EP1016783B1 - Fuel injection device for internal combustion engines - Google Patents

Fuel injection device for internal combustion engines Download PDF

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Publication number
EP1016783B1
EP1016783B1 EP99124452A EP99124452A EP1016783B1 EP 1016783 B1 EP1016783 B1 EP 1016783B1 EP 99124452 A EP99124452 A EP 99124452A EP 99124452 A EP99124452 A EP 99124452A EP 1016783 B1 EP1016783 B1 EP 1016783B1
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EP
European Patent Office
Prior art keywords
valve
fuel injection
space
section
control
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP99124452A
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German (de)
French (fr)
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EP1016783A2 (en
EP1016783A3 (en
Inventor
Roger Potschin
Friedrich Boecking
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Robert Bosch GmbH
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Robert Bosch GmbH
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Publication of EP1016783A2 publication Critical patent/EP1016783A2/en
Publication of EP1016783A3 publication Critical patent/EP1016783A3/en
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Publication of EP1016783B1 publication Critical patent/EP1016783B1/en
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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M47/00—Fuel-injection apparatus operated cyclically with fuel-injection valves actuated by fluid pressure
    • F02M47/02—Fuel-injection apparatus operated cyclically with fuel-injection valves actuated by fluid pressure of accumulator-injector type, i.e. having fuel pressure of accumulator tending to open, and fuel pressure in other chamber tending to close, injection valves and having means for periodically releasing that closing pressure
    • F02M47/027—Electrically actuated valves draining the chamber to release the closing pressure
    • 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
    • F02M45/00—Fuel-injection apparatus characterised by having a cyclic delivery of specific time/pressure or time/quantity relationship
    • F02M45/02—Fuel-injection apparatus characterised by having a cyclic delivery of specific time/pressure or time/quantity relationship with each cyclic delivery being separated into two or more parts
    • F02M45/04—Fuel-injection apparatus characterised by having a cyclic delivery of specific time/pressure or time/quantity relationship with each cyclic delivery being separated into two or more parts with a small initial part, e.g. initial part for partial load and initial and main part for full load
    • F02M45/08—Injectors peculiar thereto
    • 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
    • F02M63/00—Other fuel-injection apparatus having pertinent characteristics not provided for in groups F02M39/00 - F02M57/00 or F02M67/00; Details, component parts, or accessories of fuel-injection apparatus, not provided for in, or of interest apart from, the apparatus of groups F02M39/00 - F02M61/00 or F02M67/00; Combination of fuel pump with other devices, e.g. lubricating oil pump
    • F02M63/0012—Valves
    • F02M63/0031—Valves characterized by the type of valves, e.g. special valve member details, valve seat details, valve housing details
    • F02M63/0033—Lift valves, i.e. having a valve member that moves perpendicularly to the plane of the valve seat
    • F02M63/0035—Poppet valves, i.e. having a mushroom-shaped valve member that moves perpendicularly to the plane of the valve seat
    • 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
    • F02M63/00—Other fuel-injection apparatus having pertinent characteristics not provided for in groups F02M39/00 - F02M57/00 or F02M67/00; Details, component parts, or accessories of fuel-injection apparatus, not provided for in, or of interest apart from, the apparatus of groups F02M39/00 - F02M61/00 or F02M67/00; Combination of fuel pump with other devices, e.g. lubricating oil pump
    • F02M63/0012—Valves
    • F02M63/0031—Valves characterized by the type of valves, e.g. special valve member details, valve seat details, valve housing details
    • F02M63/0056—Throttling valves, e.g. having variable opening positions throttling the flow

