DK164827B

DK164827B - FUEL INJECTION PUMP FOR DIESEL TYPE COMBUSTION ENGINES

Info

Publication number: DK164827B
Application number: DK134188A
Authority: DK
Inventors: Hans Christian Scherrer
Original assignee: Sulzer Ag
Priority date: 1987-04-30
Filing date: 1988-03-11
Publication date: 1992-08-24
Also published as: NO881890D0; JPS63272959A; DK134188D0; EP0288669A1; FI880655A0; NO168725B; ES2022482B3; DK164827C; FI880655A; EP0288669B1; NO881890L; FI96535C; DE3862056D1; CH672005A5; DK134188A; FI96535B; NO168725C

Description

iin

DK 164827 BDK 164827 B

BRÆNDSTOFINDSPRØJTNINGSPUMPE TIL STEMPELFORBRÆNDINGSMOTORER AF DIESELTYPEFUEL INJECTION PUMP FOR DIESEL TYPE COMBUSTION ENGINES

5 Opfindelsen vedrører en brændstofindsprojtningspumpe til stempelforbrændingsmotorer af dieseltype med mindst et pumpestempel, som kan bevæges op og ned i en cylinder, hvilket pumpestempel på sin kappeflade i forhold til pumpestemplets længdeakse har skråt forlobende styrekanter, som sammen med 10 i cylinderen anbragte huller bestemmer pumpestemplets leveringsbegyndelse og leveringsafslutning, og med en pumpestemplet omgivende indstillingsbøsning, der til drejning af pumpestemplet om dets længdeakse samvirker med en udenfor cylinderen lejret reguleringsstang, som kan bevæges retli-15 net hen og tilbage.BACKGROUND OF THE INVENTION The present invention relates to a fuel injection pump for diesel-type piston combustion engines having at least one pump piston which can be moved up and down in a cylinder, which has a piston on its casing surface relative to the longitudinal axis of the pump piston, inclined leading edges of the pump piston, which together with 10 holes in the cylinder are located in the cylinder. and delivery termination, and with a pump piston surrounding adjusting bush which for rotating the pump piston about its longitudinal axis cooperates with an outside rod which is located outside the cylinder, which can be moved rectilinearly to and fro.

Ved en fra DE offentliggørelsesskrift nr. 1 910 170 kendt indsprøjtningspumpe af denne slags omgiver indstillingsbøsningen pumpestemplet koncentrisk og er drejefast forbundet 20 med pumpestemplet ved hjælp af en not og en deri ført gli-dekile. Indstillingsbøsningen har en udvendig fortanding, der griber ind i en tandstang på reguleringsstangen. Den af reguleringsstangen og indstillingsbøsningen bestående dre-jeindretning tjener til at ændre den i stempelmotorens ar-25 bejdscylinder indsprøjtede brændstofmængde i afhængighed af motorens belastning, idet de skrå styrekanters stilling i forhold til hullerne i cylinderen forandres ved drejningen, så pumpestemplets leveringsbegyndelse og/eller leveringsafslutning forskydes.In an injection pump of this kind known from DE Publication No. 1 910 170, the setting sleeve concentrically surrounds the pump piston and is pivotally connected 20 to the pump piston by means of a groove and a sliding wedge provided therein. The adjusting bush has an external tooth that engages a rack on the control rod. The rotating device of the control rod and the adjustment bushing serves to change the fuel quantity injected into the piston engine's working quantity depending on the load of the engine, changing the position of the inclined guide edges relative to the holes in the cylinder at the rotation so that the delivery or start of the pump piston and is displaced.

3030

Størrelsen af pumpestemplets drejningsområde er - betinget af pumpekonstruktionen - begrænset og andrager ca. 60*.The size of the piston rotational area is - subject to the pump design - limited and amounts to approx. 60 *.

