US3179053A

US3179053A - Fuel injector rack setting means

Info

Publication number: US3179053A
Application number: US202780A
Authority: US
Inventors: Alfonso G Jordan
Original assignee: Individual
Current assignee: Individual
Priority date: 1962-06-15
Filing date: 1962-06-15
Publication date: 1965-04-20
Anticipated expiration: 1982-04-20

Description

A. G. JORDAN FUEL. INJEGTOR RACK SETTING MEANS April zo, 1.965

Filed June 15, 1962 AES \\\\\\\\\\\\`\\\\MMXv 1 N VEN TOR. 4l ,fo/vso 6. Joemn/ H/s Arron/EY United States Patent() 3,179,053 FUEL INJECTOR RACK SETTING MEANS Alfonso G. Jordan, 879 Walnut St., San Jose, Calif. Filed June 15, 1962, Ser. No. 202,780

8 Claims. (Cl. 1013-37) This invention relates to fuel injectors of the type employed in multi-cylindered diesel engines and more particularly to an improved injector rack setting means therefor.

The present invention is more particularly directed to an injector rack setting means for unit injectors of the type used in General Motors diesels and the like. The demand for more power and greater economy of operation and maintenance in diesel engines makes it most critical that fuel distribution to all cylinders be made as equal as possible.

In the General Motors two-cycle diesel engines, equal distribution of fuel injected per stroke of each injector is set by means of its rack and gear after the injectors are installed in the cylinder heads of the engine. Each rack -is set at a pre-determined iixed measurement. For example, in the injectors utilized primarily in the railroad industry, the rack is set one inch from the end of the rack tothe 'body of the injector with no way to compensate for unequal delivery due to wear of the plunger and/ or spray tip -assembly of the injector.

The present method of equalizing fuel delivery for a particular set of injectors to be used in an engine is accomplished by running each such injector in a bench type test stand to determine its output. For example, on the General Motors Model 567C, Needle Injector at one inch rack setting `as explained above, 800 rpm. and 800 strokes pm., the `accepted delivery tolerance is from 424 to 440 ccs. In other word-s if all 16 injectors are within that range they are assumed to he Ias close to equal as is feasibly possible. This allows a latitude of a maximum of 16 ccs. differential between the least and greatest fuel delivery of a set of injectors.Y

If an injector is tes-ted and found to deliver say 4 20 ccs., the present method of correcting this to get it'into the desired range is to disassemble the injector and install a new plunger and bushing and/or an Old Tip Assembly with the holes worn sufliciently as not to allow too much back pressure so that more fuel will ow through at a given stroke. In other cases it may be necessary to install a new type gear that will advance the plunger helix a suicient amount relative to the one inch setting of the rack to increase the output of a particular injector to the 4244140 oc. accepted range. Aside from the fact that some injectors -will by chance fall into the accepted range, all others according to these methodswill require that the injector be disassembled and the parts replaced `and retested with the possibility that this operation will have to be repeated. There is stilla great deal of guesswork and Very little control over the4 increase or decrease of injector output. The prime expense of this method is an increase in inventory of injector parts, anfincrease of Vconsumption of injector parts and additional labor and usage of the injector test stand. i j

It is an object of the presentinvention to alleviate the need forsuch extensive and time consuming changes and tests in order to equalize the fuel distribution of a par-v ticular set of injectors. In accordance with the present invention under the sameconditions, assuming the `injector was set'with one inch rack setting at 80() r.p.m.s 'and 800 strokes with a delivery of 420 cos., it is contemplated that the appropriate adjustment of fuel flow Within one cc.`of delivery can be made without `disassembling the injector or retesting the injector.

`It is another object of this invention to provide a means 3,179,053 Patented Apr. 20, 1965 ice for varying the length of the rack to vary the port adjustment of the fuel intake to thereby increase and/or decrease the amount of fuel injected per stroke.

It is yet another object to provide a rack stroke adjusting means accessible to mechanics whereby compensation for fuel injection differences between injectors can he accomplished on the test stand.

