EP0864037B1 - Fuel injection pump with a timing-device piston for timing beginning of injection - Google Patents

Fuel injection pump with a timing-device piston for timing beginning of injection Download PDF

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Publication number
EP0864037B1
EP0864037B1 EP97930329A EP97930329A EP0864037B1 EP 0864037 B1 EP0864037 B1 EP 0864037B1 EP 97930329 A EP97930329 A EP 97930329A EP 97930329 A EP97930329 A EP 97930329A EP 0864037 B1 EP0864037 B1 EP 0864037B1
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EP
European Patent Office
Prior art keywords
pressure
control
piston
cylinder bore
fuel injection
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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
EP97930329A
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German (de)
French (fr)
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EP0864037A1 (en
Inventor
Wolfgang Fehlmann
Thomas Kulder
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Robert Bosch GmbH
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Robert Bosch GmbH
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Publication of EP0864037A1 publication Critical patent/EP0864037A1/en
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Classifications

    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02DCONTROLLING COMBUSTION ENGINES
    • F02D1/00Controlling fuel-injection pumps, e.g. of high pressure injection type
    • F02D1/16Adjustment of injection timing
    • F02D1/18Adjustment of injection timing with non-mechanical means for transmitting control impulse; with amplification of control impulse
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02MSUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M41/00Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor
    • F02M41/08Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor the distributor and pumping elements being combined
    • F02M41/14Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor the distributor and pumping elements being combined rotary distributor supporting pump pistons
    • F02M41/1405Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor the distributor and pumping elements being combined rotary distributor supporting pump pistons pistons being disposed radially with respect to rotation axis
    • F02M41/1411Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor the distributor and pumping elements being combined rotary distributor supporting pump pistons pistons being disposed radially with respect to rotation axis characterised by means for varying fuel delivery or injection timing
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02DCONTROLLING COMBUSTION ENGINES
    • F02D1/00Controlling fuel-injection pumps, e.g. of high pressure injection type
    • F02D1/16Adjustment of injection timing
    • F02D1/18Adjustment of injection timing with non-mechanical means for transmitting control impulse; with amplification of control impulse
    • F02D1/183Adjustment of injection timing with non-mechanical means for transmitting control impulse; with amplification of control impulse hydraulic
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02MSUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M41/00Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor
    • F02M41/08Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor the distributor and pumping elements being combined
    • F02M41/10Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor the distributor and pumping elements being combined pump pistons acting as the distributor
    • F02M41/12Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor the distributor and pumping elements being combined pump pistons acting as the distributor the pistons rotating to act as the distributor
    • F02M41/123Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor the distributor and pumping elements being combined pump pistons acting as the distributor the pistons rotating to act as the distributor characterised by means for varying fuel delivery or injection timing
    • F02M41/128Varying injection timing by angular adjustment of the face-cam or the rollers support
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02DCONTROLLING COMBUSTION ENGINES
    • F02D1/00Controlling fuel-injection pumps, e.g. of high pressure injection type
    • F02D1/16Adjustment of injection timing
    • F02D1/18Adjustment of injection timing with non-mechanical means for transmitting control impulse; with amplification of control impulse
    • F02D1/183Adjustment of injection timing with non-mechanical means for transmitting control impulse; with amplification of control impulse hydraulic
    • F02D2001/186Adjustment of injection timing with non-mechanical means for transmitting control impulse; with amplification of control impulse hydraulic using a pressure-actuated piston for adjustment of a stationary cam or roller support