Over området på ca. 60“ strækker sig forløbet af de skrå styrekanter på pumpestemplets kappeflade. Set på den teg-35 nede afvikling af kappefladen fremkommer der altså et forholdsvis stejlt, forløb af .de skrå styrekanter. Et sådant 2Over the area of approx. 60 ”extends the course of the oblique guide edges of the pump piston casing surface. Thus, as seen on the drawn unwinding of the casing surface, a relatively steep course of the inclined guide edges appears. Such a 2

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stejlt forlob har en ugunstig reproducerbarhed af den indsprøjtede brændstofmængde til følge, det vil sige, der fremkommer en forholdsvis stor afvigelse i pumpestemplets leveringsslag, altså i indsprøjtningsmængde, fra regule-5 ringsstangens position. Sådanne afvigelser er for eksempel betinget af summen af unøjagtighederne i overføringsvejen fra den ved reguleringsstangen angribende regulator til pumpestemplet (spillerum, tolerancer, montageunojagtigheder og så videre). Jo stejlere styrekantforløbet er, jo større 10 er stempelslagets unøjagtighed. Yderligere ulemper ved det stejle styrekantforløb fremkommer ved enden af indsprøjtningsfasen, idet den stempelbevægelse, som er nødvendig for helt at åbne overstrømningshullet i cylinderen af den tilhørende styrekant, bliver temmelig stor. Dette betyder, at 15 indsprøjtningen ikke afsluttes hurtigt, men "snigende", hvorved brændstoffets forbrænding forringes. Indsprøjtningspumper af den i indledningen nævnte slags anvendes desuden kun til konstant indsprøjtningsbegyndelse. En fremlægning af indsprøjtningstidspunktet før øverste dødpunkt 20 lader sig i praksis ikke realisere på grund af det stejle styrekantforløb. -steep gradients result in an adverse reproducibility of the injected fuel quantity, that is, a relatively large deviation in the delivery stroke of the pump piston, ie in the amount of injection, from the position of the control rod. Such deviations are, for example, contingent on the sum of the inaccuracies in the transfer path from the regulator engaging the regulating rod to the pump piston (clearance, tolerances, mounting inaccuracies and so on). The steeper the steering edge is, the greater the inaccuracy of the piston stroke. Further disadvantages of the steep guide edge course appear at the end of the injection phase, with the piston movement necessary to fully open the overflow hole in the cylinder of the associated guide edge. This means that the injection is not terminated quickly but "sneaking", thereby reducing the combustion of the fuel. In addition, injection pumps of the kind mentioned in the introduction are only used for constant injection initiation. In practice, the presentation of the injection time before the top dead point 20 cannot be realized due to the steep steering edge. -

Til grund for opfindelsen ligger den opgave at forbedre indsprøjtningspumpen af den i indledningen nævnte slags så-25 ledes, at de af det stejle styrekantforløb betingede mangler undgås.The object of the invention is to improve the injection pump of the kind mentioned in the preamble so as to avoid the shortcomings caused by the steep guide edge course.

Denne opgave løses ved en brændstof indsprøjtningspumpe af den indledningsvist angivne art, hvilken pumpe ifølge op-30 findelsen er særegen ved, at indstillingsbøsningen omgiver pumpestemplet excentrisk og er forsynet med en indvendig fortanding, at der på pumpestemplet er anbragt en med den indvendige fortanding indgribende udvendig fortanding, og at indstillingsbøsningen er ledforbundet med regulerings-35 stangen.This task is solved by a fuel injection pump of the type indicated initially, which pump according to the invention is peculiar in that the adjusting bush surrounds the pump piston eccentrically and is provided with an internal tooth, an external engagement engaging the internal piston and that the adjusting bush is articulated with the control rod.

