US2612841A

US2612841A - Variable retraction discharge valve for fuel injection pumps

Info

Publication number: US2612841A
Authority: US
Inventors: Robert A Lasley
Original assignee: LOUIS G SIMMONS
Current assignee: LOUIS G SIMMONS
Priority date: 1948-09-29
Filing date: 1948-09-29
Publication date: 1952-10-07
Anticipated expiration: 1969-10-07

Description

Oct. 7, 1952 R. A. LASLEY 2,612,841

VARIABLE RETRACTION DISCHARGE VALVE FOR FUEL INJECTION PUMPS Filed Sept. 29, 1948 k 2 SI-lEETS-SI-IEE'I l j 20 J fl- 2 26\ 33 5 26 27 ,2 4 5; V 36 J '2 29 I v i 43 I7 j l'l'l O 1 l6 24 33 3 34 5 x 32 38 L Z) F za INVENTOR.

Babehf A. 1051651 R. A. LASLEY 2,612,841 RETRACTI DISCHARGE VALVE FUEL IN TION PUMPS Oct. 7, 1952 VARIABLE FOR 2 SHEETS-Sl-1EE'I 2 "Filed Sept. 29, .1948

aw} ml a A m DA Patented Oct. 7, 1952 UNI E-a I, I V 2;612',84 1 VARIABLE BE raecTmN DISCHARGE vi E aim rneimms Robert A. Lesley; -Qhieago, Ill.-,-assignor, by mesne I asslgnrnentsgtogliouis G. SinxmonspChicago,

This invention relates to Narjable',1r discharge valves forifueliinjection particularly to dis'chargef valves 6 employed in fuel injetion js ys pressure operated inje'ctor'oor nected through a clse' d"fufelline pressure outlet ofta pump which,

ii" v t operable to supply etereepemouhth. 'oi i'iuel der high pressure at,each.stroke,l'pff;the ;purnp delivery of the meteredf'amount ofwfuelgand h invention has for (an ."Obiect theme is improved dischargejvalve mea s which uj ;0- mati-cally vary in accordanc'elwit, the of fuel delivered by the atfeac t V amount of fuel retracted ortvvithdr ,wn,f ro 1 n the fuel line upon closure o'f thew discha'rgieivalve. As set forth in atprior--application;,$erialno. 26,850, filed May 13, l9 l8,'in .the,-.nam off the present inventor, for 'Fueljlnjectionisvs ems of and to relieve the highpressure abruplyillpgn' r me nevseeex fe ee sf et r im'ectibn 1 which this application...-is continuation in part, fuel injectionsystemssoilthe above *el ijaracter ordinarily includefaufuel, mplll vingp spring load discharge valve; adaptedfgto loise quickly upon release. of the; ipre'ssur "so as to preventreturn offuelIffoin,thejfuellme to the pump between injections, .ajnd'gdifficultl'es have been encountered"Iwithfsecondary,injece tion caused. by the pressure ,wav'eethh Js'j jsetjpp in the sealed fuel lli'negupon closure offthe'iinjector nozzle. in the aforesaid .applieationmiitowasprom Jd' to minimize or eliminate. such. .,.secondary, infection or dribble at the fuelginjectp" ndz designing the dischargevalvesjfof'the ufnps;to provide a predeterminedgamoiintgofgretraction upon closure, that is, withdrawallofl'iullfmm the fuel line during closure, of. ;thel;ldischarge valve. i T The amount of fuel to: be .withdrawnh'from Priorjtqhthefinvn jhgdis' used the fuel line to ,wpreventi secondary injection 5 without interierihglwith the aeur yimsu sequent primary injectlohs depen erous factors including primarily of fuel injected, which iszajlfuric 'QnUOf f h and speed of the engine. lftoou nmh 'retrac tion is provided the fuel; line, maygbefpartially emptied and consequently insufiicintfful may be supplied to the inject r}forQtheguxt'i {action, particularly (at lightfloadshjwhilelif too little retraction is provided. seohoa y i'i'r' -j efotion may not be prevented. i. Consequently';;.'it was .the practice prior toithe-inventio ,,the,a resaid application to design.-the disqhar'gel'valves o s to P vi ee he 1 v hey said prior application discloses and- ,ing 'mpvement imparted tothe A val e ,v 1ve,,m ans,. pbodyine t e pr ent ,inve

