel must pass. If the screen were provided in the small cross sectional area outlet section, only a few of the orifices would be exposed to the fuel stream. Accordingly, to increase the number of orifices and the number and length of wires exposed to the fuel stream, the present invention teaches enlarging the cross sectional area of a downstream portion of the outlet section and locating the atomizing device in such downstream portion. The atomizing device is spaced from the juncture of the downstream portion of the passage with the upstream portion of the passage to thereby expose more and greater lengths of wires. Another advantage of exposing a greater number of orifices of the atomizing device is that the likelihood of complete clogging of the atomizing device is reduced.

When the screen is used as the atomizing device, the degree of atomization can be controlled, to some extent, by the size and number of the orifices and wires. For improved atomization, it is preferred to utilize a large number of small diameter wires for the screen.

The nozzle of the present invention is adapted to be mounted on the intake manifold to discharge fuel therein. The present invention. recognizes that it is desirable for the nozzle to distribute the atomized fuel substantially throughout the manifold without excessively wetting the walls of the manifold. The present invention is also based, to some degree, on the discovery that engine horsepower can be increased somewhat by directing fuel flow into the air stream in the manifold generally coaxial therewith and in a pattern, the cross section of which is generally similar to the cross sectional configuration of the surrounding portion of the intake manifold. The spray pattern should be controlled so as to avoid wetting of the walls of the manifold with fuel.

With the present invention, the shape of the outlet of the nozzle controls the shape of the spray pattern. For example, a circular outlet provides a conical spray pattern. The direction of the spray pattern is controlled by the angle at which the nozzle is mounted on the manifold. The rate at which the pattern diverges can be controlled by controlling the area of the nozzle outlet and the distances from the atomizing device to the nozzle outlet and to the juncture of the upstream and downstream portions of the outlet section.

The invention, both to its organization and method of operation together with further features and advantages thereof, may best be understood by reference to the following description taken in connection with the accompanying illustrative drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a partially schematic view of a fuel injection system constructed in accordance with the teachings of this invention. In FIG. 1, an engine intake manifold is illustrated in axial cross section and a fuel injection nozzle constructed in accordance with the teachings of this invention is shown in side elevation.

FIG. 2 is an axial sectional view through the fuel injection nozzle.

FIG. 3 is an enlarged fragmentary side elevational view partially in section of the nozzle tip.

FIG. 4 is an end elevational view of the nozzle tip.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings and in particular to FIG. 1, reference numeral 11 designates a fuel injection system constructed in accordance with the teachings of this invention. The fuel injection system 11 includes a fuel supply tank 13, a fuel pump 15, a metering valve 17 and a plurality of fuel in jection nozzles 19 (only one being shown in FIG. 1). Although any number of the nozzles 19 may be utilized depending upon the number of engine cylinders, only one of these nozzles is described herein in detail, it being understood that the other nozzles may be of similar or identical construction. The fuel pump 15 supplies fuel under pressure through a fuel supply conduit 21 and the metering valve 17 to the nozzle 19. The metering valve 17 controls the rate of fuel flow to the nozzle 19 and the metering valve may itself be controlled, for example, by the throttle linkage (not shown).

To provide additional control over the rate of fuel supply to the nozzle 19, the system 11 also preferably includes at least one fuel bypass which, in the embodiment illustrated, is a primary bypass 23. The primary bypass 23 leads from the pump 15 back to the tank 13 and includes a selector valve 25 and a plurality (three being illustrated) of parallel passages 27. The primary bypass 23 receives fuel under pressure from the pump 15 and returns it through one of the passages 27 which has been selected by the valve 25 to the tank 13. Each of the passages 27 contains a restriction 29 which may be, for example, a metering orifice with each of the orifices providing a different restriction to the flow of fuel therethrough. The selector valve 25 is manually adjustable to provide a return path through any one of the passages 27. Accordingly, by selecting the appropriate passage 27 for the return of bypassed fuel to the tank 13, the degree of restriction, and hence, the rate of fuel flow through the primary bypass can be adjusted. The primary bypass 23 can be used, for example, to permit the driver to adjust the fuel-air ratio supplied to the engine, and this is particularly useful when switching from one fuel to another.