Definitions

  • the invention relates to a fuel injection device for internal combustion engines according to the preamble of the patent claim 1 off.
  • DE 196 24 001 A1 known fuel injection device is the valve chamber in a first version without Cross-section reduction connected to the control room.
  • the Control valve controls when actuated by the Piezo actuator the drain cross section to the drain channel either fully open or close it.
  • the valve chamber is designed with a connection channel connected to the control room, this connecting channel is coaxial to the valve seat on the side of the drain channel.
  • the amount of pre-injection is in the second described design so that the adjustment speed of the control valve member by the piezo actuator and the geometrically defined path of the control valve member determining parameters for the degree of pressure relief are in the control room.
  • the maximum Relief cross section for both the relief for the Pre-injection as well as for the discharge for the Main injection the same size, what a fine-tuning the opening speed of the injection valve different operating conditions is disadvantageous.
  • the fuel injection device according to the invention with the characterizing features of claim 1 has against it the advantage that two different discharge cross-sections sequentially can be set one after the other by in Dependence on the position of the control valve member two different connection cross-sections to the control room getting produced.
  • a gradation of the drain cross section depending on the stroke Especially for low relief of the control pressure in the Control room can have a first, smaller discharge cross-section come into effect with the higher accuracy the pre-injection stroke of the injection valve member is set can be. Afterwards stands for the main injection large drainage cross-section available, which is quick Movement of the injection valve member allowed.
  • connection cross-section to the first connection cross-section additional cross section provided. So that will enables a large effective cross-sectional change can be achieved.
  • the first connection cross-section lies in a space-saving manner Intermediate valve member on which according to claim 4 to 7 A sufficiently large flow cross-section on the outer circumference provided.
  • the second connection cross-section can be used through the flow cross section to the Spaces between the longitudinal ribs must be defined or it is advantageous according to claim 7 by the stroke of the intermediate valve member that determines a certain Flow cross section between sealing seat shoulder and Seals sealing surface.
  • connection channel of the valve member there are always open connections between the Connection channel of the valve member and the valve chamber provided so that this connection channel as always open first connection cross-section is available, at open intermediate valve member another second Connection cross section is switched on.
  • connection channel in the intermediate valve member with the system of To close control valve member on this and thus instead of the cross section of the connecting channel in the intermediate valve member now the cross section of a connecting channel to provide along the outer periphery of the intermediate valve member.
  • FIG. 1 shows a schematic representation of a fuel injection device with fuel supply from a high-pressure fuel accumulator and a fuel injector known Type
  • Figure 2 shows a first embodiment of the Invention with a control valve member, which is an intermediate valve member actuated a first embodiment
  • Figure 3a to Figure 3c shows the stroke profiles of Injection valve member, control valve member and intermediate valve member of the embodiment of Figure 2
  • Figure 4 a modification of the embodiment of Figure 2 with an intermediate valve member, the connecting channel through the control valve member is closable
  • Figures 5a to 5b the stroke profiles of the injection valve member, control valve member and intermediate valve member of the embodiment Figure 4.
  • a fuel injector with which at high Injection pressures a large variation with little effort the fuel injection with respect to the injection quantity and Injection time is possible by a so-called Common Rail System implemented.
  • the invention is fundamental also with conventional fuel injection pumps usable.
  • the use is particularly advantageous with a common rail injection system.
  • a high-pressure fuel reservoir as a high-pressure fuel source 1 provided by a high pressure fuel pump 2 from a fuel tank 4 is supplied with fuel.
  • the pressure in the high-pressure fuel reservoir 1 is by a pressure sensor 6 detected and as a signal from an electrical control device 8 supplied, the pressure in a pressure control valve 5 in High-pressure fuel reservoir controls.
  • the control device also controls the opening and closing of high-pressure fuel injection valves 9, which is used to inject fuel from High-pressure fuel storage are supplied.
  • the fuel injection valve has 9 a valve housing 11 on its one end that is for installation in the internal combustion engine is determined, has injection openings 12, the outlet from inside the fuel injector by a Injection valve member 14 is controlled.
  • This is in the executed example as an elongated valve needle trained that a conical at one end Has sealing surface 15 with an inner Valve seat cooperates on the valve housing from which the Remove injection openings 12.
  • the injection ports can also assume that there is a blind hole connects the valve seat.
  • the valve needle is in one Longitudinal bore 13 on its upper, sealing surface 15 end facing away and is on the sealing surface 15th facing away from the longitudinal bore 13 end acted upon by a compression spring 18 in the closing direction.
  • valve needle 14 Between the guide in the longitudinal bore 13 and the The valve seat is the valve needle 14 from an annular space 19 surrounded, which opens into a pressure chamber 16, which in turn via a pressure line 17 in constant connection with the High-pressure fuel accumulator 1 stands.
  • the valve needle 14 In the area of this Pressure chamber, the valve needle 14 has a pressure shoulder 20 on, over which they oppose the pressure in the pressure chamber 16 Force of the spring 18 in the sense of lifting the sealing surface 15 is acted upon by the valve seat.
  • the valve needle continues to be driven by a plunger 21 actuated, the end of the valve needle 14 facing away 22 a control chamber 24 in a tappet guide bore 23 limited.
  • This is via an inlet channel 26 in which one Inlet throttle 28 is provided continuously with the pressure line 17 or the high-pressure fuel reservoir 1 connected.
  • the inlet channel opens to the side and cannot be closed in the control room 24.
  • Coaxial to the plunger 21 leads from the control room 24 from a connecting channel 29, which in a valve chamber 30 of a control valve 31 opens.
  • Connection channel which is also a drain channel is a diameter restriction, preferably provided in the form of a discharge throttle 32.
  • control valve 31 has a control valve member 34 consisting of a Valve tappet 35, which is guided in a tappet bore 36, and a valve head 37 on the valve chamber 30 projecting end of the control valve member 34.
  • a spring plate 38 is provided at the Valve head opposite end of the valve lifter 35 on which there is a compression spring 39 supports, which strives to the control valve member in Bring closed position.
  • the control valve member 34 is actuated by a piston 40 acted upon, which is part of a piezo actuator 41 and Exciting the piezo depending on the degree of excitement Control valve member in different open positions can bring.
  • the piston can directly with the piezo be connected to the piezo actuator or by means of a hydraulic or mechanical translation of this be moved.
  • valve head 37 arranged at the end of the valve tappet 35 has a conical, the entry of the connecting channel 29 valve head sealing surface 51 facing away from valve chamber 30 on, which cooperates with the valve seat 46 and so the Connection between the valve chamber 30 and the annular chamber 48 or the subsequent drain channel 49 controls.
  • the Annulus 48 is in this case in contact with the valve head sealing surface 37 subsequent recess on the circumference of the Valve tappet 35 in connection with that of the valve chamber 30 laxative tappet bore 36 is formed.
  • the side of the valve head facing the connecting channel 29 has a flat end face 53 which, when the valve lifter is actuated 35 in contact with an end face 54 of an intermediate valve 56 forming intermediate valve member 57 comes to rest and with a further actuation of the valve tappet 35, the intermediate valve member 57 is movable from its closed position.
  • the intermediate valve member 57 has ribs 59 on its outer circumference on, between which flow cross sections are formed and which are guided with their end faces in a guide bore 60 become.
  • the guide bore 60 tapers to the side of the Valve chamber 30 in via a sealing seat shoulder 62 to one end the valve chamber 30 coaxially to the guide bore Connection bore 63.
  • the sealing seat shoulder 62 thus represents the Valve seat of the intermediate valve member.
  • the part of the intermediate valve member 57 which carries the ribs 59 tapers after the ribs over a conical Sealing surface 64 to a cylindrical actuating part 65, the at a distance to the connection hole through this in the Valve chamber 30 protrudes.
  • a closing spring 68 On the opposite side Intermediate valve member 57 loaded by a closing spring 68, the the intermediate valve member with its sealing surface 64 in contact brings the sealing seat shoulder 62.
  • the closing spring 68 is supported thereby at the transition between the guide bore 60 and the continuing section 29 of the drain channel from the coaxial to the guide bore 60 opens into the control room 24.
  • An axial connecting channel leads through the intermediate valve member 57 69, which is also in the closed position Intermediate valve member 57, the valve chamber 30 via the section 29 the drain channel connects to the control chamber 24.
  • the connecting channel can be designed as a stepped bore from the one stepped bore part 70, the one to the control room side 24 lies and with a smaller diameter a first Connection cross section determined.
  • the mode of operation of the embodiment according to FIG. 2 is such that that to trigger a fuel injection with With the help of the control valve 31, the pressure in the control chamber 24 is reduced is opened by the drain channel 29, 70, 69, 30, 48, 49 becomes. Decoupled by the throttle 28 in the inflow channel 26, decreases the pressure in the control chamber 24 such that the valve member below Action of the opening forces of the pressure chamber 60 against the Force of the spring 18 opens.
  • the degree of opening of the injector member 14 can by the size of the discharge of the Control room or the amount of pressure medium flowing out there or fuel are affected. Guides the control valve member 34 only a partial stroke, such that the end face 53 is not in System with the intermediate valve member 57 arrives, the maximum flow through section 70 of the connecting channel 69 determined.
  • the relief rate is correspondingly low thus the stroke of the injection valve member 14 only a small amount of fuel injection, for example Introduction of a pre-injection quantity promoted in the combustion chamber.
  • the control valve member 34 opens completely and comes while in contact with the intermediate valve member 57, this lifts the actuating part 65 from the sealing seat shoulder 62 and provides one in addition to the first cross section second connection cross section, which is determined by section 70 is available.
  • the second connection cross section can either through the passage cross-section between the sealing seat shoulder 62 and sealing surface 64 can be determined or it can Cross-section of connection through the remaining passage area be defined between the ribs 59.
  • the partial relief of the control room 24 for performing the Pre-injection has the advantage that when closing the Control valve member 34, the pressure, since less lowered, can rebuild very quickly.
  • FIGS. 3a to 3d show the stroke of the injection valve member 14 over time.
  • the stroke of the injection valve element for the pre-injection V and the stroke of the injection valve element for carrying out the main injection quantity H can be seen there. These are interrupted by an injection break P.
  • the necessary stroke of the control valve member 34 is shown with a small stroke V S and a large stroke H S.
  • the stroke of the intermediate valve member Z is plotted over time with the assignment to the stroke H S of the control valve member 34 and the stroke H for the main injection of the injection valve member 14.
  • FIG. 4 is a second embodiment of the invention shown as a modification to the embodiment according to FIG. 2.
  • the valve head has 134 instead of the flat end face 53 now a conical, formed as a sealing surface end face 73, which with a Valve seat 74 formed end face of the intermediate valve member 157 works together.
  • the valve seat 74 surrounds the at Intermediate valve member 57 of Figure 2 provided axial connection channel 69 in the area of its outlet on the actuating part 65 in the valve chamber 30.
  • leaf spring 68 is now a coil spring 168 provided that the intermediate valve member 157 from the side of the Control chamber 24 loaded and this with its sealing surface 64th holds in contact with the sealing seat shoulder 62 as long as that The intermediate valve member 157 is not lifted from the control valve member 134 becomes.
  • the part 70 of the connecting channel 69 again the first connection cross section between control chamber 24 and valve chamber 30, however when the control valve member 134 with its valve head 137 comes into contact with the conical valve seat 74, closed becomes. But now by lifting the intermediate valve member 157 the second connection cross section between the ribs 59 or between the sealing seat shoulder 62 and the sealing surface 64 open.
  • the second connection cross-section is like this designed that it is correspondingly larger than the first Connection cross section 70 of the part of the connection channel 69 taking into account that here the flow cross section of the second connection cross-section in the place of the passage cross-section of the first connection cross section occurs.
  • This Design can be cheaper in individual cases, to the exact to be able to define the second connection cross-section.
  • FIG. 5a the stroke of the injection valve member 14 over time is shown analogously to FIG. 3a, likewise with the stroke V for the pre-injection and the stroke H for the main injection.
  • FIG. 5b the further advantage of the embodiment according to FIG. 4 is that the control valve member does not have to be returned to its original closed position in order to interrupt the fuel injection between the pre-injection V and the main injection H.
  • the control valve member 134 executes a stroke hv and thereby comes to bear against the conical valve seat 74 of the intermediate valve member.
  • the relief of the control chamber 24 is determined by the first connection cross section of the part 70 of the connection channel 69, which leads to the pre-injection. Then, when the connecting channel 69 is closed, the pressure in the control chamber 24 can build up again and the injection valve member can close.
  • the control valve member 134 is moved up to the stroke h h and thereby opens the intermediate valve member according to the stroke curve Z. With this opening of the intermediate valve, the relief of the control chamber 24 takes place with a higher relief rate and accordingly the opening stroke of the injection valve member required for the main injection is made possible.

