EP2402588B1 - Fuel injection system - Google Patents

Fuel injection system Download PDF

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Publication number
EP2402588B1
EP2402588B1 EP11179810.4A EP11179810A EP2402588B1 EP 2402588 B1 EP2402588 B1 EP 2402588B1 EP 11179810 A EP11179810 A EP 11179810A EP 2402588 B1 EP2402588 B1 EP 2402588B1
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EP
European Patent Office
Prior art keywords
pressure
fuel
injection system
compression
boosting device
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EP11179810.4A
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German (de)
French (fr)
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EP2402588A1 (en
Inventor
Joachim Boltz
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Robert Bosch GmbH
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Robert Bosch GmbH
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M59/00—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps
    • F02M59/02—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
    • 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
    • F02M63/02—Fuel-injection apparatus having several injectors fed by a common pumping element, or having several pumping elements feeding a common injector; Fuel-injection apparatus having provisions for cutting-out pumps, pumping elements, or injectors; Fuel-injection apparatus having provisions for variably interconnecting pumping elements and injectors alternatively
    • F02M63/0225—Fuel-injection apparatus having a common rail feeding several injectors ; Means for varying pressure in common rails; Pumps feeding common rails
    • 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
    • F02M59/022—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 having an accumulator storing pressurised fuel during pumping stroke of the piston for subsequent delivery to the injector
    • 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
    • F02M59/16—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps characterised by having multi-stage compression of fuel