Definitions

  • the invention is based on a fuel injection pump the genus of claim 1.
  • a fuel injection pump known from DE-A1-35 32 719 is a connecting line between the work area and Cylinder bore one of the facing the work area Front side of the spray adjustment piston outgoing axially parallel Blind hole provided at its end by a transverse bore running radially from the outside to the cylinder bore is cut.
  • the cross section of this cross hole at the entrance to the cylinder bore has a circular area.
  • control spool is adjusted to known manner by an actuator that in a part of the injection adjuster fixed to the housing has a pressure chamber includes with a surface acted upon by the control pressure.
  • an actuator that in a part of the injection adjuster fixed to the housing has a pressure chamber includes with a surface acted upon by the control pressure.
  • FIG. 1 shows a section through a fuel injection pump the distributor type with radial Pump piston and a device for spray start adjustment in the configuration according to the invention.
  • the fuel injection pumps of the distributor type can either as pumps with one as both distributor and Pump piston serving axially driven pump piston be, or radial pistons can be provided, the radially into a delivery channel arranged in a distributor promote.
  • a so-called radial piston pump of the known Design is shown in section in Figure 1.
  • Pump piston 1 is provided, the same angular distance in a common radial plane to Axis of distributor 2 in radial bores 3 of distributor 2 are tightly slidably mounted.
  • the pump piston 1 On one end enclose a common pump work room 4, the in a known, not shown here manner in the radial outward stroke the pump piston 1 is filled with fuel and with the radial inward stroke of the pump piston via one here also not recognizable pressure line with a distributor opening is connected to the outer surface of the distributor 2, the distributor opening at the circumference of the distributor controls outgoing injection lines, each of which one with inward moving pump pistons with injection pressure brought fuel is supplied.
  • the distributor is thereby by means not shown from one Drive shaft rotatably driven in such a way that on the one hand the distributor opening can perform its control function and on the other hand, the pump piston moves in the circumferential direction become.
  • cam ring 8 represents the essentially stationary Part of the cam drive of the pump pistons. While the device moving the pump piston, the z. B. the roller plunger 6 leading ring 9 can be the is coupled to the drive shaft, the moving part of the Represent cam drive.
  • the one with its cylindrical outer wall in a corresponding cylindrical recess 10 of the pump housing 11 of the Fuel injection pump is a previous or later emergence of the rollers 12 of the roller tappet 6 on the causes respective cams 13 which are arranged so that all roller tappets synchronously inwards or outwards around the same strokes.
  • the cam ring 8 has a nose 14 which in a recess 15 in an injection piston 16 whose cylindrical surface engages.
  • the injection adjustment piston is tightly displaceable in a cylinder 17 and closes with its one end 18 with the closed End of the cylinder 17 a work space 20 and with its opposite, other end face in there as well closed cylinder a spring chamber 22.
  • a return spring 23 is arranged on the one hand on a closing part closing the cylinder 17 24 and on the other hand on the end face 21 of the adjusting piston 16 supports and strives so clamped, the Injection adjusting piston 16 with its one end face 18 in System to the cylinder 17 closing opposite Bring wall 25.
  • the injection adjusting piston 16 there is also an axial blind bore 27 as a control valve 28 leading Cylinder bore provided, which extends to the spring chamber 22 opens.
  • the control slide 28 used there closes its one end face 29 with the closed end of the Cylinder bore a space 30 in which a compression spring 36th axially loaded the spool and protrudes with his other end in the spring chamber 22, where it is from a control spring 31 is applied, which on the other hand also is supported on the closure part 24.
  • Parallel to the cylinder bore 27 runs in the actuating piston from one end face 18 outgoing connecting line 32, the radial in the area of Coverage by the control spool in the cylinder bore opens.
  • This junction can by a collar 33 of the Control spool are closed, this ring collar an annular groove 34 on the work space side of one Separates the annular space 35, with a pressure medium inlet in the annular groove 34 opens and the annular space 35 in the spring space 22nd flows, which relieves a relief line, not shown is.
  • the ring edges delimiting the ring collar are Control edges through which a relative displacement of the Control spool the connecting line 32 either over the Annular groove 34 connected to the pressure medium inlet 39 or via the annular space 35 to the spring space 22 is relieved.
  • the control spool is adjusted using a Tappet 49 with which the control slide under the influence of Compression spring 36 is coupled so that it is in the spring chamber 22nd protruding end of the spool on the plunger 49 to the system comes.
  • This extends coaxially to the axis of the adjusting piston 16 or the control slide 28 and occurs on the End face 21 of the control slide opposite side in an axial bore 52 provided in the closure part 24.
  • a closed working cylinder 53 arranged coaxially to the axial Hole 52 connects and the other end through a cover 54 is closed.
  • the inlet 60 is the Connecting line 39 in the cylinder bore 27 with a elongated, preferably elliptical cross section with lying in the direction of the spool Main extension provided so that when the Control spool relative to the injection piston through the The control edge of the ring collar is initially only a small, throttling one Cross section open to the working space 20 becomes. So can vibrate the work area 20 only slightly supplied or from this pressure medium be dissipated. The tendency to vibrate when occurring Interference forces, such as engine impacts, are therefore essential reduced. Instead of an elliptical cross section, too other cross-sectional profiles that support this effect the opening of the inlet cross-section of the pressure medium inlet be realized. Compound are to be mentioned Parabolic branches or hyperbaric branches or other limitations the cross-sectional area as conic curves.
  • This configuration is particularly advantageous in connection with the one described above outside the injection adjustment piston arranged housing-fixed pressure chamber 56.
  • This Arrangement is also the occurrence of vibrations due to shocks transmitted by the cam drive avoided because this pressure chamber over the unloaded spring chamber from the shock-loaded pressure side and the resulting Movements of the injection adjustment piston is decoupled.

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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

Stand der TechnikState of the art

Die Erfindung geht von einer Kraftstoffeinspritzpumpe gemäß der Gattung des Patentanspruchs 1 aus. Bei einer solchen, durch die DE-A1-35 32 719 bekannte Kraftstoffeinspritzpumpe ist als Verbindungsleitung zwischen Arbeitsraum und Zylinderbohrung eine von der dem Arbeitsraum zugewandten Stirnseite des Spritzverstellkolbens ausgehende achsparallele Sacklochbohrung vorgesehen, die an ihrem Ende von einer radial von außen zur Zylinderbohrung verlaufende Querbohrung geschnitten wird. Der Querschnitt dieser Querbohrung am Eintritt in die Zylinderbohrung hat eine Kreisfläche.The invention is based on a fuel injection pump the genus of claim 1. With such a through the fuel injection pump known from DE-A1-35 32 719 is a connecting line between the work area and Cylinder bore one of the facing the work area Front side of the spray adjustment piston outgoing axially parallel Blind hole provided at its end by a transverse bore running radially from the outside to the cylinder bore is cut. The cross section of this cross hole at the entrance to the cylinder bore has a circular area.

