EP0372211B1 - Fuel injection pump for injection internal-combustion engines - Google Patents

Fuel injection pump for injection internal-combustion engines Download PDF

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Publication number
EP0372211B1
EP0372211B1 EP19890119889 EP89119889A EP0372211B1 EP 0372211 B1 EP0372211 B1 EP 0372211B1 EP 19890119889 EP19890119889 EP 19890119889 EP 89119889 A EP89119889 A EP 89119889A EP 0372211 B1 EP0372211 B1 EP 0372211B1
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EP
European Patent Office
Prior art keywords
suction
pump piston
fuel injection
pump
overflow
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
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EP19890119889
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German (de)
French (fr)
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EP0372211A1 (en
Inventor
Stanislaw Dr.-Dipl.-Ing. Bodzak
Theodor Dr.-Dipl.-Ing. Stipek
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Robert Bosch GmbH
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Robert Bosch GmbH
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    • 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

Definitions

  • the invention relates to 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 closed at the start of delivery by an upper control edge of the pump piston and is released at the end of delivery by a lower control edge of the pump piston.
  • the terms “above” and “below” refer to a position in which the working space of the pump piston is arranged at the top and the drive element or the drive cam is arranged at the bottom.
  • Very high pressures for example of 1500 bar or more, occur in the working area of the pump piston.
  • pressure fluctuations with high pressure peaks occur in the suction and overflow bores and in the suction chamber.
  • There are air bubbles or voids in the fuel and these high pressure peaks lead on the one hand to the implosion of the voids that already existed from the previous control process at the start of delivery, and on the other hand to the formation and subsequent implosion of new voids in the area of the liquid jet flowing in at high speed. If the cavities implode near the wall, cavitation occurs (cavity cavitation or jet cavitation). This causes material to be removed and, if this effect lasts for a sufficiently long time, the pumps will malfunction.
  • a so-called pilot control already controls a small amount of fuel from the working area of the pump piston into the suction area before the geometric end of the delivery, which is determined by smoothing the lower control edge over the suction and overflow bore.
  • This quantity of fuel changes the flow of the delivery tube from the working area of the pump piston to the nozzle only insignificantly, but causes an initially "soft", that is, a flatter rise in pressure in the suction space and thereby a "softer” imploding of the already existing cavities and a substantial reduction in the fuel volume which arises with higher pressure Cavities.
  • control groove consists of a longitudinal groove, which is located upstream of the suction and overflow bore to the pump piston drive side and whose lower pump piston drive-side boundary edge runs perpendicular to the cylinder wall.
  • the fuel jet entering the suction and overflow bore is directed axially parallel and then strongly deflected in the bore, so that cavities can still remain in the fuel volume in the suction and overflow bore, which then cause cavitation in their impolation.
  • a fuel injection pump is also known in which the suction and overflow bore is in the form of a Laval nozzle with an approximately funnel-shaped inlet and diffuser-shaped outlet.
  • Such types of holes can hardly be produced for large-scale products with reasonable effort.
  • the invention now aims to improve such a design and consists essentially in the fact that the base of the pilot valve groove runs obliquely upwards in the direction away from the piston running surface. It is thereby achieved that the pilot valve groove does not extend at least in its full depth over the entire length of the suction and overflow bore and therefore the risk of breakage of the pump piston liner is reduced.
  • the inclined position also ensures that the fuel jet flowing into the suction and overflow bore is directed towards the axis of the same and therefore includes the entire fuel volume in the suction and overflow bore and also has a discharge effect on the cavities in the direction of the suction. and overflow space, whereby cavitation in the suction and overflow bore, where these have the worst effect, is avoided or at least reduced.