Definitions

  • the invention relates to a fuel injection system according to the preamble of claim 1, as in DE 199 39 420 shown.
  • a fuel injection system for an internal combustion engine with a high-pressure fuel storage (common rail) and a plurality of injectors each having a pressure boosting device is known, wherein in the fuel delivery direction between the high-pressure fuel storage and the injectors, a compensation device for minimizing pressure oscillations is arranged.
  • the large number of pressure boosters required for the realization of high injection pressures beyond 2000 bar is disadvantageous.
  • Another disadvantage is the high space requirement of the entire injection system due to the large number of pressure amplifiers required.
  • the invention is therefore based on the object to propose a fuel injection system for an internal combustion engine with a central pressure booster, which has a high efficiency.
  • the invention is based on the idea of controlling a differential pressure quantity (control quantity) of fuel from the pressure amplification device into a low-pressure region of the fuel injection system.
  • differential pressure chambers of the pressure amplification device which are still to be explained later, can be hydraulically connected to a low-pressure region of the injector.
  • the differential pressure amount is diverted directly in front of the high-pressure fuel pump and after a metering unit for the suction control of the high-pressure fuel pump in the low pressure region, being conveyed via a prefeed pump fuel in the low pressure range.
  • an intermediate fuel accumulator is arranged in the fuel delivery direction downstream of the high-pressure fuel pump and upstream of the hydraulic pressure boosting device.
  • the pressure boosting device has two compression chambers which can be operated in an alternately compressing manner.
  • the compression chambers are coupled in such a way that the fuel pressure and the fuel volume during a refilling operation of the first compression space is utilized for compressing the fuel in the second compression space, ie the first compression space has a control space for compressing the fuel in the second Compression space forms.
  • the second compression space in its refill phase forms a second control space for compressing the fuel in the first compression space.
  • each compression chamber is associated with a differential pressure chamber, which can be acted upon for the purpose of compressing the fuel in the associated compression chamber with low pressure, so that the compressive force acting as a control chamber compression space counteracting compressive force is reduced, which in the sequence minimizing the volume of the compression space and, associated therewith, increasing the fuel pressure in the compression space.
  • the two compression chambers of the pressure amplifying device can be coupled to one another via a common pressure piston, which alternately compresses the fuel in the two, preferably opposing compression chambers, that is, is adjustable alternately into two opposite axial directions.
  • a common pressure piston which alternately compresses the fuel in the two, preferably opposing compression chambers, that is, is adjustable alternately into two opposite axial directions.
  • the differential pressure chambers are located on opposite axial sides (end faces) of the pressure piston.
  • the common pressure piston is designed as a double hollow piston with two hollow chambers, preferably arranged at the end, each defining a compression space and / or a respective differential pressure space.
  • the compression chambers and / or the differential pressure chambers are preferably formed in this case in a guide housing of the double plunger.
  • each functional unit consisting of compression space and differential pressure chamber is a, in particular designed as a 3/2-way valve control valve is provided.
  • Control valves are actuated, for example, with electromagnetic or piezoelectric actuators.
  • first compression chamber is connected to the high-pressure fuel pump and the second compression chamber associated (preferably arranged on the same side of the pressure pin) differential pressure chamber placed on low pressure, so that an adjustment of a pressure piston into the second compression chamber he follows.
  • To compress the fuel in the first compression chamber after the completion of the compression process in the second compression chamber is proceeded in an analogous manner.
  • each functional unit consisting of compression chamber and differential pressure chamber, two check valves associated with fuel can flow through a first check valve from the differential pressure chamber to the associated compression chamber and a second check valve from the compression chamber to the high-pressure fuel storage.
  • the embodiment described above allows a wiring of the control valves, in which the pressure boosting device is deactivated, the fuel from the high-pressure pump so without a triggering of the compression function can be conveyed through the pressure booster.
  • the fuel injection system equipped with a described pressure boosting device can be operated (at least temporarily) without the pressure boosting function. In other words, the fuel can be conveyed through the pressure boosting device.
  • At least one differential pressure chamber preferably both differential pressure chambers, are designed as radially outer annular spaces and at least one compression space, preferably both compression spaces, as central spaces, ie radially inner and preferably axially spaced spaces from the differential pressure spaces.
  • this embodiment is due to a greater wall thickness of the hollow piston in terms of increased strength of the pressure booster, in terms of ease of manufacture of the pressure piston and lower leakage in the Operation of advantage.
  • the transmission ratio of the pressure booster is above 2 a design is preferred in which the arrangement of the differential pressure chambers and the associated compression spaces is reversed, so the compression chambers are designed as annular spaces and the differential pressure chambers as central spaces.
  • the housing of the pressure booster from a pressure piston radially outwardly enclosing the housing sleeve and two adjacent to the end faces of the housing sleeve housing components is formed, which preferably by means of a respective union nut which cooperates with an external thread of the housing sleeve, axially against the Housing sleeve are clamped.
  • the housing components preferably serve for holding or receiving the control valves and / or the check valves.
  • a fuel injection system 1 for an internal combustion engine, not shown, is shown.
  • Fuel is conveyed from a fuel tank 2 by means of a prefeed pump 3 into a low-pressure region 15 of the fuel injection system 1.
  • a metering device 4 is used in a conventional manner for the suction control of a high-pressure fuel pump 5.
  • fuel is in this embodiment, about 1500 to 2000 bar in a central, in Fig. 2 conveyed in detail pressure boosting device 6 promoted.
  • the pressure boosting device 6 is, as will be explained later, formed as a double-acting pressure booster.
  • a fuel intermediate storage are arranged.
  • the compressed by the pressure booster 6 to a pressure of, for example, over 2500 bar fuel passes into a pressure booster 6 downstream high-pressure fuel storage 7 and from there into a plurality of injectors 8, which inject the fuel in each case in a combustion chamber, not shown, of an internal combustion engine.
  • the high-pressure fuel accumulator 7 is equipped with a pressure sensor 9.
  • the pressure sensor 9 is signal-conducting connected to a control unit 10, which in turn forms a control loop for the high-pressure fuel pump 5 together with the metering unit 4.
  • the control unit 10 is further signal-conducting with control valves 11, 12 of the pressure amplifying device 6 and not shown with control valves of the injectors 8 (the signal lines are shown in dashed lines).
  • Fig. 2 is the in Fig. 1 merely indicated pressure amplifying device 6 shown schematically in detail.
  • the two control valves 11, 12 are of the in Fig. 1 represented high-pressure fuel pump 5 is supplied via a supply line 14 with compressed fuel.
  • the control valves 11, 12 can be connected via the diversion line 13 to the low-pressure region 15 of the fuel injection system 1.
  • from the first control valve 11 opens a first supply line 16 to a first differential pressure chamber 17 and from the second control valve 12, a second supply line 18 to a second differential pressure chamber 19.
  • the first differential pressure chamber 17 is designed as an annular space and is bounded by a first housing component 20, a housing sleeve 21 and by a first end face 22 of a pressure piston 23.
  • the pressure piston 23 is designed as a double hollow piston and limited with a first pin 24 of the housing member 20 has a first compression space 25 which acts on a radially inner portion of the first end face 22 of the pressure piston 23.
  • the first supply line 16 is hydraulically connected to a first connecting line 27 to or from the first compression chamber 25 and the first connecting line 27 in turn is connected by means of a second check valve 28 with the high-pressure fuel storage 7.
  • the second control valve 12 is connected via the second supply line 18 to the second differential pressure chamber 19, which of a second, the first end face 22 of the plunger 23 opposite end face 29, a second housing member 30 and the housing sleeve 21 limited.
  • a second compression space 31 is provided which on a radially inner portion of the second Front side 29 of the pressure piston 23 acts.
  • the second supply line 18 is connected via a third check valve 32 hydraulically connected to a second connecting line 33 which is guided centrally by a second pin 34 of the second housing member 30 and opens into the second compression chamber 31, wherein the second connecting line 33 in turn via a fourth check valve 35 is connectable to the high-pressure fuel storage 7.
  • the two housing components 20, 30 are bolted to the housing sleeve 21 via a respective union nut 36, 37.
  • the housing components 20, 30 are preferably used to hold the only schematically indicated, each designed as a 3/2-way valve control valves 11, 12th
  • the operation of the pressure booster 6 is as follows.
  • the first differential pressure chamber 17 is connected to the low-pressure region 15 by means of the first control valve 11.
  • the supply line 14 is hydraulically connected to the second supply line 18 by means of the second control valve 12, so that fuel delivered by the high-pressure fuel pump 5 is directed into the second differential pressure chamber 19 and via the third check valve 32 into the second compression space 31 acting as a control chamber.
  • the pressure piston 23 moves in the plane of the drawing to the left, whereby the fuel in the first compression space 25 is compressed and flows through the first connecting line 27 through the second check valve 28 into the high-pressure fuel accumulator 7.
  • a fuel flow from the high-pressure fuel accumulator 7 into the second compression space 31 is prevented by the fourth check valve 35.
  • the control valves 11,12 are switched.
  • the second differential pressure chamber 19 is connected by means of the second control valve 12 to the low pressure region 15 of the fuel injection system 1 and the first supply line 16 hydraulically connected to the supply line 14 so that fuel in both the first differential pressure chamber 17 and the first check valve 26 in the first ,
  • acting as a control room compression chamber 22 flows. Due to the pressure force difference on the pressure piston 23, this moves in the plane of the drawing to the right and compresses the fuel in the second compression chamber 31, which flows through the second connection line 33 and the check valve 35 into the high-pressure fuel accumulator 7. A fuel flow from the high-pressure fuel accumulator 7 into the first compression space 25 is prevented by the second check valve 28.
  • the embodiment described above is particularly suitable for injection systems in which the transmission ratio of the pressure boosting device (pressure of the fuel compressed by the pressure booster 6 to pressure of the fuel in the flow direction behind the high-pressure fuel pump 5) of over 2.

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

Abstract

The fuel injection system (1) comprises a high-pressure fuel pump (5), which supplies a fuel to a high-pressure fuel accumulator (7). The high-pressure fuel accumulator comprises multiple injectors (8) and a central pressure boosting device (6). The pressure boosting device is provided in a fuel supply direction between the high-pressure fuel pump and the high-pressure fuel accumulator. An independent claim is also included for a pressure boosting device for a fuel injection system.

Description

Stand der TechnikState of the art

Die Erfindung betrifft ein Kraftstoffeinspritzsystem gemäß dem Oberbegriff des Anspruchs 1, wie in der DE 199 39 420 gezeigt.The invention relates to a fuel injection system according to the preamble of claim 1, as in DE 199 39 420 shown.