These and other objects and advantages of the present invention will become apparent from a reading of the following description in the light of :the drawings in which:

FIG. l is a detailed section (partially in elevation) of a General Motors diesel fuel injector with linkage for operating the same.

FIG. 2 is a fragmentary portion of FIG. 1 with p-arts thereof in a diiferent position.

FIG. 3 is an enlarged longitudinal section of the right hand end of the rack bar of FIGS. 1 and 2.

FIG. 4 is an elevational view of FIG. 3 as seen from above therein. Y

FIG. 5 is an end elevation and partial section of FIG. 3 taken substantially along line 5 5 thereof.

The injector 1) shown in FIG. 1 consists of a forged steel, hollow body 11 in which is housed a high pressure pump 12 by which a measured quantity of fuel is forced intoand through a `spray nozzle 13 for discharge into the cylinder of a diesel engine (not shown);

Tihe pump 12 consistsof a bushing 14 so disposed in the hollow body 11 as to provide a somewhat cylindrical clearance space 15 between the bushing 14 and inner Wall of the housing 11 to allow fuel oil to surround the bushing.

The housing 11 has an inlet passage 16 communicating with the cylindrical space 15 and with a fuel supply line or conduit 17 in a manner well known in the art.

A plunger 18 is arranged in an axial bore 19 in the bushing 14 for reciprocation therein by means of a spring loaded plunger follower 20 which extends upwardly exteriorly of the A'body 11 for operation by one end 21 of a rocker arm (not shown) synchronized with stroke of the cylinder of the diesel `engine on which the injector `1() is installed.

As best seen in FIGS. 1 and 2 the bushing 14 has upper and

lower ports

22 and 23 formed therein between the cylindrical space 15 and the pump bore 19 to admit fuel oil into the latter. The fuel oil is constantly present inthe space 1S and under suicient pressure to supply the demand lof the pump 12, limited only by the stroke of the plunger 18 and a helical chamber or recess 25 formed on the plunger for periodic communication with the upper and

lower ports

22 and 23.

Periodic communication of the helical recess 25 with the fuel admittance ports 22-23 is controlled by relative turning of therentire plunger 18 within the pump bore 19. The means for turning the plunger 18 includes a pinion gear 26 slid-ably -arranged -on the upper end of the plunger 18 in an area of confinement Within the housing 11, the

plunger and pinion gear having related flat surfaces, one i of which is shown at 27 in FIG. 2 to assure turning of the plunger as it is reciprocated within the pump bore 19 of `the bushing 14. j

A rack'bar 30 is arranged upon the housing 11 for reciprocation through the same tangentially of the pinion gear 26 so that the teeth 31 on the rack bar mesh with the gear 26 to tur-n the latter in accordance with the later-al strokes of the rack `bar 30.`

. The present'invention resides `in means 35 for lengthening and/or shortening the rack bar 30 for changing Vthe relative disposition of the helical chamber 25 on the plunger 18 .relative to the upper and

lower ports

22 and 23 respectively. j i

The means (FIGS. 3, 4 and 5) includes a movable drive end 36 for the rack 30 having the conventional roller 3:'7y kmounted on a pin 33 which is sweat onto the end 36. The main body 32 of the rack 3i) is drilled and tapped axially thereof as at 33 for receiving one end of a self locking screw shank 39 of an adjusting bolt 40. This bolt t0 vhas a headed end 41 disposed in an enlarged bore 42 in the drive end 36 of the rack, the screw shank 39 extending through a minor bore i3 for threaded connection in the tapped bore 33 of the main body 32 of the rack 30. As best seen in FIGS.v 3 and 4 the roller Carrying pin 3S extends diametrically across the bore 42 and has a transverse bore 44 formed therethrough in axial alignment with the rack 30 `and its drive end 36. This provides an access opening from the open end 45 of the bore 42 to the head 4l of the adjusting bolt 4t). This access opening is necessary for a hex-wrench W adapted to fit the hex-socket 46 in the head 4f. of bolt 40. The wrench is the well known Allen head Wrench W and bolt now so widely used. j

Y The head 41 of the bolt et) is disposed between the pin 33 and the shoulder 47 provided at the junction ofthe minor and major bores 43 and 42. A neoprene washer 48 is disposed between the head 4I of bolt 40 and the shoulder 47 to maintain the head 4l against the pin 38 and to prevent back lash when the head 4I is turned relativeto the metal surface at the shoulder 47.

