WO2001027464A1 - Common-rail fuel injection system - Google Patents

Common-rail fuel injection system Download PDF

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Publication number
WO2001027464A1
WO2001027464A1 PCT/DE2000/003242 DE0003242W WO0127464A1 WO 2001027464 A1 WO2001027464 A1 WO 2001027464A1 DE 0003242 W DE0003242 W DE 0003242W WO 0127464 A1 WO0127464 A1 WO 0127464A1
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WO
WIPO (PCT)
Prior art keywords
pressure
injection system
fuel injection
common rail
low
Prior art date
Application number
PCT/DE2000/003242
Other languages
German (de)
French (fr)
Inventor
Klaus Dobler
Friedrich Boecking
Original Assignee
Robert Bosch Gmbh
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Robert Bosch Gmbh filed Critical Robert Bosch Gmbh
Priority to KR1020017007019A priority Critical patent/KR20010080693A/en
Priority to EP00978945A priority patent/EP1144856A1/en
Priority to JP2001529578A priority patent/JP2003511624A/en
Publication of WO2001027464A1 publication Critical patent/WO2001027464A1/en

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Classifications

    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02MSUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M47/00Fuel-injection apparatus operated cyclically with fuel-injection valves actuated by fluid pressure
    • F02M47/02Fuel-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
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02MSUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M59/00Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps
    • F02M59/02Pumps 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
    • F02M59/10Pumps 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
    • F02M59/105Pumps 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
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02MSUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M63/00Other 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
    • F02M63/02Fuel-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
    • F02M63/0225Fuel-injection apparatus having a common rail feeding several injectors ; Means for varying pressure in common rails; Pumps feeding common rails
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04BPOSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B9/00Piston machines or pumps characterised by the driving or driven means to or from their working members
    • F04B9/08Piston machines or pumps characterised by the driving or driven means to or from their working members the means being fluid
    • F04B9/10Piston machines or pumps characterised by the driving or driven means to or from their working members the means being fluid the fluid being liquid
    • F04B9/103Piston machines or pumps characterised by the driving or driven means to or from their working members the means being fluid the fluid being liquid having only one pumping chamber
    • F04B9/107Piston machines or pumps characterised by the driving or driven means to or from their working members the means being fluid the fluid being liquid having only one pumping chamber rectilinear movement of the pumping member in the working direction being obtained by a single-acting liquid motor, e.g. actuated in the other direction by gravity or a spring
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04BPOSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B9/00Piston machines or pumps characterised by the driving or driven means to or from their working members
    • F04B9/08Piston machines or pumps characterised by the driving or driven means to or from their working members the means being fluid
    • F04B9/10Piston machines or pumps characterised by the driving or driven means to or from their working members the means being fluid the fluid being liquid
    • F04B9/109Piston machines or pumps characterised by the driving or driven means to or from their working members the means being fluid the fluid being liquid having plural pumping chambers
    • F04B9/117Piston machines or pumps characterised by the driving or driven means to or from their working members the means being fluid the fluid being liquid having plural pumping chambers the pumping members not being mechanically connected to each other