  • the base of the pilot valve groove is inclined at an angle of 5 ° to 45 °, in particular 15 ° to 45 °, to the axis of the suction and overflow bore. This advantageously results in the shortening of the pre-tax groove and therefore the reduction in the risk of breakage. This angle is also favorable for the removal of the cavities from the suction and overflow bore and for the detection of the entire fuel volume located in the suction and overflow bore.
  • the pilot valve groove expediently extends only over part of the cylindrical region of the suction and overflow bore.
  • FIG. 1 and 2 show a known suction and overflow bore
  • FIG. 1 being an axial partial section through the pump piston liner in the area of the suction and overflow bore
  • FIG. 2 being a view in the direction of arrow II of FIG. 1.
  • 3 and 4 show the invention Formation of the suction and overflow bore
  • FIG. 3 being a partial axial section through the pump piston liner in the area of the suction and overflow bore
  • FIG. 4 being a view in the direction of arrow IV of FIG. 3.
  • FIG. 5 shows a diagram and FIG. 6 shows a partial axial section through a pump element of the fuel injection pump according to the invention.
  • a known suction and overflow bore 1 in the pump piston liner 2 is shown.
  • the pre-control groove 3 runs parallel to the axis 4 over the entire cylindrical area 5 of the suction and overflow bore 1.
  • the suction and overflow bore 1 widens conically and in this area an exemption 7 of the pre-flow groove 3 is also incorporated.
  • the pump piston sleeve Due to the pre-control groove 3 running over the entire cylindrical area and also due to the exemption 7, the pump piston sleeve is weakened and prone to breakage.
  • the fuel jet entering beforehand runs parallel to the axis and does not cover the entire fuel volume located in the suction and overflow bore 1 and, moreover, has an insufficient effect on the cavities in the direction of the suction and overflow chamber 8.
  • pilot valve groove 11 is arranged obliquely so that the base 12 of the pilot valve groove 11 is inclined at an angle ⁇ to the axis 13.
  • the pilot control groove 11 thus extends only over part of the length of the cylindrical region 14 of the suction and overflow bore 9, and this results in a lower risk of breakage for the pump piston bushing 10.
  • the lower control edge of the pump piston which determines the delivery end, overrides the pilot control groove 11 at the delivery end before it begins to expose the full cross section 15 of the suction and overflow bore 9.
  • the direction of the fuel jet entering beforehand is indicated by arrow 16. Due to the oblique course of this in advance entering jet according to arrow 16, therefore, on the one hand, the fuel volume located in the suction and overflow bore 9 is better detected and the fuel jet entering beforehand has a more favorable discharge effect on the cavities in the direction of the suction and overflow chamber 17.
  • Curve a shows the pressure curve in the working chamber of the pump cylinder and curve b shows the pressure curve in the suction and overflow chamber 17 or in the suction and overflow bore 9.
  • the dashed part a 'of curve a and the dashed part b' of curve b shows the pressure curve in an embodiment without a pilot groove 11.
  • the pressure values are plotted in the ordinate and the piston paths or the rotation angles of the cam are plotted in the abscissa.
  • the position c indicates the opening of the pilot control groove 11, d indicates the opening of the suction and overflow bore 9.
  • curve b which shows the pressure curve in the suction and overflow chamber 17 in the arrangement of a pilot valve groove
  • curve b ' which shows the pressure curve in the suction and overflow chamber in an arrangement in which no pre-flow groove 11 is provided.
  • 18 represents the pump housing, 10 the pump piston sleeve inserted into this, 19 the pump piston and 20 the working space of the pump piston 19.
  • 21 is the pressure valve and 22 is the delivery channel for the pressure in the working space 20
  • Fuel. 23 is an intermediate piece, which is pressed against the pump piston liner 10 by means of screws 25 acting on the pump housing 18 by means of the pressure valve housing 24.
  • the suction and overflow bore is again designated 9 and the suction and overflow chamber 17. Furthermore, the oblique pilot control groove 11 can be seen, the control edges of the pump piston interacting with the suction and overflow bore being designated by 26 and 27, respectively.

