EP1370766A1 - Fuel-injection valve for internal combustion engines - Google Patents

Fuel-injection valve for internal combustion engines

Info

Publication number
EP1370766A1
EP1370766A1 EP02732326A EP02732326A EP1370766A1 EP 1370766 A1 EP1370766 A1 EP 1370766A1 EP 02732326 A EP02732326 A EP 02732326A EP 02732326 A EP02732326 A EP 02732326A EP 1370766 A1 EP1370766 A1 EP 1370766A1
Authority
EP
European Patent Office
Prior art keywords
pressure
fuel
chamber
injection
valve member
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.)
Withdrawn
Application number
EP02732326A
Other languages
German (de)
French (fr)
Inventor
Roger Potschin
Wolfgang Albrecht
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 GmbH
Original Assignee
Robert Bosch GmbH
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 GmbH filed Critical Robert Bosch GmbH
Publication of EP1370766A1 publication Critical patent/EP1370766A1/en
Withdrawn legal-status Critical Current

Links

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
    • F02M61/00—Fuel-injectors not provided for in groups F02M39/00 - F02M57/00 or F02M67/00
    • F02M61/16—Details not provided for in, or of interest apart from, the apparatus of groups F02M61/02 - F02M61/14
    • F02M61/20—Closing valves mechanically, e.g. arrangements of springs or weights or permanent magnets; Damping of valve lift
    • F02M61/205—Means specially adapted for varying the spring tension or assisting the spring force to close the injection-valve, e.g. with damping of valve lift