The shank 39 ofthe bolt 4i) is of alloyed steel to likewise prevent galling of the metals when the bolt is turned to draw its head 4l and the drive end 36 of the rack toward the main, body 32 thereof. The shank 39 of the bolt it? has a Nylock insert 49 (FIG. 3) which expands against the inside threading in the main body 32 of the rack 39 to frictionally hold the screw shank in any adjusted position relative thereto. Upon turning of the screw bolt 40 by means of the Allen head wrench W the movable drive end 36 is moved toward and/ or from the main 'body 32 of the rack 30 to change the relative position of the helical chamber 25 relative to the

pump ports

22 and 23.

This means 5I comprises a pair of spring steel expansion pins 52 and 53 arranged in aligned bores in the main bodyl 31'and the drive end 36 of the rack 30. The bores 54 and 55 in the-main body 31 are diametrically opposite each other as are the bores 54' and 55 in the drive end 36. As best seen in FIG. 5, the pins 52 and 53 are identically Cshaped inY cross section and being precision made of spring steel tend to assume a slightly greater diameter than the bores into which they are to fit.

These pins are seated firmly in the bores 54 and 55 in they main body 31 and extend beyond the outer end thereof a length substantially comparable to `that of Athe drive end 36 ofthe rack. The pins 52 and 5,3 serve to guide and support the drive end 36 in alignment with the main body 31 and to maintain theroller y357 in correct position yfor operation by itsoperating 1everv5t). The lever 5@ rocks to and fro in timed relation with the engine in the usual manner to load the'pump with fuel once in each cycle of the engine.

Referring toFIG. l it will be noted that when the plunger 18 is all the Way up (withdrawn) relative to the bore "19 of the pump bushing I4. fuel ,is admittedk into the bore i9 below the plunger via the lower port 23.

The plunger IS has a relief -port 56 formed axially thereof from its lower end to a T head cross port 57 which opens up into the recess chamber 25. By this arrangement when the plunger moves downwardly to compress the full charge of fuel oil below it, any excess fuel will j surge up through relief port 56 and into the helical recess `or chamber 25. This will occur as long as the chamber 25 is in communicaion with either the vupper and/or the d lower ports 2243. However, once these

ports

22 and 23 are cut off from the chamber 25, the charge of fuel oil beneath the plunger is compressed sufficiently to overcome a spring loaded check valve 60 (dotted lines FIG. l) so that the charge of fuel will be squirted out the nozzle end 13 of the injector body. It will thus be appreciated that the position of the Arecess chamber 25 relative to the ports 22-23 as determined by the'stroke of the rack 34B is very critical,

By the arrangement of this invention the rack 30 can be set at any desired vposition of adjustment to Yprolong or shorten the .period of communication of the helical chamber 25 with the fuel intake phase of the operation of the injector and thereby increase or decrease the amount `of fuel injected per stroke. In other words, turning of the screw bolt 40 to lengthen the rack 30 will increase the output of fuel and by tightening the screw into the tapped bore 33 the output of fuel will be decreased.

With the rack adjusting feature of the present invention the several injectors on an engine can all be calibrated to any-output of fuel within one cc. Moreover, this can be done 'on the test stand,` ie., with assurance that the injector will admit fuel well Within the allowed limits. In this manner, injectors which might otherwise be discarded will be saved and the life of injectors can be prolonged with assurance of uniform, i.e., equalized fuel injectors on all cylinders.