The nozzle 19 is mounted on an intake manifold 31 of an engine (not shown) of a vehicle such as a racing car. The intake manifold 31 includes a manifold wall 33 defining a main manifold passage 35 for supplying air to the engine. A throttle valve or butterfly valve 37 is suitably pivotally mounted within the main manifold passage 35 for controlling the flow of air to the engine. The throttle valve 37 is illustrated in FIG. 1 as being in the closed position and it is preferably controlled by the same linkage as the metering valve 17 so that fuel and air will be supplied to the engine in the proper proportions. Air is supplied to the main manifold passage 35 upstream of the throttle valve 37 by a supercharger (not shown); however, the present invention is applicable to systems not employing a supercharger.

The manifold wall 33 also defines an auxiliary manifold passage 39 which provides communication between the main manifold passage 35 upstream of the throttle valve 37 and the nozzle 19. In the embodiment illustrated, the nozzle 19 is mounted on the intake manifold 31 downstream of the throttle valve 37, and accordingly, the auxiliary manifold passage 39 forms a bypass around the throttle valve 37. The manifold passage 39 is preferably formed by the manifold wall rather than by a separate tube or other member attached to the manifold 31.

The manifold wall 33 has an inclined mounting portion 41 having an aperture 43 extending therethrough. The manifold wall 33 also has a threaded opening 45 coaxial with the opening 43. The nozzle 19 has an externally threaded portion 47 mounted within the opening 45 and a nut 49 which bears on the outer surface of the mounting portion 41 to thereby securely mount the nozzle 19 on the manifold 31.

It will be readily appreciated that the size and configuration of an intake manifold can vary widely and the intake manifold 31 is illustrated merely by way of example. In the embodiment illustrated, the main manifold passage 35 is circular in transverse cross section. Specifically, the upper portion of the passageway 35 is generally cylindrical and the lower portion of the passageway 35 curves slightly. Air is supplied from above the throttle valve 37 and flows along a path which extends in the same general direction as the axis of the main manifold passage 35.

With reference to FIG. 2, the nozzle 19 includes a body member 51 and a nozzle tip 53 mounted within the body member 51 to define body means for the nozzle. The nozzle 19 has an axial passage 55 extending therethrough. The passage 55 includes an inlet section 57, a first intermediate section 59, a second intermediate section or chamber 61 and an outlet section 63, all of which are coaxial. The

section

57, 59 and 61 are cylindrical and of progressively increasing diameter. The inlet section 55 may be connected to the conduit 21 by a suitable connector (not shown) which may utilize external threads 65 which surround the inlet section. The outlet section 63 includes a frusto conical flared portion 67, an upstream portion 69 and a downstream portion 71 with the downstream portion 71 terminating in an outlet 73. In the embodiment illustrated, the

portions

69 and 71 are cylindrical and coaxial.

A tubular member 75 is suitably mounted within the chamber 61. The tubular member 75 has a block portion 77 of substantially the same cross sectional area and configuration as the chamber 61 and a coaxial tube portion 79 of substantially smaller diameter than the block portion and spaced radially inwardly from the peripheral wall of the chamber 61. The tubular member 75 has a relatively small diameter passageway 81 extending axially therethrough and coaxial with the chamber 61. The inlet end of the passage 81 has a flared portion 83 and the outlet of the passage 81 terminates in coaxial spaced relationship to the outlet section 63. Preferably the diameter of the passage 81 is smaller than the diameter of the upstream portion 69 ofthe outlet section 63.

A fuel filter may be provided in the passage 59 if desired so long as it does not atomize the fuel.

A plurality of radially extending ports 85 provide communication between the chamber 61 and the exterior of the nozzle 19. The tubular member 75 and the nozzle tip 53 may be mounted on the body member 51 in any suitable manner such as by soldering.

The details of the nozzle tip can best be seen in FIGS. 3 and 4. The nozzle tip 53 includes a body section 87 having an annular end face 89. In the embodiment illustrated, the body section 87 defines the flared portion 67, the upstream portion 69, and a portion of the downstream portion 71 of the passage 55.

An atomizing device in the form of a screen 91 is clamped against the end face 89 by an annular retainer 93. The retainer 93 may be removably affixed to the body section 87 as by screw threads but it is preferably permanently attached to the body section as by soldering. The retainer 93 forms the remainder of the downstream portion 71 of the passage 55 and also defines the outlet 73.