Definitions

  • the invention is based on a fuel injection valve according to the preamble of claim 1.
  • a fuel injection valve is known, for example, from the published patent application DE 197 52 496 AI.
  • the fuel injection valve comprises a valve body which is braced against a valve holding body in the axial direction.
  • a bore is formed in the valve body, in which a piston-shaped valve member is arranged to be longitudinally displaceable.
  • the valve member is guided in the bore in a section facing away from the combustion chamber and has on its end facing the combustion chamber a valve sealing surface which interacts with a valve seat formed in the valve body for controlling at least one injection opening.
  • the valve member At the end facing away from the combustion chamber, the valve member is connected to a spring plate which projects into a spring chamber formed in the valve holding body and between the end of the spring chamber facing away from the combustion chamber and a spring is arranged under prestress.
  • the spring acts on the valve member towards the valve seat with a closing force.
  • the valve member is surrounded by a pressure chamber which connects the valve seat to the guided section of the valve member and which can be filled with fuel under high pressure via an inlet channel.
  • a pressure surface is formed on the valve member, which is acted upon by the fuel in the pressure chamber, as a result of which a force acts on the spring in the axial direction against the closing force of the spring Valve element results.
  • the fuel injection valve is opened hydraulically at a certain fuel pressure in the pressure chamber, which pressure is referred to as the opening pressure. Between the individual injections there is a low stand pressure in the pressure chamber, the level of which is determined by the fuel supply system.
  • the post-injection comprising only a small amount of fuel compared to the main injection.
  • the post-injection should take place at as high a pressure as possible, which is only possible due to the small injection quantity if the opening pressure of the fuel injection valve is significantly higher than that of the main injection.
  • the spring chamber is connected to the pressure chamber via a throttle gap which is formed between the guided section of the valve member and the bore. The spring chamber is closed except for this throttle gap, so that fuel which flows into the spring chamber via the throttle gap leads to an increase in the fuel pressure there and thus to an increased closing force on the valve member.
  • the known fuel injection valve has the disadvantage that the fuel pressure in the spring chamber between the injections does not drop completely and a high static pressure is maintained in the spring chamber which is higher than the pressure in the pressure chamber between the successive injections by this injection valve. This leads to a delayed and damped opening of the valve member, which means exact metering and controllability of an injection divided into a first and a second partial injection of the fuel with different opening pressure in one cycle of the internal combustion engine.
  • the fuel injection valve according to the invention with the characterizing features of claim 1 has the advantage that the throttle connection from the pressure chamber to the spring chamber is designed so that the fuel pressure in the spring chamber increases during the first partial injection per work cycle of the corresponding cylinder of the internal combustion engine, the first Partial injection is called main injection here, and that the fuel pressure has dropped back to an initial pressure which is at least approximately that by the start of the second partial injection
  • Stand pressure in the pressure room corresponds. If the injection is carried out in two steps, namely in a first and a second partial injection, here called main injection and post-injection, the pressure in the spring chamber during post-injection is significantly increased due to the small time interval between the main and post-injection, which leads to an increased opening pressure of the Fuel injection valve leads in the post-injection. As a result, post-injection at high pressure is achieved and thereby a reduction in pollutant emissions and a lower noise level from the internal combustion engine.
  • a first and a second partial injection here called main injection and post-injection
  • the pressure increase in the spring chamber during the main injection can be caused by the volume of the spring chamber and by the flow resistance of the throttle connection from the pressure chamber into the
  • the pressure increase in the spring chamber during the main injection is increased in that a displacement body is arranged in the spring chamber is, which reduces the volume of the spring chamber, so that there is a higher pressure increase in the spring chamber with the same fuel flow.
  • the throttle connection from the pressure chamber to the spring chamber is formed by an additional bore in which a corresponding throttle cross section is provided. This allows the throttle connection to be manufactured separately, and the guidance of the valve member in the bore remains unchanged.
  • FIG. 1 shows a longitudinal section through a fuel injection valve according to the invention
  • FIG. 2 shows an enlarged illustration of FIG. 1 in the region of the guided section of the valve element with the definition of a few geometrical variables
  • FIG. 3 shows a diagram with the schematic course of the fuel pressure in the spring chamber and in the pressure chamber
  • 4 shows a further illustration of a fuel injection valve according to the invention in the area of the spring chamber
  • FIG. 5 shows a further illustration of a fuel injection valve according to the invention in longitudinal section.
  • FIG. 1 shows a longitudinal section through a fuel injection valve according to the invention.
  • a valve body 1 is clamped in the axial direction by a clamping nut 13 against a valve holding body 5 with the interposition of an intermediate disk 3.
  • a bore 7 is formed in the valve body 1, at the combustion chamber end of which a valve seat 16 is formed, in which at least one injection opening 20 is arranged, which connects the bore 7 to the combustion chamber of the internal combustion engine.
  • a valve member 10 is arranged in the bore 7, which is guided in a section facing away from the combustion chamber in the bore 7 and which tapers towards the combustion chamber with the formation of a pressure shoulder 11.
  • a valve sealing surface 18 is formed, which cooperates with the valve seat 16 to control the at least one injection opening 20.
  • a pressure chamber 12 is formed in the valve body 1, which is formed by a radial enlargement of the bore 7 and surrounds the valve member 10.
  • the pressure chamber 12 continues towards the valve seat 16 as an annular channel surrounding the valve member 10 and can be filled with fuel under high pressure via an inlet channel 15 running in the valve body 1, the intermediate disk 3 and the valve holding body 5.
  • the inlet channel 15 is connected at its end facing away from the pressure chamber 12 to a high-pressure fuel system, not shown in the drawing.
  • the valve member 10 is connected at its end facing away from the combustion chamber to a spring plate 22 arranged in the intermediate disk 3, which spring plate 22 projects into a spring chamber 25 formed in the valve holding body 5. Between the spring plate 22 and the end of the spring chamber 25 facing away from the combustion chamber, a spring 27 is arranged under prestress, which acts on the valve member 10 with a closing force in the direction of the valve seat 16.
  • the pressure chamber 12 is connected to the spring chamber 25 via a throttle connection.
  • the throttle connection is in the Figure 1 and on an enlarged scale also shown in Figure 2 fuel injector formed by an annular gap 32 formed between the guided portion of the valve member 10 and the bore 7.
  • the flow resistance of the fuel when flowing through the annular gap 32 is determined here by the length L of the guided section of the valve member 10, by the throttle gap dimension S of the guided section of the valve member 10 in the bore 7 and by the diameter D of the bore 7.
  • the fuel injection valve works as follows: The fuel is injected into the combustion chamber of the internal combustion engine in two steps: first, a main injection quantity is injected into the combustion chamber of the internal combustion engine and then, after a certain time interval, a post-injection quantity, which is mainly used to reduce the pollutant of the exhaust gas serves. At the beginning of the injection process, there is a low standing pressure p 0 in the inlet duct 15 and in the pressure chamber 12.
  • the fuel pressure increases up to a first opening pressure p x , the opening pressure of the main injection, until the hydraulic force acting in the axial direction of the valve member 10 on the pressure shoulder 11 is greater than the force of the Closing spring 27 and the hydraulic force acting on the valve member 10 due to the pressure on the surfaces of the valve member 10 which are exposed to the pressure in the spring chamber 25.
  • the valve member 10 lifts with its valve sealing surface 18 from the valve seat 16, and the pressure chamber 12 is connected to the injection openings 20. Since the valve member 10 travels only a very small stroke during this opening stroke movement, the pressure increase due to the displacement of the fuel in the spring chamber 25 is small and has no significant influence on the function of the fuel injection valve.
  • Valve member 10 in the direction of the valve seat 16 provides.
  • the post-injection therefore takes place at a pressure which is substantially higher than the opening pressure of the main injection, which has a favorable effect on the pollutant content of the internal combustion engine due to the better atomization of the fuel.
  • the fuel supply through the inlet channel 15 is completely interrupted and the pressure in the pressure chamber 12 drops rapidly.
  • the valve member 10 is pressed back into the closed position by the pressure in the spring chamber 25 and the force of the closing spring 27 and the - in comparison to the pressure chamber 12 - high fuel pressure in the spring chamber 25 leads to a fuel flow from the spring chamber 25 through the annular gap 32 on the valve member 10 past into the pressure chamber 12 until the pressure in the spring chamber 25 has adapted to the static pressure p 0 in the inlet channel 15.
  • the flow resistance of the Throttle connection which is designed here as an annular gap 32, is dimensioned such that the fuel pressure in the spring chamber 25 has dropped back to the starting pressure at the beginning of the injection process by the beginning of the next main injection.
  • the pressure p D in the pressure chamber 12 and the pressure p F in the spring chamber 25 against the valve member stroke h is shown schematically as a function of time t.
  • the upper diagram shows the course of the valve member stroke
  • the middle diagram shows the course of the fuel pressure p D in the pressure chamber 12
  • the lower diagram shows the course of the fuel pressure p p in the spring chamber 25, the time on the abscissa being the same in all diagrams.
  • the internal combustion engine is operated in work cycles, with an injection cycle taking place in each work cycle. In the injection cycle, fuel is injected into the combustion chamber of the internal combustion engine in one or more partial injections, the duration of the injection cycle generally being only a fraction of the duration of the working cycle.
  • the standing pressure p 0 prevails in the pressure chamber 12, which increases with the beginning of the injection cycle until the first opening pressure ⁇ of the fuel injection valve is reached and the valve element 10 through it Opening stroke movement releases the injection openings 20.
  • the pressure in the pressure chamber 12 continues to increase during the entire main injection and also with a slight time delay in the spring chamber 25 due to the fuel inflow.
  • the valve member 10 closes and the pressure in the pressure chamber 12 drops rapidly, while the pressure in the spring chamber 25 reacts much more slowly and remains relatively high.
  • the pressure in the pressure chamber 12 rises again until the second opening pressure p 2, which is increased by the fuel pressure in the spring chamber 25 is reached and the valve member 10 moves to the open position for the post-injection.
  • the pressure in the pressure chamber 12 drops rapidly to the stand pressure p 0 and the injection cycle is ended at the time t x .
  • the pressure in the spring chamber 25, takes a long time to drop back to the stand pressure p 0 due to fuel outflow via the throttle connection into the pressure chamber 12, but this took place at the beginning of the next main injection at time t 2 .
  • the duration of the work cycle depends on the speed of the internal combustion engine and is approximately 0.02 to 0.2 seconds.
  • the duration of the injection cycle depends on the type of internal combustion engine and is, for example, 1/20 of the duration of the work cycle.
  • FIG. 4 shows a further exemplary embodiment of a fuel injection valve according to the invention in the area of the spring chamber 25.
  • the volume In order to keep the pressure increase in the spring chamber 25 as large as possible when a quantity of fuel flows in, the volume must be kept as small as possible.
  • this is achieved in that a cylindrical displacement piston 30 is arranged in the spring chamber 25 and is surrounded by the closing spring 27, so that the volume of the spring chamber 25 that can be filled with fuel is reduced.
  • the length and the diameter of the displacement piston 30 can vary, so that the volume of the spring chamber 25 can be adapted to different requirements.
  • FIG. 5 shows a further exemplary embodiment of a fuel injection valve according to the invention. Is the
  • the throttle gap dimension S in particular in the case of a long guided section L of the valve member 10, may have to be as large as possible. be chosen that an impermissibly high wear of the valve member 10 occurs in the bore 7. If the flow resistance is nevertheless to be reduced further, this can be achieved in that part of the length L of the guided section of the valve member 10 is bridged by one or more recesses 23 which extend from the end of the valve member 10 facing away from the combustion chamber to one in the Section of the valve member 10 formed annular groove 24. As a result, the effective length L * of the throttling annular gap 32 is reduced and the flow resistance of the fuel is accordingly reduced.
  • valve member 10 extends from the end of the guided section of the valve member 10 facing the combustion chamber to the end remote from the combustion chamber. With a corresponding cross section and a corresponding number of these recesses, the flow resistance of the throttle connection can be adjusted and adapted to the requirements of the fuel injector without this
  • Throttle gap dimension S must be changed. Provision can also be made to arrange the recesses on the wall of the leading section of the bore 7, the recesses being designed, for example, as longitudinal grooves.

Abstract

The invention relates to a fuel-injection valve comprising a valve member (10) that co-operates with a valve seat (16) to control injection openings (20). The valve member (10) is configured in a bore (7) in a section facing away from the combustion chamber and is surrounded by a pressure chamber (12) that can be filled with pressurised fuel. The valve member (10) is subjected to a closing force in the direction of the valve seat (16) by a spring (27) located in a spring chamber (25) and is raised from the valve seat (16) at a corresponding opening pressure in the pressure chamber (12) by the hydraulic pressure on an exposed annular area (11) configured on the valve member (10), thus opening the injection openings (20), the fuel being injected separately in a primary injection and a subsequent secondary injection. The pressure chamber (12) and the spring chamber (25) are connected by a throttle connection in such a way that the pressure in the otherwise closed spring chamber (25) increases during the primary injection and raises the opening pressure of the secondary injection by means of the additional hydraulic force on the valve member (10), the pressure in the spring chamber returning to the initial value (25) by the start of the next injection cycle.