Bei einer solchen Spritzverstelleinrichtung tritt das Problem auf, daß es auf Grund der Lastwechsel im Nockenantrieb der Kraftstoffeinspritzpumpe zu Druckschwankungen im Bereich der Druckräume des Spritzverstellers bzw. zu Relativbewegungen zwischen Spritzverstellkolben und Steuerschieber kommt. This occurs with such a spray adjustment device Problem on that it is due to the load change in the cam drive the fuel injection pump to pressure fluctuations in the Area of the pressure adjuster of the injection adjuster or too Relative movements between injection adjustment pistons and Control spool comes.

Vorteile der ErfindungAdvantages of the invention

Durch die erfindungsgemäße Kraftstoffeinspritzpumpe mit den kennzeichnenden Merkmalen des Patentanspruchs 1 ergibt sich der Vorteil, daß sich bei Relativverschiebungen des Steuerschiebers zunächst nur eine kleine Querschnittsfläche aufgesteuert wird, die bei gleichem Stellweg kleiner ist als die üblicherweise sich einstellende Querschnittsfläche bei kreisrundem Eintrittsquerschnitt der Verbindungsleitung in die Zylinderbohrung. Damit wird dann, wenn auf Grund der Relativbewegung zwischen Spritzverstellkolben und Steuerschieber der Steuerschieber kurzzeitig aus seiner an sich richtigen Position relativ zum Spritzverstellkolben verstellt wird nur ein sehr kleiner, drosselnder Querschnitt aufgesteuert, so daß sich die Fehleinstellung des Steuerschiebers nicht sofort in Form einer wesentlichen Druckänderung im Arbeitsraum des Spritzverstellkolbens auswirkt. Damit entfällt eine schnelle, heftige Reaktion des Spritzverstellkolbens auf die kurzzeitige Fehlstellung des Steuerschiebers derart, daß sich solche schwingenden Fehlstellungen nicht verstärkt zu einem weiteren Schwingen des Spritzverstellkolbens aufschaukeln können.By the fuel injection pump according to the invention with the characteristic features of claim 1 results the advantage that there is relative displacement of the spool initially only controlled a small cross-sectional area that is smaller than that with the same travel range cross-sectional area that is usually established circular inlet cross section of the connecting line in the cylinder bore. This means that if Relative movement between the injection piston and Control spool the spool briefly out of its on correct position relative to the injection piston only a very small, restricting cross-section is adjusted opened, so that the incorrect setting of the spool not immediately in the form of a significant change in pressure in the working area of the injection adjustment piston. This eliminates the need for a quick, violent reaction from the injection adjustment piston to the brief misalignment of the control spool such that such vibrating misalignments does not intensify to further oscillation of the injection adjustment piston can rock.

In den Unteransprüchen sind vorteilhafte Weiterbildungen der Ausgestaltung des Eintrittsquerschnitts der Verbindungsleitung in die Zylinderbohrung angegeben. Wesentlich ist dabei, einen quasi kontinuierlichen Querschnittsverlauf bei stetiger Verstellung der diesen Querschnitt steuernden Steuerkante zu erzielen, wobei die Zunahme des Querschnitts über einen relativ langen Verstellweg allmählich erfolgt. In geöffneter Stellung steht dann der volle Überströmquerschnitt zur Verfügung, so daß bei gewollter Verstellung des Steuerschiebers mit der erforderlichen Schnelligkeit eine Korrektur der Spritzverstellkolbenstellung erfolgen kann. Advantageous further developments of the Design of the inlet cross section of the connecting line indicated in the cylinder bore. Is essential in doing so, a quasi-continuous cross-sectional course constant adjustment of those controlling this cross-section Achieve control edge, increasing the cross section gradually takes place over a relatively long adjustment path. In The full overflow cross-section is then in the open position are available so that when the adjustment of the Control spool with the required speed one Correction of the injection piston position can be done.

In weiterhin vorteilhafter Ausgestaltung gemäß Patentanspruch 5 erfolgt die Verstellung des Steuerschiebers in an sich bekannter Weise durch ein Stellglied, das in einem gehäusefesten Teil des Spritzverstellers einen Druckraum einschließt mit einer vom Steuerdruck beaufschlagten Fläche. Durch diesen außerhalb des Spritzverstellkolbens untergebrachten Druckraum erfolgt eine Entkopplung dieses Druckraumes von den Druckschwankungen im Arbeitsraum des Spritzverstellkolbens insbesondere durch den zwischen beiden liegenden Entlastungsraum. Auch dies trägt in Ergänzung zur obigen Ausgestaltung nach Patentanspruch 1 zur Reduzierung von Druckschwingungen des Spritzverstellkolbens bei.In a further advantageous embodiment according to claim 5 the control spool is adjusted to known manner by an actuator that in a part of the injection adjuster fixed to the housing has a pressure chamber includes with a surface acted upon by the control pressure. Through this outside the injection adjustment piston decoupled this takes place Pressure room from the pressure fluctuations in the work area of the Injection adjusting piston in particular through the between the two lying relief room. This also contributes to Above embodiment according to claim 1 for reduction of pressure fluctuations of the injection adjustment piston.