Aus der DE 102 46 208 A1 ist ein Kraftstoffeinspritzsystem für eine Brennkraftmaschine mit einem Kraftstoff-Hochdruckspeicher (Common Rail) und mehreren Injektoren mit jeweils einer Druckverstärkungseinrichtung bekannt, wobei in Kraftstoffförderrichtung zwischen dem Kraftstoff-Hochdruckspeicher und den Injektoren eine Ausgleichseinrichtung zur Minimierung von Druckschwingungen angeordnet ist. Bei dem bekannten Kraftstoffeinspritzsystem ist die große Anzahl an benötigten Druckverstärkern zur Realisierung hoher Einspritzdrücke jenseits von 2000 bar nachteilig. Ferner von Nachteil ist der hohe Bauraumbedarf des gesamten Einspritzsystems aufgrund der großen Anzahl an benötigten Druckverstärkern.From the DE 102 46 208 A1 a fuel injection system for an internal combustion engine with a high-pressure fuel storage (common rail) and a plurality of injectors each having a pressure boosting device is known, wherein in the fuel delivery direction between the high-pressure fuel storage and the injectors, a compensation device for minimizing pressure oscillations is arranged. In the known fuel injection system, the large number of pressure boosters required for the realization of high injection pressures beyond 2000 bar is disadvantageous. Another disadvantage is the high space requirement of the entire injection system due to the large number of pressure amplifiers required.

Aus der EP 1 123 463 B1 ist ein weiteres Kraftstoffeinspritzsystem bekannt, bei dem eine zentrale Druckverstärkungseinrichtung realisiert ist, wobei die Druckverstärkungseinrichtung in Kraftstoffförderrichtung zwischen dem Kraftstoff-Hochdruckspeicher und den Injektoren angeordnet ist. Über eine der Druckverstärkungseinrichtung nachgeordnete Verteilereinrichtung wird der komprimierte Kraftstoff unmittelbar auf die einzelnen Injektoren verteilt. Bei dem bekannten Kraftstoffeinspritzsystem ist von Vorteil, dass lediglich eine einzige Druckverstärkungseinrichtung benötigt wird. Nachteilig sind jedoch die von der zentralen Druckverstärkungseinrichtung verursachten Druckschwingungen im Hochdruckleitungssystem, die sich negativ auf die Einspritzmengenbemessung auswirken.From the EP 1 123 463 B1 Another fuel injection system is known, in which a central pressure booster is realized, wherein the pressure booster is arranged in the fuel delivery direction between the high-pressure fuel storage and the injectors. The compressed fuel is distributed directly to the individual injectors via a distribution device arranged downstream of the pressure boosting device. In the known fuel injection system is advantageous that only a single pressure boosting device is needed. However, the disadvantages are the pressure oscillations in the high-pressure line system caused by the central pressure boosting device, which have a negative effect on the injection quantity measurement.

Offenbarung der ErfindungDisclosure of the invention Technische AufgabeTechnical task

Der Erfindung liegt daher die Aufgabe zugrunde, ein Kraftstoffeinspritzsystem für eine Brennkraftmaschine mit einer zentralen Druckverstärkungseinrichtung vorzuschlagen, die eine hohe Effizienz aufweist.The invention is therefore based on the object to propose a fuel injection system for an internal combustion engine with a central pressure booster, which has a high efficiency.

Technische LösungTechnical solution

Hinsichtlich des Kraftstoffeinspritzsystems wird die Aufgabe mit den Merkmalen des Anspruchs 1 gelöst. Eine Weiterbildung der Erfindung ist im abhängigen Anspruch angegeben.With regard to the fuel injection system, the object is achieved with the features of claim 1. A development of the invention is specified in the dependent claim.

Hinsichtlich des Kraftstoffeinspritzsystems für eine Brennkraftmaschine liegt der Erfindung der Gedanke zugrunde, eine Differenzdruckmenge (Steuermenge) an Kraftstoff aus der Druckverstärkungseinrichtung in einen Niederdruckbereich des Kraftstoffeinspritzsystems abzusteuern. Anders ausgedrückt, sind später noch zu erläuternde Differenzdruckräume der Druckverstärkungseinrichtung hydraulisch mit einem Niederdruckbereich des Injektors verbindbar. Dabei wird die Differenzdruckmenge unmittelbar vor der Kraftstoffhochdruckpumpe und nach einer Zumesseinheit für die Saugregelung der Kraftstoffhochdruckpumpe in den Niederdruckbereich abgesteuert, wobei über eine Vorförderpumpe Kraftstoff in den Niederdruckbereich gefördert wird.With regard to the fuel injection system for an internal combustion engine, the invention is based on the idea of controlling a differential pressure quantity (control quantity) of fuel from the pressure amplification device into a low-pressure region of the fuel injection system. In other words, differential pressure chambers of the pressure amplification device, which are still to be explained later, can be hydraulically connected to a low-pressure region of the injector. In this case, the differential pressure amount is diverted directly in front of the high-pressure fuel pump and after a metering unit for the suction control of the high-pressure fuel pump in the low pressure region, being conveyed via a prefeed pump fuel in the low pressure range.

Um das Förderverhalten der insbesondere saugdruckgeregelten Kraftstoffhochdruckpumpe positiv zu beeinflussen, ist mit Vorteil zusätzlich zu dem eigentlichen Kraftstoff-Hochdruckspeicher ein Kraftstoffzwischenspeicher in Kraftstoffförderrichtung nach der Kraftstoffhochdruckpumpe und vor der hydraulischen Druckverstärkungseinrichtung angeordnet. Hierdurch wird eine permanente Bereitstellung von über die Kraftstoffhochdruckpumpe druckbeaufschlagtem Kraftstoff realisiert.In order to positively influence the delivery behavior of the particular suction-pressure-controlled high-pressure fuel pump, in addition to the actual high-pressure fuel accumulator, an intermediate fuel accumulator is arranged in the fuel delivery direction downstream of the high-pressure fuel pump and upstream of the hydraulic pressure boosting device. As a result, a permanent provision of pressurized fuel via the high-pressure fuel pump is realized.

