US3750960A

US3750960A - Fuel injector

Info

Publication number: US3750960A
Application number: US00196153A
Authority: US
Inventors: S Kranc; R Mcdowell; J Back; E Johnson
Original assignee: Caterpillar Tractor Co
Current assignee: Caterpillar Inc
Priority date: 1971-11-05
Filing date: 1971-11-05
Publication date: 1973-08-07
Anticipated expiration: 1990-08-07

Abstract

A fuel injector of the inwardly opening type wherein an end of the fuel line is utilized as an integral part of the injector.

Description

United States Patent 1191 [111 3,750,960 Back et al. Aug. 7, 1973 FUEL INJECTOR [56] References Cited [75] Inventors: John H. Back, Washington; Elling Z. UNITED STATES PATENTS Johnson, Dunlap; Stanley J. Kranc, 2,470,717 5/1949 Palumbo 239/533 Morton; Robert D, McDowell, 7 2,974,881 3/1961 Garday 239/533 Peoria, 11 of II] 3,598,314 8/1971 Bailey et al.... 239/533 X [73] Assignee: Caterpillar Tractor Co., Peoria, 111. FOREIGN PATENTS OR MQPLICATIONS Filed ov 5 19 1 686,943 12/1939 Germany 239/533 [21] Appl. No.: 196,153 Primary ExaminerM. Henson Wood, Jr.

Assistant Examiner-John J. Love kexlated Apphcat'on Data Attorney-Martin Majestic et a1. [63] Continuation-impart of Ser. No. 836,303, June 25, 1969, abandoned. [52] U S Cl 239/533 A fuel injector of the inwardly opening type wherein an 51 In t. Cl. 1305b 1/30 the fuel line is utilized as an integral Of the 58 Field of Search 239/96, 533

6 Claims, 4 Drawing Figures PATENTEU 3,750,960

I saw 2 OF 3 INV'ENTORS JOHN H. BACK ELLING Z. JO'HNSON BY STANLEY J. KRANC ROBERT D. M DOWELL w gdmx4 aw, 734-14 M ATTO PATENIED 3.750.960

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464 H 455 ELUNG 2. JOHNSON STANLEY J. KRANC BY ROBERT D. MCDOWELL W, 7 WTZTTOEQEQS FUEL INJECTOR This is a Continuation-in-Part of Application Ser. No. 836,303, filed June 25,1969, and now abandoned.

BACKGROUND AND SUMMARY OF THE INVENTION Fuel injectors of the inwardly opening type generally have a rather complex structure requiring a number of precision parts which are difficult and costly to manufacture. Some previously proposed fuel injectors of this type have a tip welded thereon which is prone to distortion.

In the present invention, the number of components utilized in an injector has been reduced and a tip is fitted within the injector such that no distortion between the tip and the injector occurs. Further, an end of the fuel line is utilized as a part of the injector so that, while decreasing the number of components, a potential source of fuel leakage is deleted from the system. If desired, the invention also provides a solution to the industry desire to eliminate injector bleed-off lines by providing an accumulator chamber within the injector.

Further objects, advantages, modes, and embodiments of this invention will become obvious to those skilled in the art by reference to the Detailed Description and accompanying drawings which illustrate what are presently considered to be preferred embodiments of the best modes contemplated for utilizing the novel principles set forth in the claims.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal sectional view of a first embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of a second embodiment of the present invention.

FIG. 3 is a longitudinal sectional view of a third embodiment of the present invention.

FIG. 4 is a longitudinal sectional view of a forth embodiment of the present invention.

DETAILED DESCRIPTION Referring now to FIG. 1, there is shown an engine cylinder block 11 in which an injector, generally desig nated at 13, has been installed within a bore 15. The injector is held within the bore, being suitably positioned therein by a conical surface 17 at the lower end and a locking plate 19 at the upper end thereof.

A fuel injection line 21, delivering fuel from a source (not shown), has an end portion which extends into a casing 23 of the injector and is suitably attached to the casing such as by brazing in an area indicated at 25. The fuel line fuel bore 29 is enlarged at the lower end thereof, along a length of the line designated as 27, to form a counterbore 31. Communication between the bore 29 and counterbore 31 is blocked by a pin 33 which is interposed between them. At the lower end of reduced portion 27, a stop 35 is inserted within the bore 31 for cooperation with a collar 37 along a mutually conical surface 39.

The lower end of casing 23, below the end of the portion 27 of the fuel line, forms a valve chamber 41 in which a check valve 43 is located. Valve 43 has an enlarged upper end portion 45 which is slidable within the collar 37 and a valve head 47 on the opposite end thereof which cooperates with a seat 49 of an injector 51.