Zeichnungdrawing

Ein Ausführungsbeispiel der Erfindung ist in der Zeichnung dargestellt und wird in der nachfolgenden Beschreibung näher erläutert. Es zeigt Figur 1 einen Schnitt durch eine Kraftstoffeinspritzpumpe der Verteilerbauart mit radial liegenden Pumpenkolben und einer Einrichtung zur Spritzbeginnverstellung in der erfindungsgemäßen Ausgestaltung.An embodiment of the invention is in the drawing shown and is described in more detail in the following description explained. FIG. 1 shows a section through a fuel injection pump the distributor type with radial Pump piston and a device for spray start adjustment in the configuration according to the invention.

Beschreibung des AusführungsbeispielsDescription of the embodiment

Die Kraftstoffeinspritzpumpen der Verteilerbauart können entweder als Pumpen mit einem sowohl als Verteiler als auch Pumpenkolben dienenden axial angetriebenen Pumpenkolben versehen werden, oder es können Radialkolben vorgesehen werden, die radial in einen in einem Verteiler angeordneten Förderkanal fördern. Eine solche sogenannte Radialkolbenpumpe der bekannten Bauart ist im Schnitt in Figur 1 dargestellt. Dabei sind vier Pumpenkolben 1 vorgesehen, die im gleichen Winkelabstand in einer gemeinsamen Radialebene zur Achse des Verteilers 2 in Radialbohrungen 3 des Verteilers 2 dicht verschiebbar gelagert sind. Auf ihrer einen Stirnseite schließen sie einen gemeinsamen Pumpenarbeitsraum 4 ein, der in bekannter, hier nicht weiter gezeigten Weise beim Radialauswärtshub der Pumpenkolben 1 mit Kraftstoff gefüllt wird und beim Radialeinwärtshub der Pumpenkolben über eine hier ebenfalls nicht erkennbare Druckleitung mit einer Verteileröffnung an der Mantelfläche des Verteilers 2 verbunden wird, wobei die Verteileröffnung am Umfang des Verteilers abgehende Einspritzleitungen ansteuert, von denen jeweils eine bei einwärts bewegten Pumpenkolben mit auf Einspritzdruck gebrachten Kraftstoff versorgt wird. Der Verteiler ist dabei durch nicht weiter gezeigte Mittel von einer Antriebswelle rotierend angetrieben derart, daß einerseits die Verteileröffnung ihre Steuerfunktion ausführen kann und andererseits die Pumpenkolben in Umfangsrichtung bewegt werden. Dabei liegen an der dem Pumpenarbeitsraum 4 gegenüberliegenden Seite der Pumpenkolben Rollenstößel 6 an, die einer Nockenbahn 7 folgen, die auf einem Nockenring 8 an dessen einwärts zum Verteiler weisenden Ringfläche angeordnet ist. Der Nockenring 8 stellt den im wesentlichen stillstehenden Teil des Nockenantriebs der Pumpenkolben dar. Während die die Pumpenkolben bewegende Einrichtung, die z. B. der die Rollenstößel 6 führende Ring 9 sein kann, der mit der Antriebswelle gekoppelt ist, den bewegten Teil des Nockenantriebs darstellen. Je nach Stellung des Nockenrings, der mit seiner zylindrischen Außenwand in einer entsprechenden zylindrischen Ausnehmung 10 des Pumpengehäuses 11 der Kraftstoffeinspritzpumpe geführt ist, wird ein früheres oder späteres Auflaufen der Rollen 12 der Rollenstößel 6 auf die jeweiligen Nocken 13 bewirkt, die so angeordnet sind, daß alle Rollenstößel synchron einwärts oder auswärts um die gleichen Hübe bewegt werden. Mit der Verstellung des Nockenrings wird somit der Beginn des Förderhubs der Pumpenkolben und damit der Spritzbeginn im Verhältnis zum Antrieb der Kraftstoffeinspritzpumpe verändert.The fuel injection pumps of the distributor type can either as pumps with one as both distributor and Pump piston serving axially driven pump piston be, or radial pistons can be provided, the radially into a delivery channel arranged in a distributor promote. Such a so-called radial piston pump of the known Design is shown in section in Figure 1. There are four Pump piston 1 is provided, the same angular distance in a common radial plane to Axis of distributor 2 in radial bores 3 of distributor 2 are tightly slidably mounted. On one end enclose a common pump work room 4, the in a known, not shown here manner in the radial outward stroke the pump piston 1 is filled with fuel and with the radial inward stroke of the pump piston via one here also not recognizable pressure line with a distributor opening is connected to the outer surface of the distributor 2, the distributor opening at the circumference of the distributor controls outgoing injection lines, each of which one with inward moving pump pistons with injection pressure brought fuel is supplied. The distributor is thereby by means not shown from one Drive shaft rotatably driven in such a way that on the one hand the distributor opening can perform its control function and on the other hand, the pump piston moves in the circumferential direction become. Thereby lie on the pump working space 4 opposite Side of the pump piston roller tappet 6, the follow a cam track 7 on a cam ring 8 its inwardly facing annular surface is arranged is. The cam ring 8 represents the essentially stationary Part of the cam drive of the pump pistons. While the device moving the pump piston, the z. B. the roller plunger 6 leading ring 9 can be the is coupled to the drive shaft, the moving part of the Represent cam drive. Depending on the position of the cam ring, the one with its cylindrical outer wall in a corresponding cylindrical recess 10 of the pump housing 11 of the Fuel injection pump is a previous or later emergence of the rollers 12 of the roller tappet 6 on the causes respective cams 13 which are arranged so that all roller tappets synchronously inwards or outwards around the same strokes. With the adjustment of the cam ring is the beginning of the delivery stroke of the pump piston and thus the start of spraying in relation to the drive of the Fuel injection pump changed.

