EP1397593B1 - Fuel injection device with a pressure booster - Google Patents

Fuel injection device with a pressure booster Download PDF

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Publication number
EP1397593B1
EP1397593B1 EP02742762A EP02742762A EP1397593B1 EP 1397593 B1 EP1397593 B1 EP 1397593B1 EP 02742762 A EP02742762 A EP 02742762A EP 02742762 A EP02742762 A EP 02742762A EP 1397593 B1 EP1397593 B1 EP 1397593B1
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EP
European Patent Office
Prior art keywords
pressure
piston
fuel
injection device
chamber
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Expired - Lifetime
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EP02742762A
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German (de)
French (fr)
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EP1397593A1 (en
Inventor
Wolfgang Braun
Bernd Mahr
Martin Kropp
Hans-Christoph Magel
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Robert Bosch GmbH
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Robert Bosch GmbH
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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
    • F02M57/00—Fuel-injectors combined or associated with other devices
    • F02M57/02—Injectors structurally combined with fuel-injection pumps
    • F02M57/022—Injectors structurally combined with fuel-injection pumps characterised by the pump drive
    • F02M57/025—Injectors structurally combined with fuel-injection pumps characterised by the pump drive hydraulic, e.g. with pressure amplification
    • F02M57/026—Construction details of pressure amplifiers, e.g. fuel passages or check valves arranged in the intensifier piston or head, particular diameter relationships, stop members, arrangement of ports or conduits
    • 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
    • F02M55/00—Fuel-injection apparatus characterised by their fuel conduits or their venting means; Arrangements of conduits between fuel tank and pump F02M37/00
    • F02M55/002—Arrangement of leakage or drain conduits in or from injectors
    • 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
    • F02M57/00—Fuel-injectors combined or associated with other devices
    • F02M57/02—Injectors structurally combined with fuel-injection pumps
    • F02M57/022—Injectors structurally combined with fuel-injection pumps characterised by the pump drive
    • F02M57/025—Injectors structurally combined with fuel-injection pumps characterised by the pump drive hydraulic, e.g. with pressure amplification
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M59/00—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps
    • F02M59/02—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps of reciprocating-piston or reciprocating-cylinder type
    • F02M59/10—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps of reciprocating-piston or reciprocating-cylinder type characterised by the piston-drive
    • F02M59/105—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps of reciprocating-piston or reciprocating-cylinder type characterised by the piston-drive hydraulic drive
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M59/00—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps
    • F02M59/20—Varying fuel delivery in quantity or timing
    • F02M59/34—Varying fuel delivery in quantity or timing by throttling of passages to pumping elements or of overflow passages, e.g. throttling by means of a pressure-controlled sliding valve having liquid stop or abutment