While I have described my Yinvention in specific detail it will be appreciated by those skilled in the art that the same may be susceptible to variations, alterations and/ or modifications Without departing from the spirit of my invention. I therefore Vdesire to avail myself of all variations, alterations and/or modifications of structure which may reasonably come within the purview of the following claims. Y

What I claim -as new and desire to protectby Letters Patent is:

l. In a fuel injector including a pump in which a pump plunger reciprocable within the injector body has a helical recess communicable with xed fuel inlet ports in the injector body, Iand yan injector rack having itstoothed main body meshing with a pinion gear on said plunger and its drive end engaged by a rocker arm for moving said rack axially to and froto turn the plunger while the latter reciprocates for maintaining said lhelical recess in communication With at least one of the fixed ports for a period of time sufficient to load said pump with a predetermined quantity of fuel; an injector rack setting means comprising a separate drive end on said body having a rocker arm engaging roller Von one side thereof, la pin on said roller projecting diametrically through' the drive end of said rack, said'drive Vend having a major bore and a minor bore the latter facing said main body of the rack and in axial alignment therewith, a screw shank extending through said minor bore, said screw shank having a head portion within said major bore and engaging said pin, a tapped axial bore in the main body of saidV -same to lengthen and shorten the rack to thereby change the period of communication of'said recess with one or Vboth ofsaid ports; n

2. I n a fuel injector including a pump in which a pump *plunger reciprocable within the injector body has a helical recess communicable with fixed fuel inlet ports in the injector body, and an injector rack having its toothed main body meshing with a piniongear on said plunger 'and its drive end engaged by a rocker arm for moving said rack y.axially to and fro to turn"the plunger during its reciprocation for maintaining said helical recess in communication with at least `one-lof the fixed ports for a periodofwtime suiiicient -to load, said pump with apredetermined quantity of fuel; an injector rack setting means comprising :a separate driveend on said body having a rocker arm engaging roller on one side thereof, a pin on said roller projecting diametrically through the drive end of said rack, said drive end having a major bore and a minor bore the latter facing said main body of the rack and in axial alignment therewith, a screw shank extending through said minor bore, said screw shank having a head portion within said major bore and engaging said pin, a tapped axial bore in the main body of said rack for receiving the threaded end of saidV screw shank, an access bore diametrically through said pin in axial alignment with said major bore facilitating admittance of a tool to the head of said screw shank for turning the same to lengthen and shorten the rack to therebychange the period of communication of said recess with one or both of said ports, and means offset radially from the screw shank in said main body of said rack and extending into said drive end thereof for resisting turning of the latter relative to said main body during turning of said screw to thereby maintain said roller in correct position to engage said rocker arm.

3. In a fuel injector including a pump in which a pump plunger reciprocable within'the injector body has a helical recess communicable with fixed fuel inlet ports in the injector body, and an injector rack having its toothed main body meshing with a pinion gear on said plunger and its drive end engaged by a rocker arm for moving said rack axially to and fro to Iturn the plunger as the plunger reciprocates for maintaining said helical recess in communication with :at least one of the fixed ports for a period of time sufficient to load said pump with a predetermined quantity of fuel; an injector rack setting means comprising a separate drive end on said body having a rocker arm engaging roller on one side thereof, a pin on said roller projecting diametrically through the drive end of said rack, said drive end having a major bore and a minor bore the latter facing said main body of the rack and in axial alignment therewith, a screw shank extending through said minor bore, said screw shank having a head portion within said major bore and engaging said pin, a tapped .axial bore in the main body of said rack for receiving the threaded end of said screw shank, an access bore diametrically through said pin in axial alignment with said major bore facilitating admittance of a tool to the head of said screw shank for turning the same to lengthen and shorten the rack to thereby change the period of communication of said recess with one or both of said ports, said main body and said drive end thereof having diametrically opposed .aligned bores extending parallel to the axis of said screw shank, and an expansion pin extending into each set of said diametrically opposed bores for maintaining said main body and drive body againstV relative rotation during turning of said screw shank and for guiding said drive end of said rack during movement thereof toward and from said main body during turning of said screw shank.