The screen 91 is spaced downstream from a shoulder 95 which defines the juncture between the

passage portions

69 and 71. The screen 91 is spaced upstream from the outlet 73. The screen 91 extends transverse to the axis of the outlet section 63 and, in the embodiment illustrated, is perpendicular to the axis of the outlet section.

The screen 91 includes a plurality of fine wires or strandlike elements 97 and 99 (FIG. 4) which define a plurality of small orifices 101 (FIG. 4). In the embodiment illustrated, the wires 97 are in spaced parallel relationship and extend generally transversely to the wires 99. Similarly, the wires 99 are in spaced parallel relationship, it being understood that the orientation of the

wires

97 and 99 can be varied. Accordingly, the orifices 101 are generally square. The function of the screen 91 is to finely divide and atomize the fuel stream which impinges thereagainst. Although the present invention is not limited to any particular size or arrangement of wires for accomplishing this atomizing result, optimum results can be obtained if numerous small diameter slightly spaced wires are utilized.

In operation of the fuel injection system 11, the fuel pump 15 supplies fuel under pressure to the nozzle 19 with the quantity of fuel supplied being controlled by the metering valve 17 and the bypass 23. Simultaneously, air is supplied through the main manifold passage 35 at a rate which is dependent upon the position of the throttle valve 37 and other factors. Air is also supplied to the nozzle 19 through the auxiliary manifold passage 39, such air entering the ports which are exposed within the passage 39. Thus, the air supplied to the ports 85 of the nozzle 19 is independent of the position of the throttle valve 37.

The fuel under pressure travels through the inlet section 57 and the intermediate section 59 to the passageway 81 without atomizing. The passageway 81 is of smaller diameter than the intermediate section 59, and accordingly, the velocity of the fuel is increased in the passageway 81. This permits the tubular member 75 to shoot a high velocity, small diameter stream or needle of fuel across the gap between the tube 79 and the nozzle tip 53. Such stream of fuel enters the outlet passage 63 and travels therethrough substantially to the screen 91 without atomizing. Simultaneously, the air from the manifold passage 39 enters the ports 85 and surrounds the fuel stream. This air is drawn into the outlet passage 63 in a tubular column which surrounds the fuel stream within the outlet section 63 but substantially no atomization of the fuel stream occurs upstream of the screen 91.

When the high velocity needle of fuel and the surrounding tubular column of air impinge against the

wires

97 and 99, such wires are operative to finely atomize or divide the fuel stream into minute particles while the orifices 101 are operative to permit passage of such finely divided particles therethrough to the outlet 73 and into the main manifold passage 35.

As the screen 91 is spaced downstream from the shoulder (FIG. 3) a larger area of the screen 91 is exposed to the fuel stream than if the screen were clamped directly against the shoulder 95. In addition, more of the orifices 101 are exposed to the fuel stream thereby making complete clogging of the orifices 101 much less likely.

The cross sectional configuration of the fuel pattern sprayed into the manifold passage 35 is a function of the cross sectional configuration of the outlet 73. In the embodiment illustrated, the outlet 73 is circular and this produces a conical spray pattern. The rate of divergence of the cone can be decreased by decreasing the diameter of the outlet 73 or by increasing the distance between the screen 91 and the outlet 73. The degree of atomization is effected by varying the distance between the screen 91 and the shoulder 95 and by the number, diameter and spacing of the

wires

97 and 99. It is preferred to have the screen 91 spaced from but closely adjacent the screen 95. The spacing between the screen 91 and the shoulder 95 should be sufficient to allow the fuel stream to take advantage of the greater cross sectional area of the screen which is exposed to the fuel in the passage portion 71. For convenience in manufacturing, it is preferred that the downstream portion 71 be a cylindrical bore in which event the outer diameter of the shoulder 95 would be the same as the diameter as the outlet 73.

Another feature of the present invention is the mounting of the nozzle 19 in such a relationship to the manifold passage 35 that the fuel injected by the nozzle flows in substantially the same direction as the air flow through the manifold passage 35. Specifically the fuel preferably forms a spray pattern 103, the axis of which generally follows the axis of the surrounding portion of the manifold. In addition, the shape of the spray pattern 103 is adjusted so that wetting of the wall of the manifold passage 35 by the atomized fuel is substantially eliminated.

