US3325104A

US3325104A - Fuel injection nozzle

Info

Publication number: US3325104A
Application number: US295136A
Authority: US
Inventors: Vernon D Roosa
Original assignee: HARTFORD MACHINE SCREW
Current assignee: HARTFORD MACHINE SCREW
Priority date: 1963-07-15
Filing date: 1963-07-15
Publication date: 1967-06-13
Anticipated expiration: 1984-06-13
Also published as: DE1285787B; DE1601416A1; ES302011A1; SE313217B; GB1039848A

Description

June 13, 1967 v. D. Roos/.

FUEL INJECTION NOLZLE 2 Sheets-Sheet l Filed July l5, 1965 INVENTOR. VERNON D.. ROOS WM? ATTORNEYS June 3 1967 V. D. @005A FUEL INJECTION NOZZLE Filed July 15. 1965 2 Sheets-Sheet 2 INVENTOR. VERNON D. ROOSA ATTORNEYS United States Patent O 3,325,104 FUEL INJECTION NOZZLE Vernon D. Roosa, Hartford Machine Screw, P. 0. Box 1440, West Hartford, Conn. 66101 Filed July 15, 1963, Ser. No. 295,136 3 Claims. (Cl. 239-584) This application is a continuation-in-part of application Ser. No. 275,789 filed Apr. 16, 1963, now Patent No. 3,224,684 issued Dec. 21, 1965, which application is a continuation-in-part of the application Ser. No. 123,581, filed July 12, 1961, now abandoned.

This invention relates generally to fuel injection nozzles for internal combustion engines and more particularly to an improved nozzle of the type having a plunger valve that is op-erated by high pressure fuel supplied to the nozzle such as discolsed in my U.S. Patent No. 2,865,675 entitled, Fuel Injection Nozzle.

In fuel injection nozzles of the type involved in this invention, it is essential that the high pressure fuel supply line be secured to the nozzle by a particularly tight fit so that the leakage of metered high pressure fuel does not occur. In many applications, particularly where the engine involved has overhead valves, the space available for mounting the projection nozzle is restrict-ed and it may be mounted in a deep narrow recess in the engine block making access to the joint :between the fuel line and the inlet port of the fuel injection nozzle difficult. `In conventional fuel injection nozzles, the inlet fitting is formed as an integral stud on the barrel of the nozzle. Thus, the nozzle barrel must have suiiicient mechanical strength and rigidity to withstand the torque applied thereto during the connection of the fuel supply line without permanent deformation which could result in erratic operation of the plunger valve. Accordingly, it is an object of the present invention to provide a fuel injection nozzle in which the mechanical strength of the `barrel portion of the nozzle need not be such as to with stand the torsion forces required for securing the high pressure supply line thereto.

Another object of this invention is to provide a joint between the fuel supply line and the injection nozzle which is spaced from the barrel portion of the nozzle by a deformable thin-walled tube which may be bent to any desired configuration to simplify the design of the fuel supply lines from the fuel pump.

A further object of this invention is the provision of an improved nozzle having simplified and economical construction which is adapted so as to be interchangeable with other fuel injection nozzles so that it may be used as a replacement part on engines in which other types of fuel injection nozzles were installed.

Still another object of this invention is the provision of an improved low cost nozzle suitable for use as a replacement part whereby field reworking adjustment of nozzles is eliminated.

Another object of this invention is the provision of a fuel injection nozzle having a joint spaced from the barrel portion thereof which joint is so constructed as to prevent destructive shearing stresses from being applied to the thin-walled tube connecting the joint to the barrel of the nozzle during the attachment of a fuel supply line.

Other objects will be in part obvious and in part pointed out `more in detail hereinafter.

The invention accordingly consists in the features of construction, combination of elements and arrangement of parts which will be exemplified in the construction hereafter set forth and the scope of the application of which will be indicated in the appended claims.

In the drawings:

FIG. lis a fragmentary top View of a portion of a cylinder of an internal combustion engine showing the assembly thereon of the fuel injection device of this invention;

FIG. 2 is a fragmentary cross-sectional view taken generally along the lines 2 2 of FIG. 1; and

FIG. 3 is an enlarged longitudinal sectional view partly broken away and partly in section constructed in accordance with the invention.