Definitions

  • the invention relates to a fuel injection device according to the preamble of claim 1.
  • the fuel injection device according to the invention may be formed both stroke-controlled and pressure-controlled.
  • a stroke-controlled fuel injection device is understood to mean that the opening and closing of the injection opening takes place by means of a displaceable nozzle needle due to the hydraulic interaction of the fuel pressures in a nozzle chamber and in a control chamber. A pressure reduction within the control chamber causes a stroke of the nozzle needle. Alternatively, the deflection of the nozzle needle by an actuator (actuator, actuator) take place.
  • a pressure-controlled fuel injection device In a pressure-controlled fuel injection device according to the invention, the nozzle needle is moved by the pressure prevailing in the nozzle chamber of an injector fuel pressure against the action of a closing force (spring), so that the injection port for injection of the fuel from the nozzle chamber is released into the cylinder.
  • injection pressure The pressure with which fuel exits the nozzle chamber into a cylinder of an internal combustion engine
  • system pressure is understood to mean the pressure below which fuel is available or stored in the fuel injector.
  • a fuel injection device with a pressure booster wherein the stroke of a piston of the pressure booster can be controlled substantially by the pressure in a differential space of the pressure booster.
  • means for cross-section control of a flow cross-section from the differential space are provided, which are formed by controllable valve devices.
  • a leakage line is opened and closed in a controlled manner by means of the valve device.
  • a fuel injection device with the features of claim 1 is proposed. If, for example, two outlet cross-sections (one larger and one smaller) are released successively from the differential space of the pressure intensifier as a function of the piston stroke of the pressure intensifier, a so-called boat injection can be carried out.
  • the first embodiment of a stroke-controlled fuel injection device 1 promotes a fuel quantity controlled fuel from a storage tank via a delivery line in a central pressure storage space (common rail), of which several, the number of individual cylinders corresponding pressure lines 2 to the individual, in the combustion chamber of the engine to be supplied protruding injectors 3 (injector) dissipate.
  • a first system pressure is generated and stored in the pressure storage space. This first system pressure is used for pre-injection and, if necessary, for post-injection (HC enrichment for exhaust gas aftertreatment or soot reduction) and for displaying an injection profile with plateau (boat injection).
  • each injector 3 is assigned a respective local pressure booster 4 with a check valve 5 and with a displaceable piston 6 .
  • Such fuel injectors are for example from the DE-A1-19910970 known.
  • the pressure is used in the formed by a transition from a larger to a smaller piston cross-section space 7 .
  • the differential space 7 is acted upon by a supply pressure (rail pressure). Then prevail at all pressure surfaces of a piston 6, the same pressure conditions (rail pressure).
  • the piston 6 is pressure balanced.
  • the piston 6 is pressed into its starting position.
  • the differential space 7 is relieved of pressure and the pressure booster 4 generates a pressure boost according to the area ratio.
  • a throttle 11 and a simple 2/2-way valve 12 can be used instead of a complex 3/2-way valve.
  • the throttle 11 connects the differential space 7 with standing under supply pressure fuel from an accumulator chamber.
  • the 2/2-way valve 12 connects the differential space 7 to a leakage line 13.
  • the throttle 11 should be designed as small as possible, but still so large that the piston 6 returns to its original position between the injection cycles. As a throttle and a pilot leakage of the piston 6 can be used.
  • the throttle can also be integrated in the piston.
  • the injector 3 is under the pressure of the pressure storage chamber.
  • the pressure booster 4 is in the starting position. Now can be done by the valve 14 an injection with rail pressure. If an injection with a higher pressure is desired, then the 2/2-way valve 12 is activated (opened) and thus reaches a pressure boost.
  • the injection takes place via a fuel metering with the aid of a guide needle axially displaceable nozzle needle 15 with a conical valve sealing surface at one end, with which it has a valve seat surface on the injector of the injector. 3 interacts.
  • a pressure surface pointing in the opening direction of the nozzle needle 15 is exposed to the pressure prevailing there, which pressure is supplied to the nozzle chamber 16 via a pressure line.
  • Coaxial with a valve spring 17 also engages on the nozzle needle 15 to a pressure piece 18, which limits the control chamber 19 with its end facing away from the valve sealing face.
  • the control room 19 has from Fuel pressure port forth an inlet with a first throttle and a flow to a pressure relief line 20 with a second throttle, which is controlled by the 2/2-way valve 14.
  • the end of the injection is initiated by renewed actuation (closing) of the 2/2-way valve 14, which decouples the control chamber 19 again from the leakage line 20, so that pressure builds up again in the control chamber 19, the pressure piece 18 in the closing direction can move.
  • a continuous cross-sectional enlargement can also be achieved be formed ( Figures 2 and 3 ). It can be achieved a uniform, flat pressure increase without disturbing pressure oscillations. 2, only a partial area 25 of a slot-shaped opening 26 is released up to a control edge by the direction of movement 23 of a piston 24 (longitudinal direction of the opening and the piston) depending on the position of the piston 24 and a partial surface 27 of the opening 26 covered.
  • the opening 26 in the wall surface of the differential space establishes the connection of the differential space 7 (see FIG. 1) to the leakage line (see FIG. 1) and can be closed by the piston. With increasing piston stroke, a larger discharge cross section is released. According to FIG.
  • a slot-shaped opening 28 in the wall surface of a pressure booster chamber has a variable cross-sectional area in the direction of movement 29 of the piston 30 .
  • the piston 30 itself has a recess 31 , which produces the continuous connection of the differential space 7 (see FIG. 1) to the leakage line.
  • the recess 31 forms a kind of control window, which slides along the slot 28.
  • the flow cross-section can be varied as desired via the stroke profile of the piston.
  • the slot-shaped opening 28 may also be formed in the piston and the control edge or a recess 31 in the wall surface.

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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 betrifft eine Kraftstoffeinspritzeinrichtung gemäß dem Oberbegriff des Anspruchs 1.The invention relates to a fuel injection device according to the preamble of claim 1.