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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)

Description

Die Erfindung bezieht sich auf eine Kraftstoffeinspritzpumpe für Einspritzbrennkraftmaschinen, bei welcher die Pumpenkolbenbüchse wenigstens eine Saug- und Überströmbohrung aufweist, welche bei Förderbeginn durch eine obere Steuerkante des Pumpenkolbens abgeschlossen wird und bei Förderende durch eine untere Steuerkante des Pumpenkolbens freigegeben wird. Hiebei ist der Begriff "oben" und "unten" auf eine Lage bezogen, in welcher der Arbeitsraum des Pumpenkolbens oben und das Antriebselement bzw. der Antriebsnocken unten angeordnet ist.The invention relates to 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 closed at the start of delivery by an upper control edge of the pump piston and is released at the end of delivery by a lower control edge of the pump piston. The terms "above" and "below" refer to a position in which the working space of the pump piston is arranged at the top and the drive element or the drive cam is arranged at the bottom.

Im Arbeitsraum des Pumpenkolbens treten sehr hohe Drücke, beispielsweise von 1500 bar oder darüber, auf. Beim Absteuern des Kraftstoffes bei Förderende kommt es daher in der Saug- und Überströmbohrung und im Saugraum zu Druckschwingungen mit hohen Druckspitzen. Im Kraftstoff befinden sich Luftblasen bzw. Hohlräume und diese hohen Druckspitzen führen einerseits zur Implosion der Hohlräume, die vom vorhergehenden Zusteuervorgang bei Förderbeginn bereits vorhanden sind, und anderseits zur Bildung und anschließenden Implosion von neuen Hohlräumen im Bereich des mit hoher Geschwindigkeit einströmenden Flüssigkeitsstrahles. Wenn die Hohlräume in Wandnähe implodieren, kommt es zu Kavitation (Hohlraumkavitation bzw Strahlkavitation). Dadurch entstehen Materialabtragungen und bei genügend langer Einwirkung dieses Effektes Funktionsstörungen der Pumpen. Es wurden daher bereits verschiedene Maßnahmen vorgeschlagen, welche geeignet sind, den Druckaufbau im Saugraum bei Förderende nicht schlagartig zu gestalten. So wird beispielsweise durch eine sogenannte Vorabsteuerung bereits vor dem geometrischen Förderende, welches durch das Überschleifen der unteren Steuerkante über die Saug- und Überströmbohrung bestimmt ist, eine kleine Kraftstoffmenge aus dem Arbeitsraum des Pumpenkolbens in den Saugraum abgesteuert. Diese Kraftstoffmenge verändert den Fördermensenverlauf aus dem Arbeitsraum des Pumpenkolbens zur Düse nur unwesentlich, bewirkt aber einen vorerst "weichen", also flacheren Druckanstieg im Saugraum und dadurch ein "weicheres" Implodieren der bereits vorhandenen Hohlräume und eine wesentliche Verringerung der im Kraftstoffvolumen mit höherem Druck entstehenden Hohlräume. Es ist auch bei auf dem Markt befindlichen Kraftstoffeinspritznumpen bekannt, diese Absteuerung dadurch durchzuführen, daß in die Wandung der Saug- und Überströmbohrung an der Unterseite derselben eine Vorabsteuernut eingearbeitet ist. Die Erfindung bezieht sich nun im besonderen auf eine solche Kraftstoffeinspritzpumpe, bei welcher die Wandung der Saug- und Überströmbohrung an ihrer von der oberen Steuerkante abgewendeten Unterseite eine durch die GB-A 930 076 bekannte Vorabsteuernut aufweist, welche von der unteren Steuerkante des Pumpenkolbens überschliffen wird, bevor der