Die Druckverstärkungseinrichtung weist zwei Kompressionsräume auf, die alternierend komprimierend betreibbar sind. Dabei sind die Kompressionsräume derart gekoppelt, dass der Kraftstoffdruck und das Kraftstoffvolumen bei einem Wiederbefüllvorgang des ersten Kompressionsraums zur Komprimierung des Kraftstoffs im zweiten Kompressionsraum ausgenutzt wird, d.h. der erste Kompressionsraum einen Steuerraum zur Komprimierung des Kraftstoffs im zweiten Kompressionsraum bildet. Analog bildet der zweite Kompressionsraum in dessen Wiederbefüllungsphase einen zweiten Steuerraum zur Komprimierung des Kraftstoffs im ersten Kompressionsraum. Dabei gibt es keine passive Rückstellung eines Hochdruckkolbens. Jede Verstellbewegung wird zur Komprimierung des Kraftstoffs in einem Kompressionsraum ausgenutzt. Durch die Realisierung der beschriebenen doppelt wirkenden Druckverstärkungseinrichtung wird u.a. eine verbesserte Regelbarkeit des Hochdruckbereichs des Kraftstoffeinspritzsystems erreicht.The pressure boosting device has two compression chambers which can be operated in an alternately compressing manner. The compression chambers are coupled in such a way that the fuel pressure and the fuel volume during a refilling operation of the first compression space is utilized for compressing the fuel in the second compression space, ie the first compression space has a control space for compressing the fuel in the second Compression space forms. Analogously, the second compression space in its refill phase forms a second control space for compressing the fuel in the first compression space. There is no passive provision of a high-pressure piston. Each adjustment movement is utilized to compress the fuel in a compression space. The realization of the described double-acting pressure boosting device achieves, among other things, improved controllability of the high-pressure region of the fuel injection system.

Es kann vorgesehen sein, dass jedem Kompressionsraum ein Differenzdruckraum zugeordnet ist, der zu Zwecken der Komprimierung des Kraftstoffs in dem zugeordneten Kompressionsraum mit Niederdruck beaufschlagbar ist, so dass die der Druckkraft des als Steuerraum wirkenden Kompressionsraums entgegen wirkende Druckkraft reduzierbar ist, was in der Folge zu einer Minimierung des Volumens des Kompressionsraums und damit verbunden zu einer Erhöhung des Kraftstoffdrucks im Kompressionsraum führt.It can be provided that each compression chamber is associated with a differential pressure chamber, which can be acted upon for the purpose of compressing the fuel in the associated compression chamber with low pressure, so that the compressive force acting as a control chamber compression space counteracting compressive force is reduced, which in the sequence minimizing the volume of the compression space and, associated therewith, increasing the fuel pressure in the compression space.

Weiter können die beiden Kompressionsräume der Druckverstärkungseinrichtung über einen gemeinsamen Druckkolben miteinander gekoppelt sein, der alternierend den Kraftstoff in den beiden, vorzugsweise gegenüber liegenden Kompressionsräumen komprimiert, also alternierend in zwei gegenüberliegende Axialrichtungen verstellbar ist. Diese Bauform ist von besonderem Vorteil, da das benötigte Bauraumvolumen der Druckverstärkungseinrichtung minimiert ist und gleichzeitig Druckschwingungen aufgrund der erzielten quasikontinuierlichen Komprimierung ebenfalls minimal sind. Bevorzugt befinden sich auch die Differenzdruckräume auf gegenüberliegenden Axialseiten (Stirnseiten) des Druckkolbens.Further, the two compression chambers of the pressure amplifying device can be coupled to one another via a common pressure piston, which alternately compresses the fuel in the two, preferably opposing compression chambers, that is, is adjustable alternately into two opposite axial directions. This design is particularly advantageous since the required installation space volume of the pressure amplification device is minimized and at the same time pressure oscillations due to the achieved quasi-continuous compression are also minimal. Preferably, the differential pressure chambers are located on opposite axial sides (end faces) of the pressure piston.

Weiter kann vorgesehen sein, dass der gemeinsame Druckkolben als Doppelhohlkolben mit zwei, vorzugsweise endseitig angeordneten, jeweils einen Kompressionsraum und/oder jeweils einen Differenzdruckraum begrenzenden Hohlkammern ausgebildet ist. Alternativ hierzu kann auch ein einfacher Doppelstö-ßel eingesetzt werden, wobei die Kompressionsräume und/oder die Differenzdruckräume in diesem Fall bevorzugt in einem Führungsgehäuse des Doppelstößels ausgebildet sind.It can further be provided that the common pressure piston is designed as a double hollow piston with two hollow chambers, preferably arranged at the end, each defining a compression space and / or a respective differential pressure space. Alternatively, a simple Doppelstö-ßel be used, the compression chambers and / or the differential pressure chambers are preferably formed in this case in a guide housing of the double plunger.

Zur Schaltung jeder Funktionseinheit bestehend aus Kompressionsraum und Differenzdruckraum ist ein, insbesondere als 3/2-Wege-Ventil ausgebildetes Steuerventil vorgesehen. Steuerventile werden beispielsweise mit elektromagnetischen oder piezoelektrischen Aktuatoren betätigt. Zur Komprimierung des Kraftstoffs in dem zweiten Kompressionsraum wird der als Steuerraum wirkende erste Kompressionsraum mit der Kraftstoffhochdruckpumpe verbunden und der dem zweiten Kompressionsraum zugeordnete (bevorzugt auf derselben Seite des Druckbolzens angeordnete) Differenzdruckraum auf Niederdruck gelegt, so dass eine Verstellung eines Druckkolbens in den zweiten Kompressionsraum hinein erfolgt. Zur Komprimierung des Kraftstoffs im ersten Kompressionsraum nach der Beendigung des Kompressionsvorgangs im zweiten Kompressionsraum wird in analoger Weise vorgegangen.For switching each functional unit consisting of compression space and differential pressure chamber is a, in particular designed as a 3/2-way valve control valve is provided. Control valves are actuated, for example, with electromagnetic or piezoelectric actuators. For compressing the fuel in the second compression chamber acting as a control chamber first compression chamber is connected to the high-pressure fuel pump and the second compression chamber associated (preferably arranged on the same side of the pressure pin) differential pressure chamber placed on low pressure, so that an adjustment of a pressure piston into the second compression chamber he follows. To compress the fuel in the first compression chamber after the completion of the compression process in the second compression chamber is proceeded in an analogous manner.