The injector tip 51 has an axial passage 53 for delivery of fuel to nozzle orifices 55 which extend into the combustion chamber. The tip is lightly pressed within a bore 57 in the casing 23 and is held within the lower end thereof by the mutually conical surfaces at 59.

As fuel enters the injector via line 21, its passage through the axial bore 29 is stopped by pin 33 so that it is forced into a plurality of grooves 61 about the periphery of the portion 27 via a cross passage 63. The fuel in grooves 61 then enters the valve chamber 41 and exerts a pressure on the exposed portion of the under surface 65 of the valve head 47, thereby overcoming the force exerted by a spring 67 between the collar 37 and the valve head 47. When the fluid pressure reaches a predetermined level, the valve head 47 will move upwardly and fuel will flow through the passageway 53 and into the combustion cylinder via orifices 55. In this condition, the fluid pressure acting upon the under surface 47 will be able to act upon the entire under surface to produce a more rapid upward movement of the valve head until the enlarged portion on the upper end of the stem of the valve abuts the stop member 35. Until portion 45 abuts stop member 35, leakage of fuel occurs between the stem portion 45 and the collar 37 and into the enlarged bore 31 of the fuel line section 27, the bore 31 thereby forming an accumulator chamber. The fuel trapped in that chamber increases in pressure to an extent determined by the extent of the upward movement of the stern portion 45, the bulk modulus of the fuel, and the amount of leakage of fuel that has occurred. When the injection of fuel is terminated, the pressure in chamber 41 and passageway 53 decreases as the result of the escape of fuel through the orifices 55, and the reverse flow of fuel through the line 21 and back to the pump in the conventional manner. When this pressure has sufficiently decreased, the spring 67 will urge the valve head 47 downwardly into its seated position. Since the fuel in chamber 31 is then'under comparatively great pressure, reverse leakage into the chamber 41 occurs, until the pressures areequalized. Thus, any effective back pressure above valve stem portion 45 which would later serve to assist in holding valve 43 closed is eliminated without requiring a bleed-off line.

It should be noted, that this valve structure is similar to that disclosed in U.S. Pat. No. 3,598,314, issued Aug. 10, 1971, and assigned to the assignee hereof.

Referring now to FIG. 2 of the drawings it will be noted that parts which are identical to those described relative to FIG. 1 will be similarly labeled, except that all labels will be preceded by the numeral 2.

As shown in FIG. 2, a fuel injector 213 is formed by taking a fuel line 221 having an internal bore 229 and enlarging its lower end portion, to form a case 227, so as to form an enlarged bore 241 therein which forms a valve chamber at the lower end thereof. A closed-end tube 2121s fixedly mounted within the bore 241 and a stop 235 is mounted in the lower end thereof for cooperation with both a collar 237 and an enlarged portion 245 of a check valve 243.

Thus, the interior of tube 212 forms an accumulator chamber 231. The tube 212 also has a plurality of formed grooves 261 about the outer edges thereof for communication of fluid from bore 229 to bore 241 for actuation of valve 243 in the manner previously described.

An injector tip 251 is mounted in the lower end of section 227 by rolling or other suitable means.

In FIG. 3, it will be noted that parts therein which are identical to previously described parts will carry the same label, preceded by the numeral 3. The fuel injector line 321, having an internal bore 329, is enlarged at the lower end thereof to form a casing 327 in which a fuel injector tip 351 is suitably mounted. A check valve 343 is mounted within a check valve compartment 341 for cooperation with a collar 337 in a manner previously described. A tube 352, having an internal bore 354, is fixedly mounted within the enlarged portion 327 of the fuel line and abuts the necked portion of the line as at 356 so as to cause the fuel in bore 329 to pass through bore 354 in the tube. The fuel then passes through a cross passage 358 in a stop member 360 which is inserted in the lower end of tube 352. Next, the fuel is communicated to chamber 341 via a longitudinal groove 362 in the stop member.

Fuel leaking between the valve section 345 and collar 337 will enter a cross passage 364 in the stop member, flow along a longitudinal groove 366 thereof, pass between the enlarged portion 327 and tube 352, and return to the fluid source via a fuel leak-off line 368.