DK 164827 BDK 164827 B

33

Ved den excentriske anbringelse af den mel· indvendig for-tanding forsynede indstillingsbøsning, og anbringelsen af en dertil passende udvendig fortanding på pumpestemplet, omsættes indstillingsbøsningens drejebevægelse til en stør-5 re drejebevægelse af pumpestemplet, hvorved der kan opnås omtrent en fordobling af pumpestemplets hidtidige drejningsområde, det vil sige ca. 120°. Denne forøgelse af pumpestemplets drejningsområde opnås derved med en retlinet indstillingsvej for reguleringsstangen, hvilken indstil-10 lingsvej forbliver lige så stor som ved indsprøjtningspumpen af den i indledningen nævnte slags. Pumpestemplets større drejningsområde tillader nu at udstrække forløbet af de skrå styrekanter over et større område af pumpestemplets kappeflade, så styrekanterne set på den tegnede afvikling 15 udviser en væsentlig mindre stigning end hidtil. Dermed er de i sammenhæng med det stejle styrekantforløb ved den hidtil kendte indsprøjtningspumpe beskrevne ulemper formindsket væsentligt. Stempelslagets afvigelser som følge af u-nøjagtigheder i overføringsvejen er altså væsentligt min-20 dre, indsprøjtningsfasen afsluttes hurtigere, fordi også stempelbevægelsen til fuld åbning af overstrømningshullet af den tilhørende styrekant bliver mindre. Endeligt bliver det muligt at køre med en variabel leveringsbegyndelse med den nye indsprøjtningspumpe, det vil sige at forskyde ind-25 sprøjtningens begyndelse til at ligge før øverste dødpunkt.By the eccentric application of the adjustable internal bushing, and the application of a suitable external toothing to the pump piston, the rotary movement of the adjusting bush is converted to a larger rotational movement of the pump piston, whereby a doubling of the pump piston can be doubled over time. , that is, approx. 120 °. This increase in the piston's rotational range is thereby achieved with a rectilinear adjustment path for the control rod, which adjustment path remains as large as with the injection pump of the kind mentioned in the introduction. The larger pivot area of the pump piston now allows to extend the course of the oblique guide edges over a larger area of the casing surface of the pump piston, so that the guide edges seen on the drawn run 15 exhibit a substantially smaller increase than hitherto. Thus, in the context of the steep steering edge process at the known injection injection pumps, the disadvantages described so far have been substantially reduced. Thus, the piston stroke deviations due to inaccuracies in the transmission path are substantially smaller, the injection phase terminating faster because also the piston movement for full opening of the overflow hole of the associated guide edge becomes smaller. Finally, it will be possible to run a variable delivery start with the new injection pump, that is, to delay the beginning of the injection to lie before the top dead center.

Et udførelseseksempel for opfindelsen forklares i det følgende ved hjælp af tegningen, hvor: 30 Fig. 1 viser et aksialsnit gennem en brændstofindsprøjt ningspumpe ifølge opfindelsen, som er monteret i motorhuset, fig. 2 viser et tværsnit gennem pumpen svarende til snit-35 linierne A-B og C-D i fig. 1, og 4An embodiment of the invention is explained in the following by means of the drawing, in which: FIG. 1 shows an axial section through a fuel injection pump according to the invention mounted in the engine housing; FIG. 2 shows a cross section through the pump corresponding to the section lines A-B and C-D in FIG. 1, and 4

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fig. 3 viser et tværsnit gennem en del af-pumpen i fig. 1 i området ved fortandingerne.FIG. 3 is a cross-section through a portion of the pump of FIG. 1 in the area of the teeth.

Ifølge fig. 1 findes i et pumpehus 1 en pumpecylinder 2, 5 som fikseres af et pumpehusdæksel 3 i pumpehuset 1. I pumpecylinderen 2 er et pumpestempel 4 styret bevægeligt opog nedad, hvilket pumpestempel på sin kappeflade nær den øverste stempelende er forsynet med i forhold til stempel-længdeaksen skråt forløbende styrekanter 5. Disse styrekan-10 ter samvirker på kendt måde med to i fig. 1 ikke-vis te radiale boringer i pumpecylinderens 2 væg, hvorved pumpestemplets 4 leveringsbegyndelse og leveringsafslutning bestemmes. Brændstoffet, der skal indsprøjtes, tilføres gennem en i fig. 1 ligeledes ikke-vist tilførselsledning til 15 et ringrum 6 mellem pumpehuset 1 og pumpecylinderen 2, fra hvilket ringrum 6 brændstoffet gennem de netop omtalte boringer, som bestemmer leveringstidspunktets begyndelse, når ind i pumpens leveringsrum 7. Gennem en centralboring 8 i pumpehusdækslet 3 kommer brændstofmængden, der skal ind-20 sprøjtes under pumpestemplets 4 leveringslag, frem til en ikke-vist indsprøjtningsventil i dieselmotorens topstykke.According to FIG. 1, in a pump housing 1, there is a pump cylinder 2, 5 which is fixed by a pump housing cover 3 in the pump housing 1. In the pump cylinder 2 a pump piston 4 is guided upwards and downwards, which pump piston on its casing surface near the upper piston end is provided with respect to the piston. the longitudinal axis obliquely extending guide edges 5. These control edges cooperate in a known manner with two in FIG. 1 not shown in radial bores in the wall of the pump cylinder 2, which determines the delivery start and delivery end of the pump piston 4. The fuel to be injected is fed through one in FIG. 1 likewise not shown supply line 15 for an annulus 6 between the pump housing 1 and the pump cylinder 2, from which annulus 6 the fuel through the just mentioned bores, which determines the start of the delivery time, reaches the delivery room of the pump 7. Through a central bore 8 in the pump housing cover 3 the amount of fuel comes which is to be injected under the delivery layer of the pump piston 4 to a non-shown injection valve in the cylinder head of the diesel engine.