Turning now to the drawings in which like numerals refer to like parts, the exemplary nozzle shown therein is generally similar to that disclosed in my U.S. Patent No. 2,865,675 and my copending patent application Ser. No. 275,789, tiled Apr. 16, 1963, and includes a generally tubular barrel or body 10 formed from tubing of any suitable material such as 4130 stainless steel and having a central bore 14 extending throughout its length. A nozzle tip 12 is affixed at one end of the nozzle .body 10. A reciprocably mounted plunger 16 is positioned within the central bore 14 for controlling the passage of fuel from the central bore 14 tothe nozzle tip 12. A plunger guide 13 is provided in the central bore 14 for slidably mounting the plunger 16. A fuel inlet port 20 communicates with the central Ibore 14 between the plunger guide 18 and the tip 12 so that metered fuel under high pressure in the bore 14 causes the plunger to be urged away from the tip against the bias of a return spring (not shown) whereby pressurized fuel may be discharged from the tip through outlet passages 19'. Preferably, the bore of the plunger guide 18 and the mating portion of the plunger 16 are provided with a lapped t to minimize fuel leakage therebetween. A fuel leak-oft connection, generally designated 22, is connected to the outer end of the tubular body 1? to provide a leak-off passage for the fuel injection nozzle.

Referring now particularly to FGS. 1 and 2, there is shown a portion of a cylinder head 24 of an internal combustion engine having a bore 26 into which the body lil of the fue] injection nozzle is inserted. An annular sealing ring 28 positioned in an annular groove 30 of the nozzle body 10 aids in sealing the interior of a cylinder adjacent the tip 12 of the nozzle.

Surrounding the outer end of the bore 26 is an annular shoulder 32 on which is positioned a sealing washer 34 which is clamped between the annular hold-down member 36 and the shoulder 32 `by `a bifurcated clamp 38` which is urged against the top surface of annular member 36 by a clamping bolt 40.

As shown in FIGS. 1 and 2, the bore 26 for the reception of the nozzle body 10 of the injection nozzle is located at the bottom of a deep narrow recess in the engine block having side walls 42 which extend beyond the end of the injection nozzle (see FlG. 2). It will also be observed that the bifurcated clamp 38 further restricts the accessibility of nozzle body 1t) for detachably connecting a supply line thereto. Accordingly, in accordance with one aspect of this invention, there is provided an inlet tube which is permanently secured to nozzle body 10 to provide communication with the inlet port 2d and has, on the free end thereof, a joint for detachably connecting a supply line thereto at a point spaced from the nozzle body where it is readily accessible for the connection of the fuel supply line. As shown, inlet tube 44 is formed of any suitable thin-walled deformable tubing such as 1015 steel injection tubing. The inner end of inlet tube 44 is tapered as indicated at 46 so -as to be received in a mating taper of supply port 20 in the side wall of the nozzle body 10. Annular member 36 is apertured to receive the body llt) and is further provided with a laterally extending apertured portion l48 to receive the tapered end 46 of the inlet tube 44.

As shown in FIG. 3, the annular member 36 is provided with annular grooves 50, 52 and the tapered end 46 of the supply line 44 likewise is provided with an annular groove 54. With the annular member 36 positioned around .body member so that the laterally extending portion 48 is aligned with inlet port 20, a ring of silver solder may be positioned in the annular groove 54 of inlet tube 44 which is then inserted axially in apertured portion 48 and placed in alignment with inlet port 20. With the inlet port so positioned, silver solder may also be positioned in annular grooves 50, 52 and, while the various parts are held in assembled position, annular member 36 and inlet tube y44 are metallically lbonded in place by the application of heat.

It will be observed that the laterally extending apertured portion 48 of the annular member 36, while not bonded to the inlet tube 44 throughout its length, provides lateral support therefor and minimizes the strain applied to the silver solder 54 by any lateral loading which might be encountered. Moreover, the mating connection between tapered end 46 of the inlet tube 44 and the tapered recess of the inlet port serves to precisely locate the annular member 36 axially on the nozzle body and serves to key the annular member 36 to the nozzle body 10 in the event of any fracture of the silver solder in the grooves 50, 52 during use.