Vorzugsweise sind jeder Funktionseinheit, bestehend aus Kompressionsraum und Differenzdruckraum, zwei Rückschlagventile zugeordnet, wobei Kraftstoff über ein erstes Rückschlagventil von dem Differenzdruckraum zu dem zugehörigen Kompressionsraum und über ein zweites Rückschlagventil von dem Kompressionsraum zu dem Kraftstoff-Hochdruckspeicher strömen kann.Preferably, each functional unit, consisting of compression chamber and differential pressure chamber, two check valves associated with fuel can flow through a first check valve from the differential pressure chamber to the associated compression chamber and a second check valve from the compression chamber to the high-pressure fuel storage.

Die zuvor beschriebene Ausführungsform ermöglicht eine Beschaltung der Steuerventile, bei der die Druckverstärkungseinrichtung deaktiviert ist, der Kraftstoff von der Hochdruckpumpe also ohne eine Auslösung der Kompressionsfunktion durch die Druckverstärkungseinrichtung hindurch gefördert werden kann. Bei einer derartigen Steuerventilschaltung, zu der als Alternative eine zuschaltbare Bypassleitung einsetzbar ist, kann das mit einer beschriebenen Druckverstärkungseinrichtung ausgerüstete Kraftstoffeinspritzsystem ohne die Druckverstärkungsfunktion (zumindest vorübergehend) betrieben werden. Anders ausgedrückt, kann der Kraftstoff durch die Druckverstärkungseinrichtung hindurch gefördert werden.The embodiment described above allows a wiring of the control valves, in which the pressure boosting device is deactivated, the fuel from the high-pressure pump so without a triggering of the compression function can be conveyed through the pressure booster. In such a control valve circuit, to which an alternative switchable bypass line can be used as an alternative, the fuel injection system equipped with a described pressure boosting device can be operated (at least temporarily) without the pressure boosting function. In other words, the fuel can be conveyed through the pressure boosting device.

Mindestens ein Differenzdruckraum, vorzugsweise beide Differenzdruckräume, sind als radial äußere Ringräume und mindestens ein Kompressionsraum, vorzugsweise beide Kompressionsräume, als Zentralräume, also radial innere und vorzugsweise axial von den Differenzdruckräumen beabstandete Räume ausgebildet. Für den Fall, dass das Übersetzungsverhältnis der Druckverstärkungseinrichtung unterhalb von 2 liegt (Übersetzungsverhältnis = Druck des von der Druckverstärkungseinrichtung komprimierten Kraftstoffs zu Druck des von der Kraftstoffhochdruckpumpe geförderten Kraftstoffs) ist diese Ausführungsform aufgrund einer größeren Wandstärke des Hohlkolbens hinsichtlich einer erhöhten Festigkeit der Druckverstärkungseinrichtung, hinsichtlich einer erleichterten Herstellbarkeit des Druckkolbens und hinsichtlich geringerer Leckagen im Betrieb von Vorteil. Für den Fall, dass das Übersetzungsverhältnis der Druckverstärkungseinrichtung oberhalb von 2 liegt, ist eine Bauform zu bevorzugen, bei der die Anordnung der Differenzdruckräume und der zugehörigen Kompressionsräume vertauscht ist, also die Kompressionsräume als Ringräume und die Differenzdruckräume als Zentralräume ausgebildet sind.At least one differential pressure chamber, preferably both differential pressure chambers, are designed as radially outer annular spaces and at least one compression space, preferably both compression spaces, as central spaces, ie radially inner and preferably axially spaced spaces from the differential pressure spaces. In the event that the transmission ratio of the pressure booster is below 2 (gear ratio = pressure of the pressure booster compressed fuel to the pressure of the fuel delivered by the high-pressure fuel pump), this embodiment is due to a greater wall thickness of the hollow piston in terms of increased strength of the pressure booster, in terms of ease of manufacture of the pressure piston and lower leakage in the Operation of advantage. In the event that the transmission ratio of the pressure booster is above 2, a design is preferred in which the arrangement of the differential pressure chambers and the associated compression spaces is reversed, so the compression chambers are designed as annular spaces and the differential pressure chambers as central spaces.

Fertigungstechnisch ist es von Vorteil, wenn das Gehäuse der Druckverstärkungseinrichtung aus einer den Druckkolben radial außen umschließenden Gehäusehülse und zwei an den Stirnseiten der Gehäusehülse anliegenden Gehäusebauteilen gebildet ist, welche bevorzugt mittels jeweils einer Überwurfmutter, die jeweils mit einem Außengewinde der Gehäusehülse zusammenwirkt, axial gegen die Gehäusehülse verspannt sind.Manufacturing technology, it is advantageous if the housing of the pressure booster from a pressure piston radially outwardly enclosing the housing sleeve and two adjacent to the end faces of the housing sleeve housing components is formed, which preferably by means of a respective union nut which cooperates with an external thread of the housing sleeve, axially against the Housing sleeve are clamped.

Bevorzugt dienen die Gehäusebauteile zur Halterung bzw. Aufnahme der Steuerventile und/oder der Rückschlagventile.The housing components preferably serve for holding or receiving the control valves and / or the check valves.

Kurze Beschreibung der ZeichnungenBrief description of the drawings

Weitere Vorteile, Merkmale und Einzelheiten der Erfindung ergeben sich aus der nachfolgenden Beschreibung der Ausführungsbeispiele, sowie anhand der Zeichnungen; diese zeigen in

Fig. 1
eine schematische Darstellung eines erfindungsgemäßen Kraftstoffeinspritzsystems für Brennkraftmaschinen mit einer zentralen Druckverstärkungseinrichtung und
Fig. 2
eine schematische Darstellung eines möglichen Aufbaus einer Druckverstärkungseinrichtung des in Fig. 1 gezeigten Kraftstoffeinspritzsystems.
Further advantages, features and details of the invention will become apparent from the following description of the embodiments, and with reference to the drawings; these show in
Fig. 1
a schematic representation of a fuel injection system according to the invention for internal combustion engines with a central pressure boosting device and
Fig. 2
a schematic representation of a possible construction of a pressure amplifying device of in Fig. 1 shown fuel injection system.

Ausführungsformen der ErfindungEmbodiments of the invention

In den Figuren sind gleiche Bauteile und Bauteile gleicher Funktion mit den gleichen Bezugszeichen gekennzeichnet.In the figures, the same components and components have the same function with the same reference numerals.