11 a1 loads and speeds Wlth theresul-tthatrangeoffloafifandlspeeds that the engine equldfideliver countering objection- ,i swe e ve el i broadlyclaims improved ii 1- wherein v the above indicate "n je ction systems v roblem is o'verc m by in or ratin i 11 t t f th the retraction; *the" amount of--ffuel-withdratvn from' the fuel line between -';i-njections.-- Although vthe specific I construgtions h disclosed in the said prior application operate satisfactorily to accomplish-t intendedpurpps'e's the' 'ihcdrporation' sugh syste rnsl pf a plurality offd'ischar e, ve Y f Wo v s e di i n fi nd the particular j single valve'f er'nloodirr ient diss d-in v fie ep e 1on finvolves malnufagcturiiiig' diff culties due' 1 to -certaii1' critical design t eetq sc pr in v t t i ,v t ix hifsi nf ent s "to vi I m Q able retraption"dischargdvalves, fQruse in iich systems," which a he 'jinanufactur'd 'at -low steed whi h 91 9mm, w th re iab i a va a i li r e tio dis har e i VQf I dd compris ng a valve -niemhrhaving a hollow eie d n a ine headportion surrounding h'estem adjacent -the closed end, ja nd-fthe size N portion- 1s provided with a pl ura lity of aperture extending through the we l thereo be ee ht e' hm-1.1a h p a e ur s? beix e me d: a ally; i p tion and g"rad ated in size so: as aut'onratially to, var .7 laqqx en efjw h ith m "f delivered by thelpumpytheextefit'fo the openme of retractioh jergejoteageun e of-the-valve'mniberJ mjpie' e understanding nd th tea i l 'ihemp fim nt iFor t l mo e invention; ref ere feet-"should Riots fbehaelfto {the Fig; lis an" elevationalview partly;in section of a fuel pump"provided"Withdischarge 3 E le-: is cif e 'me iiervl 'er i in larg a e, how n t ejiiv lv 'rheahs' of -"rig.

ilar to Fig. 2 showing a further embodiment of Y the invention.

Referring now to the drawings the invention is shown as embodied. in a fuel pump'of a type well known in the art comprising a longitudinally bored pump body l formed to provide a primary fuel chamber H to which fuel is supplied and held in place by a cap member 25 secured to the pump body by suitable cap screws 26.

As shown the retainer member 24 is shaped to provide in conjunction with the valve guide 22 a valve chamber 21 which communicates directly with the high pressure pump outlet 20. the valve guide 22 being bored to provide an opening 28 which communicates with the pressure chamber 19 of the pump, the upper surface of; the valve guide 22 being formed to provide an annular valve seat 29.

; opening 28 in the valve guide 22 is a valve member* 30 which includes a hollow stem portionthrough a suitable inlet fitting I2. Disposed within the pump body It] is a. cylinder barrel l3 having an inlet port [4 and a spill port I 5 communicating with the fuel chamber ll. cylinder barrel l3 as shown contains a recip rocatable piston [6 which is provided adjacent its upper end with a longitudinally extending slot I! which communicates with an inclined or helically disposed slot [8 adapted to cooperate with the spill port [5 in a manner Well understood in the art and which will be-briefly described hereinafter.

As will be understood by those skilled'in the art, the pump is of the constant stroke type and the piston I6 is rotatably adjustable in the cylinder barrel [3 to vary the amount of high pressure fuel delivered at each stroke of the pump. When the piston is in its lowermost position the pressure chamber l9 within the cylinder barrel and above the piston will be filled with fuel by suction through the inlet port l4 and the spill port [5. As the piston begins its upward travel the fuel in the chamber l9 will be placed under pressure and as soon as the upper edge of the piston moves beyond the inlet port l4, high pressure will be developed so as to force fuel through the discharge valve, as hereinafter described, and through the high pressure outlet passage of the pump to the fuel line and the injector nozzle (not shown). As soon as the piston reaches a position in which the helical groove l8 communicates with the spill port IS, the pressure chamber [9 above the piston will be immediately relieved and consequently the amount of fuel discharged from the pump on each stroke may be adjusted by rotating the piston I6 so as to vary the point in its stroke The.

at which communication of the inclined groove IS with the spill port IE will be established.

Various mechanisms well known to the art may be employed for effecting rotation of the piston I6 to adjust the capacity of the pump and it is not believed necessary to illustrate or describe such mechanism further than to point out that a slidable rack 2| is connected to the adjusting mechanism so as to effect rotation of the piston IS, the rack 2| preferably being provided with suitable calibrations, as shown, to indicate the adjustment of the piston in the cylinder barrel. Fuel pumps of the type shown and thus far described are well known in the art and constitute no part of the presentinvention.

Mounted directly above the cylinder barrel l3 in the bore of the pump body In is a suitable valve guide 22 adapted to be engaged and held in position by a compressible sealing ring 23 which is in turn engaged by a retainer member 24 mounted within the bore of the pump body 3! which is closed at its upper end, as shown best in Fig. 2 and is provided with an enlarged valve head 32 adapted to engage the valve seat 29. Disposed within the valve chamber 21 is a valve spring 33 the lower end of which engages a suitable shoulder on the valve head 32 and the upper end of which engages a suitable flange on a stop member 34 which is disposed within the valve chamber 21 and provided with

suitable apertures

35, 36 and 31 communicating the valve chamber 21 with the pressure outlet 29.