Description

Kraftstoffeinspritzventil für BrennkraftmaschinenFuel injection valve for internal combustion engines
Stand der TechnikState of the art
Die Erfindung geht von einem Kraftstoffeinspritzventil nach der Gattung des Patentanspruchs 1 aus. Ein solches Kraft- stoffeinspritzventil ist beispielsweise aus der Offenle- gungsschrift DE 197 52 496 AI bekannt. Das Kraftstoffeinspritzventil umfaßt einen Ventilkörper, der in axialer Rich- tung gegen einen Ventilhaltekörper verspannt ist. Im Ventilkörper ist eine Bohrung ausgebildet, in der ein kolbenförmiges Ventilglied längsverschiebbar angeordnet ist. Das Ventilglied ist in einem brennraumabgewandten Abschnitt in der Bohrung geführt und weist an seinem brennraumzugewandten Ξn- de eine Ventildichtfläche auf, die mit einem im Ventilkörper ausgebildeten Ventilsitz zur Steuerung wenigstens einer Einspritzöffnung zusammenwirkt. Am brennraumabgewandten Ende ist das Ventilglied mit einem Federteller verbunden, der bis in einen im Ventilhaltekörper ausgebildeten Federraum ragt und zwischen dem und dem brennraumabgewandten Ende des Federraums eine Feder unter Vorspannung angeordnet ist. Durch die Feder wird das Ventilglied auf den Ventilsitz zu mit einer Schließkraft beaufschlagt. Das Ventilglied ist von einem Druckraum umgeben, der sich dem Ventilsitz zu an den geführten Abschnitt des Ventil- glieds anschließt und der über einen Zulaufkanal mit Kraftstoff unter hohem Druck befüllt werden kann. Am Ventilglied ist eine Druckfläche ausgebildet, die vom Kraftstoff im Druckraum beaufschlagt wird, wodurch sich eine Kraft in axialer Richtung entgegen der Schließkraft der Feder auf das Ventilglied ergibt. Die Öffnung des Kraftstoffeinspritzven- tils erfolgt hydraulisch bei einem bestimmten Kraftstoffdruck im Druckraum, welcher Druck als Öffnungsdruck bezeichnet wird. Zwischen den einzelnen Einspritzungen herrscht im Druckraum ein niedriger Standdruck, dessen Höhe vom Kraftstoffzufuhrsystem bestimmt wird.The invention is based on a fuel injection valve according to the preamble of claim 1. Such a fuel injection valve is known, for example, from the published patent application DE 197 52 496 AI. The fuel injection valve comprises a valve body which is braced against a valve holding body in the axial direction. A bore is formed in the valve body, in which a piston-shaped valve member is arranged to be longitudinally displaceable. The valve member is guided in the bore in a section facing away from the combustion chamber and has on its end facing the combustion chamber a valve sealing surface which interacts with a valve seat formed in the valve body for controlling at least one injection opening. At the end facing away from the combustion chamber, the valve member is connected to a spring plate which projects into a spring chamber formed in the valve holding body and between the end of the spring chamber facing away from the combustion chamber and a spring is arranged under prestress. The spring acts on the valve member towards the valve seat with a closing force. The valve member is surrounded by a pressure chamber which connects the valve seat to the guided section of the valve member and which can be filled with fuel under high pressure via an inlet channel. A pressure surface is formed on the valve member, which is acted upon by the fuel in the pressure chamber, as a result of which a force acts on the spring in the axial direction against the closing force of the spring Valve element results. The fuel injection valve is opened hydraulically at a certain fuel pressure in the pressure chamber, which pressure is referred to as the opening pressure. Between the individual injections there is a low stand pressure in the pressure chamber, the level of which is determined by the fuel supply system.
Für eine Verringerung der Schadstoffemission der Brennkraftmaschine hat es sich als vorteilhaft erwiesen, den Kraft- stoff nicht in einem Schritt, sondern getrennt in eineIn order to reduce the pollutant emissions of the internal combustion engine, it has proven to be advantageous not to separate the fuel into one step, but into one
Haupt- und eine Nacheinspritzung in den Brennraum einzubringen, wobei die Nacheinspritzung im Vergleich zur Haupteinspritzung nur eine kleine Kraftstoffmenge umfaßt. Die Nacheinspritzung sollte bei einem möglichst hohen Druck erfol- gen, was aufgrund der kleinen Einspritzmenge nur dann möglich ist, wenn der Öffnungsdruck des Kraftstoffeinspritzven- tils gegenüber dem der Haupteinspritzung deutlich angehoben ist. Bei dem bekannten Kraftstoffeinspritzventil ist der Federraum mit dem Druckraum über einen Drosselspalt verbunden, der zwischen dem geführten Abschnitt des Ventilglieds und der Bohrung ausgebildet ist. Der Federraum ist bis auf diesen Drosselspalt abgeschlossen, so daß Kraftstoff, der über den Drosselspalt in den Federraum fließt, dort zu einer Erhöhung des Kraftstoffdrucks führt und damit zu einer erhöh- ten Schließkraft auf das Ventilglied. Das bekannte Kraftstoffeinspritzventil weist jedoch den Nachteil auf, daß der Kraftstoffdruck im Federraum zwischen den Einspritzungen nicht vollständig abfällt und so ein hoher Standdruck im Federraum aufrecht erhalten wird, der höher liegt als der Druck im Druckraum zwischen den aufeinanderfolgenden Einspritzungen durch dieses Einspritzventil. Dies führt zu einem verzögerten und gedämpften Öffnen des Ventilglieds, was eine exakte Dosierung und Steuerbarkeit einer in eine erste und eine zweite Teileinspritzung unterteilte Einspritzung des Kraftstoffs mit jeweils unterschiedlichem Öffnungsdruck in einem Zyklus der Brennkraftmaschine unmöglich macht.To bring main and a post-injection into the combustion chamber, the post-injection comprising only a small amount of fuel compared to the main injection. The post-injection should take place at as high a pressure as possible, which is only possible due to the small injection quantity if the opening pressure of the fuel injection valve is significantly higher than that of the main injection. In the known fuel injection valve, the spring chamber is connected to the pressure chamber via a throttle gap which is formed between the guided section of the valve member and the bore. The spring chamber is closed except for this throttle gap, so that fuel which flows into the spring chamber via the throttle gap leads to an increase in the fuel pressure there and thus to an increased closing force on the valve member. However, the known fuel injection valve has the disadvantage that the fuel pressure in the spring chamber between the injections does not drop completely and a high static pressure is maintained in the spring chamber which is higher than the pressure in the pressure chamber between the successive injections by this injection valve. This leads to a delayed and damped opening of the valve member, which means exact metering and controllability of an injection divided into a first and a second partial injection of the fuel with different opening pressure in one cycle of the internal combustion engine.
Vorteile der ErfindungAdvantages of the invention