Thus, as shown in FIG. 1, the fuel particles in the spray pattern 103 flow in generally the same direction as the fuel flowing through that particular region of the manifold passage 35. The cross sectional configuration of the pattern 103 is generally similar to cross section configuration of the surrounding regions of the manifold passage 35. In addition, the rate of divergence of the conical spray pattern 103 is adjusted so that substantially all of the fuel particles have been picked up and are travelling with the airstream prior to the time that the spray pattern diverges sufficiently to wet the walls of the manifold passage 35. By this arrangement, it has been found that engine horsepower can be increased. Although the spray pattern 103 is shown as being conical, in actual practice of the invention the air flowing through the manifold passage 35 would affect the shape of the spray pattern.

The concepts of this invention are equally applicable to a fuel injection system having no auxiliary manifold passage 39 and in which the ports 85 are eliminated. Similarly, the shape of the fuel pattern 103 can be tailored to meet the requirements of manifold passages of different cross sectional configurations.

Although an exemplary embodiment of the invention has been shown and described, many changes, modifications and substitutions may be made by one having ordinary skill in the art without necessarily departing from the spirit and scope of this invention.

lclaim:

1. A fuel injection system for supplying fuel to an engine comprising:

an intake manifold for supplying fuel and air to the engine, a

predetermined region of the manifold adjacent the engine being of a predetermined cross sectional configuration;

a fuel injection nozzle mounted on said intake manifold adjacent said region;

means for supplying fuel under pressure to the fuel injection nozzle;

a valve means for controlling the supply of fuel under pressure to the fuel injection nozzle;

a throttle valve for controlling air flow through the manifold;

said nozzle having a fuel passage therethrough, said passage including an outlet and first and second contiguous portions with said first portion including said outlet, said outlet being adapted to direct fuel into said region and toward the engine generally in the same direction as the direction of air flow through said region of said manifold;

said nozzle having means including at least two strand-like elements adjacent the outlet and spaced from said second portion for atomizing the fuel supplied therethrough to the manifold;

the cross sectional area of said first portion immediately adjacent the strand-like elements being larger than the cross sectional area of said second portion at the juncture of said portions; and

said nozzle including means for directing the atomized fuel into the engine in a predetermined pattern which is substantially coaxial with said region and which is of a cross sectional size to substantially avoid wetting of the manifold walls with the atomized fuel, the cross sectional shape of said pattern being similar to said predetermined cross sectional configuration of said region whereby wetting of the manifold walls with the atomized fuel is minimized.

2. A fuel injection system for supplying fuel to an air intake manifold of an engine comprising:

a fuel injection nozzle connectible to the intake manifold of the engine, said nozzle having a passage therethrough for supplying fuel to the engine;

means for supplying fuel under pressure to the fuel injection nozzle;

valve means for controlling the supply of fuel under pressure to the fuel injection nozzle;

said passage terminating in an outlet;

at least two elongated elements;

means for mounting said elongated elements on said fuel injection nozzle closely adjacent said outlet, said strandlike elements extending into the path of fuel flow and generally transverse to said path; and

said elongated elements defining a plurality of impingement surfaces adjacent said outlet whereby impingement of the fuel on said elongated elements causes atomization of the fuel.

3. A fuel injection system as defined in claim 2 including a plurality of said elongated elements in addition to said two elongated elements, said elongated elements defining a screen adjacent said outlet.

4. A fuel injection system as defined in claim 2 wherein said passage has first and second contiguous portions with the first portion containing sad outlet, said first portion having a region extending from the juncture of said portions toward said outlet, the cross sectional area of said region of said first portion being greater than the cross sectional area of the second portion at the juncture of said portions, said elongated elements being in said region of said first portion.

5. A fuel injection system as defined in claim 4 wherein said elements are spaced from said juncture of said portions.

6. A fuel injection system as defined in claim 4 wherein said second portion is substantially longer than said first portion of said passage.

7. A fuel injection system as defined in claim 4 wherein the cross sectional area of said outlet is at least as large as the cross sectional area of the first portion at the juncture of said portions.