As best shown in FGS. l and 2, the use of a supply line 44 metallically bonded, fused or otherwise irremovably afixed to the body member 10 not only provides a readily accessible and separable joint for connecting the injection nozzle to a supply line of metered high pressure fuel at a point displaced from the nozzle body 10 but also, due to the deformable nature of the thin-walled inlet tube 44, accommodates the positioning of the separable joint in such a manner as to be most convenient for the particular installation involved. Moreover, the walls of inlet tu-be 44 are designed so as to have suicient strength to readily withstand the internal hydraulic pressures in any given application, but with low torsional strength so that any torsional forces which tend to be transmitted to the nozzle body 10 during the connection of a supply line thereto will not cause permanent distortion thereof with the resultant misalignment of the plunger 16 and the valve seat of tip 12 and the erratic operation resulting therefrom as more fully described in my aforesaid copending patent application Ser. No. 275,789. Accordingly, another feature of my invention resides in the provision, in a fuel injection device, of a separable joint arrangement to prevent the imposition of harmful torsion forces on the barrel of a fuel injection nozzle during the attachment thereto of a high pres-sure supply line.

The nozzle body 10 of the exemplary nozzle of this invention is formed of a relatively small diameter thinwalled tubing and is metallically bonded to inlet tube 44. For example, the body 10 may have an outer diameter of about 0.390 inch and a wall thickness of about 0.120 inch, making it subject to deformation 4by bending forces. For

such a nozzle, the inlet tube 44 may have an outer diam-V eter of about 1A inch and a wall thickness of about 0.080 to 0.100 inch.

As best shown in FIG. 3, the outer end of the thin-wall inlet tube 44 is provided with a flared end portion 56 which terminates in la generally cylindrical hoop portion 58. The taper angle of the inner end surface 60 of the flared end portion 56 is greater than the taper angle 62 of the outer surface thereof so as to provide a half section of decreasing dimension toward the end thereof. Moreover, the taper surface 62 preferably has a taper angle of about 45 for reasons hereinafter set forth.`

The hoop portion 58 has a generally cylindrical outer surface 64 and a conical inner surface 66 having a taper angle which is less than the taper angle of the surface 62. Preferably, the taper angle of surface 66 is about 10 to 12 degrees.

An externally threaded yapertured coupling element or Cit 4 screw 68 surrounds the inlet tube 44 and has an end surface complementary with the taper surface 62 of the ared end portion 56 of the inlet tube 44.

A ferrule 70 for surrounding fuel supply line 74 is provided. Ferrule 70 has an outer surface 72 which is tapered at an angle complementary to the angle of the inner surface 66 of the hoop portion ofthe flared end of inlet tube 44. The ferrule is further provided with an oppositely directed tapered outer surface 76 vshown as having a taper angle of about 10 to l2 degrees. 1t will be observed, however, that this outer surface 76 is discontinuous and that the ferrule terminates with a more sharply tapered surface 78 which has a taper angle of, say, 45 Desirably, ferrule 70 is symmetrical so that it may be assembled with either end engaging the flared end portion of inlet tube 44.

An internally threaded coupling nut 80 is also provided and is positioned around supply line 74 and threadingly engages apertured screw 68. The inner bore of coupling element or nut 80 is provided with a tapered portion 82 for engaging the ferrule 70 at the circle of discontinuityV formed Iby the tapered surfaces 76 and 78. To achieveA this result, tapered surface 82 of the coupling nut 80 has a taper angle which is greater than that of tapered surface 76 and less than that of tapered surface 78 or, say, about 25.

As shown in FIG. 3, an annular clearance 86 is provided between threaded inner bore of coupling nut 80 and the outer cylindrical surface of the hoop portion 58 of the ared end of inlet tube 44.

