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EP0263808B1 - Partie d'une pompe à combustible pour moteur à injection - Google Patents

Partie d'une pompe à combustible pour moteur à injection Download PDF

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Publication number
EP0263808B1
EP0263808B1 EP19870890210 EP87890210A EP0263808B1 EP 0263808 B1 EP0263808 B1 EP 0263808B1 EP 19870890210 EP19870890210 EP 19870890210 EP 87890210 A EP87890210 A EP 87890210A EP 0263808 B1 EP0263808 B1 EP 0263808B1
Authority
EP
European Patent Office
Prior art keywords
plunger
bore
delivery
pump element
control edge
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP19870890210
Other languages
German (de)
English (en)
Other versions
EP0263808A1 (fr
Inventor
Theodor Dipl.-Ing. Dr. Stipek
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Robert Bosch AG
Original Assignee
Robert Bosch AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Robert Bosch AG filed Critical Robert Bosch AG
Publication of EP0263808A1 publication Critical patent/EP0263808A1/fr
Application granted granted Critical
Publication of EP0263808B1 publication Critical patent/EP0263808B1/fr
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M59/00—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps
    • F02M59/20—Varying fuel delivery in quantity or timing
    • F02M59/24—Varying fuel delivery in quantity or timing with constant-length-stroke pistons having variable effective portion of stroke
    • F02M59/26—Varying fuel delivery in quantity or timing with constant-length-stroke pistons having variable effective portion of stroke caused by movements of pistons relative to their cylinders
    • F02M59/265—Varying fuel delivery in quantity or timing with constant-length-stroke pistons having variable effective portion of stroke caused by movements of pistons relative to their cylinders characterised by the arrangement or form of spill port of spill contour on the piston
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M55/00—Fuel-injection apparatus characterised by their fuel conduits or their venting means; Arrangements of conduits between fuel tank and pump F02M37/00
    • F02M55/001—Pumps with means for preventing erosion on fuel discharge
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M59/00—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps
    • F02M59/44—Details, components parts, or accessories not provided for in, or of interest apart from, the apparatus of groups F02M59/02 - F02M59/42; Pumps having transducers, e.g. to measure displacement of pump rack or piston