Zum besseren Verständnis der Beschreibung und der Patentansprüche werden nachfolgend einige Begriffe erläutert: Die Kraftstoffeinspritzeinrichtung gemäß der Erfindung kann sowohl hubgesteuert als auch druckgesteuert ausgebildet sein. Im Rahmen der Erfindung wird unter einer hubgesteuerten Kraftstoffeinspritzeinrichtung verstanden, dass das Öffnen und Schließen der Einspritzöffnung mit Hilfe einer verschiebbaren Düsennadel aufgrund des hydraulischen Zusammenwirkens der Kraftstoffdrücke in einem Düsenraum und in einem Steuerraum erfolgt. Eine Druckabsenkung innerhalb des Steuerraums bewirkt einen Hub der Düsennadel. Alternativ kann das Auslenken der Düsennadel durch ein Stellglied (Aktor, Aktuator) erfolgen. Bei einer druckgesteuerten Kraftstoffeinspritzeinrichtung gemäß der Erfindung wird die Düsennadel durch den im Düsenraum eines Injektors herrschenden Kraftstoffdruck gegen die Wirkung einer Schließkraft (Feder) bewegt, so dass die Einspritzöffnung für eine Einspritzung des Kraftstoffs aus dem Düsenraum in den Zylinder freigegeben wird. Der Druck, mit dem Kraftstoff aus dem Düsenraum in einen Zylinder einer Brennkraftmaschine austritt, wird als Einspritzdruck bezeichnet, während unter einem Systemdruck der Druck verstanden wird, unter dem Kraftstoff innerhalb der Kraftstoffeinspritzeinrichtung zur Verfügung steht bzw. bevorratet ist. Kraftstoffzumessung bedeutet, eine definierte Kraftstoffmenge zur Einspritzung bereitzustellen. Unter Leckage ist eine Menge an Kraftstoff zu verstehen, die beim Betrieb der Kraftstoffeinspritzeinrichtung entsteht (z.B. eine Führungsleckage), nicht zur Einspritzung verwendet und zum Kraftstofftank zurückgefördert wird. Das Druckniveau dieser Leckage kann einen Standdruck aufweisen, wobei der Kraftstoff anschließend auf das Druckniveau des Kraftstofftanks entspannt wird.For a better understanding of the description and the claims, some terms are explained below: The fuel injection device according to the invention may be formed both stroke-controlled and pressure-controlled. In the context of the invention, a stroke-controlled fuel injection device is understood to mean that the opening and closing of the injection opening takes place by means of a displaceable nozzle needle due to the hydraulic interaction of the fuel pressures in a nozzle chamber and in a control chamber. A pressure reduction within the control chamber causes a stroke of the nozzle needle. Alternatively, the deflection of the nozzle needle by an actuator (actuator, actuator) take place. In a pressure-controlled fuel injection device according to the invention, the nozzle needle is moved by the pressure prevailing in the nozzle chamber of an injector fuel pressure against the action of a closing force (spring), so that the injection port for injection of the fuel from the nozzle chamber is released into the cylinder. The pressure with which fuel exits the nozzle chamber into a cylinder of an internal combustion engine is referred to as injection pressure , while a system pressure is understood to mean the pressure below which fuel is available or stored in the fuel injector. Fuel metering means to provide a defined amount of fuel for injection. Leakage is understood to mean an amount of fuel that arises during operation of the fuel injection device (eg a pilot leakage ), is not used for injection and is conveyed back to the fuel tank. The pressure level of this leakage may have a steady state pressure, with the fuel subsequently being expanded to the pressure level of the fuel tank.

Viele Motorenhersteller fordern eine flache Druckanstiegsflanke zu Beginn der Einspritzung. Oftmals wird auch eine Bootphase zur Reduktion von Emissionen gewünscht. Bei Kraftstoffeinspritzeinrichtungen mit. Druckverstärker, wie sie beispielsweise aus der DE-A1-19910970 bekannt sind, kann der Druckverstärker zur Formung des Einspritzverlaufs verwendet werden. So lässt sich der gewünschte Einspritzverlauf ohne zusätzliche Teile, wie z.B. Ausweichkolben realisieren. Zur Beeinflussung des Druckverlaufs kann dabei die Bewegung des Kolbens des Druckverstärkers genutzt werden. Die hubabhängige Beeinflussung des Zulaufquerschnitts zum niederdruckseitigen Druckverstärkerraum ist aus der US-PS 5,568,317 bekannt. Durch die US-PS wird eine mehrstufige Steuerung des Zulaufquerschnitts vorgeschlagen.Many engine manufacturers demand a flat pressure rise edge at the beginning of the injection. Often, a boot phase to reduce emissions is desired. In fuel injectors with. Pressure booster, as for example from the DE-A1-19910970 are known, the pressure booster can be used to form the injection curve. Thus, the desired injection curve can be realized without additional parts, such as evasive piston. To influence the pressure curve while the movement of the piston of the booster can be used. The stroke-dependent influencing of the inlet cross section to the low pressure side pressure booster chamber is from U.S. Patent 5,568,317 known. By the US-PS a multi-stage control of the inlet cross section is proposed.