Hauptquerschnitt der Saug- und Überströmbohrung überschliffen wird. Bei der bekannten Ausbildung besteht die Absteuernut aus einer Längsnut, die der Saug- und Überströmbohrung zur Pumpenkolbenantriebsseite vorgelagert ist und deren untere pumpenkolbenantriebsseitige Begrenzungskante senkrecht zur Zylinderwand verläuft. Dadurch wird der vorab in den Saug- und Überströmbohrung eintretende Brennstoffstrahl achsparallel gerichtet und dann in der Bohrung stark umgelenkt, so daß in der Saug- und Überströmbohrung noch Hohlräume im Kraftstoffvolumen verbleiben können, welche dann ei ihrer Impolsion Kavitation verursachen.Very high pressures, for example of 1500 bar or more, occur in the working area of the pump piston. When the fuel is shut off at the end of delivery, pressure fluctuations with high pressure peaks occur in the suction and overflow bores and in the suction chamber. There are air bubbles or voids in the fuel and these high pressure peaks lead on the one hand to the implosion of the voids that already existed from the previous control process at the start of delivery, and on the other hand to the formation and subsequent implosion of new voids in the area of the liquid jet flowing in at high speed. If the cavities implode near the wall, cavitation occurs (cavity cavitation or jet cavitation). This causes material to be removed and, if this effect lasts for a sufficiently long time, the pumps will malfunction. Various measures have therefore already been proposed which are suitable are not to abruptly design the pressure build-up in the suction chamber at the end of delivery. For example, a so-called pilot control already controls a small amount of fuel from the working area of the pump piston into the suction area before the geometric end of the delivery, which is determined by smoothing the lower control edge over the suction and overflow bore. This quantity of fuel changes the flow of the delivery tube from the working area of the pump piston to the nozzle only insignificantly, but causes an initially "soft", that is, a flatter rise in pressure in the suction space and thereby a "softer" imploding of the already existing cavities and a substantial reduction in the fuel volume which arises with higher pressure Cavities. It is also known in fuel injection pumps on the market to carry out this control in that a pilot valve groove is incorporated into the wall of the suction and overflow bore on the underside thereof. The invention now relates in particular to such a fuel injection pump, in which the wall of the suction and overflow bore on its side facing away from the upper control edge Underside has a pre-control groove known from GB-A 930 076, which is ground from the lower control edge of the pump piston before the main cross section of the suction and overflow bore is ground. In the known design, the control groove consists of a longitudinal groove, which is located upstream of the suction and overflow bore to the pump piston drive side and whose lower pump piston drive-side boundary edge runs perpendicular to the cylinder wall. As a result, the fuel jet entering the suction and overflow bore is directed axially parallel and then strongly deflected in the bore, so that cavities can still remain in the fuel volume in the suction and overflow bore, which then cause cavitation in their impolation.