Definitions

  • the invention relates to a pump element of a fuel injection pump for injection internal combustion engines, in which the pump piston liner has at least one suction and overflow bore, which is ground over by control edges of the pump piston and the delivery end is determined by opening the suction and overflow bore, one in the area of the piston face arranged control edge determines the start of delivery and an arranged, in particular oblique, control edge on the piston skirt determines the delivery end, the pump piston having an axial bore, from which in the area of its end facing the piston face at least one radial bore extends, which on the piston skirt in which the suction and overflow bore overlapping area between the control edge determining the end of conveyance and the control edge determining the start of conveyance opens.
  • a device of the type mentioned at the outset has become known, for example, from DE-A 1 954 123, the axial bore in the piston originating from the working chamber thereof and via a radial bore in the region of the oblique control groove to end the injection process by connection to a suction and overflow hole opens.
  • the axial bore also opens into a throttle bore arranged between the two control edges, in order to allow part of the fuel delivered under pressure to flow away throttled in a rotational position of the pump piston corresponding to an idling operation, in order to reduce the noise load when the engine is idling.
  • the object of the invention is to counteract such cavitations and erosions.
  • the invention essentially consists in that the axial bore against the working space of the pump piston is designed to be closed, and that at least one radial bore opening at the piston skirt extends from the axial bore in the region of its end facing away from the piston face, which at least during one Part of the piston stroke is connected to a flushing oil supply bore provided in the pump piston bushing, through which fuel is supplied to the axial bore independently of the delivery of the pump element under a pressure exceeding the pressure in the suction chamber. From this flushing oil supply bore in the pump piston liner, fuel reaches the axial bore of the pump piston and from there through the radial bore into the suction and overflow bore of the pump piston liner.
  • the fuel Since the pressure of this fuel used for purging is above the pressure in the suction chamber, the fuel enters the suction and overflow bore and displaces the vapor bubbles away from the pump piston in the direction of the suction chamber. Since the radial bore emanating from the axial bore lies between the control edge that determines the delivery end and the control edge that determines the start of delivery, the steam bubbles are flushed away from the suction and overflow bore just before the control edge that determines the delivery end releases the suction and overflow bore. When the diverter jet, which has a large amount of energy, enters the suction and overflow bore, the vapor bubbles are already largely displaced from the critical point, namely from the pump piston.
  • the pressure of the flushing fuel jet is substantially lower than the pressure of the fuel jet that is turned off at the end of delivery, the vapor bubbles cannot be imploded hard by the flushing fuel jet.
  • the flushing fuel jet enters the suction and overflow bore of the pump piston liner as soon as the mouth of the radial bore begins to grind over the suction and overflow bore, and this flushing fuel jet therefore preferentially pushes the gas bubbles off the top of the suction and overflow bore, and this is the top side the critical point at which the pilot jet hits. Cavitation and erosion by hard imploding of the vapor bubbles is therefore largely avoided in this way.
  • the openings of the radial bores on the piston skirt preferably lie at equal distances from the control edge which determines the end of the delivery, so that the conditions for supplying the fuel used for purging are not changed.
  • the arrangement of several radial bores has the advantage that the flushing fuel enters the suction and overflow bore axially at all rotational positions of the piston, thereby promoting the removal of the gas or vapor bubbles.
  • the radial bore provided in the region of the end of the axial bore facing the piston end face can also open into a groove on the piston skirt that runs parallel to the control edge that determines the delivery end.
  • the arrangement can be such that the radial bore provided in the region of the end of the axial bore facing away from the piston end surface opens into a groove running parallel to the control edge which determines the conveying end, the axial distance from this control edge approximately equal to the axial distance of the flushing oil supply bore from the Suction and overflow drilling corresponds.
  • the flushing fuel is supplied intermittently whenever the mouth of the radial bore slides over the suction and overflow bore.
  • the radial bore provided in the region of the end of the axial bore facing away from the piston end face may open into an annular groove, the axial extent of which is at least equal to a substantial part of the piston stroke. In this case, the flushing fuel is supplied to the axial bore continuously, the flushing fuel only emerging from the radial bore when it drags over the suction and overflow bore of the pump piston liner.
  • Fig. 1 shows a partial axial section through a pump element
  • Fig. 2 shows the flow conditions in the S aug / overflow bore shortly before the static delivery begins
  • Fig. 3 shows a variant for flushing oil supply
  • Fig. 4 shows a development of the pump piston with modified radial Holes.
  • the pump piston with 1 and the pump piston sleeve with 2 is designated. 3 is the working area of the pump piston.
  • diametrically opposite two suction and overflow openings 4 are provided, which open into the suction chamber 5, and are ground through oblique control edges 6, which determine the end of the delivery.
  • An axial bore 7 is provided in the piston 1, which is closed off from the working space 3 by a plug 8.
  • a radial bore 10 emerges, which opens into a helical groove 11 on the jacket of the pump piston 1, which runs parallel to the oblique control edge 6.
  • the pump piston bushing 2 there is a flushing fuel supply bore 12, through which fuel is supplied via a connection 13 at a higher pressure than the pressure in the suction chamber 5.
  • radial bores 14 extend from this axial bore, the orifices 15 of which lie on the circumference of the piston in a row running parallel to the control edge 6.
  • the groove 11 is arranged so that it sweeps over the flushing fuel supply hole 12 when the mouths 15 of the holes 14 grind over the suction and overflow holes 4.
  • the condition for this is that the axial distance between the orifices 15 of the bores 14 and the bore 10 in the piston is approximately equal to the axial distance of the bore 12 from the suction and overflow bore 4.
  • Fig. 2 shows the position of the piston 1 at the start of delivery.
  • the control edge formed by the end face 9 closes off the suction and overflow opening 4 of the pump piston liner 2 and a jet of fuel enters the suction and overflow bore 4 when it is closed in the direction of arrow 18.
  • the suction and overflow opening through the end face 9 of the piston 1 is terminated, the fuel flow into the bores is suddenly interrupted, which creates a vacuum which is decisive for the formation of vapor bubbles. This illustration explains why 4 vapor bubbles occur in the suction and overflow bore.
  • Fig. 3 shows in a partial section a modified embodiment.
  • the radial bore 10 starting from the axial bore 7 of the pump piston 1 opens into an annular groove 19 of the piston 1, into which the flushing fuel feed bore 12 opens.
  • the axial extent of this annular groove is at least equal to a substantial part of the stroke of the pump piston 1, so that the flushing fuel continuously enters the axial bore 7.
  • the flushing fuel can be supplied separately under pressure via a connection 13
  • the supply can be carried out in a simple manner at a low speed low or low flow rates to save drive energy for a pump.
  • a separate pump is arranged and a valve which can be controlled via a control unit as a function of the speed or delivery rate of the pump is provided.
  • the pump can be switched by the control unit.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Fuel-Injection Apparatus (AREA)