4. In combination with an injector rack having a toothed portion meshed with pinion gear on a fuel pump the plunger of which has an helical recess communicable with fuel inlet ports for admitting a pre-determined quantity of fuel to said pump; .an injector rack setting means comprising a separate drive end on the toothed portion of said rack having a rocker arm engaging roller on one side thereof, a pin on said roller projecting diametrically through the drive end of said rack, said drive end having a minor bore at one end facing the toothed portion of said rack and in axial alignment therewith, said drive end having a major bore at its opposite end providing a shoulder at the juncture of said minor bore, a headed screw having its shank extending through said minor bore and itsV head portion within said major bore between said shoulder and said pin, a tapped axial bore in the toothed portion of said rack for receiving the threaded end of said screw shank, and an access bore diametrically through said pin in axial alignment with said major bore facilitating admittance of a tool to the head of said screw shank for turning the same to lengthen and shorten the rackand thereby change the position of the helical recess on said plunger relative to said ports.

5. In combination with an injector rack having a toothed portion meshed with pinion gear on a fuel pump the plunger of which has an helical recess communicable with fuel inlet ports for admitting a predetermined quantity of fuel to said pump; an injectorrack setting means comprising a separate drive end on the-toothed portion of said rack having a rocker arm engaging roller on one side thereof,4 a pin on said roller projecting diametrically through the drive end of said rack, said drive end having a minor bore at one end facing the toothed portion of said rack and in axial alignment, therewith, said drive end having a major bore at its opposite end providing a shoulder at the juncture of said minor bore, a headed screw having its shank extending through said minor bore and its head portion within said major bore between said shoulder and said pin, a tapped axial bore in the toothed portion of said rack for receiving the threaded end of said screw shank, an access bore diametrically through said pin in axial alignmentwith said major bore facilitating admittance of a tool to the head of said screw shank `for turning the same to lengthen and -shorten the rack and thereby change the position of the helical recess on said plunger relative to said ports, said toothed portion and said drive end of said rack having diametrically opposed aligned bores extending parallel to the axis of said screw shank, and an expansion pin extending into each set of said diametrically opposed bores for resisting relative turning of the toothed portion and the drive end of said rack during turning of said screw shank and for guiding said drive endA of said rack during movement thereof toward and from said toothed portion during turning of said screw shank.

6. In an injector rack having a main rack body provided with a toothed portion engaging a pinion gear slidable on the plunger of a pump for turning said plunger to position an helical recess thereon in communication with fuel ports for a predetermined time during each stroke of such plunger, a rack setting means comprising a separate drive end on said main body having a rocker arm engaging roller on one side thereof, a pin on said roller projecting diametrically through said drive end, said drive end having an axial minor bore at one end and a major bore at its opposite end providing a shoulder within said drive end, a screw shank extending through said minor bore, said screw shank having a head portion within said major bore engaging said shoulder and said pin for moving the drive end with said screw shank, a tapped axial bore in said main body for receiving the threaded end of said screw shank, and an access bore diametrically through said pin in axial alignment with said major bore Ifacilitating admittance of a tool to the head of said screw shank to turn the same to lengthen and shorten the rack for prolonging and diminishing the time of communication of the helical recess on said plunger with the fuel ports during each stroke of said plunger.

.7. In an injector rack having a main rack body provided with a toothed portion engaging a pinion gear slidable on the plunger of a pump for turning said plunger to position an helical recess thereon in communication with fuel ports for a predetermined time during each stroke of such plunger, a rack setting means comprising a separate drive end on said main body having a rocker arm engaging roller on one side thereof, a pin on said roller projecting diametrically through said drive end, said drive end having an axial minor bore at one end with a major bore at its opposite end providing a shoulder within said drive end, a screw shank extending through said minor bore, said screw shank having a head portion within said major bore engaging said shoulreceiving the threaded end of said screwshank, an ac- Y cess bore diametrically through said pin in axial align ment with said major bore facilitating admittance of a tool to the head of said screw shank to turn the same to lengthen and shorten the rack for prolonging and diminishing the time of communication of the helical recess on said plunger with the yfuel ports during each stroke of said plunger, and means for guiding vsaid drive lend for non-turning movement toward and from said main body during turning of said screw.-