Zur Verstellung weist der Nockenring 8 eine Nase 14 auf, die in eine Ausnehmung 15 in einem Spritzverstellkolben 16 an dessen zylindrischer Mantelfläche eingreift. Der Spritzverstellkolben ist in einem Zylinder 17 dicht verschiebbar und schließt mit seiner einen Stirnseite 18 mit dem geschlossenen Ende des Zylinders 17 einen Arbeitsraum 20 ein und mit seiner gegenüberliegenden, anderen Stirnfläche im dort ebenfalls verschlossenen Zylinder einen Federraum 22 ein. In diesem ist eine Rückstellfeder 23 angeordnet, die sich einerseits an einem den Zylinder 17 verschließenden Verschlußteil 24 und andererseits an der Stirnseite 21 des Verstellkolbens 16 abstützt und so eingespannt bestrebt ist, den Spritzverstellkolben 16 mit seiner einen Stirnseite 18 in Anlage an die den Zylinder 17 gegenüberliegend verschließenden Wand 25 zu bringen.For adjustment, the cam ring 8 has a nose 14 which in a recess 15 in an injection piston 16 whose cylindrical surface engages. The injection adjustment piston is tightly displaceable in a cylinder 17 and closes with its one end 18 with the closed End of the cylinder 17 a work space 20 and with its opposite, other end face in there as well closed cylinder a spring chamber 22. In a return spring 23 is arranged on the one hand on a closing part closing the cylinder 17 24 and on the other hand on the end face 21 of the adjusting piston 16 supports and strives so clamped, the Injection adjusting piston 16 with its one end face 18 in System to the cylinder 17 closing opposite Bring wall 25.

Im Spritzverstellkolben 16 ist ferner eine axiale Sackbohrung 27 als eine einen Steuerschieber 28 führende Zylinderbohrung vorgesehen, die sich zum Federraum 22 hin öffnet. Der dort eingesetzte Steuerschieber 28 schließt mit seiner einen Stirnseite 29 mit dem geschlossenen Ende der Zylinderbohrung einen Raum 30 ein, in dem eine Druckfeder 36 den Steuerschieber axial belastet und ragt mit seinem anderen Ende in den Federraum 22, wo er von einer Steuerfeder 31 beaufschlagt ist, die sich andererseits ebenfalls am Verschlußteil 24 abstützt. Parallel zur Zylinderbohrung 27 verläuft im Stellkolben eine von der einen Stirnseite 18 ausgehende Verbindungsleitung 32, die radial im Bereich der Überdeckung durch den Steuerschieber in die Zylinderbohrung einmündet. Diese Einmündung kann durch einen Ringbund 33 des Steuerschiebers verschlossen werden, wobei dieser Ringbund eine arbeitsraumseitig liegende Ringnut 34 von einem Ringraum 35 trennt, wobei in die Ringnut 34 ein Druckmittelzulauf einmündet und der Ringraum 35 in den Federraum 22 mündet, der über eine nicht gezeigte Entlastungsleitung entlastet ist. Die den Ringbund begrenzenden Ringkanten sind Steuerkanten, durch die bei einer Relativverschiebung des Steuerschiebers die Verbindungsleitung 32 entweder über die Ringnut 34 mit dem Druckmittelzulauf 39 verbunden oder über den Ringraum 35 zum Federraum 22 entlastet wird. Dabei ist die Ringnut 34 ständig in Verbindung mit dem Druckmittelzulauf 39, der von einem Druckspeicherraum 40 mit Druckmittel versorgt wird. Zur Versorgung des Speicherraums dient eine Kraftstoffpumpe 41 mit parallel geschaltetem Drucksteuerventil 42, durch die zusammen der Druckspeicherraum in bekannter Weise mit einem Druck versorgt wird, der im wesentlichen drehzahlabhängig mit zunehmender Drehzahl der Kraftstoffeinspritzpumpe bzw. der zugehörigen Brennkraftmaschine steigt.In the injection adjusting piston 16 there is also an axial blind bore 27 as a control valve 28 leading Cylinder bore provided, which extends to the spring chamber 22 opens. The control slide 28 used there closes its one end face 29 with the closed end of the Cylinder bore a space 30 in which a compression spring 36th axially loaded the spool and protrudes with his other end in the spring chamber 22, where it is from a control spring 31 is applied, which on the other hand also is supported on the closure part 24. Parallel to the cylinder bore 27 runs in the actuating piston from one end face 18 outgoing connecting line 32, the radial in the area of Coverage by the control spool in the cylinder bore opens. This junction can by a collar 33 of the Control spool are closed, this ring collar an annular groove 34 on the work space side of one Separates the annular space 35, with a pressure medium inlet in the annular groove 34 opens and the annular space 35 in the spring space 22nd flows, which relieves a relief line, not shown is. The ring edges delimiting the ring collar are Control edges through which a relative displacement of the Control spool the connecting line 32 either over the Annular groove 34 connected to the pressure medium inlet 39 or via the annular space 35 to the spring space 22 is relieved. It is the annular groove 34 constantly in connection with the pressure medium inlet 39, of a pressure storage space 40 with pressure medium is supplied. Serves to supply the storage space a fuel pump 41 with a pressure control valve connected in parallel 42, through which the pressure storage space in known is supplied with a pressure in the essentially speed-dependent with increasing speed of the Fuel injection pump or the associated internal combustion engine increases.