The valve spring 33 functions to maintain the valve member30 in the closed position shown in Fig. 1 with the head 32 engaging the valve seat 29 during low pressure portions of the pump cycle and it will be apparent to those skilled in the art'that when pressure is developed in the pumpchamber I9, the valve 30 will be lifted by the pressure so as to move inwardly of the valve chamber 21 against the force of the spring 33 thereby lifting the valve head 32 out of engagement with the valve seat 29.

In accordance with the present invention the hollow valve stem 3| is provided immediately below the valve head 32 with a plurality of sets of

apertures

38, 39, and 40. As shown best in Figs. 5, 6 and '7', the set of apertures 36 includes a pair of oppositely disposed apertures of relatively small cross-section, the set of apertures 39 includes three apertures which are symmetrically disposed and of somewhat larger crosssection, and the set of apertures 40 includes three apertures similarly spaced but of still larger cross-section. In accordance with the present invention the axial spacing and the relative cross-sections of the three sets of apertures are so correlated that the amount of lift imparted to the valve member 30 and consequently the amount of retraction effected by the valve member during. closing movement thereof, is a function of the amount of fuel delivered by the pump during each stroke.

In Fig. 2 the valve member 30 is shown in the position to which it will be moved under light load conditions and it will be observed that only the apertures 38 have moved to a position beyond the valve seat 29 so as to establish communication between the pressure chamber l9 and the valve chamber 21. The amount of communication provided by the apertures 38 being sufficient to accommodate the amount of oil supplied under pressure by the pump under these load conditions, no further lifting movement of the'valve member 30 takes place and consequently only a small amount of retraction occurs upon closure of the valve after the pressure in the pump chamber I9 is released.

In Fig. 3 the valve member 30 is shown in a position corresponding to intermediate load conditions and it will be observed that in this position both the apertures 38 and the apertures 39 have been uncovered. Accordingly, the valve Disposed within the s mmers lift being greater "under "these load: conditions, a greater amount of retraction is obtained. In Fig. 4 the valve member 30 is sho'wn in its maximum lift position corresponding to maximum load conditions, the head 32 being engaged by the stop-member 34 and all of the-

apertures

38, 39 and 40 being uncovered to permit the flow of "oil from the "pressure chamber l9 tothe valve chamber 21. It will be understood, of course, that inaddi-tion to the three positions show-n in Figs. 2, 3 and 4 the valve member snmay occupy an unlimited number of intermediate positions in which some or all ofthe

apertures

38, 39 and 40 are wholly or partially uncovered, the positions to which'the valve. moves being; determined by the amount of fuel delivered by thepumpon its pressure stroke. Thus the. liftof the valve and the amount of retraction "provided varies automatically in accordance-with the operating condition of the pump and 'the fuel injection system, whereby secondary injection eifectsare avoided over a wide range of load-speed conditions.

In theembodiment of the invention shownin Fig. 8 similar reference numerals have been "applied to similar parts, the onlydifference being that in this embodiment of the invention a valve member 41 is provided having a hollow stem portion 42 which is provided immediately below the head member 43with 1iwo sets of axially spaced

apertures

44 and 45 which are graduated in size to provide for automatic variation of the valve lift and retraction in the manner heretofore described in connection with the embodiment of Figs. 1 to 7. The provision of the three sets of graduated apertures in the first described embodiment provides a somewhat finer regulation of the retraction although satisfactory operation may be obtained with the embodiment of the invention disclosed in Fig. 8.

While a particular embodiment of the invention has been shown, it will be understood, of course, that the invention is not to be limited thereto, since many modifications may be made, and it is contemplated, therefore, by the appended claims, to cover any such modifications as fall within the true spirit and scope of the invention.

What is desired to be secured by Letters Patent of the United States is:

1. Variable retraction discharge valve means for a fuel injection system including a variable delivery pump for supplying metered amounts of fuel to a fuel line, said discharge valve means comprising a valve chamber in open communication with said fuel line and having a valve opening communicating with said pump and forming a valve seat, a hollow valve member slidably disposed in and substantially closing said opening and having a closed end extending into said chamber, a valve head on said valve member for engaging said valve seat, said valve member having radial apertures extending through the wall thereof below said valve head for communieating said pump with said valve chamber when said valve member moves inwardly of said chamber in response to the pressure developed by said pump, and spring means for moving said valve member outwardly to engage said valve head with said valve seat and to retract fuel from said fuel line upon release of said pump pressure, said apertures being spaced axially of said valve memher so as to open in sequence and automatically vary in accordance with the amount of fuel delivered by said pump the extent of inward movement of said valve member and the amount of ,6 retraction effected. du'ring outward movement thereof: 1 f I v 2. Variableretraction discharge-valve -means for-a fuel 'injection systemiincluding a variable delivery pump for 'supplying :metered amounts of fuel to a fuel line, said discharge ivalve means comprising a valve chamber in'open communication 'with said-fuel line-"and having a 'valve opening communicating with -said pump and forming ah-valve seat-, a hollow valve member slidably disposed in and substantially' closing said opening and having a closed end extending into solid -chamber, a valveiheadt on: said valve member for engagingsaidzvalve seatpsaid valve member having radial "apertures. extending through the wall thereof belowi'said valveihead for communicating s'aid pump *with: sai'd'ivalve :1 chamber when 'sai'd -val'vamemben' moves inwardly or: said chamher in response to theipressure' developed by said pump, spring meansfor moving vsaidvalve memher-outwardly to engagesaid valvehead with said valve-seat and to retract 1 fuel from said'fuel line upon release of "said pump pressure, said apertures beingarranged in axlallyspac'ed sets graduated in -size :s'o as'autom'atically to vary" in accordance with the amount of fuel delivered, by said pump the extent of inward movement of said valve member'andjthe amountfof retraction effected during saidioutward movementthereof.

"3-'..Var1ab1e retraction-discharge valve. means fora fuel injection systeminclu'dingya. variable delivery pump for supplying metered amounts of fuel to a fuel line, said discharge valve means comprising a valve chamber in open communication with said fuel line and having a valve opening communicating with said pump and forming a valve seat, a hollow member slidably disposed in and substantially closing said opening and having a closed end extending into said chamber, a valve head on said valve member for engaging said valve seat, said valve member having apertures in the wall thereof below saidvalve head for communicating said pump with said valve chamber when said valve member moves inwardly of said chamber in response to the pressure developed by said pump, spring means for moving said valve member outwardly to engage said valve head with said valve seat and to retract fuel from said fuel line upon release of said pump pressure, said apertures being arranged in axially spaced sets and with the area of each set increasing as the spacing from said valve head increases so as to automatically vary in accordance with the amount of fuel delivered by said pump the extent of inward movement of said valve member and the amount of retraction effected thereby during outward movement thereof.

4. Variable retraction discharge valve means for a fuel injection system including a variable delivery pump for supplying metered amounts of fuel to a fuel line, said discharge valve means comprising a valve chamber in open communication with said fuel line and having a valve opening communicating with said pump and forming a valve seat, a hollow valve member slidably disposed in and substantially closing said opening and having a closed end extending into said chamber, a valve head on said valve member for engaging said valve seat, said valve member having apertures in the wall thereof below said valve head for communicating said pump with said valve chamber when said valve member moves inwardly of said chamber in response to the pressure developed by said pump, spring means for moving said valve member outwardly to engage said valve head with said valve seat and to retract fuel from said fuel line upon release of said pump pressure, said apertures being spaced axially of said valve member so as automatically to vary in accordance withthe amount of fuel delivered by said pump the extent of inward movement of said valve member and the amount of retraction effected during outward movement thereof, and stop means in said chamber for limiting to apredetermined maximum the inward movement of said valve member.

5. Variable retraction discharge valve means for a fuel injection system including a, variable delivery pump for supplying metered amounts of fuel to a fuel line, said discharge valve means comprising a valve chamber in open communication with said fuel line and having a valve opening communicating with said pump and forming a valve seat, a hollow valve memberslidably disposed in and substantially closing said opening and having a closed end extending into said chamber, a valve head on said valve member for engaging said valve seat, said valvelmember having apertures in the wall thereof below said valve head for communicating said pump with said 25 valve chamber when said valve member moves inwardly of said chamber in response to the pressure developed by said pump, spring means for moving said valve member outwardly to engage said valve head with said'valve seat and to retract fuel from said fuel line upon release of said pump pressure, said apertures beingspaced axially of saidvalve member soas automatically to vary in accordance'with thejamount of fuel delivered by saidppump the extent of inward movement of said valve member and the amount of retraction effected, during outward movement thereof, and stop means in said chamber engageable by said valve member, to prevent further inward movement thereof after the set of apertures most remote from said valve head communicates with said chamber. 4

- ROBERT A. LASLEY.

REFERENCES CITED The following references are of record in the file of't his patent: UNITEDSTATES PA'I'ENTS Number fl Name Date 977,723 Field Dec. 6, 1910 1,919,856 McGe'orge July 25, 1933 1,954,662 Bond Apr. 10, 1934 2,126,985 Buckwalter Aug. 16, 1938 2,178,902 Clausen Nov. 7, 1939 2,211,252 Bremser Aug. 13, 1940 2,234,936 Streby Mar. 11, 1941 2,382,000. Bremser Aug. 14, 1945 l FOREIGN PATENTS Number Country Date Great Britain 1938