Das erfindungsgemäße Kraftstoffeinspritzventil mit den kennzeichnenden Merkmalen des Patentanspruchs 1 hat demgegenüber den Vorteil, daß die Drosselverbindung vom Druckraum in den Federraum so ausgebildet ist, daß der Kraftstoffdruck im Fe- derraum während der ersten Teileinspritzung pro Arbeitstakt des entsprechenden Zylinders der Brennkraftmaschine ansteigt, wobei diese erste Teileinspritzung hier Haupteinspritzung genannt ist, und das der Kraftstoffdruck bis zum Beginn der zweiten Teileinspritzung wieder auf einen Aus- gangsdruck abgefallen ist, der zumindest annähernd demThe fuel injection valve according to the invention with the characterizing features of claim 1 has the advantage that the throttle connection from the pressure chamber to the spring chamber is designed so that the fuel pressure in the spring chamber increases during the first partial injection per work cycle of the corresponding cylinder of the internal combustion engine, the first Partial injection is called main injection here, and that the fuel pressure has dropped back to an initial pressure which is at least approximately that by the start of the second partial injection
Standdruck im Druckraum entspricht. Erfolgt die Einspritzung in zwei Schritten, nämlich in einer ersten und einer zweiten Teileinspritzung, hier Haupteinspritzung und Nacheinspritzung genannt, so ist wegen des geringen zeitlichen Abstands zwischen Haupt- und Nacheinspritzung der Druck im Federraum bei der Nacheinspritzung deutlich erhöht, was zu einem erhöhten Öffnungsdruck des Kraftstoffeinspritzventils bei der Nacheinspritzung führt. Hierdurch wird eine Nacheinspritzung mit hohem Druck erreicht und dadurch eine Verminderung der Schadstoffemission und eine geringere Geräuschbelastung durch die Brennkraftmaschine .Stand pressure in the pressure room corresponds. If the injection is carried out in two steps, namely in a first and a second partial injection, here called main injection and post-injection, the pressure in the spring chamber during post-injection is significantly increased due to the small time interval between the main and post-injection, which leads to an increased opening pressure of the Fuel injection valve leads in the post-injection. As a result, post-injection at high pressure is achieved and thereby a reduction in pollutant emissions and a lower noise level from the internal combustion engine.
Der Druckanstieg im Federraum während der Haupteinspritzung kann durch das Volumen des Federraums und durch den Durch- flußwiderstand der Drosselverbindung vom Druckraum in denThe pressure increase in the spring chamber during the main injection can be caused by the volume of the spring chamber and by the flow resistance of the throttle connection from the pressure chamber into the
Federraum an die entsprechenden Bedürfnisse des Kraftstoffeinspritzventils angepaßt werden. In einer vorteilhaften Ausgestaltung des Gegenstandes der Erfindung wird der Druckanstieg im Federraum während der Haupteinspritzung dadurch erhöht, daß ein Verdrängungskörper im Federraum angeordnet ist, der das Volumen des Federraums vermindert, so daß bei gleichem Kraftstoffzufluß ein höherer Druckanstieg im Federraum erfolgt .Spring space to be adapted to the corresponding needs of the fuel injector. In an advantageous embodiment of the subject matter of the invention, the pressure increase in the spring chamber during the main injection is increased in that a displacement body is arranged in the spring chamber is, which reduces the volume of the spring chamber, so that there is a higher pressure increase in the spring chamber with the same fuel flow.
In einer weiteren vorteilhaften Ausgestaltung des Gegenstandes der Erfindung ist die Drosselverbindung vom Druckraum zum Federraum durch eine zusätzliche Bohrung ausgebildet, in der ein entsprechender Drosselquerschnitt vorgesehen ist . Dadurch läßt sich die Drosselverbindung separat fertigen, und die Führung des Ventilglieds in der Bohrung bleibt unverändert .In a further advantageous embodiment of the object of the invention, the throttle connection from the pressure chamber to the spring chamber is formed by an additional bore in which a corresponding throttle cross section is provided. This allows the throttle connection to be manufactured separately, and the guidance of the valve member in the bore remains unchanged.
Weitere Vorteile und vorteilhafte Ausgestaltungen des Gegenstandes der Erfindung sind der Beschreibung, der Zeichnung und den Ansprüchen entnehmbar.Further advantages and advantageous configurations of the subject matter of the invention can be found in the description, the drawing and the claims.
Zeichnungdrawing
In der Zeichnung ist ein Ausführungsbeispiel eines erfin- dungsgemäßen Kraftstoffeinspritzventils dargestellt. Figur 1 zeigt einen Längsschnitt durch ein erfindungsgemäßes Kraftstoffeinspritzventil , Figur 2 eine vergrößerte Darstellung von Figur 1 im Bereich des geführten Abschnitts des Ventil- glieds mit Definition einiger geometrischer Größen, Figur 3 ein Diagramm mit dem schematischen Verlauf des Kraftstoffdrucks im Federraum und im Druckraum und des Ventilgliedhubs als Funktion der Zeit, Figur 4 eine weitere Darstellung eines erfindungsgemäßen Kraftstoffeinspritzventils im Bereich des Federraums, Figur 5 eine weitere Darstellung eines er- findungsgemäßen Kraftstoffeinspritzventils im Längsschnitt.An exemplary embodiment of a fuel injection valve according to the invention is shown in the drawing. FIG. 1 shows a longitudinal section through a fuel injection valve according to the invention, FIG. 2 shows an enlarged illustration of FIG. 1 in the region of the guided section of the valve element with the definition of a few geometrical variables, FIG. 3 shows a diagram with the schematic course of the fuel pressure in the spring chamber and in the pressure chamber and 4 shows a further illustration of a fuel injection valve according to the invention in the area of the spring chamber, FIG. 5 shows a further illustration of a fuel injection valve according to the invention in longitudinal section.
Beschreibung der AusführungsbeispieleDescription of the embodiments
In Figur 1 ist ein Längsschnitt durch ein erfindungsgemäßes Kraftstoffeinspritzventil dargestellt. Ein Ventilkörper 1 ist unter Zwischenlage einer Zwischenscheibe 3 in axialer Richtung durch eine Spannmutter 13 gegen einen Ventilhaltekörper 5 verspannt. Im Ventilkörper 1 ist eine Bohrung 7 ausgebildet, an deren brennraumseitigen Ende ein Ventilsitz 16 ausgebildet ist, in dem wenigstens eine Einspritzöffnung 20 angeordnet ist, die die Bohrung 7 mit dem Brennraum der Brennkraftmaschine verbindet. In der Bohrung 7 ist ein Ventilglied 10 angeordnet, das in einem brennraumabgewandten Abschnitt in der Bohrung 7 geführt ist und das sich unter Bildung einer Druckschulter 11 zum Brennraum hin verjüngt. Am brennraumseitigen Ende des Ventilglieds 10 ist eine Ventildichtfläche 18 ausgebildet, die mit dem Ventilsitz 16 zur Steuerung der wenigstens einen Einspritzöffnung 20 zusammen-, wirkt. Im Ventilkörper 1 ist ein Druckraum 12 ausgebildet, der durch eine radiale Erweiterung der Bohrung 7 gebildet ist und das Ventilglied 10 umgibt. Der Druckraum 12 setzt sich dem Ventilsitz 16 zu als ein das Ventilglied 10 umgebender Ringkanal fort und ist über einen im Ventilkörper 1, der Zwischenscheibe 3 und dem Ventilhaltekörper 5 verlaufen- den Zulaufkanal 15 mit Kraftstoff unter hohem Druck befüll- bar. Hierbei wird der Zulaufkanal 15 an seinem dem Druckraum 12 abgewandten Ende mit einem in der Zeichnung nicht dargestellten Kraftstoffhochdrucksystem