Die Verstellung des Steuerschiebers erfolgt mit Hilfe eines Stößels 49, mit dem der Steuerschieber unter Einwirkung der Druckfeder 36 gekoppelt ist so daß er am in den Federraum 22 ragenden Ende des Steuerschiebers am Stößel 49 zur Anlage kommt. Dieser erstreckt sich koaxial zur Achse des Verstellkolben 16 bzw. des Steuerschieber 28 und tritt auf der der Stirnseite 21 des Steuerschieber gegenüberliegend Seite in eine im Verschlußteil 24 vorgesehene axiale Bohrung 52 ein. In dem Verschlußteil 24 ist ein geschlossener Arbeitszylinder 53 angeordnet, der sich koaxial an die axiale Bohrung 52 anschließt und anderen Endes durch einen Deckel 54 verschlossen ist. In dem Arbeitszylinder ist ein am Ende des Stößels 49 ausgebildeter Kolben 55 verschiebbar angeordnet, der auf seiner einen, zum Federraum 22 weisenden Seite einen Druckraum 56 und auf seiner anderen Seite zwischen dem Kolben 55 und dem Deckel 54 einen entlasteten Raum 57 einschließt, der über einen Axialbohrung 44, die in eine Querbohrung 45 übergeht und mit dem Federraum ständig verbunden ist. Mit dem Stößel 49 ist im Bereich des Federraumes ferner ein Federteller 58 verbunden, zwischen dem und dem Verschlußteil 24 sich eine Steuerfeder 31 abstützt, gegen die der Stößel 49 unter Einwirkung eines in den Druckraum 56 eingebrachten Steuerdruckes verschoben wird. Als Steuerdruck dient der obengenannte drehzahlabhängige Druck.The control spool is adjusted using a Tappet 49 with which the control slide under the influence of Compression spring 36 is coupled so that it is in the spring chamber 22nd protruding end of the spool on the plunger 49 to the system comes. This extends coaxially to the axis of the adjusting piston 16 or the control slide 28 and occurs on the End face 21 of the control slide opposite side in an axial bore 52 provided in the closure part 24. In the closure part 24 is a closed working cylinder 53 arranged coaxially to the axial Hole 52 connects and the other end through a cover 54 is closed. In the working cylinder there is one at the end of the plunger 49 formed piston 55 slidably arranged, the one on its side facing the spring chamber 22 a pressure chamber 56 and on its other side between the Piston 55 and the cover 54 encloses a relieved space 57, which has an axial bore 44 which is in a transverse bore 45 passes over and constantly connected to the spring chamber is. The plunger 49 is also in the area of the spring chamber a spring plate 58 connected between the Closure part 24 a control spring 31 is supported against that of the plunger 49 under the influence of a pressure chamber 56 introduced control pressure is shifted. As control pressure serves the above-mentioned speed-dependent pressure.

Bei einer bei steigendem Steuerdruck auftretenden Rechtsverschiebung des Steuerschiebers durch den Stößel 49 führt der Ringbund 33 eine steuernde Funktionen derart aus, daß der Arbeitsraum 20 mit Druckmittel versorgt wird so lange, bis durch eine nachfolgende Bewegung des Verstellkolbens 16 gegen die Kraft der Feder 23 die Verbindungsleitung 32, die zuvor geöffnet wurde, wieder verschlossen wird. Umgekehrt wird bei einem Sinken des Druckes im Druckraum 56 der Arbeitsraum 20 so lange entlastet, bis die Verbindungsleitung wieder verschlossen ist. Der Druck im Druckraum 56 kann dabei noch durch eine Entlastungsleitung 43, in der ein elektrisch gesteuertes Ventil 44 sitzt, entlastet bzw. modifiziert werden.In the event of a shift to the right as the control pressure increases of the control slide through the plunger 49 leads the Ring collar 33 a controlling functions such that the Working space 20 is supplied with pressure medium until by a subsequent movement of the adjusting piston 16 against the force of the spring 23, the connecting line 32, the previously opened, is closed again. Vice versa is when the pressure in the pressure chamber 56 decreases Workspace 20 relieved until the connecting line is closed again. The pressure in the pressure chamber 56 can still through a relief line 43, in the electrically controlled valve 44 sits, relieved or modified become.