8. A fuel injection system as defined in claim 2 wherein the intake manifold supplies air to the engine with the air travelling along a predetermined path in said manifold to the engine, the axis of said passage of said nozzle extending in the same general direction as said path at the location of said outlet.

9. A fuel injection system as defined in claim 1 wherein said predetermined cross sectional configuration is generally circu lar.

10. A fuel injection system as defined in claim 1 wherein said means for atomizing includes a screen adjacent said outlet against which the fuel can impinge.

11. A fuel injection nozzle for directing fuel and air into an engine comprising:

body means having a passage therethrough, said passage including an inlet section connectible to a source of fuel under pressure, an intermediate section and an outlet section, said outlet section having an outlet for directing fuel into the engine;

said body means having means for conducting air to the intermediate section whereby the fuel and air in said intermediate section can flow through the outlet section to the outlet;

said outlet section having a downstream portion and an upstream portion, said downstream portion defining said outlet, said portions of said outlet section being contiguous;

an atomizing member mounted on said body means, said atomizing member including at least two generally transversely extending elongated atomizing elements against which the fuel stream can impinge, each of said two elements extending at least partially across the downstream portion at a location spaced from said juncture; and

the cross sectional area of said downstream portion at said location being greater than the cross sectional area of said upstream portion at the juncture of said portions.

12. A nozzle as defined in claim 11 wherein said atomizing member includes a screen extending at least substantially across said downstream portion at said location.

13. A fuel injection nozzle as defined in claim 12 wherein said outlet section is elongated, said means for conducting includes at least one aperture in said body means providing communication between the intermediate section and the exterior of the body means, said inlet and outlet sections being of lesser cross sectional area than the intermediate section at their respective junctures with the intermediate section.

14 A fuel injection nozzle as defined in claim 11 wherein said location is within said downstream portion.

15. A fuel injection nozzle for supplying fuel to an engine comprising:

body means having a passage therethrough, said passage including an inlet section, an outlet section and an intermediate section, said outlet section terminating in an outlet and said inlet section being connectible to a source of fuel, said passage being adapted to conduct fuel therethrough;

said outlet section having a first portion and a second portion with said first portion including said outlet, said portions being contiguous;

said second portion being elongated;

means for directing a stream of fuel across at least a portion of said intermediate section and into said outlet section, said stream of fuel being of lesser cross sectional area than said intermediate section;

an atomizing screen;

means for mounting said atomizing screen on said body means in the path of fuel flow, said atomizing screen being adjacent said outlet and spaced from said second portion;

the cross sectional area of said first portion immediately adjacent the atomizing device being larger than the cross sectional area of said second portion at the juncture of said portions; and

said second portion of said passage being adapted to direct a stream of fuel against said atomizing screen whereby said atomizing screen atomizes the fuel directed thereagainst to produce a spray pattern with the cross sectional area of the spray pattern being a function of the distance between the atomizing screen and the adjacent end of said second portion.

16. A fuel injection nozzle as defined in claim 15 wherein said atomizing screen is mounted within said first portion axially inwardly of said outlet whereby said atomizing screen is protected by said body means.

1 A fuel in ection nozzle as defined in claim 15 wherein said outlet section includes a bore and a counterbore defining said first and second portions, respectively, said body means defining a shoulder at the juncture of said first and second portions, said atomizing screen lying axially intermediate said shoulder and said outlet.

18. A fuel injection nozzle as defined in claim 15 wherein said body means includes an annular retainer defining said outlet and clamping said atomizing device against another portion of said body means.

19. A fuel injection nozzle as defined in claim 15 wherein said intermediate section is of larger cross sectional area than said outlet section, said second portion being longer axially than said first portion, said second portion being of lesser cross sectional area throughout the full length thereof than said first portion.