Durch die DE-A 21 30 937 ist ferner eine Kraftstoffeinspritzpumpe bekannt, bei der die Saug- und Überströmbohrung in der Form einer Lavaldüse ausgebildet ist mit etwa trichterförmigen Ein- und diffuserförmigen Austritt. Solche Bohrungsformen sind kaum mit vertretbarem Aufwand für Großserienprodukte herstellbar. Im übrigen ist mit einer solchen Ausgestaltung auch keine in der Menge beherrschbare Vorabsteuerung von kleinen Kraftstoffmengen möglich, da der Übergangsquerschnitt im gegensatz zu der Ausgestaltung gemäß GB-A 930 076 größer als der eigentlichte Durchtrittsquerschnitt der Saug- und Überströmbohrung ist.From DE-A 21 30 937 a fuel injection pump is also known in which the suction and overflow bore is in the form of a Laval nozzle with an approximately funnel-shaped inlet and diffuser-shaped outlet. Such types of holes can hardly be produced for large-scale products with reasonable effort. Moreover, with such a configuration, it is also not possible to pre-control small amounts of fuel that can be controlled in terms of quantity, since, in contrast to the configuration according to GB-A 930 076, the transition cross section is larger than the actual passage cross section of the suction and overflow bore.

Die Erfindung zielt nun darauf ab, eine solche Ausbildung zu verbessern und besteht im wesentlichen darin, daß der Grund der Vorabsteuernut in Richtung von der Kolbenlauffläche weg schräg nach oben verläuft. Dadurch wird erreicht, daß sich die Vorabsteuernut zumindest nicht in ihrer vollen Tiefe über die gesamte Länge der Saug- und Überströmbohrung erstreckt und daher die Bruchgefahr der Pumpenkolbenbüchse verringert wird. Durch die Schrägstellung wird des weiteren erreicht, daß der in die Saug- und Überströmbohrung vorab einströmende Brennstoffstrahl zur Achse derselben gerichtet wird und daher das gesamte in der Saug- und Überströmbohrung befindliche Brennstoffvolumen umfaßt und überdies auch eine Abförderwirkung auf die Hohlräume in Richtung zum Saug- und Überströmraum bewirkt, wodurch Kavitation in der Saug- und Überströmbohrung, wo sich diese im ungünstigsten Maße auswirken, vermieden oder zumindest verringert wird.The invention now aims to improve such a design and consists essentially in the fact that the base of the pilot valve groove runs obliquely upwards in the direction away from the piston running surface. It is thereby achieved that the pilot valve groove does not extend at least in its full depth over the entire length of the suction and overflow bore and therefore the risk of breakage of the pump piston liner is reduced. The inclined position also ensures that the fuel jet flowing into the suction and overflow bore is directed towards the axis of the same and therefore includes the entire fuel volume in the suction and overflow bore and also has a discharge effect on the cavities in the direction of the suction. and overflow space, whereby cavitation in the suction and overflow bore, where these have the worst effect, is avoided or at least reduced.

Gemäß einer bevorzugten Ausführungsform der Erfindung ist der Grund der Vorabsteuernut unter einem Winkel von 5° bis 45°, insbesondere 15° bis 45°, zur Achse der Saug- und Überströmbohrung geneigt. Hiedurch ergibt sich günstigerweise die Verkürzung der Vorabsteuernut und daher die Verringerung der Bruchgefahr. Dieser Winkel ist auch günstig für die Abförderung der Hohlräume aus der Saug- und Überströmbohrung und für die Erfassung des gesamten, in der Saug- und Überströmbohrung befindlichen Kraftstoffvolumens. Gemäß der Erfindung erstreckt sich zweckmäßig die Vorabsteuernut nur über einen Teil des zylindrischen Bereiches der Saug- und Überströmbohrung.According to a preferred embodiment of the invention, the base of the pilot valve groove is inclined at an angle of 5 ° to 45 °, in particular 15 ° to 45 °, to the axis of the suction and overflow bore. This advantageously results in the shortening of the pre-tax groove and therefore the reduction in the risk of breakage. This angle is also favorable for the removal of the cavities from the suction and overflow bore and for the detection of the entire fuel volume located in the suction and overflow bore. According to the invention, the pilot valve groove expediently extends only over part of the cylindrical region of the suction and overflow bore.

In der Zeichnung ist die Erfindung anhand eines Ausführungsbeispieles schematisch erläutert.In the drawing, the invention is explained schematically using an exemplary embodiment.

Fig. 1 und 2 zeigen eine bekannte Saug- und Überströmbohrung, wobei Fig. 1 einen axialen Teilschnitt durch die Pumpenkolbenbüchse im Bereich der Saug- und Überströmbohrung und Fig. 2 eine Ansicht in Richtung des Pfeiles II der Fig. 1 darstellt. Fig. 3 und 4 zeigen die erfindungsgemäße Ausbildung der Saug- und Überströmbohrung, wobei Fig. 3 einen axialen Teilschnitt durch die Pumpenkolbenbüchse im Bereich der Saug- und Überströmbohrung und Fig. 4 eine Ansicht in Richtung des Pfeiles IV der Fig. 3 darstellt. Fig. 5 zeigt ein Diagramm und Fig. 6 zeigt einen teilweisen Axialschnitt durch ein Pumpenelement der erfindungsgemäßen Kraftstoffeinspritzpumpe.1 and 2 show a known suction and overflow bore, FIG. 1 being an axial partial section through the pump piston liner in the area of the suction and overflow bore and FIG. 2 being a view in the direction of arrow II of FIG. 1. 3 and 4 show the invention Formation of the suction and overflow bore, FIG. 3 being a partial axial section through the pump piston liner in the area of the suction and overflow bore and FIG. 4 being a view in the direction of arrow IV of FIG. 3. FIG. 5 shows a diagram and FIG. 6 shows a partial axial section through a pump element of the fuel injection pump according to the invention.

