US3156414A

US3156414A - Fuel injection nozzle

Info

Publication number: US3156414A
Application number: US241382A
Authority: US
Inventors: Thomas M Dressler
Original assignee: International Harverster Corp
Current assignee: Navistar Inc
Priority date: 1962-11-30
Filing date: 1962-11-30
Publication date: 1964-11-10
Anticipated expiration: 1981-11-10

Description

T. M. DRESSLER FUEL INJECTION NOZZLE Nov. 10, 1964 2 Sheets-Sheet 1 Filed Nov. 30 1962 Q INVENTOR fz' fi/zeaa zt 10, 1964 -r. M. DRESSLER 3,156,414

FUEL INJECTION NOZZLE Filed Nov. 30, 1962 2 Sheets-Sheet 2 c H36 -17 5 57 x l i e5 An 7 J6 INVENTOR.

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BY WWW United States Patent 3,156,414 FUEL INJECTION NOZZLE Thomas M. Dressler, Chicago, 111., assignor to International Harvester Company, Chicago, 111., a corporation of New Jersey Filed Nov. 30, 1962, Ser. No. 241,382 1 Claim. (Cl. 239-453) This invention concerns fuel injection nozzle means and in particular fuel injection nozzle valves of the character employed in fuel injector units for internal combustion engines. The valve is opened by fuel pressure in the direction of fuel flow through the valve into the internal combustion chamber. My invention more particularly relates to an anti-cavitation collarmeans about the injection nozzle valve.

Injection pressure on the fuel within the nozzle creates turbulence, resulting in the formation of small voids or bubbles which collapse ordinarily at the seat area of the valve. The squeezing out or collapse of these bubbles result in pressure variations in the area of the seat sufficient to erode away the valve seat, this occurrence being known as cavitation. My invention causes the erosion or collapsing of the bubbles to occur in an area removed from the valve seat.

More particularly, the fuel injection valve device provided by my invention comprises a valve seat member having a fuel passage for communication with the combustion chamber of an internal combustion engine; a pintle valve reciprocable within the passage between closed and open positions of the valve from and toward said chamber, and being biased in an axial direction toward the closed position; the passage comprising an anterior inner cylindrical bore surface, an outer cylindrical bore surface, and an outwardly tapered seat between the inner and outer bore surfaces and joined to the inner surface; the pintle valve having an anterior stem end, and a posterior head, the valve further having an enlarged collar between the stem and head, said collar presenting a cylindrical surface which extends toward the stern in an axial direction so that at least a portion of the collar is at all times in an anterior position relative to the junction between the outwardly tapered seat and the inner cylindrical bore surface of said fuel passage, the cylindrical surface of said collar being of a larger outside diameter than the valve stem and being closely spaced apart with respect to the passage to prevent the formation and collapse of gas bubbles in the fuel at the surface of the seat; and stop means presented by the valve seat member at the end thereof corresponding to the anterior stern and of the pintle valve, and engaged by means carried by the stem end for limiting the axial excursion of the valve to insure the described anterior relation of the collar; the collar having-portions thereof extending both above and below the junction of the tapered seat and the inner bore surface in the open position of the pintle valve, the valve having a valve portion between the collar and the head establishing sealing engagement with the tapered seat in the closed position of the valve.

It is therefore an object of this invention to provide a novel fuel injection valve means to greatly reduce or eliminate erosion of the valve seat.

It is still another object of this invention to provide an anti-erosion or anti-cavitation collar upstream of the valve seat of a fuel injection nozzle valve of the open type.

It is still another object of this invention to provide for anti-cavitation means for open type nozzle valves employed in the precombustion chambers of fuel injection engines.

The above and other desirable objects inherent in and encompassed by the invention are elucidated in the ensuing description, the appended claim, and the annexed drawings. However, while the invention is described by reference to its preferred structural embodiment as shown in the drawings and description, it is appreciated that changes may be made therein without departing from the spirit and scope of such appended claim.

FIG. 1 is a view taken in longitudinal section through a fuel injection nozzle assembly and illustrating the nozzle valve assembly, the precombustion chamber, and the combustion chamber;

FIG. 2 is an enlarged view of the nozzle valve assembly;

FIG. 3 is a top view of the cap seat with the valve stem of the nozzle valve assembly;

FIG. 4 is an enlarged sectional view of the valve in the closed position; and

FIG. 5 is an enlarged view of the valve and valve seat in the open position.

With continued reference to the drawings, the nozzle valve assembly 1i! shown isolated in FIG. 2 is mounted within an injector body 11 which in turn is mounted in cylinder head 3 having water jacket area 4, the cylinder head 3 being mounted above the combustion chamber 5 and passageway 6 communicates between the combustion chamber 5 and passage 7 of member 8 within precombustion chamber 9 communicating with the valve assembly 14) as shown in FIG. 1. The body 11 includes an axial bore 12 having a lower end portion 13. The precornbustion chamber 9 has a widely flared recess portion 15 in the lower end of the injection body 11 and provides a surface contour compatible with that of the remainder of the engine precombustion chamber in the cylinder head 3 to periodically inject a finely diffused pintle type fuel spray SP.

A cylindrical tip portion 16 of a valve seat member 17 is inserted downwardly and fits with a close sliding fit in the injector body bore portion 13. Fuel admitted into the coupling member 25 through a tap hole flows downwardly through a bore 27 in tubular stem 24 of the member 25 through filter element 28 into fuel chamber 29 of sleeve 22 of injection body 11 from which ejection of the fuel from the valve tip 16 is controlled by the injection nozzle assembly 10. The parts including the nozzle assembly valve seat member 17 which are in stacked relation within the injector body bore 12 are compressed firmly in such bore by capscrews 31 of which shanks 32 extend downwardly to holes 33 in the crosshead 3d of the coupling member 25 into threaded holes 36 in the upper end of the injection body 11.