In Fig. 1 ist ein erfindungsgemäßes Kraftstoffeinspritzsystem 1 für eine nicht gezeigte Brennkraftmaschine gezeigt. Aus einem Kraftstofftank 2 wird Kraftstoff mittels einer Vorförderpumpe 3 in einen Niederdruckbereich 15 des Kraftstoffeinspritzsystems 1 gefördert. Aus Übersichtlichkeitsgründen sind ein Kraftstofffilter, ein Wasserabscheider und weitere zum Verständnis der Erfindung nicht notwendige, in der Praxis jedoch vorhandene Bauteile nicht dargestellt. Eine Zumesseinrichtung 4 dient in an sich bekannter Weise zur Saugregelung einer Kraftstoffhochdruckpumpe 5. Von der Kraftstoffhochdruckpumpe 5 wird Kraftstoff mit in diesem Ausführungsbeispiel ca. 1500 bis 2000 bar in eine zentrale, in Fig. 2 im Detail gezeigte Druckverstärkungseinrichtung 6 gefördert. Die Druckverstärkungseinrichtung 6 ist dabei, wie später noch erläutert werden wird, als doppelt wirkender Druckverstärker ausgebildet. Alternativ kann zusätzlich in Kraftstoffförderrichtung zwischen der Kraftstoffhochdruckpumpe 5 und der Druckverstärkungseinrichtung 6 ein nicht gezeigter Kraftstoffzwischenspeicher angeordnet werden.In Fig. 1 a fuel injection system 1 according to the invention for an internal combustion engine, not shown, is shown. Fuel is conveyed from a fuel tank 2 by means of a prefeed pump 3 into a low-pressure region 15 of the fuel injection system 1. For reasons of clarity, a fuel filter, a water separator and other not necessary for understanding the invention, but in practice existing components are not shown. A metering device 4 is used in a conventional manner for the suction control of a high-pressure fuel pump 5. From the high-pressure fuel pump 5 fuel is in this embodiment, about 1500 to 2000 bar in a central, in Fig. 2 conveyed in detail pressure boosting device 6 promoted. The pressure boosting device 6 is, as will be explained later, formed as a double-acting pressure booster. Alternatively, in addition in the fuel delivery direction between the high-pressure fuel pump 5 and the pressure booster 6, a fuel intermediate storage, not shown, are arranged.

Der von der Druckverstärkungseinrichtung 6 auf einen Druck von beispielsweise über 2500 bar komprimierte Kraftstoff gelangt in einen der Druckverstärkungseinrichtung 6 nachgeordneten Kraftstoff-Hochdruckspeicher 7 und von dort aus in eine Vielzahl von Injektoren 8, die den Kraftstoff jeweils in einen nicht dargestellten Brennraum einer Brennkraftmaschine einspritzen. Zur Realisierung einer Druckregelung im Kraftstoffeinspritzsystem 1 ist der Kraftstoff-Hochdruckspeicher 7 mit einem Drucksensor 9 ausgestattet. Der Drucksensor 9 ist signalleitend mit einem Steuergerät 10 verbunden, welches wiederum zusammen mit der Zumesseinheit 4 eine Regelschleife für die Kraftstoffhochdruckpumpe 5 bildet. Das Steuergerät 10 ist weiterhin signalleitend mit Steuerventilen 11, 12 der Druckverstärkungseinrichtung 6 sowie mit nicht gezeigten Steuerventilen der Injektoren 8 verbunden (die Signalleitungen sind strichliert dargestellt). Bei der Komprimierung von Kraftstoff mittels der Druckverstärkungseinrichtung 6 wird eine Differenzdruckmenge (Steuermenge) an Kraftstoff über eine Absteuerleitung 13 von der Druckverstärkungseinrichtung 6 bzw. aus später noch zu erläuternden Differenzdruckräumen in den Niederdruckbereich des Kraftstoffeinspritzsystems 1, in diesem Fall in Kraftstoffströmungsrichtung unmittelbar vor die Kraftstoffhochdruckpumpe 5 abgesteuert.The compressed by the pressure booster 6 to a pressure of, for example, over 2500 bar fuel passes into a pressure booster 6 downstream high-pressure fuel storage 7 and from there into a plurality of injectors 8, which inject the fuel in each case in a combustion chamber, not shown, of an internal combustion engine. To realize a pressure control in the fuel injection system 1, the high-pressure fuel accumulator 7 is equipped with a pressure sensor 9. The pressure sensor 9 is signal-conducting connected to a control unit 10, which in turn forms a control loop for the high-pressure fuel pump 5 together with the metering unit 4. The control unit 10 is further signal-conducting with control valves 11, 12 of the pressure amplifying device 6 and not shown with control valves of the injectors 8 (the signal lines are shown in dashed lines). In the compression of fuel by means of the pressure booster 6, a differential pressure amount (control amount) of fuel via a Absteuerleitung 13 from the pressure booster 6 and from later to be explained differential pressure chambers in the low pressure region of the fuel injection system 1, in this case in the fuel flow direction immediately before the high-pressure fuel pump 5.

In Fig. 2 ist die in Fig. 1 lediglich angedeutete Druckverstärkungseinrichtung 6 schematisch im Detail dargestellt. Die beiden Steuerventile 11, 12 werden von der in Fig. 1 dargestellten Kraftstoffhochdruckpumpe 5 über eine Versorgungsleitung 14 mit komprimiertem Kraftstoff versorgt. Die Steuerventile 11, 12 sind über die Absteuerleitung 13 mit dem Niederdruckbereich 15 des Kraftstoffeinspritzsystems 1 verbindbar. Zusätzlich mündet aus dem ersten Steuerventil 11 eine erste Zuleitung 16 zu einem ersten Differenzdruckraum 17 und von dem zweiten Steuerventil 12 eine zweite Zuleitung 18 zu einem zweiten Differenzdruckraum 19 aus. Der erste Differenzdruckraum 17 ist als Ringraum ausgebildet und wird von einem ersten Gehäusebauteil 20, einer Gehäusehülse 21 und von einer ersten Stirnseite 22 eines Druckkolbens 23 begrenzt. Der Druckkolben 23 ist dabei als Doppelhohlkolben ausgebildet und begrenzt mit einem ersten Zapfen 24 des Gehäusebauteils 20 einen ersten Kompressionsraum 25, der auf einen radial inneren Abschnitt der ersten Stirnseite 22 des Druckkolbens 23 wirkt.In Fig. 2 is the in Fig. 1 merely indicated pressure amplifying device 6 shown schematically in detail. The two control valves 11, 12 are of the in Fig. 1 represented high-pressure fuel pump 5 is supplied via a supply line 14 with compressed fuel. The control valves 11, 12 can be connected via the diversion line 13 to the low-pressure region 15 of the fuel injection system 1. In addition, from the first control valve 11 opens a first supply line 16 to a first differential pressure chamber 17 and from the second control valve 12, a second supply line 18 to a second differential pressure chamber 19. The first differential pressure chamber 17 is designed as an annular space and is bounded by a first housing component 20, a housing sleeve 21 and by a first end face 22 of a pressure piston 23. The pressure piston 23 is designed as a double hollow piston and limited with a first pin 24 of the housing member 20 has a first compression space 25 which acts on a radially inner portion of the first end face 22 of the pressure piston 23.