Bei dieser bekannten Einrichtung zur Spritzbeginnverstellung tritt das Problem auf, daß über die Rollen 12 beim Antrieb der Pumpenkolben rückwirkende Kräfte auf den Nockenring 8 übertragen werden, die wiederum auf den Spritzverstellkolben 16 weitergeleitet werden so daß der Druck im Arbeitsraum 20 stoßweise erhöht wird. Dieser Druck steht dann auch am Ringbund 33 an, über den bei schwingenden Bewegungen des Steuerschiebers relativ zum Spritzverstellkolben Kraftstoff auch in den Raum 20 gelangen kann und dort zu Druckerhöhungen führt, die wieder Rückwirkungen auf die Stellung des Steuerschiebers haben. Das führt zu einem instabilen Verhalten des Spritzverstellkolbens bzw. der gesamten Einrichtung zur Spritzbeginnverstellung. In this known device for spray start adjustment the problem occurs that the rollers 12 when driving the pump piston has retroactive forces on the cam ring 8 are transferred, which in turn to the injection piston 16 are forwarded so that the pressure in the workspace 20th is increased intermittently. This pressure is then on Ring collar 33 on the swinging movements of the Control spool relative to the fuel injection piston can also get into room 20 and there Increases in pressure that have repercussions on the Position of the spool. That leads to one unstable behavior of the injection piston or the entire device for spray start adjustment.

Zur Vermeidung dieser Nachteile ist der Eintritt 60 der Verbindungsleitung 39 in die Zylinderbohrung 27 mit einem langgestreckten, vorzugsweise elliptischen Querschnitt mit in der Verschieberichtung des Steuerschiebers liegender Haupterstreckung versehen, so daß bei einer Verschiebung des Steuerschiebers relativ zum Spritzverstellkolben durch die Steuerkante des Ringbundes zunächst nur ein kleiner, drosselnder Querschnitt zum Arbeitsraum 20 hin aufgesteuert wird. So kann bei auftretenden Schwingungen dem Arbeitsraum 20 nur geringfügig Druckmittel zugeführt oder von diesem abgeführt werden. Die Schwingungsneigung bei auftretenden Störkräften, wie Triebwerksstößen, ist damit wesentlich verringert. Statt einem elliptischen Querschnitt können auch andere, diese Wirkung unterstützende Querschnittsverläufe an der Öffnung des Eintrittquerschnitt des Druckmittelzulaufes verwirklicht werden. Dazu sind zu nennen zusammengesetzte Parabeläste oder Hyperbeläste oder auch andere Begrenzungen der Querschnittsfläche als Kegelschnittkurven.To avoid these disadvantages, the inlet 60 is the Connecting line 39 in the cylinder bore 27 with a elongated, preferably elliptical cross section with lying in the direction of the spool Main extension provided so that when the Control spool relative to the injection piston through the The control edge of the ring collar is initially only a small, throttling one Cross section open to the working space 20 becomes. So can vibrate the work area 20 only slightly supplied or from this pressure medium be dissipated. The tendency to vibrate when occurring Interference forces, such as engine impacts, are therefore essential reduced. Instead of an elliptical cross section, too other cross-sectional profiles that support this effect the opening of the inlet cross-section of the pressure medium inlet be realized. Compound are to be mentioned Parabolic branches or hyperbaric branches or other limitations the cross-sectional area as conic curves.

Besonders vorteilhaft ist diese Ausgestaltung in Verbindung mit dem oben beschriebenen außerhalb des Spritzverstellkolbens angeordneten gehäusefesten Druckraum 56. Mit dieser Anordnung wird zusätzlich das Auftreten von Schwingungen aufgrund von vom Nockenantrieb übertragenen Stößen vermieden, da dieser Druckraum über den entlasteten Federraum von der stoßbelasteten Druckseite und den resultierenden Bewegungen des Spritzverstellkolben entkoppelt ist.This configuration is particularly advantageous in connection with the one described above outside the injection adjustment piston arranged housing-fixed pressure chamber 56. With this Arrangement is also the occurrence of vibrations due to shocks transmitted by the cam drive avoided because this pressure chamber over the unloaded spring chamber from the shock-loaded pressure side and the resulting Movements of the injection adjustment piston is decoupled.