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

Description

Stand der TechnikState of the art

Die Erfindung geht von einer Kraftstoffeinspritzvorrichtung für Brennkraftmaschinen nach der Gattung des Patentanspruchs 1 aus. Bei einer solchen, durch die DE 196 24 001 A1 bekannten Kraftstoffeinspritzeinrichtung ist der Ventilraum in einer ersten Ausführung ohne Querschnittsverminderung mit dem Steuerraum verbunden. Das Steuerventil steuert dabei bei Betätigung durch den Piezoaktor den Abflußquerschnitt zum Abflußkanal hin entweder ganz auf oder schließt diesen. In einer weiteren Ausführung ist der Ventilraum über ein verbindungskanal mit dem Steuerraum verbunden, wobei dieser Verbindungskanal koaxial zum Ventilsitz zur Seite des Abflußkanals liegt. Durch Betätigung des Steuerventilglieds durch den Piezoaktor wird dabei entweder der Abflußquerschnitt vom Ventilraum zum Abflußkanal hin ganz geöffnet oder geschlossen oder es wird zur Erzielung einer Voreinspritzung das Steuerventilglied vom Ventilsitz zum Abflußkanal hin weg zum Eintritt des Verbindungskanals in den Ventilraum bewegt, wobei in der Folge dieser Bewegung der Steuerraum kurzzeitig über den Ventilraum zum Abflußkanal hin geöffnet ist. Für eine anschließende Haupteinspritzung wird das Steuerventilglied in eine Mittelstellung bewegt, in der sowohl der Querschnitt zum Abflußkanal hin als auch der Querschnitt des Verbindungskanals in den Ventilraum hinein ganz geöffnet sind. Diese Ausgestaltung hat den Nachteil, daß zur Entlastung des Druckes im Steuerraum nur ein einziger geometrisch festgelegter Abflußquerschnitt zum Abflußkanal hin besteht. Die Menge der Voreinspritzung ist dabei in der zweiten geschilderten Ausführung so, daß die Verstellgeschwindigkeit des Steuerventilgliedes durch den Piezoaktor und der geometrisch festgelegte Weg des Steuerventilglieds bestimmende Größen für den Grad der Entlastung des Druckes im Steuerraum sind. Insbesondere ist der maximale Entlastungsquerschnitt sowohl für die Entlastung für die Voreinspritzung als auch für die Entlastung für die Haupteinspritzung gleich groß, was für eine Feinabstimmung der Öffnungsgeschwindigkeit des Einspritzventils bei verschiedenen Betriebszuständen von Nachteil ist.The invention relates to a fuel injection device for internal combustion engines according to the preamble of the patent claim 1 off. In such a way DE 196 24 001 A1 known fuel injection device is the valve chamber in a first version without Cross-section reduction connected to the control room. The Control valve controls when actuated by the Piezo actuator the drain cross section to the drain channel either fully open or close it. In another The valve chamber is designed with a connection channel connected to the control room, this connecting channel is coaxial to the valve seat on the side of the drain channel. By actuating the control valve member by the piezo actuator either the cross section of the discharge from Valve chamber fully opened towards the drainage channel or closed or it is used to achieve a pre-injection the control valve member from the valve seat to Drain channel away to the entry of the connecting channel in the valve chamber moves, as a result of this movement the control room for a short time via the valve room Drain channel is open. For a subsequent one The main valve injection into a control valve Moves middle position, in which both the cross section to Drain channel out as well as the cross section of the connecting channel are fully open into the valve space. This Design has the disadvantage that to relieve the Pressure in the control room only one geometrically fixed drain cross-section to the drain channel exists. The amount of pre-injection is in the second described design so that the adjustment speed of the control valve member by the piezo actuator and the geometrically defined path of the control valve member determining parameters for the degree of pressure relief are in the control room. In particular, the maximum Relief cross section for both the relief for the Pre-injection as well as for the discharge for the Main injection the same size, what a fine-tuning the opening speed of the injection valve different operating conditions is disadvantageous.

Vorteile der ErfindungAdvantages of the invention

Die erfindungsgemäße Kraftstoffeinspritzvorrichtung mit den kennzeichnenden Merkmalen des Patentanspruchs 1 hat dagegen den Vorteil, daß sequentiell zwei unterschiedliche Abflußquerschnitte nacheinander einstellbar sind, indem in Abhängigkeit von der Stellung des Steuerventilgliedes zwei verschiedene Verbindungsquerschnitte zum Steuerraum hergestellt werden. Somit kann eine Gradation des Abflußquerschnittes in Abhängigkeit vom Hub erzielt werden. Insbesondere für geringe Entlastungen des Steuerdrucks im Steuerraum kann dabei ein erster, kleinerer Abflußquerschnitt zur Wirkung kommen, mit dem mit höherer Genauigkeit der Voreinspritzhub des Einspritzventilgliedes eingestellt werden kann. Für die Haupteinspritzung steht danach ein großer Abflußquerschnitt zur Verfügung, der eine schnelle Bewegung des Einspritzventilgliedes erlaubt.The fuel injection device according to the invention with the characterizing features of claim 1 has against it the advantage that two different discharge cross-sections sequentially can be set one after the other by in Dependence on the position of the control valve member two different connection cross-sections to the control room getting produced. Thus, a gradation of the drain cross section depending on the stroke. Especially for low relief of the control pressure in the Control room can have a first, smaller discharge cross-section come into effect with the higher accuracy the pre-injection stroke of the injection valve member is set can be. Afterwards stands for the main injection large drainage cross-section available, which is quick Movement of the injection valve member allowed.

In vorteilhafter Weise ist dabei gemäß Patentanspruch 2 als zweiter Verbindungsquerschitt ein zum ersten Verbindungsquerschnitt zusätzlicher Querschnitt vorgesehen. Damit wird ermöglicht, daß eine große wirkungsvolle Querschnittsveränderung erzielt werden kann. Gemäß Patentanspruch 3 liegt dabei raumsparend der erste Verbindungsquerschnitt im Zwischenventilglied, an dem gemäß Anspruch 4 bis 7 am Außenumfang einen außreichend großer Durchflußquerschnitt bereitgestellt wird. Dabei kann der zweite Verbindungsquerschnitt durch den Durchflußquerschnitt an den Zwischenräumen zwischen den Längsrippen definiert sein oder er wird vorteilhaft gemäß Patentanspruch 7 durch den Hub des Zwischenventilgliedes bestimmt, das einen bestimmten Durchflußquerschnitt zwischen Dichtsitzschulter und Dichtfläche freigibt.Advantageously, according to claim 2 as second connection cross-section to the first connection cross-section additional cross section provided. So that will enables a large effective cross-sectional change can be achieved. According to claim 3 the first connection cross-section lies in a space-saving manner Intermediate valve member on which according to claim 4 to 7 A sufficiently large flow cross-section on the outer circumference provided. The second connection cross-section can be used through the flow cross section to the Spaces between the longitudinal ribs must be defined or it is advantageous according to claim 7 by the stroke of the intermediate valve member that determines a certain Flow cross section between sealing seat shoulder and Seals sealing surface.