In Fig. 1 und 2 ist eine bekannte Saug- und Überströmbohrung 1 in der Pumpenkolbenbüchse 2 dargestellt. Die Vorabsteuernut 3 verläuft parallel zur Achse 4 über den gesamten zylindrischen Bereich 5 der Saug- und Überströmbohrung 1. Im Bereich 6 erweitert sich die Saug- und Überströmbohrung 1 konisch und in diesem Bereich ist überdies noch eine Freistellung 7 der Vorabströmnut 3 eingearbeitet. Durch die über den gesamten zylindrischen Bereich verlaufende Vorabsteuernut 3 und überdies auch durch die Freistellung 7 wird die Pumpenkolbenbüchse geschwächt und bruchanfällig. Überdies verläuft der vorab eintretende Brennstoffstrahl achsparallel und erfaßt nicht das gesamte,in der Saug- und Überströmbohrung 1 befindliche Kraftstoffvolumen und übt überdies nur in unzureichendem Maße eine Abförderwirkung auf die Hohlräume in Richtung zum Saug- und Überströmraum 8 aus.1 and 2, a known suction and overflow bore 1 in the pump piston liner 2 is shown. The pre-control groove 3 runs parallel to the axis 4 over the entire cylindrical area 5 of the suction and overflow bore 1. In the area 6, the suction and overflow bore 1 widens conically and in this area an exemption 7 of the pre-flow groove 3 is also incorporated. Due to the pre-control groove 3 running over the entire cylindrical area and also due to the exemption 7, the pump piston sleeve is weakened and prone to breakage. In addition, the fuel jet entering beforehand runs parallel to the axis and does not cover the entire fuel volume located in the suction and overflow bore 1 and, moreover, has an insufficient effect on the cavities in the direction of the suction and overflow chamber 8.

Fig. 3 und 4 zeigen nun die erfindungsgemäße Ausbildung der Saug- und Überströmbohrung 9 in der Pumpenkolbenbüchse 10. Die Vorabsteuernut 11 ist schräg so angeordnet, daß der Grund 12 der Vorabsteuernut 11 unter einem Winkel α zur Achse 13 geneigt ist. Die Vorabsteuernut 11 erstreckt sich somit nur über einen Teil der Länge des zylindrischen Bereiches 14 der Saug- und Überströmbohrung 9 und dadurch ergibt sich eine geringere Bruchgefahr für die Pumpenkolbenbüchse 10.3 and 4 show the inventive design of the suction and overflow bore 9 in the pump piston liner 10. The pilot valve groove 11 is arranged obliquely so that the base 12 of the pilot valve groove 11 is inclined at an angle α to the axis 13. The pilot control groove 11 thus extends only over part of the length of the cylindrical region 14 of the suction and overflow bore 9, and this results in a lower risk of breakage for the pump piston bushing 10.

Die das Förderende bestimmende untere Steuerkante des Pumpenkolbens überschleift bei Förderende die Vorabsteuernut 11, bevor sie beginnt, den vollen Querschnitt 15 der Saug- und Überströmbohrung 9 freizugeben. Die Richtung des vorab eintretenden Brennstoffstrahles ist durch den Pfeil 16 angedeutet. Durch den schrägen Verlauf dieses vorab eintretenden Strahles gemäß Pfeil 16 wird daher einerseits das in der Saug- und Überströmbohrung 9 befindliche Brennstoffvolumen besser erfaßt und der vorab eintretende Brennstoffstrahl übt eine günstigere Abförderwirkung auf die Hohlräume in Richtung zum Saug- und Überströmraum 17 aus.The lower control edge of the pump piston, which determines the delivery end, overrides the pilot control groove 11 at the delivery end before it begins to expose the full cross section 15 of the suction and overflow bore 9. The direction of the fuel jet entering beforehand is indicated by arrow 16. Due to the oblique course of this in advance entering jet according to arrow 16, therefore, on the one hand, the fuel volume located in the suction and overflow bore 9 is better detected and the fuel jet entering beforehand has a more favorable discharge effect on the cavities in the direction of the suction and overflow chamber 17.