8. In an injector rack 'having a main rack body provided with a toothed portion engaging a pinion gear slidable fon the plunger of a pump for turning said plunger to position an helical recess thereon in communication with fuel ports for a predetermined time during each stroke of such plunger, a rack setting means comprising a separate drive end on said'main body having a rocker arm engaging roller on one side thereof, apin on said roller projecting diametrically through said drive end, said drive end having an axial minor bore at one end and a major bore at its opposite end providing a shoulder within said drive end, a screw shank extending through said minor bore, said screw shank having a head portion within said major bore engaging said shoulder and said pin for moving the drive end with said screw shank, a tapped axialy bore in said main body for receiving the threaded end of said screw shank, an access bore diametrically through said pin in axial alignment with said major bore facilitating admittance of a tool to the head of said screwY shank to turn the same to lengthen and shorten the rack for prolonging yand diminishing the time of communication of the helical recess on said plunger with the fuel ports during each stroke of said plunger, means for guiding said drive end for non-turning movement toward and from said main body during turning of said screw Vcomprising diametrically opposed aligned bores in said main body and said drive end extending parallel to the axis of said screw shank, and an expansion pin extending in'each of said diametrically opposed bores in said-main body and into the diametrically opposed bores in said drive end for frictionally sliding movement relative thereto as said drive end moves toward and from the main body of said rack during turning of said screw shank.

References Cited by the Examiner UNITED 'STATES PATENTS 1,520,401 k12/24 Brady 287-61 1,593,582 7/26 Leo 287-62 X 2,317,022 4/43 Benjamin 123-l40 y2,555,124 5/51 Gothberg `287--59 2,635,590 4/53 Simon 103-41 LAURENCE V. EFNER, Primary Examiner.

Claims

1. IN A FUEL INJECTOR INCLUDING A PUMP IN WHICH A PUMP PLUNGER RECIPROCABLE WITHIN THE INJECTOR BODY HAS A HELICAL RECESS COMMUNICABLE WITH FIXED FUEL INLET PORTS IN THE INJECTOR BODY, AND AN INJECTOR RACK HAVING ITS TOOTHED MAIN BODY MESHING WITH A PINION GEAR ON SAID PLUNGER AND ITS DRIVE END ENGAGED BY A ROCKER ARM FOR MOVING SAID RACK AXIALLY TO AND FRO TO TURN THE PLUNGER WHILE THE LATTER RECIPROCATES FOR MAINTAINING SAID HELICAL RECESS IN COMMUNCATION WITH AT LEAST ONE OF THE FIXED PORTS FOR A PERIOD OF TIME SUFFICIENT TO LOAD SAID PUMP WITH A PREDETERMINED QUANTITY OF FUEL; AN INJECTOR RACK SETTING MEANS COMPRISING A SEPARATE DRIVE END ON SAID BODY HAVING A ROCKER ARM ENGAGING ROLLER ON ONE SIDE THEREOF, A PIN ON SAID ROLLER PROJECTING DIAMETRICALLY THROUGH THE DRIVE END OF SAID RACK, SAID DRIVE END HAVING A MAJOR BORE AND A MINOR BORE THE LATTER FACING SAID MAIN BODY OF THE RACK AND IN AXIAL ALIGNMENT THEREWITH, A SCREW SHANK EXTENDING THROUGH SAID MINOR BORE, SAID SCREW SHANK HAVING A HEAD PORTION WITHIN SAID MAJOR BORE AND ENGAGING SAID PIN, A TAPPED AXIAL BORE IN THE MAIN BODY OF SAID RACK FOR RECEIVING THE THREADED END OF SAID SCREW SHANK, AND AN ACCESS BORE DIAMETRICALLY THROUGH SAID PIN IN AXIAL ALIGNMENT WITH SAID MAJOR BORE FACILITATING ADMITTANCE OF A TOOL TO THE HEAD OF SAID SCREW SHANK FOR TURNING THE SAME TO LENGTHEN AND SHORTEN THE RACK TO THEREBY CHANGE THE PERIOD OF COMMUNICATION OF SAID RECESS WITH ONE OR BOTH OF SAID PORTS.