In der weiteren Ausgestaltung gemäß den Patentanspruch 8 werden immer offene Querverbindungen zwischen dem Verbindungskanal des Ventilgliedes und dem Ventilraum bereitgestellt, so daß dieser Verbindungskanal als immer offener erster Verbindungsquerschnitt bereit steht, dem bei geöffnetem Zwischenventilglied ein weiterer zweiter Verbindungsquerschnitt zugeschaltet wird.In the further embodiment according to claim 8 there are always open connections between the Connection channel of the valve member and the valve chamber provided so that this connection channel as always open first connection cross-section is available, at open intermediate valve member another second Connection cross section is switched on.

Eine andere vorteilhafte Lösung besteht darin, den Verbindungskanal in dem Zwischenventilglied mit der Anlage des Steuerventilgliedes an diesem zu verschließen und somit statt des Querschnitts des Verbindungskanals im Zwischenventilglied nun den Querschnitt eines Verbindungskanals entlang dem Außenumfang des Zwischenventilglieds bereitzustellen. Another advantageous solution is the connection channel in the intermediate valve member with the system of To close control valve member on this and thus instead of the cross section of the connecting channel in the intermediate valve member now the cross section of a connecting channel to provide along the outer periphery of the intermediate valve member.

Weitere Ausgestaltungen der Erfindung mit deren Vorteilen sind der nachfolgenden Beschreibung in verbindung mit der Zeichnung zu entnehmen.Further refinements of the invention with their advantages are the following description in connection with the Take the drawing.

Zeichnungdrawing

In der Zeichnung sind zwei Ausführungsbeispiele der Erfindung dargestellt, sie werden in der nachfolgenden Beschreibung näher erläutert. Es zeigen Figur 1 eine schematische Darstellung einer Kraftstoffeinspritzvorrichtung mit Kraftstoffversorgung aus einem Kraftstoffhochdruckspeicher und einem Kraftstoffeinspritzventil bekannter Bauart, Figur 2 ein erstes Ausführungsbeispiel der Erfindung mit einem Steuerventilglied, das ein Zwischenventilglied einer ersten Ausführungsform betätigt, Figur 3a bis Figur 3c eine Darstellung des Hubverläufe von Einspritzventilglied, Steuerventilglied und Zwischenventiglied des Ausführungsbeispiels nach Figur 2, Figur 4 eine Abwandlung des Ausführungsbeispiels nach Figur 2 mit einem Zwischenventilglied, dessen Verbindungskanal durch das Steuerventilglied verschließbar ist und Figuren 5a bis 5b die Hubverläufe von Einspritzventilglied, Steuerventilglied und Zwischenventiglied des Ausführungsbeispiels nach Figur 4.In the drawing, two embodiments of the Invention shown, they are in the following Description explained in more detail. 1 shows a schematic representation of a fuel injection device with fuel supply from a high-pressure fuel accumulator and a fuel injector known Type, Figure 2 shows a first embodiment of the Invention with a control valve member, which is an intermediate valve member actuated a first embodiment, Figure 3a to Figure 3c shows the stroke profiles of Injection valve member, control valve member and intermediate valve member of the embodiment of Figure 2, Figure 4 a modification of the embodiment of Figure 2 with an intermediate valve member, the connecting channel through the control valve member is closable and Figures 5a to 5b the stroke profiles of the injection valve member, control valve member and intermediate valve member of the embodiment Figure 4.

Beschreibung der AusführungsbeispieleDescription of the embodiments

Eine Kraftstoffeinspritzeinrichtung, mit der bei hohen Einspritzdrücken mit geringem Aufwand eine große Variation der Kraftstoffeinspritzung bezüglich Einspritzmenge und Einspritzzeitpunkt möglich ist, wird durch ein sogenanntes Common Rail System verwirklicht. Dieses stellt eine andere Art von Kraftstoffhochdruckquelle zur Verfügung als es durch die üblichen Kraftstoffhochdruckeinspritzpumpen gegeben ist. Dabei ist jedoch die Erfindung prinzipiell auch bei konventionellen Kraftstoffeinspritzpumpen verwendbar. Besonders vorteilhaft ist die Verwendung jedoch bei einem Common Rail Einspritz-System.A fuel injector with which at high Injection pressures a large variation with little effort the fuel injection with respect to the injection quantity and Injection time is possible by a so-called Common Rail System implemented. This represents another Kind of high pressure fuel source available as it through the usual high pressure fuel injection pumps given is. However, the invention is fundamental also with conventional fuel injection pumps usable. However, the use is particularly advantageous with a common rail injection system.

Bei dem in Figur 1 dargestellten Common Rail-Einspritzsystem ist als Kraftstoffhochdruckquelle ein Kraftstoffhochdruckspeicher 1 vorgesehen, der von einer Kraftstoffhochdruckförderpumpe 2 aus einem Kraftstoffvorratsbehälter 4 mit Kraftstoff versorgt wird. Der Druck in dem Kraftstoffhochdruckspeicher 1 wird durch einen Drucksensor 6 erfaßt und als Signal einer elektrische Steuereinrichtung 8 zugeführt, die über ein Drucksteuerventil 5 den Druck im Kraftstoffhochdruckspeicher steuert. Alternativ kann auch die Fördermenge der Krafstoffhochdruckpumpe auf diese Weise variiert werden. Die Steuereinrichtung steuert ferner auch das Öffnen und Schließen von Kraftstoffhochdruckeinspritzventile 9, die zur Einspritzung von Kraftstoff vom Kraftstoffhochdruckspeicher versorgt werden.In the common rail injection system shown in FIG. 1 is a high-pressure fuel reservoir as a high-pressure fuel source 1 provided by a high pressure fuel pump 2 from a fuel tank 4 is supplied with fuel. The pressure in the high-pressure fuel reservoir 1 is by a pressure sensor 6 detected and as a signal from an electrical control device 8 supplied, the pressure in a pressure control valve 5 in High-pressure fuel reservoir controls. Alternatively, too the delivery rate of the high pressure fuel pump in this way can be varied. The control device also controls the opening and closing of high-pressure fuel injection valves 9, which is used to inject fuel from High-pressure fuel storage are supplied.