Im Diagramm nach Fig. 5 ist der Druckverlauf bei Förderende dargestellt. Die Kurve a zeigt den Druckverlauf im Arbeitsraum des Pumpenzylinders und die Kurve b zeigt den Druckverlauf im Saug- und Überströmraum 17 bzw. in der Saug- und Überströmbohrung 9. Der strichlierte Teil a′ der Kurve a und der strichlierte Teil b′ der Kurve b zeigt den Druckverlauf bei einer Ausführungsform ohne Vorabsteuernut 11. In der Ordinate sind die Druckwerte aufgetragen und in der Abszisse sind die Kolbenwege bzw. die Verdrehwinkel des Nockens aufgetragen. Die Stellung c deutet das Öffnen der Vorabsteuernut 11 an, d deutet das Öffnen der Saug- und Überströmbohrung 9 an. Man ersieht daraus, daß die Kurve b, welche den Druckverlauf im Saug- und Überströmraum 17 bei der Anordnung einer Vorabsteuernut anzeigt, flacher verläuft als die Kurve b′, welche den Druckverlauf im Saug- und Überströmraum bei einer Anordnung anzeigt, bei welcher keine Vorabströmnut 11 vorgesehen ist.5 shows the pressure curve at the end of the delivery. Curve a shows the pressure curve in the working chamber of the pump cylinder and curve b shows the pressure curve in the suction and overflow chamber 17 or in the suction and overflow bore 9. The dashed part a 'of curve a and the dashed part b' of curve b shows the pressure curve in an embodiment without a pilot groove 11. The pressure values are plotted in the ordinate and the piston paths or the rotation angles of the cam are plotted in the abscissa. The position c indicates the opening of the pilot control groove 11, d indicates the opening of the suction and overflow bore 9. It can be seen from this that curve b, which shows the pressure curve in the suction and overflow chamber 17 in the arrangement of a pilot valve groove, is flatter than the curve b ', which shows the pressure curve in the suction and overflow chamber in an arrangement in which no pre-flow groove 11 is provided.

Bei dem in Fig. 6 dargestellten gesamten Pumpenelement stellt 18 das Pumpengehäuse, 10 die in dieses eingesetzte Pumpenkolbenbüchse, 19 den Pumpenkolben und 20 den Arbeitsraum des Pumpenkolbens 19 dar. 21 ist das Druckventil und 22 ist der Förderkanal für den im Arbeitsraum 20 unter Druck gesetzten Brennstoff. 23 ist ein Zwischenstück, welches unter Vermittlung des Druckventilgehäuses 24 durch am Pumpengehäuse 18 angreif ende Schrauben 25 gegen die Pumpenkolbenbüchse 10 gepreßt wird.In the entire pump element shown in FIG. 6, 18 represents the pump housing, 10 the pump piston sleeve inserted into this, 19 the pump piston and 20 the working space of the pump piston 19. 21 is the pressure valve and 22 is the delivery channel for the pressure in the working space 20 Fuel. 23 is an intermediate piece, which is pressed against the pump piston liner 10 by means of screws 25 acting on the pump housing 18 by means of the pressure valve housing 24.