verbunden.FIG. 1 shows a longitudinal section through a fuel injection valve according to the invention. A valve body 1 is clamped in the axial direction by a clamping nut 13 against a valve holding body 5 with the interposition of an intermediate disk 3. A bore 7 is formed in the valve body 1, at the combustion chamber end of which a valve seat 16 is formed, in which at least one injection opening 20 is arranged, which connects the bore 7 to the combustion chamber of the internal combustion engine. A valve member 10 is arranged in the bore 7, which is guided in a section facing away from the combustion chamber in the bore 7 and which tapers towards the combustion chamber with the formation of a pressure shoulder 11. At the combustion chamber end of the valve member 10, a valve sealing surface 18 is formed, which cooperates with the valve seat 16 to control the at least one injection opening 20. A pressure chamber 12 is formed in the valve body 1, which is formed by a radial enlargement of the bore 7 and surrounds the valve member 10. The pressure chamber 12 continues towards the valve seat 16 as an annular channel surrounding the valve member 10 and can be filled with fuel under high pressure via an inlet channel 15 running in the valve body 1, the intermediate disk 3 and the valve holding body 5. Here, the inlet channel 15 is connected at its end facing away from the pressure chamber 12 to a high-pressure fuel system, not shown in the drawing.
Das Ventilglied 10 ist an seinem brennraumabgewandten Ende mit einem in der Zwischenscheibe 3 angeordneten Federteller 22 verbunden, welcher Federteller 22 bis in einen im Ventilhaltekörper 5 ausgebildeten Federraum 25 ragt. Zwischen dem Federteller 22 und dem brennraumabgewandten Ende des Feder- raums 25 ist eine Feder 27 unter Vorspannung angeordnet, die das Ventilglied 10 mit einer Schließkraft in Richtung auf den Ventilsitz 16 beaufschlagt.The valve member 10 is connected at its end facing away from the combustion chamber to a spring plate 22 arranged in the intermediate disk 3, which spring plate 22 projects into a spring chamber 25 formed in the valve holding body 5. Between the spring plate 22 and the end of the spring chamber 25 facing away from the combustion chamber, a spring 27 is arranged under prestress, which acts on the valve member 10 with a closing force in the direction of the valve seat 16.
Der Druckraum 12 ist über eine Drosselverbindung mit dem Fe- derraum 25 verbunden. Die Drosselverbindung ist bei dem in Figur 1 und in vergrößertem Maßstab auch in Figur 2 gezeigten Kraftstoffeinspritzventil durch einen zwischen dem geführten Abschnitt des Ventilglieds 10 und der Bohrung 7 gebildeten Ringspalt 32 ausgebildet. Der Durchflußwiderstand des Kraftstoffs beim Fließen durch den Ringspalt 32 wird hierbei bestimmt durch die Länge L des geführten Abschnitts des Ventilglieds 10, durch das Drosselspaltmaß S des geführten Abschnitts des Ventilglieds 10 in der Bohrung 7 und durch den Durchmesser D der Bohrung 7.The pressure chamber 12 is connected to the spring chamber 25 via a throttle connection. The throttle connection is in the Figure 1 and on an enlarged scale also shown in Figure 2 fuel injector formed by an annular gap 32 formed between the guided portion of the valve member 10 and the bore 7. The flow resistance of the fuel when flowing through the annular gap 32 is determined here by the length L of the guided section of the valve member 10, by the throttle gap dimension S of the guided section of the valve member 10 in the bore 7 and by the diameter D of the bore 7.
Die Funktionsweise des Kraftstoffeinspritzventils ist wie folgt: Die Einspritzung des Kraftstoffs in den Brennraum der Brennkraftmaschine erfolgt in zwei Schritten: Zuerst wird eine Haupteinspritzmenge in den Brennraum der Brennkraftma- schine eingespritzt und anschließend mit einem gewissen zeitlichen Abstand eine Nacheinspritzmenge, die hauptsächlich der Schadstoffreduzierung des Abgases dient. Zu Beginn des Einspritzvorgangs herrscht im Zulaufkanal 15 und im Druckraum 12 ein niedriger Standdruck p0. Durch Zufuhr von Kraftstoff über den Zulaufkanal 15 in den Druckraum 12 erhöht sich der Kraftstoffdruck bis zu einem ersten Öffnungsdruck px, dem Öffnungsdruck der Haupteinspritzung, bis die in axialer Richtung des Ventilglieds 10 wirkende hydraulische Kraft auf die Druckschulter 11 größer ist als die Kraft der Schließfeder 27 und die auf das Ventilglied 10 wirkende hydraulische Kraft durch den Druck auf die Flächen des Ventilglieds 10, die dem Druck im Federraum 25 ausgesetzt sind. Das Ventilglied 10 hebt mit seiner Ventildichtfläche 18 vom Ventilsitz 16 ab, und der Druckraum 12 wird mit den Ein- spritzöffnungen 20 verbunden. Da das Ventilglied 10 bei dieser Öffnungshubbewegung nur einen recht geringen Hub durchfährt, ist der Druckanstieg durch die Verdrängung des Kraftstoffs im Federraum 25 gering und hat auf die Funktion des Kraftstoffeinspritzventils keinen wesentlichen Einfluß. Wäh- rend der Haupteinspritzung fließt Kraftstoff aus dem Druck- räum 12 durch die als Ringspalt 32 ausgebildete Drosselverbindung in den Federraum 25 und erhöht dort den Kraftstoff- druck. Durch den über den Zulaufkanal 15 zugeführten Kraftstoff erhöht sich so einerseits der Kraftstoffdruck im Druckraum 12 und andererseits der Druck im Federraum 25. Um die Haupteinspritzung zu beenden, wird die Kraftstoffzufuhr durch den Zulaufkanal 15 unterbrochen. Durch den inzwischen hohen Druck im Federraum 25 erfolgt das Schließen des Ventilglieds 10 bereits bei einem Kraftstoffdruck im Druckraum 12, der wesentlich höher liegt als der Öffnungsdruck zu Beginn der Haupteinspritzung. Das Ventilglied 10 geht beaufschlagt durch die Kraft der Feder 27 zurück in seine Schließposition und verschließt die Einspritzöffnungen 20. Kurze Zeit später erfolgt eine Nacheinspritzung durch eine weitere Förderung einer kleinen Kraftstoffmenge in denThe fuel injection valve works as follows: The fuel is injected into the combustion chamber of the internal combustion engine in two steps: first, a main injection quantity is injected into the combustion chamber of the internal combustion engine and then, after a certain time interval, a post-injection quantity, which is mainly used to reduce the pollutant of the exhaust gas serves. At the beginning of the injection process, there is a low standing pressure p 0 in the inlet duct 15 and in the pressure chamber 12. By supplying fuel via the inlet channel 15 into the pressure chamber 12, the fuel pressure increases up to a first opening pressure p x , the opening pressure of the main injection, until the hydraulic force acting in the axial direction of the valve member 10 on the pressure shoulder 11 is greater than the force of the Closing spring 27 and the hydraulic force acting on the valve member 10 due to the pressure on the surfaces of the valve member 10 which are exposed to the pressure in the spring chamber 25. The valve member 10 lifts with its valve sealing surface 18 from the valve seat 16, and the pressure chamber 12 is connected to the injection openings 20. Since the valve member 10 travels only a very small stroke during this opening stroke movement, the pressure increase due to the displacement of the fuel in the spring chamber 25 is small and has no significant influence on the function of the fuel injection valve. During the main injection, fuel flows out of the pressure chamber 12 through the throttle connection designed as an annular gap 32 into the spring chamber 25 and increases the fuel pressure there. The fuel supplied via the inlet channel 15 thus increases the fuel pressure in the pressure chamber 12 on the one hand and the pressure in the spring chamber 25 on the other hand. To terminate the main injection, the fuel supply through the inlet channel 15 is interrupted. Due to the now high pressure in the spring chamber 25, the valve member 10 is already closed at a fuel pressure in the pressure chamber 12 which is substantially higher than the opening pressure at the beginning of the main injection. Actuated by the force of the spring 27, the valve member 10 returns to its closed position and closes the injection openings 20. A short time later, post-injection takes place by further delivery of a small amount of fuel into the