In einer bekannten Ausgestaltung weist das Kraftstoffinspritzventil 9 ein Ventilgehäuse 11 auf, das an seinem einen Ende, das zum Einbau in die Brennkraftmaschine bestimmt ist, Einspritzöffnungen 12 besitzt, deren Austritt aus dem Innern des Kraftstoffeinspritzventils durch ein Einspritzventilglied 14 gesteuert wird. Dieses ist im ausgeführten Beispiel als langgestreckte Ventilnadel ausgebildet, die an ihrem einen Ende eine konische Dichtfläche 15 besitzt, die mit einem innenliegenden Ventilsitz am Ventilgehäuse zusammenwirkt, von dem aus die Einspritzöffnungen 12 abführen. Die Einspritzöffnungen können dabei auch von einem Sackloch ausgehen, das sich an den Ventilsitz anschließt. Die Ventilnadel ist in einer Längsbohrung 13 an ihrem oberen, der Dichtfläche 15 abgewandten Ende geführt und wird am der Dichtfläche 15 abgewandten, aus der Längsbohrung 13 heraustretenden Ende durch eine Druckfeder 18 in Schließrichtung beaufschlagt. Zwischen der Führung in der Längsbohrung 13 und dem Ventilsitz ist die Ventilnadel 14 von einem Ringraum 19 umgeben, der in einen Druckraum 16 mündet, welcher wiederum über eine Druckleitung 17 in ständiger Verbindung mit dem Kraftstoffhochdruckspeicher 1 steht. Im Bereich dieses Druckraumes weist die Ventilnadel 14 eine Druckschulter 20 auf, über die sie vom Druck im Druckraum 16 entgegen der Kraft der Feder 18 im Sinne eines Abhebens der Dichtfläche 15 vom Ventilsitz beaufschlagt wird.In a known embodiment, the fuel injection valve has 9 a valve housing 11 on its one end that is for installation in the internal combustion engine is determined, has injection openings 12, the outlet from inside the fuel injector by a Injection valve member 14 is controlled. This is in the executed example as an elongated valve needle trained that a conical at one end Has sealing surface 15 with an inner Valve seat cooperates on the valve housing from which the Remove injection openings 12. The injection ports can also assume that there is a blind hole connects the valve seat. The valve needle is in one Longitudinal bore 13 on its upper, sealing surface 15 end facing away and is on the sealing surface 15th facing away from the longitudinal bore 13 end acted upon by a compression spring 18 in the closing direction. Between the guide in the longitudinal bore 13 and the The valve seat is the valve needle 14 from an annular space 19 surrounded, which opens into a pressure chamber 16, which in turn via a pressure line 17 in constant connection with the High-pressure fuel accumulator 1 stands. In the area of this Pressure chamber, the valve needle 14 has a pressure shoulder 20 on, over which they oppose the pressure in the pressure chamber 16 Force of the spring 18 in the sense of lifting the sealing surface 15 is acted upon by the valve seat.

Die Ventilnadel wird weiterhin durch einen Stößel 21 betätigt, dessen der Ventilnadel 14 abgewandte Stirnseite 22 in einer Stößelführungsbohrung 23 einen Steuerraum 24 begrenzt. Dieser ist über einen Zulaufkanal 26, in dem eine Zulaufdrossel 28 vorgesehen ist, ständig mit der Druckleitung 17 beziehungsweise dem Kraftstoffhochdruckspeicher 1 verbunden. Der Zulaufkanal mündet seitlich unverschließbar in den Steuerraum 24 ein. Koaxial zum Stößel 21 führt vom Steuerraum 24 ein Verbindungskanal 29 ab, der in einen Ventilraum 30 eines Steuerventils 31 mündet. In dem Verbindungskanal, der zugleich auch einen Abflußkanal darstellt, ist eine Durchmesserbeschränkung, vorzugsweise in Form einer Abflußdrossel 32 vorgesehen. Der nähere Aufbau des Steuerventils 31 ist in den Ausführungsbeispielen Figuren 2 und 3 detaillierter dargestellt. Diesen Ausführungsbeispielen ist gemeinsam, daß das Steuerventil 31 ein Steuerventilglied 34 aufweist, bestehend aus einem Ventilstößel 35, der in einer Stößelbohrung 36 geführt ist, und einem Ventilkopf 37 an dem in den Ventilraum 30 ragenden Ende des Steuerventilglieds 34. An dem dem Ventilkopf gegenüberliegenden Ende des Ventilstößels 35 ist eine Federteller 38 vorgesehen, an dem sich eine Druckfeder 39 abstüzt, die bestrebt ist, das Steuerventilglied in Schließstellung zu bringen. In entgegengesetzter Richtung wird das Steuerventilglied 34 durch einen Kolben 40 beaufschlagt, der Teil eines Piezoaktors 41 ist und bei Erregen des Piezos je nach Grad der Erregung das Steuerventilglied in verschiedene Öffnungsstellungen bringen kann. Dabei kann der Kolben direkt mit dem Piezo des Piezoaktors verbunden sein oder mittels einer hydraulischen oder mechanischen Übersetzung von diesem bewegt werden.The valve needle continues to be driven by a plunger 21 actuated, the end of the valve needle 14 facing away 22 a control chamber 24 in a tappet guide bore 23 limited. This is via an inlet channel 26 in which one Inlet throttle 28 is provided continuously with the pressure line 17 or the high-pressure fuel reservoir 1 connected. The inlet channel opens to the side and cannot be closed in the control room 24. Coaxial to the plunger 21 leads from the control room 24 from a connecting channel 29, which in a valve chamber 30 of a control valve 31 opens. By doing Connection channel, which is also a drain channel is a diameter restriction, preferably provided in the form of a discharge throttle 32. The closer one Structure of the control valve 31 is in the exemplary embodiments Figures 2 and 3 shown in more detail. this Embodiments has in common that the control valve 31 has a control valve member 34 consisting of a Valve tappet 35, which is guided in a tappet bore 36, and a valve head 37 on the valve chamber 30 projecting end of the control valve member 34. At the Valve head opposite end of the valve lifter 35 is a spring plate 38 is provided on which there is a compression spring 39 supports, which strives to the control valve member in Bring closed position. In the opposite direction the control valve member 34 is actuated by a piston 40 acted upon, which is part of a piezo actuator 41 and Exciting the piezo depending on the degree of excitement Control valve member in different open positions can bring. The piston can directly with the piezo be connected to the piezo actuator or by means of a hydraulic or mechanical translation of this be moved.

Zur genaueren Darstellung der erfindungsgemäßen Ausgestaltung des Steuerventils 31 wird dieses anhand von Figur 2 näher beschrieben. Dort ist wiederum das Ende des Stößel 21, der die Ventilnadel 14 betätigt, dargestellt. Der Stößel 21 schließt in der Stößelführungsbohrung 23 mit seiner als bewegliche Wand dienenden Stirnseite 22 den Steuerraum 24 ein. Die Verstellung des Stößels 21 wird nach oben hin, in Öffnungsrichtung des Einspritzventilgliedes 14, durch einen Anschlag 42 begrenzt, der einen außenliegenden Ringraum 43 freiläßt, in den der Zulauf 26 mündet. Axial führt im Bereich des Anschlags 42 der Verbindungskanal 29 ab, der in den Ventilraum 30 mündet. Dieser hat eine kreiszylindrische Umfangswand 45, die über einen konischen Ventilsitz 46 in einen den Ventilstößel 35 umgebenden Ringraum 48 übergeht. Von diesem führt ein Abflußkanal 49 zu einem Kraftstoffrücklauf oder einem Entlastungsraum ab.For a more precise representation of the configuration according to the invention of the control valve 31 is based on figure 2 described in more detail. There is the end of the pestle 21, which actuates the valve needle 14, shown. The Tappet 21 closes in the tappet guide bore 23 its end serving as a movable wall 22 den Control room 24 a. The adjustment of the plunger 21 is after towards the top, in the opening direction of the injection valve member 14, delimited by a stop 42, which is an external one Leaves annulus 43 into which the inlet 26th empties. Axial leads in the area of the stop 42 Connection channel 29, which opens into the valve chamber 30. This has a circular cylindrical circumferential wall 45 which a conical valve seat 46 into a valve tappet 35 surrounding annular space 48 passes. From this introduces Drain channel 49 to a fuel return or Relief area.

Der am Ende des Ventilstößels 35 angeordnete Ventilkopf 37 weist eine konische, dem Eintritt des Verbindungskanals 29 in den Ventilraum 30 abgewandte Ventilkopfdichtfläche 51 auf, die mit dem Ventilsitz 46 zusammenwirkt und so die Verbindung zwischen dem Ventilraum 30 und dem Ringraum 48 bzw. dem anschließenden Abflußkanal 49 steuert. Der Ringraum 48 wird dabei durch eine sich an die Ventilkopfdichtfläche 37 anschließende Ausnehmung am Umfang des Ventilstößels 35 in Verbindung mit der vom Ventilraum 30 abführenden Stößelbohrung 36 gebildet.The valve head 37 arranged at the end of the valve tappet 35 has a conical, the entry of the connecting channel 29 valve head sealing surface 51 facing away from valve chamber 30 on, which cooperates with the valve seat 46 and so the Connection between the valve chamber 30 and the annular chamber 48 or the subsequent drain channel 49 controls. The Annulus 48 is in this case in contact with the valve head sealing surface 37 subsequent recess on the circumference of the Valve tappet 35 in connection with that of the valve chamber 30 laxative tappet bore 36 is formed.