In FIG. 4, it will be noted that parts therein which are identical to previously described parts will carry the same label, preceded by the numeral 4. The fuel injector line 421, having an internal bore 429, is enlarged at the lower end thereof to form a casing 427 in which fuel injector tip 464 and valve seat 451 are suitably mounted. A valve assembly having a check valve 443 with a head 450 sealingly contacting conical seat 449 of valve seat element 451 is disposed within chamber 442. The seat has a passage 453 therethrough within which is disposed an extended portion of the check valve. A spring 467 is disposed between a spring seat 470 and a washer 458 abutting a spring retainer 460.

An insert 412, having an internal bore 454, is fixedly mounted in internal bore 441 within enlarged portion 427 of the fuel line and abuts the necked portion of the fuel line as at 456 such that fuel passes from bore 429 through bore 454 in the tube.

A pair of shoulders 466 are formed by an upsetting process during manufacture of the case to facilitate use of a conventional bifurcated hold-down assembly for retaining the injector.

Fuel in chamber 449 surrounding the valve assembly acts upon the rounded shoulder portion of valve head 450 forcing the head outwardly when the fuel pressure in the chamber exceeds the preset force of spring 467. Fuel escapes through orifices 455 thus reducing pressure in the chamber to the point where the spring causes the valve head to return to its seated position and a new cycle begins.

Thus in each of these embodiments, the Applicants have provided a fuel injector having relatively thin walls with sufficient strength for injection operation. The use of the single piece sleeve and fuel line or case and fuel line greatly simplifies the injector configuration and reduces the number of parts required. In this manner, the only precision parts which may be required are those components associated with the check valve mechanism. Many further modifications and alterations will be obvious to those skilled in the art, wherefore what is claimed as the invention is:

What is claimed is:

1. In a fuel injector having an outer case member, a fuel chamber formed therein, valve means controlling the escape of fuel therefrom into a combustion chamher, the improvement which comprises a fuel tube of unitary construction defining outer and inner diameters with one end of said tube adapted for connection with a source of fuel pressure and the other end of said tube forming an integral part of said injector, wherein said other end of said fuel tube is disposed within said case member, means affixing said tube adjacent its other end to said case member and providing an end portion disposed within said case member, said tube having longitudinal passageways disposed substantially over the entire length of said end portion, means in said end portion permitting the flow of fuel therethrough into said passageways and thence into said chamber, said tube end portion forming an accumulator chamber, and blocking means preventing direct communication between said tube and said accumulator chamber.

2. The fuel injector of claim 1 wherein the blocking means is a pin and wherein said flow permitting means are cross passages communicating said inner diameter with said outer diameter.

3. The fuel injector of claim 1 wherein the longitudinal passageways are longitudinal grooves.

4. The fuel injector of claim 1 wherein said flow permitting means are radially disposed openings communicating with said grooves.

5. In a fuel injector having an outer case member, a fuel chamber formed therein, valve means controlling the escape of fuel therefrom into a combustion chamber, the improvement which comprises a fuel tube of unitary construction defining outer and inner diameters with one end of said tube adapted for connection with a source of fuel pressure and the other end of said tube forming an integral part of said injector, wherein said other end of said fuel tube is enlarged so as to form said outer case member as an integral, one-piece unit with said one end of said fuel tube, said enlarged other end having an enlarged inner bore, the lower end of which defines said fuel chamber, and further including means defining an accumulator chamber in said case member, wherein said means defining an accumulator chamber comprises a closed-end tube fixedly mounted within said inner bore, the open end of said closed-end tube being cooperable with said valve means whereby leaked fuel which leaks past said valve means is trapped by said accumulator chamber.

6. The fuel injector of claim 5 wherein said closedend tube has longitudinal passageways thereon permitting flow of fuel therethrough from said one end of said fuel tube to said fuel chamber.

4 i i i

Claims

1. In a fuel injector having an outer case member, a fuel chamber formed therein, valve means controlling the escape of fuel therefrom into a combustion chamber, the improvement which comprises a fuel tube of unitary construction defining outer and inner diameters with one end of said tube adapted for connection with a source of fuel pressure and the other end of said tube forming an integral part of said injector, wherein said other end of said fuel tube is disposed within said case member, means affixing said tube adjacent its other end to said case member and providing an end portion disposed within said case member, said tube having longitudinal passageways disposed substantially over the entire length of said end portion, means in said end portion permitting the flow of fuel therethrough into said passageways and thence into said chamber, said tube end portion forming an accumulator chamber, and blocking means preventing direct communication between said tube and said accumulator chamber.

6. The fuel injector of claim 5 wherein said closed-end tube has longitudinal passageways thereon permitting flow of fuel therethrough from said one end of said fuel tube to said fuel chamber.