Aus den Druckschriften EP 0 879 954 A2 und WO 01/52916 A2 ist jeweils eine Kraftstoffeinspritzeinrichtung mit einem Druckverstärker bekannt, wobei der Hub eines Kolbens des Druckverstärkers im Wesentlichen durch den Druck in einem Differenzraum des Druckverstärkers steuerbar ist. Dabei sind Mittel zur Querschnittssteuerung eines Ablaufquerschnitts aus dem Differenzraum vorgesehen, die durch ansteuerbare Ventileinrichtungen gebildet werden. Zur Querschnittssteuerung wird eine Leckageleitung mittels der Ventileinrichtung kontrolliert geöffnet und geschlossen.From the pamphlets EP 0 879 954 A2 and WO 01/52916 A2 In each case, a fuel injection device with a pressure booster is known, wherein the stroke of a piston of the pressure booster can be controlled substantially by the pressure in a differential space of the pressure booster. In this case, means for cross-section control of a flow cross-section from the differential space are provided, which are formed by controllable valve devices. For cross-sectional control, a leakage line is opened and closed in a controlled manner by means of the valve device.

Vorteile der ErfindungAdvantages of the invention

Zur Beeinflussung des Kraftstoffdrucks während der Einspritzung und zur Erzielung eines Druckanstiegs mit einfachen Mitteln wird eine Kraftstoffeinspritzeinrichtung mit den Merkmalen von Anspruch 1 vorgeschlagen. Werden zum Beispiel zwei Ablaufquerschnitte (ein größerer und ein kleinerer) aus dem Differenzraum des Druckverstärkers in Abhängigkeit vom Kolbenhub des Druckverstärkers nacheinander freigegeben, so lässt sich eine sog. Bootinjektion durchführen.To influence the fuel pressure during the injection and to achieve a pressure increase by simple means, a fuel injection device with the features of claim 1 is proposed. If, for example, two outlet cross-sections (one larger and one smaller) are released successively from the differential space of the pressure intensifier as a function of the piston stroke of the pressure intensifier, a so-called boat injection can be carried out.

Zeichnungdrawing

Drei Ausführungsbeispiele der erfindungsgemäßen Kraftstoffeinspritzeinrichtung sind in der schematischen Zeichnung dargestellt und werden in der nachfolgenden Beschreibung erläutert. Es zeigen:

Fig. 1
eine hubgesteuerte Kraftstoffeinspritzeinrichtung mit einem Druckverstärker mit einem zweistufigen Ablaufquerschnitt;
Fig. 2
eine erste stufenlose Änderung des Ablaufquerschnitts;
Fig. 3
eine zweite stufenlose Änderung des Ablaufquerschnitts.
Three embodiments of the fuel injection device according to the invention are illustrated in the schematic drawing and are explained in the following description. Show it:
Fig. 1
a stroke-controlled fuel injection device with a pressure booster with a two-stage flow cross-section;
Fig. 2
a first stepless change of the flow cross section;
Fig. 3
a second continuous change of the flow cross-section.