Die dem Verbindungskanal 29 zugewandte Seite des Ventilkopfes hat eine ebene Stirnseite 53, die bei Betätigung des Ventilstößels 35 in Anlage an eine Stirnseite 54 eines ein Zwischenventil 56 bildenden Zwischenventilglieds 57 zur Anlage kommt und bei einer weiteren Betätigung des Ventilstößels 35 das Zwischenventilglied 57 aus seiner Schließstellung bewegbar ist.The side of the valve head facing the connecting channel 29 has a flat end face 53 which, when the valve lifter is actuated 35 in contact with an end face 54 of an intermediate valve 56 forming intermediate valve member 57 comes to rest and with a further actuation of the valve tappet 35, the intermediate valve member 57 is movable from its closed position.

Das Zwischenventilglied 57 weist an seinem Außenumfang Rippen 59 auf, zwischen denen Durchflußquerschnitte gebildet werden und die mit ihren Stirnseiten in einer Führungsbohrung 60 geführt werden. Die Führungsbohrung 60 verjüngt sich zur Seite des Ventilraums 30 in über eine Dichtsitzschulter 62 zu einer koaxial zur Führungsbohrung hin den Ventilraum 30 mündenden Anschlußbohrung 63. Die Dichtsitzschulter 62 stellt somit den Ventilsitz des Zwischenventilgliedes dar.The intermediate valve member 57 has ribs 59 on its outer circumference on, between which flow cross sections are formed and which are guided with their end faces in a guide bore 60 become. The guide bore 60 tapers to the side of the Valve chamber 30 in via a sealing seat shoulder 62 to one end the valve chamber 30 coaxially to the guide bore Connection bore 63. The sealing seat shoulder 62 thus represents the Valve seat of the intermediate valve member.

Der die Rippen 59 tragende Teil des Zwischenventilglieds 57 verjüngt sich im Anschluß an die Rippen über eine kegelförmige Dichtfläche 64 zu einem zylindrischen Betätigungsteil 65, der mit Abstand zur Anschlußbohrung durch diese hindurch in den Ventilraum 30 ragt. Auf der gegenüberliegenden Seite wird das Zwischenventilglied 57 durch eine Schließfeder 68 belastet, die das Zwischenventilglied mit seiner Dichtfläche 64 in Anlage an die Dichtsitzschulter 62 bringt. Die Schließfeder 68 stützt sich dabei an dem Übergang zwischen der Führungsbohrung 60 und dem weiterführenden Teilstück 29 des Abflußkanals ab, der koaxial zur Führungsbohrung 60 in den Steuerraum 24 mündet. The part of the intermediate valve member 57 which carries the ribs 59 tapers after the ribs over a conical Sealing surface 64 to a cylindrical actuating part 65, the at a distance to the connection hole through this in the Valve chamber 30 protrudes. On the opposite side Intermediate valve member 57 loaded by a closing spring 68, the the intermediate valve member with its sealing surface 64 in contact brings the sealing seat shoulder 62. The closing spring 68 is supported thereby at the transition between the guide bore 60 and the continuing section 29 of the drain channel from the coaxial to the guide bore 60 opens into the control room 24.

Durch das Zwischenventilglied 57 führt ein axialer Verbindungskanal 69, der auch bei in Schließstellung befindlichem Zwischenventilglied 57 den Ventilraum 30 über das Teilstück 29 des Abflußkanals mit dem Steuerraum 24 verbindet. Der Verbindungskanal kann dabei als Stufenbohrung ausgeführt werden, von der der eine Stufenbohrungsteil 70, der zur Seite des Steuerraums 24 liegt und mit einem kleineren Durchmesser einen ersten Verbindungsquerschnitt bestimmt. Zur Seite des Ventilraums 30 im Bereich des Betätigungsteils 65 führt vom Verbindungskanal 69 wenigstens eine quer zu diesem verlaufende Ausnehmung 71 ab, dergestalt, daß bei Auflage der ebenen Stirnseite 53 des Ventilkopfes 37 auf der Stirnseite 54 des Zwischenventilglieds 57 die Verbindung zwischen Steuerraum 24 und Ventilraum 30 erhalten bleibt und weiterhin der Teil 70 des Verbindungskanals 69 den Verbindungsquerschnitt bestimmt.An axial connecting channel leads through the intermediate valve member 57 69, which is also in the closed position Intermediate valve member 57, the valve chamber 30 via the section 29 the drain channel connects to the control chamber 24. The connecting channel can be designed as a stepped bore from the one stepped bore part 70, the one to the control room side 24 lies and with a smaller diameter a first Connection cross section determined. To the side of the valve chamber 30 in The area of the actuating part 65 leads from the connecting channel 69 at least one recess 71 running transversely to this, such that when the flat end face 53 of the Valve head 37 on the end face 54 of the intermediate valve member 57 the connection between control chamber 24 and valve chamber 30 remains and part 70 of the connecting channel 69 determines the connection cross section.

Die Wirkungsweise der Ausgestaltung gemäß Figur 2 ist dergestalt, daß zur Auslösung einer Kraftstoffeinspritzung mit Hilfe des Steuerventils 31 der Druck im Steuerraum 24 abgesenkt wird, indem der Abflußkanal 29, 70, 69, 30, 48, 49 geöffnet wird. Durch die Drossel 28 im Zuflußkanal 26 abgekoppelt, sinkt der Druck im Steuerraum 24 derart, daß das Ventilglied unter Einwirkung der Öffnungskräfte des Druckraums 60 entgegen der Kraft der Feder 18 öffnet. Der Grad der Öffnung des Einspritzventilglieds 14 kann dabei durch die Größe der Entlastung des Steuerraums bzw. der Menge des dort abfließenden Druckmittels bzw. Kraftstoffs beeinflußt werden. Führt das Steuerventilglied 34 nur einen Teilhub aus, derart, daß die Stirnseite 53 nicht in Anlage mit dem Zwischenventilglied 57 gelangt, so wird der maximale Durchfluß durch das Teilstück 70 des Verbindungskanals 69 bestimmt. Entsprechend gering ist die Entlastungsrate und somit der Hub des Einspritzventilglieds 14. Entsprechend wird nur eine geringe Kraftstoffeinspritzmenge, beispielsweise zur Einbringung einer Voreinspritzmenge in den Brennraum gefördert. Soll jedoch eine größere Kraftstoffmenge zur Einspritzung gelangen, so öffnet das Steuerventilglied 34 ganz und kommt dabei in Anlage an das Zwischenventilglied 57, hebt dieses über das Betätigungsteil 65 von der Dichtsitzschulter 62 ab und stellt dabei zusätzlich zum ersten Verbindungsquerschnitt einen zweiten Verbindungsquerschnitt, der durch Teilstück 70 bestimmt ist, zur Verfügung. Der zweite Verbindungsquerschnitt kann dabei entweder durch den Durchtrittsquerschnitt zwischen Dichtsitzschulter 62 und Dichtfläche 64 bestimmt werden oder es kann der Verbindungsquerschnitt durch die verbleibende Durchtrittsfläche zwischen den Rippen 59 definiert sein. Durch den nun zugeschalteten zweiten Verbindungsquerschnitt erfolgt die Entlastung des Steuerraums 24 schneller und im größeren Maße, so daß das Einspritzventilglied 14 im vorgesehenen Maße voll geöffnet werden kann, z.B. mit einem durch Anlage seiner Stirnfläche 22 an dem Anschlag 42 bestimmten Hub .The mode of operation of the embodiment according to FIG. 2 is such that that to trigger a fuel injection with With the help of the control valve 31, the pressure in the control chamber 24 is reduced is opened by the drain channel 29, 70, 69, 30, 48, 49 becomes. Decoupled by the throttle 28 in the inflow channel 26, decreases the pressure in the control chamber 24 such that the valve member below Action of the opening forces of the pressure chamber 60 against the Force of the spring 18 opens. The degree of opening of the injector member 14 can by the size of the discharge of the Control room or the amount of pressure medium flowing out there or fuel are affected. Guides the control valve member 34 only a partial stroke, such that the end face 53 is not in System with the intermediate valve member 57 arrives, the maximum flow through section 70 of the connecting channel 69 determined. The relief rate is correspondingly low thus the stroke of the injection valve member 14 only a small amount of fuel injection, for example Introduction of a pre-injection quantity promoted in the combustion chamber. However, should a larger amount of fuel for injection arrive, the control valve member 34 opens completely and comes while in contact with the intermediate valve member 57, this lifts the actuating part 65 from the sealing seat shoulder 62 and provides one in addition to the first cross section second connection cross section, which is determined by section 70 is available. The second connection cross section can either through the passage cross-section between the sealing seat shoulder 62 and sealing surface 64 can be determined or it can Cross-section of connection through the remaining passage area be defined between the ribs 59. Through the now switched on second connection cross-section takes the load off the Control room 24 faster and to a greater extent, so that Injection valve member 14 fully opened to the intended extent can be e.g. with one by abutting its end face 22nd stroke 42 determined at the stop.