Claims (9)

1. Elément de pompe d'une pompe d'injection de carburant pour moteurs à combustion interne à injection, dans lequel la chemise (2) du piston plongeur comprend au moins un alésage d'aspiration et d'écoulement (4) sur lequel passent en glissant les arêtes de commande (6, 9) du piston plongeur (1) et la fin du refoulement est déterminée par la mise en service de l'alésage d'aspiration et d'écoulement (4), une arête de commande prévue dans la région de la surface frontale (9) du piston déterminant le début du refoulement et une arête de commande (6) prévue sur le corps du piston, notamment en oblique, déterminant la fin du refoulement, le piston plongeur (1) comprenant un alésage axial à partir duquel part dans la région de son extrémité qui est tournée vers la surface frontale (9) du piston au moins un alésage radial (14) qui débouche sur le corps du piston dans la région de glissement de l'alésage d'aspiration et d'écoulement (4) entre l'arête de commande (6) déterminant la fin du refoulement et l'arête de commande (9) déterminant le début du refoulement, caractérisé en ce que l'alésage axial (7) est fermé vis à vis de l'enceinte de travail du piston plongeur (1) et qu'à partir de l'alésage axial (7) part dans la région de son extrémité qui est à l'opposé de la surface frontale (9) du piston au moins un alésage radial (10) débouchant sur le corps du piston, qui est en liaison au moins pendant une partie de la course du piston avec un alésage d'amenée d'huile de lavage (12) prévue dans la chemise du piston plongeur, par lequel du carburant est envoyé dans l'alésage axial (10) indépendamment du refoulement de l'élément de pompe et sous une pression dépassant la pression dans l'enceinte d'aspiration.
2. Elément de pompe selon la revendicatoin 1, caractérisé en ce que plusieurs alésages radiaux (14) sont prévus dans la région de l'extrémité de l'alésage axial (7) qui est tournée vers la surface frontale (9) du piston, dont les ouvertures (15) sur le corps du piston sont situées à une certaine distance les unes des autres qui est inférieure au diamètre de l'alésage d'aspiration et d'écoulement (4).
3. Elément de pompe selon la revendication 2, caractérisé en ce que les ouvertures (15) des alésages radiaux (14) sur le corps du piston sont situées à des distances égales de l'arête de commande (6) déterminant la fin du refoulement.
4. Elément de pompe selon la revendication 1, 2 ou 3, caractérisé en ce que les alésages radiaux (14) présentent des diamètres différents, les diamètres les plus importants étant prévus dans les régions où la course de roufoulement est la plus importante.
5. Elément de pompe selon la revendication 1, caractérisé en ce que l'alésage radial (14) prévu dans la région de l'extrémité de l'alésage axial (7) qui est tournée vers la surface frontale (9) du piston débouche sur le corps du piston dans une gorge parallèle à l'arête de commande (6) déterminant la fin du refoulement.
6. Elément de pompe selon l'une quelconque des revendications 1 à 5, caractérisé en ce que l'alésage radial (10) prévu dans la région d'extrémité de l'alésage axial (7) qui est à l'opposé de la surface frontale (9) du piston débouche dans une gorge (11) parallèle à l'arête de commande (6) déterminant la fin du refoulement, dont la distance axiale par rapport à cette arête de commande correspond sensiblement à la distance axiale entre l'alésage d'amenée d'huile de lavage (12) et l'alésage d'aspiration et d'écoulement (4).
7. Elément de pompe seon l'une quelconque des revendications 1 à 5, caractérisé en ce que l'alésage radial (10) prévu dans la région de l'extrémité de l'alésage axial (7) qui est à l'opposé de la surface frontale (9) du piston débouche dans une gorge annulaire (11) dont l'étendue axiale est au moins égale à une partie importante de la course du piston.
8. Elément de pompe selon l'une quelconque des revendications 1 à 7, caractérisé en ce que le carburant de lavage n'est alimenté qu'à partir d'une vitesse de rotation déterminée.
9. Elément de pompe selon l'une quelconque des revendications 1 à 8, caractérisé en ce que le carburant de lavage n'est alimenté qu'à partir d'une quantité refoulée déterminée.
EP19870890210 1986-09-10 1987-09-10 Partie d'une pompe à combustible pour moteur à injection Expired - Lifetime EP0263808B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
AT2438/86 1986-09-10
AT0243886A AT404058B (de) 1986-09-10 1986-09-10 Pumpenelement einer brennstoffeinspritzpumpe für einspritzbrennkraftmaschinen