Druckraum 12. Der zweite Öffnungsdruck p2 des Ventilglieds 10, der Öffnungsdruck der Nacheinspritzung, liegt jetzt deutlich höher als der Öffnungsdruck der Haupteinspritzung, da der Kraftstoffdruck im Federraum 25 weiterhin für eine zusätzliche Kraft auf die brennraumabgewandte Stirnseite desPressure chamber 12. The second opening pressure p 2 of the valve member 10, the opening pressure of the post-injection, is now significantly higher than the opening pressure of the main injection, since the fuel pressure in the spring chamber 25 continues for an additional force on the end of the chamber facing away from the combustion chamber
Ventilglieds 10 in Richtung auf den Ventilsitz 16 sorgt. Die Nacheinspritzung findet also mit einem gegenüber dem Öffnungsdruck der Haupteinspritzung wesentlich erhöhten Druck statt, was sich auf den Schadstoffgehalt der Brennkraftma- schine durch die bessere Zerstäubung des Kraftstoffs günstig auswirkt. Schließlich wird die Kraftstoffzufuhr durch den Zulaufkanal 15 gänzlich unterbrochen, und der Druck im Druckraum 12 fällt rasch ab. Das Ventilglied 10 wird durch den Druck im Federraum 25 und die Kraft der Schließfeder 27 zurück in die Schließposition gedrückt und der - im Vergleich zum Druckraum 12 - hohe Kraftstoffdruck im Federraum 25 führt zu einem Kraftstofffluß aus dem Federraum 25 durch den Ringspalt 32 am Ventilglied 10 vorbei in den Druckraum 12, bis sich der Druck im Federraum 25 dem Standdruck p0 im Zulaufkanal 15 angepaßt hat. Der Durchflußwiderstand der Drosselverbindung, die hier als Ringspalt 32 ausgebildet ist, ist dabei so bemessen, daß der Kraftstoffdruck im Federraum 25 bis zum Beginn der nächsten Haupteinspritzung wieder auf den Ausgangsdruck zu Beginn des Einspritzvorgangs abgesunken ist .Valve member 10 in the direction of the valve seat 16 provides. The post-injection therefore takes place at a pressure which is substantially higher than the opening pressure of the main injection, which has a favorable effect on the pollutant content of the internal combustion engine due to the better atomization of the fuel. Finally, the fuel supply through the inlet channel 15 is completely interrupted and the pressure in the pressure chamber 12 drops rapidly. The valve member 10 is pressed back into the closed position by the pressure in the spring chamber 25 and the force of the closing spring 27 and the - in comparison to the pressure chamber 12 - high fuel pressure in the spring chamber 25 leads to a fuel flow from the spring chamber 25 through the annular gap 32 on the valve member 10 past into the pressure chamber 12 until the pressure in the spring chamber 25 has adapted to the static pressure p 0 in the inlet channel 15. The flow resistance of the Throttle connection, which is designed here as an annular gap 32, is dimensioned such that the fuel pressure in the spring chamber 25 has dropped back to the starting pressure at the beginning of the injection process by the beginning of the next main injection.
In Figur 3 ist der Druck pD im Druckraum 12 und der Druck pF im Federraum 25 gegenüber dem Ventilgliedhub h als Funktion der Zeit t schematisch dargestellt. Das obere Diagramm zeigt den Verlauf des Ventilgliedhubs, das mittlere Diagramm den Verlauf des Kraftstoffdrucks pD im Druckraum 12 und das untere Diagramm den Verlauf des Kraftstoffdrucks pp im Federraum 25, wobei die Zeit auf der Abszisse bei allen Diagrammen gleich ist. Die Brennkraftmaschine wird in Arbeitszyklen betrieben, wobei in jedem Arbeitszyklus ein Einspritzzyklus stattfindet. Im Einspritzzyklus wird Kraftstoff in einer oder mehreren Teileinspritzungen in den Brennraum der Brennkraftmaschine eingespritzt, wobei die Dauer des Einspritzzyklus in der Regel nur einen Bruchteil der Dauer des Arbeits- zyklus beträgt. Zu Beginn des Arbeitszyklus zum Zeitpunkt t0, der auch den Beginn des Einspritzzyklus darstellt, herrscht im Druckraum 12 der Standdruck p0, der mit Beginn des Einspritzzyklus ansteigt, bis der erste Öffnungsdruck ^ des Kraftstoffeinspritzventils erreicht wird und das Ventil- glied 10 durch seine Öffnungshubbewegung die Einspritzöffnungen 20 freigibt. Der Druck im Druckraum 12 steigt während der gesamten Haupteinspritzung weiter an und durch den Kraftstoffzufluß mit einer geringen zeitlichen Verzögerung auch im Federraum 25. Nach Beendigung der Haupteinspritzung schließt das Ventilglied 10 und der Druck im Druckraum 12 sinkt schnell ab, während der Druck im Federraum 25 deutlich träger reagiert und relativ hoch bleibt . Durch die erneute Kraftstoffzufuhr zu Beginn der Nacheinspritzung steigt der Druck im Druckraum 12 wieder an, bis der durch den Kraft- stoffdruck im Federraum 25 erhöhte zweite Öffnungsdruck p2 erreicht ist und das Ventilglied 10 für die Nacheinspritzung in die Öffnungsposition fährt . Nach Beendigung der Nacheinspritzung fällt der Druck im Druckraum 12 rasch wieder auf den Standdruck p0 ab und der Einspritzzyklus ist zum Zeit- punkt tx beendet. Der Druck im Federraum 25 braucht hingegen längere Zeit, um durch Kraftstoffabfluß über die Drosselverbindung in den Druckraum 12 wieder auf den Standdruck p0 abzusinken, was zu Beginn der nächsten Haupteinspritzung zum Zeitpunkt t2 jedoch erfolgt ist. Die Dauer des Arbeitszyklus hängt von der Drehzahl der Brennkraftmaschine ab und beträgt ungefähr 0,02 bis 0 , 2 Sekunden. Die Dauer des Einspritzzyklus hängt vom Typ der Brennkraftmaschine ab und beträgt beispielsweise 1/20 der Dauer des Arbeitszyklus.In Figure 3, the pressure p D in the pressure chamber 12 and the pressure p F in the spring chamber 25 against the valve member stroke h is shown schematically as a function of time t. The upper diagram shows the course of the valve member stroke, the middle diagram shows the course of the fuel pressure p D in the pressure chamber 12 and the lower diagram shows the course of the fuel pressure p p in the spring chamber 25, the time on the abscissa being the same in all diagrams. The internal combustion engine is operated in work cycles, with an injection cycle taking place in each work cycle. In the injection cycle, fuel is injected into the combustion chamber of the internal combustion engine in one or more partial injections, the duration of the injection cycle generally being only a fraction of the duration of the working cycle. At the beginning of the working cycle at time t 0 , which also represents the beginning of the injection