Die Teilentlastung des Steuerraums 24 zur Durchführung der Voreinspritzung hat dabei den Vorteil, daß beim Schließen des Steuerventilglieds 34 sich der Druck, da geringer abgesenkt, sehr schnell wieder aufbauen kann.The partial relief of the control room 24 for performing the Pre-injection has the advantage that when closing the Control valve member 34, the pressure, since less lowered, can rebuild very quickly.

Der beschriebene Funktionsablauf läßt sich anhand der Figuren 3a bis 3d nachvollziehen. Dabei zeigt die Figur 3a den Hub des Einspritzventilglieds 14 über der Zeit. Man erkennt dort den Hub des Einspritzventilglieds für die Voreinspritzung V und den Hub des Einspritzventilglieds zur Durchführung der Haupteinspritzmenge H. Diese sind durch eine Spritzpause P unterbrochen. In Figur 3b ist dazu der notwendige Hub des Steuerventilglieds 34 dargestellt mit einem kleinen Hub VS und einem großen Hub HS. In Figur 3c schließlich wird der Hub des Zwischenventilglieds Z über der Zeit aufgetragen mit der Zuordnung zum Hub HS des Steuerventilglieds 34 und des Hubs H für die Haupteinspritzung des Einspritzventilglieds 14.The functional sequence described can be understood with reference to FIGS. 3a to 3d. 3a shows the stroke of the injection valve member 14 over time. The stroke of the injection valve element for the pre-injection V and the stroke of the injection valve element for carrying out the main injection quantity H can be seen there. These are interrupted by an injection break P. In Figure 3b, the necessary stroke of the control valve member 34 is shown with a small stroke V S and a large stroke H S. Finally, in FIG. 3c, the stroke of the intermediate valve member Z is plotted over time with the assignment to the stroke H S of the control valve member 34 and the stroke H for the main injection of the injection valve member 14.

In Figur 4 ist ein zweites Ausführungsbeispiel der Erfindung gezeigt in Abwandlung zu der Ausführung gemäß Figur 2. Abweichend bei ansonsten gleicher Konstruktion hat der Ventilkopf 134 statt der ebenen Stirnseite 53 nun eine kegelförmige, als Dichtfläche ausgebildete Stirnseite 73, die mit einer als Ventilsitz 74 ausgebildeten Stirnseite des Zwischenventilglieds 157 zusammen wirkt. Der Ventilsitz 74 umgibt den bei dem Zwischenventilglied 57 von Figur 2 vorgesehenen axialen Verbindungskanal 69 im Bereich seines Austritts am Betätigungsteil 65 in den Ventilraum 30. Statt einer im Ausführungsbeispiel nach Figur 2 vorgesehenen Blattfeder 68 ist nun eine Spiralfeder 168 vorgesehen, die das Zwischenventilglied 157 von der Seite des Steuerraums 24 her belastet und dieses mit seiner Dichtfläche 64 in Anlage an der Dichtsitzschulter 62 hält, solange das Zwischenventilglied 157 nicht vom Steuerventilglied 134 abgehoben wird. Bei dieser Ausgestaltung stellt der Teil 70 des Verbindungskanals 69 wiederum den ersten Verbindungsquerschnitt zwischen Steuerraum 24 und Ventilraum 30 dar, der allerdings dann, wenn das Steuerventilglied 134 mit seinem Ventilkopf 137 in Anlage an den kegelförmigen Ventilsitz 74 kommt, verschlossen wird. Nun aber wird durch Abheben des zwischenventilglieds 157 der zweite Verbindungsquerschnitt zwischen den Rippen 59 oder zwischen der Dichtsitzschulter 62 und der Dichtfläche 64 geöffnet. Der zweite Verbindungsquerschnitt ist dabei so ausgelegt, daß er entsprechend größer ist als der erste Verbindungsquerschnitt 70 des Teils des Verbindungskanals 69 unter der Brücksichtigung, daß hier der Durchflußquerschnitt des zweiten Verbindungsquerschnitts an die Stelle des Durchtrittsquerschnitts des ersten Verbindungsquerschnitts tritt. Diese Ausgestaltung kann im Einzelfall günstiger sein, um exakter den zweiten Verbindungsquerschnitt festlegen zu können.In Figure 4 is a second embodiment of the invention shown as a modification to the embodiment according to FIG. 2. Deviating from the otherwise identical construction, the valve head has 134 instead of the flat end face 53 now a conical, formed as a sealing surface end face 73, which with a Valve seat 74 formed end face of the intermediate valve member 157 works together. The valve seat 74 surrounds the at Intermediate valve member 57 of Figure 2 provided axial connection channel 69 in the area of its outlet on the actuating part 65 in the valve chamber 30. Instead of one in the embodiment Figure 2 provided leaf spring 68 is now a coil spring 168 provided that the intermediate valve member 157 from the side of the Control chamber 24 loaded and this with its sealing surface 64th holds in contact with the sealing seat shoulder 62 as long as that The intermediate valve member 157 is not lifted from the control valve member 134 becomes. In this embodiment, the part 70 of the connecting channel 69 again the first connection cross section between control chamber 24 and valve chamber 30, however when the control valve member 134 with its valve head 137 comes into contact with the conical valve seat 74, closed becomes. But now by lifting the intermediate valve member 157 the second connection cross section between the ribs 59 or between the sealing seat shoulder 62 and the sealing surface 64 open. The second connection cross-section is like this designed that it is correspondingly larger than the first Connection cross section 70 of the part of the connection channel 69 taking into account that here the flow cross section of the second connection cross-section in the place of the passage cross-section of the first connection cross section occurs. This Design can be cheaper in individual cases, to the exact to be able to define the second connection cross-section.