Pumpestemplet 4 har på sin nederste, fra pumpecylinderen 2 udragende ende en flange 9, med hvilken det ligger an mod 25 en pumpeløfter 10, som er styret aksialt bevægelig i pumpehuset 1. Flangen 9 overgribes af en kappe 11, . som også omgiver en del af pumpeløfteren 10, og på hvilken den nederste ende af en trykfjeder 12 støtter sig. Den øverste ende af trykfjederen 12 støtter sig mod en fjedertallerken 30 13, som er fikseret i pumpehuset 1. Ved hjælp af trykfje deren 12 er et konstant anlæg for flangen 9 mod pumpeløfteren 10 sikret. Ved den nederste ende af pumpeløfteren 10 er der i denne drejeligt lejret en rulle 14, som ruller på en knast 15 på en knastaksel, som driver pumpestemplet 4 i 35 dieselmotorens takt.The pump piston 4 has at its lower end projecting from the pump cylinder 2 a flange 9 with which it abuts 25 a pump lifter 10, which is axially movable in the pump housing 1. The flange 9 is gripped by a sheath 11,. which also surrounds a portion of the pump lifter 10 and on which the lower end of a compression spring 12 rests. The upper end of the compression spring 12 rests on a spring plate 30 13, which is fixed in the pump housing 1. By means of the compression spring 12, a constant abutment of the flange 9 against the pump lifter 10 is secured. At the lower end of the pump lifter 10 there is rotatably mounted therein a roller 14 which rolls on a cam 15 on a camshaft which drives the pump piston 4 at the rate of the diesel engine.