Beschreibung der AusführungsbeispieleDescription of the embodiments

Bei dem in der Fig. 1 dargestellten ersten Ausführungsbeispiel einer hubgesteuerten Kraftstoffeinspritzeinrichtung 1 fördert eine mengengeregelte Kraftstoffpumpe Kraftstoff aus einem Vorratstank über eine Förderleitung in einen zentralen Druckspeicherraum (Common-Rail), von dem mehrere, der Anzahl einzelner Zylinder entsprechende Druckleitungen 2 zu den einzelnen, in den Brennraum der zu versorgenden Brennkraftmaschine ragenden Injektoren 3 (Einspritzvorrichtung) abführen. In der Fig. 1 ist lediglich einer der Injektoren 3 eingezeichnet. Mit Hilfe der Kraftstoffpumpe wird ein erster Systemdruck erzeugt und im Druckspeicherraum gelagert. Dieser erste Systemdruck wird zur Voreinspritzung und bei Bedarf zur Nacheinspritzung (HC-Anreicherung zur Abgasnachbehandlung oder Rußreduktion) sowie zur Darstellung eines Einspritzverlaufs mit Plateau (Bootinjektion) verwendet. Zur Einspritzung von Kraftstoff mit einem zweiten höheren Systemdruck ist jedem Injektor 3 jeweils ein lokaler Druckverstärker 4 mit einem Rückschlagventil 5 und mit einem verschieblichen Kolben 6 zugeordnet. Derartige Kraftstoffeinspritzeinrichtungen sind beispielsweise aus der DE-A1-19910970 bekannt.In the illustrated in Fig. 1 the first embodiment of a stroke-controlled fuel injection device 1 promotes a fuel quantity controlled fuel from a storage tank via a delivery line in a central pressure storage space (common rail), of which several, the number of individual cylinders corresponding pressure lines 2 to the individual, in the combustion chamber of the engine to be supplied protruding injectors 3 (injector) dissipate. In Fig. 1, only one of the injectors 3 is located . With the aid of the fuel pump, a first system pressure is generated and stored in the pressure storage space. This first system pressure is used for pre-injection and, if necessary, for post-injection (HC enrichment for exhaust gas aftertreatment or soot reduction) and for displaying an injection profile with plateau (boat injection). For injecting fuel with a second higher system pressure, each injector 3 is assigned a respective local pressure booster 4 with a check valve 5 and with a displaceable piston 6 . Such fuel injectors are for example from the DE-A1-19910970 known.

Zur Steuerung des Druckverstärkers 4 wird der Druck im durch einen Übergang von einem größeren zu einem kleineren Kolbenquerschnitt ausgebildeten Differenzraum 7 verwendet. Zur Wiederbefüllung und Deaktivierung des Druckverstärkers wird der Differenzraum 7 mit einem Versorgungsdruck (Raildruck) beaufschlagt. Dann herrschen an allen Druckflächen eines Kolbens 6 die gleichen Druckverhältnisse (Raildruck). Der Kolben 6 ist druckausgeglichen. Durch eine zusätzliche Feder 8 wird der Kolben 6 in seine Ausgangsstellung gedrückt. Zur Aktivierung des Druckverstärkers 4 wird der Differenzraum 7 druckentlastet und der Druckverstärker 4 erzeugt eine Druckverstärkung gemäß dem Flächenverhältnis. Durch diese Art der Steuerung kann erreicht werden, dass zur Rückstellung des Druckverstärkers 4 und zum Wiederbefüllen einer Druckkammer 9 ein niederdruckseitiger Druckverstärkerraum 10 nicht druckentlastet werden muss. Bei einer kleinen hydraulischen Übersetzung können damit die Entspannungsverluste stark reduziert werden.To control the pressure booster 4 , the pressure is used in the formed by a transition from a larger to a smaller piston cross-section space 7 . For refilling and deactivating the pressure booster, the differential space 7 is acted upon by a supply pressure (rail pressure). Then prevail at all pressure surfaces of a piston 6, the same pressure conditions (rail pressure). The piston 6 is pressure balanced. By an additional spring 8 , the piston 6 is pressed into its starting position. To activate the pressure booster 4, the differential space 7 is relieved of pressure and the pressure booster 4 generates a pressure boost according to the area ratio. Through this type of control can be achieved that to reset the pressure booster 4 and to refill a pressure chamber 9, a low-pressure side pressure booster chamber 10 need not be depressurized. With a small hydraulic ratio, the relaxation losses can be greatly reduced.

Zur Steuerung des Druckverstärkers 4 kann anstelle eines aufwendigen 3/2-WegeVentils eine Drossel 11 und ein einfaches 2/2-Wege-Ventil 12 verwendet werden. Die Drossel 11 verbindet den Differenzraum 7 mit unter Versorgungsdruck stehendem Kraftstoff aus einem Druckspeicherraum. Das 2/2-Wege-Ventil 12 schließt den Differenzraum 7 an eine Leckageleitung 13 an. Die Drossel 11 sollte möglichst klein ausgelegt Werden, aber dennoch so groß, dass der Kolben 6 zwischen den Einspritzzyklen in seine Ausgangslage zurückkehrt. Als Drossel kann auch eine Führungsleckage des Kolbens 6 verwendet werden. Bei geschlossenem 2/2-Wege-Ventil 12 entsteht keine Leckage in den Führungen des Kolbens 6, da der Differenzraum 7 druckbeaufschlagt ist. Die Drossel kann auch im Kolben integriert sein.To control the pressure booster 4, a throttle 11 and a simple 2/2-way valve 12 can be used instead of a complex 3/2-way valve. The throttle 11 connects the differential space 7 with standing under supply pressure fuel from an accumulator chamber. The 2/2-way valve 12 connects the differential space 7 to a leakage line 13. The throttle 11 should be designed as small as possible, but still so large that the piston 6 returns to its original position between the injection cycles. As a throttle and a pilot leakage of the piston 6 can be used. When the 2/2-way valve 12 is closed, there is no leakage in the guides of the piston 6, since the differential space 7 is pressurized. The throttle can also be integrated in the piston.