cycle, the standing pressure p 0 prevails in the pressure chamber 12, which increases with the beginning of the injection cycle until the first opening pressure ^ of the fuel injection valve is reached and the valve element 10 through it Opening stroke movement releases the injection openings 20. The pressure in the pressure chamber 12 continues to increase during the entire main injection and also with a slight time delay in the spring chamber 25 due to the fuel inflow. After the main injection has ended, the valve member 10 closes and the pressure in the pressure chamber 12 drops rapidly, while the pressure in the spring chamber 25 reacts much more slowly and remains relatively high. As a result of the renewed supply of fuel at the beginning of the post-injection, the pressure in the pressure chamber 12 rises again until the second opening pressure p 2, which is increased by the fuel pressure in the spring chamber 25 is reached and the valve member 10 moves to the open position for the post-injection. After the post-injection has ended, the pressure in the pressure chamber 12 drops rapidly to the stand pressure p 0 and the injection cycle is ended at the time t x . The pressure in the spring chamber 25, on the other hand, takes a long time to drop back to the stand pressure p 0 due to fuel outflow via the throttle connection into the pressure chamber 12, but this took place at the beginning of the next main injection at time t 2 . The duration of the work cycle depends on the speed of the internal combustion engine and is approximately 0.02 to 0.2 seconds. The duration of the injection cycle depends on the type of internal combustion engine and is, for example, 1/20 of the duration of the work cycle.
In Figur 4 ist ein weiteres Ausführungsbeispiel eines erfindungsgemäßen Kraftstoffeinspritzventils im Bereich des Federraums 25 zu sehen. Um den Druckanstieg im Federraum 25 bei Zufluß einer Menge Kraftstoff möglichst groß zu halten, muß das Volumen möglichst klein gehalten werden. Dies ist im vorliegenden Ausführungsbeispiel dadurch realisiert, daß im Federraum 25 ein zylinderförmiger Verdrängungskolben 30 angeordnet ist, der von der Schließfeder 27 umgeben ist, so daß das mit Kraftstoff befüllbare Volumen des Federraums 25 verkleinert wird. Die Länge und der Durchmesser des Verdrän- gungskolbens 30 kann dabei variieren, so daß das Volumen des Federraums 25 an verschiedene Anforderungen angepaßt werden kann.FIG. 4 shows a further exemplary embodiment of a fuel injection valve according to the invention in the area of the spring chamber 25. In order to keep the pressure increase in the spring chamber 25 as large as possible when a quantity of fuel flows in, the volume must be kept as small as possible. In the present exemplary embodiment, this is achieved in that a cylindrical displacement piston 30 is arranged in the spring chamber 25 and is surrounded by the closing spring 27, so that the volume of the spring chamber 25 that can be filled with fuel is reduced. The length and the diameter of the displacement piston 30 can vary, so that the volume of the spring chamber 25 can be adapted to different requirements.
In Figur 5 ist ein weiteres Ausführungsbeispiel eines erfin- dungsgemäßen Kraftstoffeinspritzventils gezeigt. Ist dieFIG. 5 shows a further exemplary embodiment of a fuel injection valve according to the invention. Is the
Drosselverbindung vom Druckraum 12 in den Federraum 20 ausschließlich über den Ringspalt zwischen dem geführten Abschnitt des Ventilglieds 10 und der Bohrung 7 gegeben, so muß das Drosselspaltmaß S, insbesondere bei langem geführten Abschnitt L des Ventilglieds 10, unter Umständen so groß ge- wählt werden, daß ein unzulässig hoher Verschleiß des Ventilglieds 10 in der Bohrung 7 auftritt. Soll der Durchflußwiderstand trotzdem weiter erniedrigt werden, so kann dies dadurch erreicht werden, daß ein Teil der Länge L des ge- führten Abschnitts des Ventilglieds 10 durch eine oder mehrere Ausnehmungen 23 überbrückt wird, die vom brennraumabgewandten Ende des Ventilglieds 10 bis zu einer im geführten Abschnitt des Ventilglieds 10 ausgebildeten Ringnut 24 verlaufen. Dadurch wird die wirksame Länge L* des drosselnden Ringspalts 32 verkleinert und somit der Durchflußwiderstand des Kraftstoffs entsprechend verringert.Given the throttle connection from the pressure chamber 12 into the spring chamber 20 exclusively via the annular gap between the guided section of the valve member 10 and the bore 7, the throttle gap dimension S, in particular in the case of a long guided section L of the valve member 10, may have to be as large as possible. be chosen that an impermissibly high wear of the valve member 10 occurs in the bore 7. If the flow resistance is nevertheless to be reduced further, this can be achieved in that part of the length L of the guided section of the valve member 10 is bridged by one or more recesses 23 which extend from the end of the valve member 10 facing away from the combustion chamber to one in the Section of the valve member 10 formed annular groove 24. As a result, the effective length L * of the throttling annular gap 32 is reduced and the flow resistance of the fuel is accordingly reduced.
Alternativ zu der in Figur 5 gezeigten Ausführung kann es auch vorgesehen sein, daß Ausnehmungen am Ventilglied 10 vom brennraumzugewandten bis zum brennraumabgewandten Ende des geführten Abschnitts des Ventilglieds 10 verlaufen. Durch einen entsprechenden Querschnitt und eine entsprechende Anzahl dieser Ausnehmungen, läßt sich so der Durchflußwiderstand der Drosselverbindung einstellen und den Erfordernis- sen des Kraftstoffeinspritzventils anpassen, ohne daß dasAs an alternative to the embodiment shown in FIG. 5, it can also be provided that recesses on the valve member 10 extend from the end of the guided section of the valve member 10 facing the combustion chamber to the end remote from the combustion chamber. With a corresponding cross section and a corresponding number of these recesses, the flow resistance of the throttle connection can be adjusted and adapted to the requirements of the fuel injector without this
Drosselspaltmaß S geändert werden muß. Es kann auch vorgesehen sein, die Ausnehmungen an der Wand des führenden Abschnitts der Bohrung 7 anzuordnen, wobei die Ausnehmungen beispielsweise als Längsnuten ausgebildet sind.Throttle gap dimension S must be changed. Provision can also be made to arrange the recesses on the wall of the leading section of the bore 7, the recesses being designed, for example, as longitudinal grooves.
Neben der Ausbildung der Drosselverbindung des Druckraums 12 mit dem Federraum 25 durch einen Ringspalt 32 zwischen Ventilglied 10 und Bohrung 7 kann es auch vorgesehen sein, die Drosselverbindung durch einen separaten Kraftstoffkanal mit einem Drosselquerschnitt zu erzeugen, welcher Kraf stoff anal im Ventilkörper 1 verläuft und den Druckraum 12 mit dem Federraum 25 verbindet. In addition to the formation of the throttle connection of the pressure chamber 12 with the spring chamber 25 through an annular gap 32 between the valve member 10 and the bore 7, it can also be provided to produce the throttle connection through a separate fuel channel with a throttle cross-section, which fuel runs anal in the valve body 1 and the Pressure chamber 12 connects to the spring chamber 25.