To connect inlet tube 44 to the supply line 74, the ferrule 70 is positioned over the end of the supply line 74. The end of the supply line 74 is positioned against the tapered surface 60 of the ared end 56 of inlet tube 44. The coupling nut 80 is then tightened onto the apertured screw 68 and as screw 68 and nut 80 move axially toward each other, the tapered surface 82 of the coupling nut engages the ferrule along the circle of discontinuity of tapered

surfaces

76 and 78 to urge mating surfaces 66 and 72 into contact with each other. This relative axial movement of apertured screw 68 and coupling nut 80 likewise compresses the ferrule to cause it to tightly grip supply line 74.

lt will be noted that the wedging action between the ferrule 70 and the hoop portion 58 of the ared end of the inlet tube 44 tends to expand the hoop portion 58 so as to place it under hoop tension. Also, by providing large nonlockin-g tapered surfaces at 62 between the ared end of inlet tube 44 and apertured screw 68, a nonlocking connection is provided, making it necessary to use a w-rench on the polygon shaped portion 84 of screw 68 in order to prevent its rotation. Thus, the Ipossibility that the thin-walled inlet tube 44 may be sheared by twisting during tightening as well as the imposition of harmful bending forces on nozzle body 10, is eliminated. In this regard also, the theoretical line contact between the coupling nut 80 and the ferrule 70 minimizes the tendency of the ferrule to rotate with the coupling nut and thus minimize the torsion forces imposed on inlet tube 44 through the ferrule during the tighening of the joint. Further, by providing that the taper angle at 62 be approximately 45, the hoop portion is reinforced even though the taper angle is sufficiently large to minimize the possibility of applying torsion forces during tightening sufficient to shear inlet tube 44.

From the foregoing, it will be apparent that this invention provides a new and novel design for a fuel supply line wherein a deformable inlet line is permanently connected to the body of the nozzle which, together with a unique joint construction, facilitates the connecting of the nozzle to a supply line, prevents destructive torsion forces from being imposed on the nozzle body, accommodates any desired configuration of the fuel supply line, and

eliminates the possibility that the thin-walled deformable inlet tube might be sheared off during assembly.

As will be apparent to persons skilled in the art, various modifications and adaptations of the structure above-described will become readily apparent without departure from the spirit and scope of the invention, the scope of which is dened in the appended claims.

I claim:

1. In a fuel injection system for an internal combustion engine having a fuel injection nozzle, a fuel supply line and a means connecting said nozzle to said supply line, the improvement wherein the connection means comprises a thin-walled inlet tube having one end inseparably secured to the nozzle body to provide Huid communication with the interior thereof, and a separable coupling positioned at the other end of said inlet tube spaced from the nozzle body to connect said inlet tube to said supply line, said coupling comprising a captive apertured coupling element coaxially disposed around said other end of said inlet tube and being relatively rotatable therewith to engage a mating coupling element on the supply line and an annular flange on the other end of said inlet tube to permanently retain said captive apertured coupling element thereon, said inlet tube being bent to dispose said captive apertured coupling element in a preselected position relative to the nozzle body and to point said coupling element in a preselected angular direction, said an nular flange on said other end of said inlet tube terminating in a generally cylindrical end portion provided with an inner tapered surface, said separable coupling further including an annular ferrule positioned over the end of said fuel supply line to be engaged by the inner tapered surface of said cylindrical end portion and a second apertured coupling element positioned on the end of said supply line and engaging said captive apertured coupling element for compressing said ferrule inwardly toward said supply line, said coupling further providing an annular clearance around said generally cylindrical end portion of said inlet tube whereby the engagement of the apertured coupling elements subjects the cylindrical end portion of the inlet tube to hoop tension as the ferrule is compressed.