Sind die 2/2-Wege-Ventile 12 und 14 geschlossen, so steht der Injektor 3 unter dem Druck des Druckspeicherraums. Der Druckverstärker 4 befindet sich in der Ausgangsstellung. Nun kann durch das Ventil 14 eine Einspritzung mit Raildruck erfolgen. Wird eine Einspritzung mit höherem Druck gewünscht, so wird das 2/2-Wege-Ventil 12 angesteuert (geöffnet) und damit eine Druckverstärkung erreicht.If the 2/2-way valves 12 and 14 are closed, the injector 3 is under the pressure of the pressure storage chamber. The pressure booster 4 is in the starting position. Now can be done by the valve 14 an injection with rail pressure. If an injection with a higher pressure is desired, then the 2/2-way valve 12 is activated (opened) and thus reaches a pressure boost.

Die Einspritzung erfolgt über eine Kraftstoff-Zumessung mit Hilfe einer in einer Führungsbohrung axial verschiebbaren Düsennadel 15 mit einer konischen Ventildichtfläche an seinem einen Ende, mit der es mit einer Ventilsitzfläche am Injektorgehäuse des Injektors . 3 zusammenwirkt. An der Ventilsitzfläche des Injektorgehäuses sind Einspritzöffnungen vorgesehen. Innerhalb eines Düsenraums 16 ist eine in Öffnungsrichtung der Düsennadel 15 weisende Druckfläche dem dort herrschenden Druck ausgesetzt, der über eine Druckleitung dem Düsenraum 16 zugeführt wird. Koaxial zu einer Ventilfeder 17 greift ferner an der Düsennadel 15 ein Druckstück 18 an, das mit seiner der Ventildichtfläche abgewandten Stirnseite den Steuerraum 19 begrenzt. Der Steuerraum 19 hat vom Kraftstoffdruckanschluß her einen Zulauf mit einer ersten Drossel und einen Ablauf zu einer Druckentlastungsleitung 20 mit einer zweiten Drossel, die durch das 2/2-Wege-Ventil 14 gesteuert wird.The injection takes place via a fuel metering with the aid of a guide needle axially displaceable nozzle needle 15 with a conical valve sealing surface at one end, with which it has a valve seat surface on the injector of the injector. 3 interacts. On the valve seat surface of the injector housing injection openings are provided. Within a nozzle chamber 16, a pressure surface pointing in the opening direction of the nozzle needle 15 is exposed to the pressure prevailing there, which pressure is supplied to the nozzle chamber 16 via a pressure line. Coaxial with a valve spring 17 also engages on the nozzle needle 15 to a pressure piece 18, which limits the control chamber 19 with its end facing away from the valve sealing face. The control room 19 has from Fuel pressure port forth an inlet with a first throttle and a flow to a pressure relief line 20 with a second throttle, which is controlled by the 2/2-way valve 14.

Unter dem ersten oder zweiten Systemdruck stehender Kraftstoff. füllt ständig den Düsenraum 16 und den Steuerraum 19. Bei Betätigung (Öffnen) des 2/2-WegeVentils 14 kann der Druck im Steuerraum 19 abgebaut werden, so dass in der Folge die in Öffnungsrichtung auf die Düsennadel 15 wirkende Druckkraft im Düsenraum 16 den in Schließrichtung auf die Düsennadel 15 wirkende Druckkraft übersteigt. Die Ventildichtfläche hebt von der Ventilsitzfläche ab und Kraftstoff wird eingespritzt. Dabei lässt sich der Druckentlastungsvorgang des Steuerraums 19 und somit die Hubsteuerung der Düsennadel 1 5 über die Dimensionierung der Drosseln beeinflussen.Under the first or second system pressure standing fuel. When operating (opening) of the 2/2-way valve 14, the pressure in the control chamber 19 can be reduced, so that in the sequence acting in the opening direction of the nozzle needle 15 compressive force in the nozzle chamber 16 in Closing direction on the nozzle needle 15 acting pressure force exceeds. The valve sealing surface lifts off the valve seat surface and fuel is injected. In this case, the pressure relief process of the control chamber 19 and thus the stroke control of the nozzle needle 1 5 can influence the dimensioning of the throttles.