The lower outer end of the valve seat member 17 contains a conical valve seat 35 and terminates at its outer extremity into a widened bore 37. A valve stem bore 38 extends upwardly communicatively from this seat 35 through the upper end of the valve seat member 1'7.

The seat member 17 has an axially projecting annular flange 46 to function as a seat for the lower inner end of a spring 47 and spring seat means for the upper outer end of the spring 47 is in the form of a spring seat member 48 having a generally square outer surface, as shown in FIG. 3, to provide wrench-engaging facets 49. Rounded corners 50 of this periphery slidingly bear against the inner periphery of the sleeve 22 to pilot the upper end of a pintle valve stem 57 of the assembled device. A keyhole opening 51 extending axially through the member 48 has a central seat portion 52 communicating with a hole-like portion 53' of greater diameter than the width of such seat portion. The lower portion 54 of the spring seat member 48 presents a face 55 opposing a face 56 of an upward extending tubular stop sion-defining clearance 57a exists between faces 55 and 3 56 to allow the valve 57 to move into the open position as shown according to FIGURE 5.

The pintle 57 has a guide projection 57b for guiding the movement of the valve stem or pintle 57 within the bore 33 and has at its lower end a valve head 58. A stem portion 59 of this pintle extends upwardly from the head 58 through the bore 38 and member 48 and is of a length to dispose a stern enlargement 61 above the inner end of the member 48. In assembling the device the enlargement 61 of the pintle valve 57 is placed in registry with the opening portion 53 through the valve seat member 48 while the latter is forced downwardly to compress the spring 46 and insert the enlargement 61 into the registered opening portion 53, subsequent to which the seat member 48 is moved laterally to carry the enlargement 61 into registration with the seat 52, where such enlargement is retained by force exerted upon such member by the then captive spring 46.

The valve head 53 has an inwardly located conical portion 65 having its external surfaces diverging outwardly in the direction of fuel how and has a cylindrical shaped portion or cavitation collar 66 approximate but slightly less than the diameter of the bore 33 and is formed continuous with the conical portion 65. The pintle has a third portion or pintle portion of greater diameter than the cylindrical portion 66. The pintle portion 67 has an upward outwardly diverging tapered portion or seat face portion 68 for registry with the seat surface 35 of the valve seat member 17, said tapered surface 63 curving outwardly from its juncture with the cylindrical portion 66.

Each time the liquid fuel in the chamber 29 is subject to a pressure impulse from the fuel pump (not shown), fuel is forced to flow downwardly through the opening portion 53 in the member 48 and thence downwardly in the clearance space between the pintle 57 and the tubular stop member 42 and into the space between the pintle and the valve seat member bore 38. The pressure of fuel against that portion 65 of the valve head 48 extending radially inwardly from the valve seat to the pintle stem 59 is built up sufficiently to force the valve head 58, the pintlc stem 59 and the spring seat member 48 downwardly into the valve-open position permitting fuel to escape in the form of a conical spray pattern SP between the seat 35 and the seat face 68. The distance by which the valve head 58 is displaced from the seat 57 in reaching its fully open position is determined by the abutment of the spring seat projection 56 with the upper end of the tubular stop member 42.

At the time of injection of the fuel as it traverses down the bore 38 adjacent and about the stem, the turbulence of the fuel results in the formation of gas particles or bubbles within the fluid stream and in the fully open position as shown in FIG. the bubbles are forced to collapse toward the bottom of the cone portion 65 because of the convergence of the cone portion outwardly and downwardly close to the surface of the bore 38. Bubbles are absent at and immediately above the seat face 35 because of the cylindrical cavitation collar 66 having a diameter only slightly less than the inner diameter of the bore 33 to prevent cavitation. 29, and due to the fluid pressure acting downwardly as In the fuel chamber the engaging seat face 68 of the valve is prevented. Any

pitting or cavitation can only take place above the juncture of the conical portion with the cavitation collar 66, and cannot take place therebelow with this outwardly opening type of valve.

I claim:

A fuel injection valve for an internal combustion engine provided with a combustion chamber, said valve comprising:

a valve seat member having a fuel passage for communication with said chamber;

a pintle valve reciprocable within the passage between closed and open positions of the valve from and toward said chamber, and being biased in an axial direction toward the closed position;

said passage comprising an anterior inner cylindrical bore surface, an outer cylindrical bore surface, and an outwardly tapered seat between the inner and outer bore surfaces and joined to the inner surface;

said pintle valve having an anterior stem end, and a posterior head, said pintle valve further having an enlarged collar between the stem and head, said collar presenting a cylindrical surface which extends toward the stem in an axial direction so that at least a portion of the collar is at all times in an anterior position relative to the junction between the outwardly tapered seat and the inner cylindrical bore surface of said fuel passage, the cylindrical surface of said collar being of a larger outside diameter than the valve stem and being closely spaced apart with respect to the passage to prevent the formation and collapse of gas bubbles in the fuel at the surface of the seat; and

stop means presented by the valve seat member at the end thereof corresponding to the anterior stem end of said pintle valve, and engaged by means carried by the stem end for limiting the axial excursion of the valve to insure the described anterior relation of the collar;

said collar having portions thereof extending both above and below the junction of the tapered seat and the inner bore surface in the open position of the valve, said pintle valve having a valve portion between the collar and the head establishing sealing engagement with said tapered seat in the closed position of the valve.

References Cited in the file of this patent UNITED STATES PATENTS 2,154,875 Streby Apr. 18, 1939 2,743,962 Dressler May 1, 1956 2,796,296 Campbell June 18, 1957 FOREIGN PATENTS 101,487 Sweden Apr. 29, 1941