2. In the combination of a fuel injection nozzle having a nozzle body to be positioned in an engine bore provided with an annular shoulder at the outer end thereof, a fuel supply line, and means connecting said nozzle to said supply line, the improvement wherein said nozzle body is provided with an annular flange having an annular shoulder to be sealed to the annular shoulder at the outer end of the eng-ine bore and said connecting means comprises a deformable inlet tube having its first end inseparably Xed to said annular flange to provide fluid communication with the interior of the nozzle body, the inlet tube having at the other end thereof and spaced from said nozzle body a coupling for connecting the same to the supply line, said coupling comprising a captive apertured coupling element coaXially disposed about said other end of said inlet tube and being relatively rotatable therewith for engagement with a mating coupling element on said supply line, said other end of said inlet tube being flared to permanently retain said apertured coupling element thereon and said inlet tube being bendable to dispose said apertured coupling element in a preselected position relative to the nozzle body and to point said coupling element in a preselected angular direction.

3. A device as recited in claim 2 wherein the nozzle has a thin-wall tubular body and said annular flange is disposed intermediate the ends of the nozzle body.

References Cited UNITED STATES PATENTS 2,120,067 6/1938 Gray et al, 285-287 2,148,746 2/1939 Hampe et al 285-287 2,279,010 4/1942 -Nicho'ls 239-533 2,295,081 9/ 1942 Horvath 239-533 2,934,362 4/1960' Franck 285-341 3,092,405 6/ 1962 Wu-rzburger 2i85-341 EVERETT W. KIRBY, Primary Examiner.

Claims

1. IN A FUEL INJECTION SYSTEM FOR AN INTERNAL CONBUSTION ENGINE HAVING A FUEL INJECTION NOZZLE, A FUEL SUPPLY LINE AND A MEANS CONNECTING SAID NOZZLE TO SAID SUPPLY LINE, THE IMPROVEMENT WHEREIN THE CONNECTION MEANS COMPRISES A THIN-WALLED INLET TUBE HAVING ONE END INSEPARABLY SECURED TO THE NOZZLE BODY TO PROVIDE FLUID COMMUNICATION WITH THE INTERIOR THEREOF, AND A SEPARABLE COUPLING POSITIONED AT THE OTHER END OF SAID INLET TUBE SPACED FROM THE NOZZLE BODY TO CONNECT SAID INLET TUBE TO SAID SUPPLY LINE, SAID COUPLING COMPRISING A CAPTIVE APERTURED COUPLING ELEMENT COAXIALLY DISPOSED AROUND SAID OTHER END OF SAID INLET TUBE AND BEING RELATIVELY ROTATABLE THEREWITH TO ENGAGE A MATING COUPLING ELEMENT ON THE SUPPLY LINE AND AN ANNULAR FLANGE ON THE OTHER END OF SAID INLET TUBE TO PERMANENTLY RETAIN SAID CAPTIVE APERTURED COUPLING ELEMENT THEREON, SAID INLET TUBE BEING BENT TO DISPOSE SAID CAPTIVE APERTURED COUPLING ELEMENT IN A PRESELECTED POSITION RELATIVE TO THE NOZZLE BODY AND TO A POINT SAID COUPLING ELEMENT IN A PRESELECTED ANGULAR DIRECTION, SAID ANNULAR FLANGE ON SAID OTHER END OF SAID INLET TUBE TERMINATING IN A GENERALLY CYLINDRICAL END PORTION PROVIDED WITH AN INNER TAPERED SURFACE, SAID SEPARABLE COUPLING FURTHER INCLUDING AN ANNULAR FERRULE POSITIONED OVER THE END OF SAID FUEL SUPPLY LINE TO BE ENGAGED BY THE INNER TAPERED SURFACE OF SAID CYLINDRICAL END PORTION AND A SECOND APERTURED COUPLING ELEMENT POSITIONED ON THE END OF SAID SUPPLY LINE AND ENGAGING SAID CAPTIVE APERTURED COUPLING ELEMENT FOR COMPRESSING SAID FERRULE INWARDLY TOWARD SAID SUPPLY LINE, AND COUPLING FURTHER PROVIDING AN ANNULAR CLEARANCE AROUND SAID GENERALLY CYLINDRICAL END PORTION OF SAID INLET TUBE WHEREBY THE ENGAGEMENT OF THE APERTURED COUPLING ELEMENTS SUBJECTS THE CYLINDRICAL END PORTION OF THE INLET TUBE TO HOOP TENSION AS THE FERRULE IS COMPRESSED.