Über ein erstes Rückschlagventil 26 ist die erste Zuleitung 16 hydraulisch mit einer ersten Verbindungsleitung 27 zum bzw. vom ersten Kompressionsraum 25 verbindbar und die erste Verbindungsleitung 27 wiederum ist mittels eines zweiten Rückschlagventils 28 mit dem Kraftstoff-Hochdruckspeicher 7 verbindbar.Via a first check valve 26, the first supply line 16 is hydraulically connected to a first connecting line 27 to or from the first compression chamber 25 and the first connecting line 27 in turn is connected by means of a second check valve 28 with the high-pressure fuel storage 7.

In analoger Weise ist die spiegelsymmetrische Druckverstärkungseinrichtung 6 in der rechten Zeichnungshälfte der Fig. 2 aufgebaut. Das zweite Steuerventil 12 ist über die zweite Zuleitung 18 mit dem zweiten Differenzdruckraum 19 verbunden, welcher von einer zweiten, der ersten Stirnseite 22 des Druckkolbens 23 gegenüberliegenden, Stirnseite 29, einem zweiten Gehäusebauteil 30 und der Gehäusehülse 21 begrenzt. Radial innerhalb des zweiten Differenzdruckraums 19 sowie in axialer Richtung versetzt hierzu ist ein zweiter Kompressionsraum 31 vorgesehen, der auf einen radial inneren Abschnitt der zweiten Stirnseite 29 des Druckkolbens 23 wirkt. Die zweite Zuleitung 18 ist über ein drittes Rückschlagventil 32 hydraulisch mit einer zweiten Verbindungsleitung 33, welche zentrisch durch einen zweiten Zapfen 34 des zweiten Gehäusebauteils 30 geführt ist und in den zweiten Kompressionsraum 31 mündet, verbindbar, wobei die zweite Verbindungsleitung 33 wiederum über ein viertes Rückschlagventil 35 mit dem Kraftstoff-Hochdruckspeicher 7 verbindbar ist.Analogously, the mirror-symmetrical pressure amplifying device 6 in the right half of the drawing Fig. 2 built up. The second control valve 12 is connected via the second supply line 18 to the second differential pressure chamber 19, which of a second, the first end face 22 of the plunger 23 opposite end face 29, a second housing member 30 and the housing sleeve 21 limited. Radially within the second differential pressure chamber 19 and in the axial direction offset therefrom, a second compression space 31 is provided which on a radially inner portion of the second Front side 29 of the pressure piston 23 acts. The second supply line 18 is connected via a third check valve 32 hydraulically connected to a second connecting line 33 which is guided centrally by a second pin 34 of the second housing member 30 and opens into the second compression chamber 31, wherein the second connecting line 33 in turn via a fourth check valve 35 is connectable to the high-pressure fuel storage 7.

Die beiden Gehäusebauteile 20, 30 sind über jeweils eine Überwurfmutter 36, 37 mit der Gehäusehülse 21 verschraubt. Die Gehäusebauteile 20, 30 dienen bevorzugt zur Aufnahme der lediglich schematisch angedeuteten, jeweils als 3/2-Wege-Ventil ausgebildeten Steuerventile 11, 12.The two housing components 20, 30 are bolted to the housing sleeve 21 via a respective union nut 36, 37. The housing components 20, 30 are preferably used to hold the only schematically indicated, each designed as a 3/2-way valve control valves 11, 12th

Die Funktionsweise der Druckverstärkungseinrichtung 6 ist wie folgt. Zur Komprimierung des Kraftstoffs im ersten Kompressionsraum 25 wird der erste Differenzdruckraum 17 mittels des ersten Steuerventils 11 mit dem Niederdruckbereich 15 verbunden. Gleichzeitig wird die Versorgungsleitung 14 mittels des zweiten Steuerventils 12 mit der zweiten Zuleitung 18 hydraulisch verbunden, so dass von der Kraftstoffhochdruckpumpe 5 geförderter Kraftstoff in den zweiten Differenzdruckraum 19 sowie über das dritte Rückschlagventil 32 in den als Steuerraum wirkenden zweiten Kompressionsraum 31 geleitet wird. Hierdurch bewegt sich der Druckkolben 23 in der Zeichnungsebene nach links, wodurch der Kraftstoff im ersten Kompressionsraum 25 komprimiert wird und über die erste Verbindungsleitung 27 durch das zweite Rückschlagventil 28 in den Kraftstoff-Hochdruckspeicher 7 strömt. Ein Kraftstoffstrom von dem Kraftstoff-Hochdruckspeicher 7 in den zweiten Kompressionsraum 31 wird durch das vierte Rückschlagventil 35 verhindert.The operation of the pressure booster 6 is as follows. For compressing the fuel in the first compression space 25, the first differential pressure chamber 17 is connected to the low-pressure region 15 by means of the first control valve 11. At the same time, the supply line 14 is hydraulically connected to the second supply line 18 by means of the second control valve 12, so that fuel delivered by the high-pressure fuel pump 5 is directed into the second differential pressure chamber 19 and via the third check valve 32 into the second compression space 31 acting as a control chamber. As a result, the pressure piston 23 moves in the plane of the drawing to the left, whereby the fuel in the first compression space 25 is compressed and flows through the first connecting line 27 through the second check valve 28 into the high-pressure fuel accumulator 7. A fuel flow from the high-pressure fuel accumulator 7 into the second compression space 31 is prevented by the fourth check valve 35.