In Figur 5a ist nun analog zu Figur 3a der Hub des Einspritzventilglieds 14 über der Zeit dargestellt mit ebenfalls dem Hub V für die Voreinspritzung und dem Hub H für die Haupteinspritzung. Anhand der Figur 5b erkennt man, daß im vorliegenden Falle der weitere Vorteil der Ausgestaltung nach Figur 4 darin besteht, daß das Steuerventilglied zur Unterbrechung der Kraftstoffeinspritzung zwischen Voreinspritzung V und Haupteinspritzung H nicht wieder in seine Ursprungsschließstellung zurückgefahren werden muß. Gemäß dem Kurvenzug S führt das Steuerventilglied 134 einen Hub hv aus und kommt dabei zur Anlage an dem kegelförmigen Ventilsitz 74 des Zwischenventilglieds. Über die Wegstrecke zwischen Schließstellung des Steuerventilglieds 134 an seinem konischen Ventilsitz 46 und der Anlage am kegelförmigen Ventilsitz 74 erfolgt die Entlastung des Steuerraums 24 bestimmt durch den ersten Verbindungsquerschnitt des Teils 70 des Verbindungskanals 69, was zur Voreinspritzung führt. Danach kann mit Schließen des Verbindungskanals 69 sich der Druck im Steuerraum 24 wieder aufbauen und das Einspritzventilglied schließen. Zur Haupteinspritzung wird das Steuerventilglied 134 weiterbewegt bis zum Hub hh und öffnet dabei das Zwischenventilglied gemäß der Hubkurve Z. Mit diesem Öffnen des Zwischenventils erfolgt die Entlastung des Steuerraums 24 mit einer höheren Entlastungsrate und demgemäß wird der für die Haupteinspritzung erforderliche Öffnungshub des Einspritzventilglieds ermöglicht.In FIG. 5a, the stroke of the injection valve member 14 over time is shown analogously to FIG. 3a, likewise with the stroke V for the pre-injection and the stroke H for the main injection. It can be seen from FIG. 5b that in the present case the further advantage of the embodiment according to FIG. 4 is that the control valve member does not have to be returned to its original closed position in order to interrupt the fuel injection between the pre-injection V and the main injection H. According to the curve S, the control valve member 134 executes a stroke hv and thereby comes to bear against the conical valve seat 74 of the intermediate valve member. Over the distance between the closed position of the control valve member 134 on its conical valve seat 46 and the contact with the conical valve seat 74, the relief of the control chamber 24 is determined by the first connection cross section of the part 70 of the connection channel 69, which leads to the pre-injection. Then, when the connecting channel 69 is closed, the pressure in the control chamber 24 can build up again and the injection valve member can close. For the main injection, the control valve member 134 is moved up to the stroke h h and thereby opens the intermediate valve member according to the stroke curve Z. With this opening of the intermediate valve, the relief of the control chamber 24 takes place with a higher relief rate and accordingly the opening stroke of the injection valve member required for the main injection is made possible.

Claims (11)

  1. Fuel injection device for internal combustion engines having a high-pressure fuel source (1) from which a fuel injection valve (9) is supplied with fuel, said fuel injection valve (9) having an injection valve element (14) for controlling an injection opening (12), and having a control space (24) which is bounded by a moveable wall (22) which is connected at least indirectly to the injection valve element (14) and which has an inflow duct (26) coming from a high-pressure source, preferably from the high-pressure fuel source (1), and an outflow duct (29) which leads to a relief space and whose pressure is controlled by a control valve (31) which controls the outflow through the outflow duct (29, 49) and which has a control valve element (34) which is activated by a piezoactuator (41), having a valve tappet (35) which is guided in a housing and at whose end there is a valve head (37) which projects into a valve space (30), is provided with a valve head sealing face (51) and interacts with a valve seat (46) in order to control the outflow, the valve space (30) being connected via a part (29) of the outflow duct to the control space (24) which is subjected to the pressure of the high-pressure fuel source (1) when the control valve (31) is closed, characterized in that an intermediate valve (56) with an intermediate valve element (57, 157) is arranged in the part (29) of the outflow duct, and a connecting duct (69) with a first connection cross section is provided between the valve space and control space, and in that the intermediate valve element can be pushed by the valve head (37) of the control valve element from its closed position in the direction of the control space counter to a closing force, and in the process a second connection cross section between the valve space (30) and control space (24) is opened.
  2. Fuel injection device according to Claim 1, characterized in that the second connection cross section is a connection cross section which is additional to the first connection cross section.
  3. Fuel injection device according to Claim 1, characterized in that the connecting duct (69) leads through the intermediate valve element (57, 157) and is closed off by the control valve element (34) when the intermediate valve element (57, 157) is lifted off from its valve seat (62), and in that the second connection cross section is larger than the first connection cross section (70).
  4. Fuel injection device according to Claim 2 or 3, characterized in that the intermediate valve element (57, 157) is guided at its external circumference in a guide bore (60) which starts from the control space (24), tapers over a sealing seat shoulder (62), serving as valve seat, to a subsequent connecting bore (63) which opens into the valve space (30), and the intermediate valve element (57, 157) has a sealing face (64) at a transition from its guide part, guided in the guide bore (60), to an activation part (65) which projects into the valve space (30) at a distance from the wall of the connecting bore (63), and whose sealing face can be moved into an abutting position against the sealing seat shoulder (62) by the force of a closing spring (68).
  5. Fuel injection device according to Claim 4, characterized in that the intermediate valve element (57, 157) has, for guiding purposes, longitudinal ribs (59) which slide along the wall of the guide bore (60).
  6. Fuel injection device according to Claim 5, characterized in that the second connection cross section is formed between the longitudinal ribs (59) and the wall of the guide bore (60).
  7. Fuel injection device according to Claim 5, characterized in that the second connection cross section is set between the sealing seat shoulder (62) and the sealing face (64) when the intermediate valve element (57, 157) is lifted off.
  8. Fuel injection device according to Claims 5 to 7, characterized in that the connecting duct (69) leads axially through the intermediate valve element (57, 157) and has, at the valve space end of the activation part (65), transverse connections (71) which maintain the connection between the valve space (30) and connecting duct (69) when there is a valve head (37) bearing against the end of the activation part (65).
  9. Fuel injection device according to Claims 5 to 7, characterized in that the connecting duct (69) leads axially through the intermediate valve element (57, 157) and ends at the valve space end of the activation part (65) in a valve seat (74), on which the valve head (73) abuts before the intermediate valve element (57, 157) is lifted off from the valve seat (62) by the valve head (37), and the connection between the valve space (30) and connecting duct (69) is thus closed off.
  10. Fuel injection device according to Claim 4, characterized in that the closing spring is a leaf spring (68).
  11. Fuel injection device according to Claim 4, characterized in that the closing spring is a helical spring (168).
EP99124452A 1998-12-28 1999-12-08 Fuel injection device for internal combustion engines Expired - Lifetime EP1016783B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19860397A DE19860397A1 (en) 1998-12-28 1998-12-28 Fuel injection device for internal combustion engines
DE19860397 1998-12-28

Publications (3)

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EP1016783A2 EP1016783A2 (en) 2000-07-05
EP1016783A3 EP1016783A3 (en) 2002-10-23
EP1016783B1 true EP1016783B1 (en) 2004-03-17

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EP99124452A Expired - Lifetime EP1016783B1 (en) 1998-12-28 1999-12-08 Fuel injection device for internal combustion engines

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US (1) US6168096B1 (en)
EP (1) EP1016783B1 (en)
JP (1) JP2000192870A (en)
DE (2) DE19860397A1 (en)

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Publication number Publication date
JP2000192870A (en) 2000-07-11
EP1016783A2 (en) 2000-07-05
EP1016783A3 (en) 2002-10-23
DE59908876D1 (en) 2004-04-22
DE19860397A1 (en) 2000-06-29
US6168096B1 (en) 2001-01-02

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