55

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Den neders te ende af pumpecylinderen 2 er omgivet af en bøsning 16, som på sin nederste, over pumpecylinderen udragende ende er forsynet med to aksiale, overfor hinanden diamentralt modsat liggende slidser, ind i hvilke der hver 5 rager en radial arm 17 fra pumpestemplet 4. Slidsernes aksiale længde er mindst lige så stor som pumpestemplets 4 maksimale slag. På denne måde er der fremstillet en dreje-fast forbindelse mellem pumpestemplet 4 og bøsningen 16, som glider drejeligt i cylinderen 2. Bøsningen 16 har i sit 10 område oven over slidserne en udvendig fortanding 18, som står i indgreb med en indvendig fortanding 19, som findes i en i forhold til bøsningen 16 og dermed i forhold til pumpestemplet 4 excentrisk anbragt indstillingsbøsning 20. Indstillingsbøsningen 20 er lejret drejeligt om sin dreje-15 akse 21 (fig. 3) i pumpehuset 1, og har på sin ydre omkreds et udad ragende anslagsøre 22. På anslagsøret 22 er der fastgjort en i fig. 1 nedad ragende medbringerstift 23, som rager ind i et gaffelstykke 24, der er indstilleligt fastgjort til en reguleringsstang 25, som kan bevæges hen og 20 tilbage på tværs af pumpestemplet 4. Ved bevægelse af reguleringsstangen 25 med størrelsen "s" (fig. -2), lader indstillingsbøsningen 20 sig altså ved hjælp af gaffelstykket 24 og medbringerstiften 23 dreje med en vinkel på ca. 60®, således som det er vist med stiplede linier i fig. 2. I den 25 i fig. 2 øverste med stiplet linie viste stilling ligger anslagsørets 22 sideværts begrænsningsflade 22' (fig. 3) an mod en anslagsskrue 26, som er anbragt på pumpehuset 1. Anslagsskruen 26 er indstillelig ved hjælp af en indstillingsmøtrik 27. Et lignende arrangement af anslagsskrue 30 og indstillingsmøtrik befinder sig på den modsatte side af indstillingsbøsningens 20 svingområde og samvirker med anslagsørets 22 begrænsningsflade 22''. Størrelsen af vandringen "s" og dermed af ørets 22 svingområde er begrænset derved, at huset 1 ikke kan svækkes yderligere i det nævnte 35 område. Ved hjælp af den indvendige fortanding 19 og den udvendige fortanding 18 omsættes indstillingsbøsningens 20 6The lower end of the pump cylinder 2 is surrounded by a bushing 16, which is provided at its lower end extending over the pump cylinder with two axially opposite diametrically opposed slots into which each 5 projects a radial arm 17 from the pump piston 4. The axial length of the slots is at least as large as the maximum stroke of the pump piston 4. In this way, a pivot-fixed connection is made between the pump piston 4 and the sleeve 16 which slides pivotally into the cylinder 2. The sleeve 16 has in its region 10 above the slots an external tooth 18 which engages an internal tooth 19. which is located in a positioning sleeve 20 which is eccentrically disposed relative to the pump piston 4 and thus relative to the pump piston 4. The setting sleeve 20 is pivotally mounted about its pivot axis 21 (Fig. 3) in the pump housing 1 and has an outward circumference thereof. projecting impact ear 22. On the impact ear 22 an attachment in FIG. 1, a downwardly projecting carrier pin 23 projecting into a fork piece 24 adjustably attached to a regulating rod 25 which can be moved back and forth across the pump piston 4. By movement of the regulating rod 25 of size "s" (FIG. 2), the adjusting bush 20 can thus be turned by means of the fork piece 24 and the carrier pin 23 at an angle of approx. 60®, as shown in broken lines in FIG. 2. In the 25 of FIG. 2 in the upper position shown in dashed line, the lateral limiting surface 22 '(Fig. 3) of the abutment ear 22 abuts against an abutment screw 26 which is mounted on the pump housing 1. The abutment screw 26 is adjustable by means of an adjustment nut 27. A similar arrangement of abutment screw 30 and the adjusting nut is on the opposite side of the pivot area of the adjusting bush 20 and cooperates with the limiting surface 22 '' of the stop ear 22. The size of the migration "s" and thus of the swing region of the ear 22 is limited in that the housing 1 cannot be further weakened in the said 35 area. By means of the internal tooth 19 and the outer tooth 18 the adjusting bush 20 6 is reacted.

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drejebevægelse i en større indstillingsbevægelse for bøsningen 16 og dermed for pumpehuset 4. Størrelsen af bøsningens 16 drejebevægelse er afhængig af størrelsen af excentriciteten "e" (fig. 3) mellem pumpestemplets længdeakse og 5 indstillingsbøsningens 20 akse 21. Der kan opnås et maksimalt drejningsområde på omtrent 120° for bøsningen 16 henholdsvis pumpestemplet 4.turning movement in a larger adjusting movement for the bush 16 and thus for the pump housing 4. The size of the turning movement of the bushing 16 is dependent on the magnitude of the eccentricity "e" (Fig. 3) between the longitudinal axis of the pump piston and the axis 21 of the adjusting bush 20. about 120 ° for the bush 16 and the pump piston 4, respectively.