Claims

1. A fuel injection system for supplying fuel to an engine comprising: an intake manifold for supplying fuel and air to the engine, a predetermined region of the manifold adjacent the engine being of a predetermined cross sectional configuration; a fuel injection nozzle mounted on said intake manifold adjacent said region; means for supplying fuel under pressure to the fuel injection nozzle; a valve means for controlling the supply of fuel under pressure to the fuel injection nozzle; a throttle valve for controlling air flow through the manifold; said nozzle having a fuel passage therethrough, said passage including an outlet and first and second contiguous portions with said first portion including said outlet, said outlet being adapted to direct fuel into said region and toward the engine generally in the same direction as the direction of air flow through said region of said manifold; said nozzle having means including at least two strand-like elements adjacent the outlet and spaced from said second portion for atomizing the fuel supplied therethrough to the manifold; the cross sectional area of said first portion immediately adjacent the strand-like elements being larger than the cross sectional area of said second portion at the juncture of said portions; and said nozzle including means for directing the atomized fuel into the engine in a predetermined pattern which is substantially coaxial with said region and which is of a cross sectional size to substantially avoid wetting of the manifold walls with the atomized fuel, the cross sectional shape of said pattern being similar to said predetermined cross sectional configuration of said region whereby wetting of the manifold walls with the atomized fuel is minimized.

2. A fuel injection system for supplying fuel to an air intake manifold of an engine comprising: a fuel injection nozzle connectible to the intake manifold of the engine, said nozzle having a passage therethrough for supplying fuel to the engine; means for supplying fuel under pressure to the fuel injection nozzle; valve means for controlling the supply of fuel under pressure to the fuel injection nozzle; said passage terminating in an outlet; at least two elongated elements; means for mounting said elongated elements on said fuel injection nozzle closely adjacent said outlet, said strandlike elements extending into the path of fuel flow and generally transverse to said path; and said elongated elements defining a plurality of impingement surfaces adjacent said outlet whereby impingement of the fuel on said elongated elements causes atomization of the fuel.

9. A fuel injection system as defined in claim 1 wherein said predetermined cross sectional configuration is generally circular.

11. A fuel injection nozzle for directing fuel and air into an engine comprising: body means having a passage therethrough, said passage including an inlet section connectible to a source of fuel under pressure, an intermediate section and an outlet section, said outlet section having an outlet for directing fuel into the engine; said body means having means for conducting air to the intermediate section whereby the fuel and air in said intermediate section can flow through the outlet section to the outlet; said outlet section having a downstream portion and an upstream portion, said downstream portion defining said outlet, said portions of said outlet section being contiguous; an atomizing member mounted on said body means, said atomizing member including at least two generally transversely extending elongated atomizing elements against which the fuel stream can impinge, each of said two elements extending at least partially across the downstream portion at a location spaced from said juncture; and the cross sectional area of said downstream portion at said location being greater than the cross sectional area of said upstream portion at the juncture of said portions.

13. A fuel injection nozzle as defined in claim 12 wherein said outlet section is elongated, said means for conducting includes at least one aperture in said body means providing communication between the intermediate section and the exterior of the body means, said inlet and outlet sections being of lesser cross sectional area than the intermediate section at their respective junctures with the intermediate section. 14 A fuel injection nozzle as defined in claim 11 wherein said location is within said downstream portion.

15. A fuel injection nozzle for supplying fuel to an engine comprising: body means having a passage therethrough, said passage including an inlet section, an outlet section and an intermediate section, said outlet section terminating in an outlet and said inlet section being connectible to a source of fuel, said passage being adapted to conduct fuel therethrough; said outlet section having a first portion and a second portion with said first portion incLuding said outlet, said portions being contiguous; said second portion being elongated; means for directing a stream of fuel across at least a portion of said intermediate section and into said outlet section, said stream of fuel being of lesser cross sectional area than said intermediate section; an atomizing screen; means for mounting said atomizing screen on said body means in the path of fuel flow, said atomizing screen being adjacent said outlet and spaced from said second portion; the cross sectional area of said first portion immediately adjacent the atomizing device being larger than the cross sectional area of said second portion at the juncture of said portions; and said second portion of said passage being adapted to direct a stream of fuel against said atomizing screen whereby said atomizing screen atomizes the fuel directed thereagainst to produce a spray pattern with the cross sectional area of the spray pattern being a function of the distance between the atomizing screen and the adjacent end of said second portion.

17. A fuel injection nozzle as defined in claim 15 wherein said outlet section includes a bore and a counterbore defining said first and second portions, respectively, said body means defining a shoulder at the juncture of said first and second portions, said atomizing screen lying axially intermediate said shoulder and said outlet.