Die Saug- und Überströmbohrung ist wiederum mit 9 und der Saug- und Überströmraum mit 17 bezeichnet. Weiters ist die schräg verlaufende Vorabsteuernut 11 zu erkennen, wobei die mit der Saug- und Überströmbohrung zusammenwirkenden Steuerkanten des Pumpenkolbens mit 26 bzw. 27 bezeichnet sind. Die das Förderende bestimmende untere Steuerkante 27 überschleift bei Förderende zuerst die geneigt verlaufende Vorabsteuernut 11, bevor der volle Querschnitt der Saug- und Überströmbohrung 9 freigegeben wird, so daß der erste geneigt austretende Brennstoffstrahl einen flacheren Druckanstieg im Saug- und Überströmraum 17 ergibt.The suction and overflow bore is again designated 9 and the suction and overflow chamber 17. Furthermore, the oblique pilot control groove 11 can be seen, the control edges of the pump piston interacting with the suction and overflow bore being designated by 26 and 27, respectively. The lower control edge 27 that determines the end of the conveyance blends over Conveying end first of all the inclined pilot valve groove 11 before the full cross section of the suction and overflow bore 9 is released, so that the first inclined fuel jet results in a flatter pressure increase in the suction and overflow chamber 17.

Claims (3)

1. Fuel injection pump, for fuel injection internal combustion engines, in which the pump piston sleeve (10) has at least one suction and relief hole (9) which is shut off at the beginning of delivery by an upper control edge (26) of the pump piston and is released by a lower control edge (27) of the pump piston at the end of delivery, the wall of the suction and relief hole having a pilot release groove (11) at its bottom side remote from the upper control edge, the lower control edge of the pump piston sliding over, this pilot release groove (11) before sliding over the main cross-section of the suction and relief hole, characterised in that the bottom (12) of the pilot release groove (11) extends obliquely upwards in the direction away from the piston running surface.
2. Fuel injection pump according to Claim 1, characterised in that the bottom (12) of the pilot release groove (11) is inclined at an angle (α) of between 5° and 45°, in particular between 15° and 45°, to the axis (13) of the suction and relief hole (9).
3. Fuel injection pump according to Claim 1 or 2, characterised in that the pilot release groove (11) only extends over a part of the cylindrical region (14) of the suction and relief hole (9).
EP19890119889 1988-11-26 1989-10-26 Fuel injection pump for injection internal-combustion engines Expired - Lifetime EP0372211B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19883840022 DE3840022A1 (en) 1988-11-26 1988-11-26 FUEL INJECTION PUMP FOR INJECTION COMBUSTION ENGINES
DE3840022 1988-11-26

Publications (2)

Publication Number Publication Date
EP0372211A1 EP0372211A1 (en) 1990-06-13
EP0372211B1 true EP0372211B1 (en) 1992-06-17

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EP19890119889 Expired - Lifetime EP0372211B1 (en) 1988-11-26 1989-10-26 Fuel injection pump for injection internal-combustion engines

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EP (1) EP0372211B1 (en)
JP (1) JPH0754618Y2 (en)
DE (2) DE3840022A1 (en)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4227854B4 (en) * 1992-08-22 2005-12-15 Robert Bosch Gmbh Fuel injection pump for internal combustion engines
JP4098738B2 (en) * 2004-03-05 2008-06-11 ボッシュ株式会社 Fuel injection pump for internal combustion engines
DE102008027651A1 (en) * 2008-06-10 2009-12-17 Man Diesel Se Injection pump for an internal combustion engine and internal combustion engine with injection pump

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DK94066C (en) * 1958-10-21 1962-08-06 Burmeister & Wains Mot Mask Fuel injection system for internal combustion engines.
NL125952C (en) * 1964-04-21
GB1322694A (en) * 1970-06-22 1973-07-11 Nippon Denso Co Fuel injection pumps for internal combustion engines

Also Published As

Publication number Publication date
JPH0278764U (en) 1990-06-18
EP0372211A1 (en) 1990-06-13
JPH0754618Y2 (en) 1995-12-18
DE3840022A1 (en) 1990-05-31
DE58901695D1 (en) 1992-07-23

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