Claims

Ansprüche Expectations
1. Kraftstoffeinspritzventil für Brennkraftmaschinen mit einem Ventilkörper (1) , in dem in einer Bohrung (7) ein Ventilglied (10) längsverschiebbar angeordnet ist, das an seinem brennraumseitigen Ende eine Ventildichtfläche (18) aufweist, die mit einem im Ventilkörper (1) ausgebildeten Ventilsitz (16) zur Steuerung wenigstens einer Ein- spritzöffnung (20) zusammenwirkt, wobei das Ventilglied (10) brennraumabgewandt zumindest mittelbar in einen Federraum (25) ragt und dort von einer im Federraum (25) angeordneten Feder (27) zum Ventilsitz (16) hin beaufschlagt wird, und mit einem mit Kraftstoff befüllbaren Druckraum (12) , der das Ventilglied (10) umgibt und in dem eine am Ventilglied (10) ausgebildete Druckfläche1. Fuel injection valve for internal combustion engines with a valve body (1), in which in a bore (7) a valve member (10) is arranged to be longitudinally displaceable, which has a valve sealing surface (18) at its combustion chamber end, which is formed with a valve body (1) Valve seat (16) cooperates to control at least one injection opening (20), the valve member (10) projecting at least indirectly away from the combustion chamber into a spring chamber (25) and there from a spring (27) arranged in the spring chamber (25) to the valve seat (16 ) is acted upon, and with a fuel-filled pressure chamber (12) which surrounds the valve member (10) and in which a pressure surface formed on the valve member (10)
(11) angeordnet ist, so daß durch Kraftstoffzufuhr in den Druckraum (12) der dortige Kraftstoffdruck ausgehend von einem Standdruck (p0) ansteigt und eine entgegen der Schließkraft der Feder (27) gerichtete hydraulische Kraft auf die Druckfläche (11) ausübt, wodurch das Ventilglied(11) is arranged so that by supplying fuel to the pressure chamber (12) the fuel pressure there increases from a standing pressure (p 0 ) and exerts a hydraulic force directed against the closing force of the spring (27) on the pressure surface (11), thereby the valve member
(10) bei einem Öffnungsdruck (p2; p2) im Druckraum (12) von einer Schließstellung in eine Öffnungsstellung bewegt wird, in welcher Öffnungsstellung eine Kraftstoffeinspritzung durch die wenigstens eine Einspritzöffnung (20) erfolgt, und mit einer zwischen dem Druckraum (12) und dem Federraum (25) ausgebildeten Drosselverbindung, wobei der Federraum (25) bis auf diese Drosselverbindung abgeschlossen ist, dadurch gekennzeichnet, daß die Drossel - Verbindung so ausgebildet ist, daß der Druck im Federraum (25) nach Beendigung des Einspritzzyklus bis zum Beginn des nachfolgenden Einspritzzyklus zumindest annähernd auf den Standdruck (p0) abgefallen ist.(10) at an opening pressure (p 2 ; p 2 ) in the pressure chamber (12) is moved from a closed position into an open position, in which open position fuel is injected through the at least one injection opening (20), and with one between the pressure chamber (12 ) and the spring chamber (25) designed throttle connection, the spring chamber (25) being closed except for this throttle connection, characterized in that the throttle connection is designed such that the pressure in the spring chamber (25) after the end of the injection cycle until the beginning of the subsequent injection cycle has fallen at least approximately to the stand pressure (p 0 ).
2. Kraftstoffeinspritzventil nach Anspruch 1, dadurch gekennzeichnet, daß die Einspritzung in einem Einspritzzy- klus durch Teileinspritzungen mit wenigstens einer ersten und einer zeitlich nachfolgenden zweiten Teileinspritzung erfolgt .2. Fuel injection valve according to claim 1, characterized in that the injection in an injection cycle is carried out by partial injections with at least one first and a subsequent second partial injection.
3. Kraftstoffeinspritzventil nach Anspruch 2, dadurch gekennzeichnet, daß der Öffnungsdruck (p2) der zweiten Tei- leinspritzung höher ist als der Öffnungsdruck (p- der ersten Teileinspritzung.3. Fuel injection valve according to claim 2, characterized in that the opening pressure (p 2 ) of the second partial injection is higher than the opening pressure (p- the first partial injection.
4. Kraftstoffeinspritzventil nach Anspruch 1, dadurch gekennzeichnet, daß die Drosselverbindung durch einen zwischen einem geführten Abschnitt des Ventilglieds (10) und der Bohrung (7) ausgebildeten Ringspalt (32) gebildet wird.4. Fuel injection valve according to claim 1, characterized in that the throttle connection is formed by an annular gap (32) formed between a guided section of the valve member (10) and the bore (7).
5. Kraftstoffeinspritzventil nach Anspruch 1, dadurch gekennzeichnet, daß die Drosselverbindung durch Ausnehmungen (23) am Ventilglied (10) gebildet wird. 5. Fuel injection valve according to claim 1, characterized in that the throttle connection is formed by recesses (23) on the valve member (10).
6. Kraftstoffeinspritzventil nach Anspruch 5, dadurch gekennzeichnet, daß sich die Ausnehmungen (23) über einen Teil der Länge des geführten Abschnitts des Ventilglieds (10) erstrecken.6. Fuel injection valve according to claim 5, characterized in that the recesses (23) extend over part of the length of the guided section of the valve member (10).
7. Kraftstoffeinspritzventil nach Anspruch 1, dadurch ge- kennzeichnet, daß die Drosselverbindung durch Ausnehmungen an dem führenden Abschnitt der Bohrung (7) gebildet wird.7. Fuel injection valve according to claim 1, characterized in that the throttle connection is formed by recesses in the leading section of the bore (7).
8. Kraftstoffeinspritzventil nach Anspruch 7, dadurch gekennzeichnet, daß sich die Ausnehmungen über einen Teil der Länge des geführten Abschnitts des Ventilglieds (10) erstrecken.8. Fuel injection valve according to claim 7, characterized in that the recesses extend over part of the length of the guided section of the valve member (10).
9. Kraftstoffeinspritzventil nach Anspruch 1, dadurch gekennzeichnet, daß im Federraum (25) ein an dessen Wand befestigter Verdrängungskörper (30) angeordnet ist. 9. Fuel injection valve according to claim 1, characterized in that a displacement body (30) attached to the wall thereof is arranged in the spring chamber (25).
10. Kraftstoffeinspritzventil nach Anspruch 9, dadurch gekennzeichnet, daß der Verdrängungskörper (30) kolbenförmig ausgebildet ist und vom Federelement (25) umgeben ist . 10. Fuel injection valve according to claim 9, characterized in that the displacement body (30) is piston-shaped and is surrounded by the spring element (25).
11. Kraftstoffeinspritzventil nach Anspruch 1, dadurch gekennzeichnet, daß der Kraftstoff im Federraum (25) zumindest einen Teil der brennraumabgewandten Stirnfläche des Ventilglieds (10) beaufschlagt.11. Fuel injection valve according to claim 1, characterized in that the fuel in the spring chamber (25) acts on at least part of the end face of the valve member (10) facing away from the combustion chamber.
12. Kraftstoffeinspritzventil nach Anspruch 1, dadurch ge- kennzeichnet, daß die Drosselverbindung durch einen Verbindungskanal ausgebildet ist, in dem ein Drosselquerschnitt angeordnet ist und der den Druckraum (12) mit dem Federraum (25) verbindet. 12. Fuel injection valve according to claim 1, character- ized in that the throttle connection is formed by a connecting channel in which a throttle cross section is arranged and which connects the pressure chamber (12) with the spring chamber (25).
EP02732326A 2001-03-15 2002-03-13 Fuel-injection valve for internal combustion engines Withdrawn EP1370766A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE10112426 2001-03-15
DE10112426A DE10112426A1 (en) 2001-03-15 2001-03-15 Fuel injection valve has pressure chamber and spring chamber connected by throttling connection so that pressure in spring chamber after termination of injection cycle up to beginning of next cycle falls off to standing pressure
PCT/DE2002/000880 WO2002075149A1 (en) 2001-03-15 2002-03-13 Fuel-injection valve for internal combustion engines

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EP1370766A1 true EP1370766A1 (en) 2003-12-17

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US (1) US20030164404A1 (en)
EP (1) EP1370766A1 (en)
JP (1) JP2004518880A (en)
DE (1) DE10112426A1 (en)
WO (1) WO2002075149A1 (en)

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Publication number Priority date Publication date Assignee Title
GB0209049D0 (en) * 2002-04-20 2002-05-29 Delphi Tech Inc Fuel injector
US20050224044A1 (en) * 2004-04-08 2005-10-13 Stojkovic Boris D Injection strategy for low noise and soot combustion

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DE3341300A1 (en) * 1983-11-15 1985-05-23 Robert Bosch Gmbh, 7000 Stuttgart PRESSURE CONTROL VALVE FOR FUEL INJECTION PUMPS
GB8402469D0 (en) * 1984-01-31 1984-03-07 Lucas Ind Plc Fuel injection nozzles
EP0267177A1 (en) * 1986-10-30 1988-05-11 VOEST-ALPINE AUTOMOTIVE Gesellschaft m.b.H. Fuel injection nozzle
DE59008568D1 (en) * 1989-01-12 1995-04-06 Bosch Robert FUEL INJECTION NOZZLE.
JP2616825B2 (en) * 1989-12-28 1997-06-04 トヨタ自動車株式会社 Fuel injection valve for internal combustion engine
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See references of WO02075149A1 *

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DE10112426A1 (en) 2002-09-19
WO2002075149A1 (en) 2002-09-26
JP2004518880A (en) 2004-06-24
US20030164404A1 (en) 2003-09-04

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