Publications (2)

Publication Number Publication Date
EP0263808A1 EP0263808A1 (fr) 1988-04-13
EP0263808B1 true EP0263808B1 (fr) 1990-04-25

Family

ID=3534355

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19870890210 Expired - Lifetime EP0263808B1 (fr) 1986-09-10 1987-09-10 Partie d'une pompe à combustible pour moteur à injection

Country Status (3)

Country Link
EP (1) EP0263808B1 (fr)
AT (1) AT404058B (fr)
DE (1) DE3762446D1 (fr)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3839753A1 (de) * 1988-11-25 1990-05-31 Bosch Gmbh Robert Pumpenelement einer brennstoffeinspritzpumpe fuer einspritzbrennkraftmaschinen
DE4006409A1 (de) * 1990-03-01 1991-09-19 Bosch Gmbh Robert Kraftstoffeinspritzeinrichtung fuer einspritzbrennkraftmaschinen

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR788642A (fr) * 1935-04-11 1935-10-14 Pompes d'injection de combustible
FR843031A (fr) * 1938-02-25 1939-06-23 Prec Mecanique S A Perfectionnements apportés aux pompes à piston, notamment aux pompes à injection de combustible
US2513883A (en) * 1947-01-15 1950-07-04 Ingersoll Rand Co Fuel pump for engines
DE1954123A1 (de) * 1968-11-04 1970-05-27 Nippon Denso Co Kraftstoffeinspritzpumpe fuer Dieselmotoren
GB1594472A (en) * 1977-04-30 1981-07-30 Lucas Industries Ltd Fuel injection pumps
GB1594124A (en) * 1977-04-30 1981-07-30 Lucas Industries Ltd Liquid fuel injection pumps
DE3347430A1 (de) * 1983-12-29 1985-07-11 Robert Bosch Gmbh, 7000 Stuttgart Kraftstoffeinspritzpumpe fuer brennkraftmaschinen

Also Published As

Publication number Publication date
AT404058B (de) 1998-08-25
EP0263808A1 (fr) 1988-04-13
ATA243886A (de) 1997-12-15
DE3762446D1 (de) 1990-05-31

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