Das Ende der Einspritzung wird durch erneutes Betätigen (Schließen) des 2/2-Wege-Ventils 14 eingeleitet, das den Steuerraum 19 wieder von der Leckageleitung 20 abkoppelt, so dass sich im Steuerraum 19 wieder ein Druck aufbaut, der das Druckstück 18 in Schließrichtung bewegen kann.The end of the injection is initiated by renewed actuation (closing) of the 2/2-way valve 14, which decouples the control chamber 19 again from the leakage line 20, so that pressure builds up again in the control chamber 19, the pressure piece 18 in the closing direction can move.

Zur Verbesserung des Druckanstiegs wird der Ablaufquerschnitt des Differenzraums 7 mehrstufig ausgeführt. In der Ausgangsstellung des Kolbens 6 ist nur der Ablaufpfad 21 geöffnet. Dadurch erfolgt beim Öffnen des Ventils 12 ein langsamer Druckabfall innerhalb des Differenzraums 7, eine gedämpfte Bewegung des Kolbens 6 und ein langsamer Druckanstieg in der Druckkammer 9 auf ein mittleres Duckniveau. Nach einem Hub h wird zusätzlich ein zweiter, größerer Ablaufpfad 22 vom Kolben 6 freigegeben. Es erfolgt ein verstärkter Druckabfall innerhalb des Differenzraums 7 und eine ungedämpfte Bewegung des Kolbens 6 mit einem resultierenden maximalen Druckniveau in der Druckkammer 9. Nach dem Schließen des Ventils 12 wird der Kolben 6 in seine Ausgangsstellung zurück bewegt. Der Druckverstärker 4 ist deaktiviert.To improve the pressure rise of the flow cross-section of the differential space 7 is performed in multiple stages. In the initial position of the piston 6, only the discharge path 21 is opened. As a result, when opening the valve 12, a slow pressure drop within the differential space 7, a damped movement of the piston 6 and a slow increase in pressure in the pressure chamber 9 to a middle duck level. After a stroke h, a second, larger drainage path 22 is additionally released by the piston 6. There is an increased pressure drop within the differential space 7 and an undamped movement of the piston 6 with a resulting maximum pressure level in the pressure chamber 9. After closing the valve 12, the piston 6 is moved back to its original position. The pressure booster 4 is deactivated.

An Stelle der abgestuften Querschnittsvergrößerung des Ablaufs aus dem Differenzraum 7 kann auch eine kontinuierliche Querschnittsvergrößerung ausgebildet sein (Fign. 2 und 3). Es kann ein gleichmäßiger flacher Druckanstieg ohne störende Druckschwingungen erreicht werden. Gemäß Fig. 2 wird durch die Bewegungsrichtung 23 eines Kolbens 24 (Längsrichtung der Öffnung und des Kolbens) je nach Stellung des Kolbens 24 lediglich eine Teilfläche 25 einer schlitzförmigen Öffnung 26 bis zu einer Steuerkante freigegeben und eine Teilfläche 27 der Öffnung 26 abgedeckt. Die Öffnung 26 in der Wandfläche des Differenzraums stellt die Verbindung des Differenzraums 7 (siehe Fig. 1) zur Leckageleitung her (siehe Fig. 1) und ist durch den Kolben verschließbar. Mit zunehmendem Kolbenhub wird ein größerer Ablaufquerschnitt freigegeben. Gemäß Fig. 3 weist eine schlitzförmige Öffnung 28 in der' Wandfläche eines Druckverstärkerraums eine in Bewegungsrichtung 29 des Kolbens 30 variable Querschnittsfläche auf. Der Kolben 30 besitzt selbst eine Ausnehmung 31, welche die durchgängige Verbindung des Differenzraums 7 (siehe Fig. 1) zur Leckageleitung herstellt. Die Ausnehmung 31 bildet eine Art Steuerfenster, das an dem Schlitz 28 entlang gleitet. Der Ablaufquerschnitt kann über den Hubverlauf des Kolbens beliebig variiert werden. Alternativ kann die schlitzförmige Öffnung 28 auch im Kolben und die Steuerkante bzw. eine Ausnehmung 31 in der Wandfläche ausgebildet sein.Instead of the stepped cross-sectional enlargement of the outlet from the differential space 7, a continuous cross-sectional enlargement can also be achieved be formed ( Figures 2 and 3 ). It can be achieved a uniform, flat pressure increase without disturbing pressure oscillations. 2, only a partial area 25 of a slot-shaped opening 26 is released up to a control edge by the direction of movement 23 of a piston 24 (longitudinal direction of the opening and the piston) depending on the position of the piston 24 and a partial surface 27 of the opening 26 covered. The opening 26 in the wall surface of the differential space establishes the connection of the differential space 7 (see FIG. 1) to the leakage line (see FIG. 1) and can be closed by the piston. With increasing piston stroke, a larger discharge cross section is released. According to FIG. 3 , a slot-shaped opening 28 in the wall surface of a pressure booster chamber has a variable cross-sectional area in the direction of movement 29 of the piston 30 . The piston 30 itself has a recess 31 , which produces the continuous connection of the differential space 7 (see FIG. 1) to the leakage line. The recess 31 forms a kind of control window, which slides along the slot 28. The flow cross-section can be varied as desired via the stroke profile of the piston. Alternatively, the slot-shaped opening 28 may also be formed in the piston and the control edge or a recess 31 in the wall surface.