Som det ses af fig. 1, er indsprøjtningspumpen med sin ne-10 derste halvdel stukket ind i et motorhus 30, i hvilket også knastakslen er lejret. Væsentligt for indsprøjtningspumpen er, at anslagsørets 22 ydre begrænsning ligger indenfor diameteren af den øverste boring 31, som optager pumpehuset 1, så indsprøjtningspumpen uden videre lader sig ind- og 15 udmontere. For hver arbejdscylinder i dieselmotoren er en indsprøjtningspumpe anbragt på den beskrevne måde i motorhuset, og på samme måde findes der på den fælles knastaksel en knast svarende til knasten 15. Også reguleringsstangen 25 er fælles for alle arbejdscylindre, og har for hver ar-20 bejdscylinder et gaffelstykke 24. Ved indstilling af gaffelstykket 24 i forhold til reguleringsstangen og indstilling af anslagsskruerne 26 kan de brændstofmængder, der skal indsprøjtes i arbejdscylinderen, gøres indbyrdes lige store.As seen in FIG. 1, the injection pump with its lower half is inserted into a motor housing 30, in which also the camshaft is mounted. Essential to the injection pump is that the outer constraint of the stop 22 lies within the diameter of the top bore 31 which accommodates the pump housing 1, so that the injection pump can easily be mounted and removed. For each working cylinder of the diesel engine, an injection pump is arranged in the manner described in the engine housing, and in the same way there is on the common camshaft a cam corresponding to the cam 15. Also the control rod 25 is common to all working cylinders and has for each working cylinder 20 a fork piece 24. By adjusting the fork piece 24 relative to the control rod and adjusting the stop screws 26, the fuel quantities to be injected into the working cylinder can be made equal.

2525

Afvigende fra det beskrevne udførelseseksempel er det også muligt at udelade bøsningen 16, og anbringe dennes udvendige fortanding direkte på pumpestemplet 4. I et sådant tilfælde skulle den udvendige fortanding være udformet længere 30 i aksial retning, for at den under pumpestemplets op- og nedadbevægelse forbliver i indgreb med indstillingsbøsningens 20 indvendige fortanding 19.By way of derogation from the described embodiment, it is also possible to omit the sleeve 16 and apply its external tooth directly to the pump piston 4. In such a case, the external tooth should be formed longer in the axial direction so that it remains during the up and down movement of the pump piston. in engagement with the internal tooth 19 of the adjustment sleeve 20.

Claims

7 DK 164827 B

A fuel injection pump for diesel-type piston combustion engines having at least one pump piston (4) movable up and down in a cylinder (2), which pump piston (4) on its casing surface has the inclined guide edges of the pump piston (4) 5) which together with holes arranged in the cylinder (2) determine the delivery start and delivery of the pump piston (4), and with a setting bushing (20) surrounding a pump piston (4) which rotates the pump piston (4) about its longitudinal axis with a outside the cylinder (2), the regulating rod (25), which can be moved rectilinearly, is mounted, characterized in that the adjusting bush (20) 15 surrounds the pump piston (4) eccentrically and is provided with an internal tooth (19) that on the pump piston ( 4) an external tooth (18) engaging with the internal tooth (19) is arranged and the adjusting bush (20) is connected to the control rod (25). 20

Pump according to claim 1, with a pump housing (3r) which receives the cylinder (2) and with its lower end surrounds a lifter (10) which transmits the up and down movement of the pump piston (4) and is inserted into the a motor housing (30) containing 25 a camshaft drive mechanism, characterized in that the connection point between the adjusting bush (20) and the control rod (25) is within the circumference of the pump housing (1) occupied by the motor housing (30).

Pump according to claim 2, characterized in that the adjusting bush (20) on the outside is provided with a stop ear (22) which cooperates with its two lateral end faces (22 ', 22' ') with stops (26) on the pump housing (1), to limit the turning range of the adjusting bush (20). 8 DK 164827 B

Pump according to claim 3, characterized in that the stops (26) located on the pump housing (1) are adjustable.

Pump according to claim 3, characterized in that a carrier pin (23) is mounted on the stop (22) which projects into a fork (24) which is in turn fixed adjustably to the control rod (25).

Pump according to one of Claims 1 to 5, characterized in that the pump piston (4) is connected to an axially fixed coupling bushing (16) which is pivotally mounted in the cylinder (2), which has an external tooth (18) on the outside thereof. .