Nach Beendigung des Kompressionsvorgangs werden die Steuerventile 11,12 umgeschaltet. Dabei wird der zweite Differenzdruckraum 19 mittels des zweiten Steuerventils 12 mit dem Niederdruckbereich 15 des Kraftstoffeinspritzsystems 1 verbunden und die erste Zuleitung 16 hydraulisch mit der Versorgungsleitung 14 verbunden, so dass Kraftstoff sowohl in den ersten Differenzdruckraum 17 als auch über das erste Rückschlagventil 26 in den ersten, in diesem Fall als Steuerraum wirkenden Kompressionsraum 22 strömt. Aufgrund der Druckkraftdifferenz am Druckkolben 23 bewegt sich dieser in der Zeichnungsebene nach rechts und komprimiert dabei den Kraftstoff im zweiten Kompressionsraum 31, welcher durch die zweite Verbindungsleitung 33 und das Rückschlagventil 35 in den Kraftstoff-Hochdruckspeicher 7 strömt. Ein Kraftstoffstrom von dem Kraftstoff-Hochdruckspeicher 7 in den ersten Kompressionsraum 25 wird von dem zweiten Rückschlagventil 28 verhindert.After completion of the compression operation, the control valves 11,12 are switched. In this case, the second differential pressure chamber 19 is connected by means of the second control valve 12 to the low pressure region 15 of the fuel injection system 1 and the first supply line 16 hydraulically connected to the supply line 14 so that fuel in both the first differential pressure chamber 17 and the first check valve 26 in the first , In this case acting as a control room compression chamber 22 flows. Due to the pressure force difference on the pressure piston 23, this moves in the plane of the drawing to the right and compresses the fuel in the second compression chamber 31, which flows through the second connection line 33 and the check valve 35 into the high-pressure fuel accumulator 7. A fuel flow from the high-pressure fuel accumulator 7 into the first compression space 25 is prevented by the second check valve 28.

Auf diese Weise wird mittels der Druckverstärkungseinrichtung 6 ein quasi kontinuierlicher Hochdruckvolumenstrom in den Kraftstoff-Hochdruckspeicher 7 bereitgestellt.In this way, a quasi-continuous high-pressure volume flow is provided in the fuel high-pressure accumulator 7 by means of the pressure booster 6.

Die zuvor beschriebene Ausführungsform eignet sich besonders für Einspritzsysteme, bei denen das Übersetzungsverhältnis der Druckverstärkungseinrichtung (Druck des von der Druckverstärkungseinrichtung 6 komprimierten Kraftstoffes zu Druck des Kraftstoffes in Strömungsrichtung hinter der Kraftstoffhochdruckpumpe 5) von über 2.The embodiment described above is particularly suitable for injection systems in which the transmission ratio of the pressure boosting device (pressure of the fuel compressed by the pressure booster 6 to pressure of the fuel in the flow direction behind the high-pressure fuel pump 5) of over 2.

Claims (2)

  1. Fuel injection system (1) for an internal combustion engine, having at least one high-pressure fuel pump (5) which supplies fuel to at least one high-pressure fuel accumulator (7), having multiple injectors (8) and having at least one central pressure boosting device (6), wherein the pressure boosting device (6) is arranged between the high-pressure fuel pump (5) and the high-pressure fuel accumulator (7) as viewed in the fuel delivery direction, characterized in that fuel is delivered into a low-pressure region (15) by means of a predelivery pump (3), and a differential pressure quantity of fuel can be discharged from the pressure boosting device (6) into the low-pressure region (15) of the fuel injection system (1) directly upstream of the high-pressure fuel pump (5).
  2. Fuel injection system (1) according to Claim 1, characterized in that a fuel buffer store is arranged between the high-pressure fuel pump (5) and the pressure boosting device (6) as viewed in the fuel delivery direction.
EP11179810.4A 2007-03-05 2008-01-24 Fuel injection system Not-in-force EP2402588B1 (en)

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DE102007010495A DE102007010495A1 (en) 2007-03-05 2007-03-05 Fuel injection system and pressure boosting device for a fuel injection system
EP08701662A EP2132434B1 (en) 2007-03-05 2008-01-24 Fuel injection system and pressure boosting device for a fuel injection system

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DE102010002033A1 (en) 2010-02-17 2011-08-18 Robert Bosch GmbH, 70469 Hydraulic system and fuel injection system for an internal combustion engine
DE102012011583A1 (en) * 2012-06-13 2013-12-19 Robert Bosch Gmbh Device, particularly hydraulic ram for pressurization of flowable medium in motor vehicle, has pressure generating unit comprises recirculation unit which returns back flowable medium into pressure generating unit

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DE904858C (en) * 1951-12-04 1954-02-22 Wilhelm Reppel Back and forth pressure intensifier for pneumatic systems
DE1577188A1 (en) 1966-01-13 1969-09-25 Stahl Und Appbau Hans Leffer G Hydraulic pressure generation system with double-acting pressure intensifier
US3386384A (en) * 1966-06-27 1968-06-04 Cicero C Brown Multiple power consuming devices
DE19939420B4 (en) * 1999-08-20 2004-12-09 Robert Bosch Gmbh Fuel injection method and system for an internal combustion engine
DE19939423A1 (en) 1999-08-20 2001-03-01 Bosch Gmbh Robert Fuel injection system for an internal combustion engine
DE10151885A1 (en) * 2001-10-20 2003-05-08 Bosch Gmbh Robert Fuel injection system has gear pump to supply fuel at medium pressure before booster
DE10246208A1 (en) 2002-10-04 2004-04-15 Robert Bosch Gmbh Surge suppression device for storage injection system has equalizing device between high pressure storage cavity and fuel injector
US7464697B2 (en) * 2005-08-19 2008-12-16 The United States Of America, As Represented By The Administrator Of The U.S. Environmental Protection Agency High-pressure fuel intensifier system

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EP2402588A1 (en) 2012-01-04
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EP2132434B1 (en) 2011-10-26
WO2008107220A1 (en) 2008-09-12

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