Claims (4)

  1. Fuel injection device (1) having a pressure amplifier (4) which has a displaceable piston (6; 24; 30), which can be pressurized via a pressure-amplifying chamber (10) on the low-pressure side, for compressing the fuel, which is to be supplied to an injector (3), in a pressure-amplifying chamber (9) on the highpressure side, the stroke of the piston (6; 24; 30) being controllable essentially by the pressure in a differential chamber (7) of the pressure amplifier (4) and being used for influencing the pressure of the fuel supplied to the injector (3), means (24, 25; 28, 31) for cross-sectional control of the discharge cross section from the differential chamber (7) of the pressure amplifier (4) being provided, characterized in that the means are formed by at least one slot-shaped opening (26; 28) between the differential chamber (7) of the pressure amplifier (4) and a leakage line (21) and the piston (24; 30) which closes or releases the opening (26; 28).
  2. Fuel injection device according to Claim 1, characterized in that a first cross section (first stage) which is dependent on the piston stroke (h) and a second cross section (second stage) of the discharge are provided.
  3. Fuel injection device according to Claim 1, characterized in that the piston (24) has a control edge with the opening (26) being released up to it.
  4. Fuel injection device according to Claim 1, characterized in that the piston (30) has a recess (31) which can be arranged over the opening (28) and defines a released region of the opening (28).
EP02742762A 2001-06-01 2002-05-17 Fuel injection device with a pressure booster Expired - Lifetime EP1397593B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE10126686 2001-06-01
DE10126686A DE10126686A1 (en) 2001-06-01 2001-06-01 Fuel injection system, for an IC motor, has a pressure amplifier with a sliding piston and controlled outflow cross section stages to set the fuel pressure according to the piston stroke and give a boot injection action
PCT/DE2002/001792 WO2002099270A1 (en) 2001-06-01 2002-05-17 Fuel injection device with a pressure booster

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EP1397593A1 EP1397593A1 (en) 2004-03-17
EP1397593B1 true EP1397593B1 (en) 2007-08-15

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US (1) US6938610B2 (en)
EP (1) EP1397593B1 (en)
JP (1) JP4126011B2 (en)
DE (2) DE10126686A1 (en)
WO (1) WO2002099270A1 (en)

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DE10251932B4 (en) * 2002-11-08 2007-07-12 Robert Bosch Gmbh Fuel injection device with integrated pressure booster
JP4196869B2 (en) * 2004-03-31 2008-12-17 三菱ふそうトラック・バス株式会社 Fuel injection device
JP4075894B2 (en) * 2004-09-24 2008-04-16 トヨタ自動車株式会社 Fuel injection device
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DE102007002761A1 (en) * 2007-01-18 2008-07-24 Robert Bosch Gmbh Fuel injector with integrated pressure booster
DE102010039051A1 (en) 2010-08-09 2012-02-09 Robert Bosch Gmbh Injector

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US6938610B2 (en) 2005-09-06
WO2002099270A1 (en) 2002-12-12
DE50210713D1 (en) 2007-09-27
JP2004521242A (en) 2004-07-15
JP4126011B2 (en) 2008-07-30
US20040089269A1 (en) 2004-05-13
EP1397593A1 (en) 2004-03-17
DE10126686A1 (en) 2002-12-19

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