Claims (5)

  1. Fuel injection pump having an injection timing piston (16), which is used for timing the beginning of injection and, in a cylinder (17), delimits a working chamber (20) which is acted on by a controllable pressure medium which adjusts the injection timing piston counter to a restoring force, and having a control slide (28), which is arranged in a cylinder bore (27), which is closed on one side, in the injection timing piston (16) in such a manner that it can be displaced in the axial direction of the injection timing piston (16), can be adjusted by a control pressure counter to the force of a control spring (31), and in the cylinder bore (27) uses control edges to control a connection of a connecting line (32) from the cylinder bore (27) to the working chamber (20) to a pressure-medium inlet (39) into the cylinder bore (27) or a pressure-medium outlet (35) from the cylinder bore, characterized in that the entry cross section (60), which is controlled by the control edge of the control slide (28), of the connecting line (32) into the cylinder bore (27) is designed as an elongate cross section which extends in the direction of displacement of the control slide.
  2. Fuel injection pump according to Claim 1, characterized in that the cross section is designed in the form of an ellipse.
  3. Fuel injection pump according to Claim 1, characterized in that the cross section is designed in the shape of a parabola.
  4. Fuel injection pump according to Claim 1, characterized in that the cross section is designed in the shape of a hyperbola.
  5. Fuel injection pump according to one of the preceding claims, characterized in that an actuator (49, 55), which effects an adjustment of the control slide (28), has a surface which is acted on by the control pressure, and this surface of the actuator (49, 55) projects into a pressure chamber (56), which is arranged in a part (24) which is fixed to the housing and is separated from the working chamber (20), and a pressure-relief chamber (22), which is delimited by the end side (21) of the injection timing piston (16), is arranged between the pressure chamber (56) and the working chamber (20) of the injection timing piston (16), and the working chamber (20) is arranged on the opposite side of the injection timing piston (16) from the pressure-relief chamber (22).
EP97930329A 1996-10-02 1997-06-17 Fuel injection pump with a timing-device piston for timing beginning of injection Expired - Lifetime EP0864037B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE19640678A DE19640678A1 (en) 1996-10-02 1996-10-02 Fuel injection pump with a spray adjustment piston that serves to adjust the start of injection
DE19640678 1996-10-02
PCT/DE1997/001225 WO1998014695A1 (en) 1996-10-02 1997-06-17 Fuel injection pump with a timing-device piston for timing beginning of injection

Publications (2)

Publication Number Publication Date
EP0864037A1 EP0864037A1 (en) 1998-09-16
EP0864037B1 true EP0864037B1 (en) 2002-03-20

Family

ID=7807696

Family Applications (1)

Application Number Title Priority Date Filing Date
EP97930329A Expired - Lifetime EP0864037B1 (en) 1996-10-02 1997-06-17 Fuel injection pump with a timing-device piston for timing beginning of injection

Country Status (8)

Country Link
US (1) US6041760A (en)
EP (1) EP0864037B1 (en)
JP (1) JP2000501478A (en)
KR (1) KR100453752B1 (en)
CN (1) CN1079897C (en)
DE (2) DE19640678A1 (en)
HU (1) HU222147B1 (en)
WO (1) WO1998014695A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102305140A (en) * 2011-08-30 2012-01-04 潍柴动力股份有限公司 Fuel injector starting time measuring equipment and fuel injector

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19849925A1 (en) * 1998-10-29 2000-05-04 Bosch Gmbh Robert Fuel injection pump
GB9914150D0 (en) * 1999-06-18 1999-08-18 Rotech Holdings Limited Improved pump
GB0303603D0 (en) * 2003-02-17 2003-03-19 Delphi Tech Inc Improvements in or relating to pressurisation pumps
US7048516B2 (en) * 2003-06-09 2006-05-23 Delphi Technologies, Inc. High pressure fuel pump with multiple radial plungers

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3532719A1 (en) 1985-09-13 1987-03-26 Bosch Gmbh Robert Fuel injection pump for internal combustion engines
JPH0814067A (en) * 1994-06-24 1996-01-16 Zexel Corp Servo valve type timer for fuel injection pump
DE4440749A1 (en) * 1994-11-15 1996-05-23 Bosch Gmbh Robert Fuel injection pump
JPH08261019A (en) * 1995-01-24 1996-10-08 Nippon Soken Inc Injection timing control device for fuel injection pump
DE19533807A1 (en) * 1995-09-13 1997-03-20 Bosch Gmbh Robert Fuel injection pump
JPH10274059A (en) * 1997-03-28 1998-10-13 Zexel Corp Timer device for distributor type fuel injection device

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102305140A (en) * 2011-08-30 2012-01-04 潍柴动力股份有限公司 Fuel injector starting time measuring equipment and fuel injector
CN102305140B (en) * 2011-08-30 2014-06-11 潍柴动力股份有限公司 Fuel injector starting time measuring equipment and fuel injector

Also Published As

Publication number Publication date
JP2000501478A (en) 2000-02-08
KR19990071634A (en) 1999-09-27
US6041760A (en) 2000-03-28
HUP9901493A2 (en) 1999-08-30
HUP9901493A3 (en) 2000-03-28
DE19640678A1 (en) 1998-04-09
CN1205048A (en) 1999-01-13
CN1079897C (en) 2002-02-27
HU222147B1 (en) 2003-04-28
WO1998014695A1 (en) 1998-04-09
DE59706678D1 (en) 2002-04-25
KR100453752B1 (en) 2004-12-23
EP0864037A1 (en) 1998-09-16

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