Definitions

  • the invention relates to a common rail fuel injection system for internal combustion engines, with a high-pressure fuel reservoir for supplying a plurality of injectors which are used to inject fuel into the combustion chamber of the internal combustion engine.
  • Such a common rail fuel injection system is e.g. described in DE 197 28 111.
  • a high-pressure pump possibly with the aid of a prefeed pump, conveys the fuel to be injected from a tank into the central high-pressure fuel reservoir, which is referred to as a common rail.
  • Fuel lines run from the rail to the individual injectors, which are the cylinders of the
  • the injectors are individually controlled by the engine electronics in order to inject fuel into the combustion chamber of the internal combustion engine.
  • High-pressure fuel accumulators separate the pressure generation and the injection from each other.
  • the object of the invention is to improve the known common rail fuel injection system in such a way that the stress on the high pressure pump is reduced.
  • the common rail fuel injection system according to the invention should be simple in construction and inexpensive to manufacture.
  • the task is with a Com on Rail
  • Fuel injection system for internal combustion engines with a high-pressure fuel reservoir for supplying a plurality of injectors which serve to inject fuel into the combustion chamber of the internal combustion engine, in that the high-pressure fuel reservoir is hydraulically coupled to a low-pressure reservoir via a hydraulic transmission device.
  • the low-pressure accumulator can be used to generate high-pressure fuel.
  • a high-pressure pump as used in conventional common rail fuel injection systems, can be dispensed with entirely.
  • a special embodiment of the invention is characterized in that the hydraulic transmission device comprises at least one transmission piston, the end face of which is larger on the primary side subjected to low pressure than the end face of which is on the opposite secondary side.
  • the booster piston is a simply constructed booster device through which the fuel can be subjected to high pressure.
  • the low pressure side of the common rail fuel injection system according to the invention is separated from the high pressure side by the booster piston.
  • Another special embodiment of the invention is characterized in that the secondary side of the Translator piston with the interposition of a first check valve with a fuel inlet and with the interposition of a second check valve with the high-pressure fuel accumulator in connection.
  • fuel is drawn from the fuel supply via the first check valve on the secondary side.
  • the fuel drawn in is subjected to high pressure in the delivery stroke of the booster piston and reaches the high-pressure fuel reservoir via the second check valve.
  • a further special embodiment of the invention is characterized in that a plurality of booster pistons are connected in parallel, an actuating device being arranged between the booster piston and the low-pressure accumulator. With several booster pistons, a large amount of fuel can be subjected to high pressure. The conveying work of the translation pistons is coordinated by the actuating device.
  • a further special embodiment of the invention is characterized in that the actuating device is formed by a 3/2 way valve, which forms the primary side of the associated booster piston in the first switching position with the low-pressure accumulator and in the second
  • Switch position connects with a fuel drain.
  • the primary side of the associated booster piston is subjected to low pressure and the delivery stroke is carried out.
  • the second switching position of the adjusting device the associated one moves
  • the booster piston for example supported by the biasing force of a spring, returns to its starting position.
  • the fuel displaced in the suction stroke on the primary side of the associated booster piston can escape via the fuel outlet.
  • a further special embodiment of the invention is characterized in that the actuating devices are controlled in such a way that at least one booster piston is constantly in the delivery stroke. This ensures that in the common rail according to the invention
  • Fuel injection system pressure and quantity are continuously promoted.
  • Another particular embodiment of the invention is characterized in that the low-pressure accumulator is supplied with oil via a feed pump. This has the advantage that the pumped medium can also be used to lubricate the pump. A separate lubrication circuit is not necessary.
  • a further special embodiment of the invention is characterized in that further hydraulically actuable components, such as braking devices, hydraulic valve controls, etc., are connected to the low-pressure accumulator.
  • further hydraulically actuable components such as braking devices, hydraulic valve controls, etc.
  • the fuel injection system can be integrated into the oil hydraulic management of the internal combustion engine.
  • FIG. 1 A hydraulic circuit diagram is shown in simplified form in FIG. 1 in order to illustrate the common rail fuel injection system according to the invention.
  • Feed pump 1 sucks from a (not shown) Hydraulic oil reservoir on.
  • the suctioned hydraulic oil is conveyed by the feed pump 1 via a line 2 into a low-pressure accumulator 3.
  • the low-pressure accumulator 3 is connected to a hydraulic valve control (not shown) via a line 4 shown as an example.
  • a pressure of 100-300 bar prevails in the low-pressure accumulator 3.
  • the low pressure accumulator 3 can also be connected to a hydraulic brake system.
  • the low-pressure accumulator 3 is connected to two actuating devices 7, 8 via two lines 5, 6.
  • the actuating devices 7, 8 are 3/2 directional valves.
  • valve member 9, 10 is received in a reciprocating manner.
  • the valve member 9, 10 is displaceable between a first valve seat 11, 12 and a second valve seat 13, 14.
  • Valve seat 13, 14 is in contact, the line 5, 6 coming from the low-pressure accumulator 3 is connected to a line 17, 18.
  • the line 17, 18 opens into a cylinder 19, 20.
  • a booster piston 21, 22 is received in a reciprocating manner.
  • a plunger 31, 32 is formed on the secondary side 27, 28 of the cylinder 19, 20 on the booster piston 21, 22.
  • the plunger 31, 32 projects into a fuel line 33, 34.
  • the primary-side end surface 25, 26 of the booster piston 21, 22, like the secondary-side end surface 45, 46 of the plunger 31, 32, is circular.
  • the primary end face 25, 26 of the booster piston 21, 22 is significantly larger than the secondary end face 45, 46 of the tappet 31, 32. This ensures that the low pressure prevailing on the primary side 23, 24 prevails in the secondary side 27, 28 High pressure is translated.
  • a check valve 39, 40 arranged at the end of the fuel line 33, 34 opens, and the high-pressure fuel reaches a high-pressure fuel reservoir 41.
  • the high-pressure fuel reservoir 41 is in turn over
  • High-pressure fuel lines 42 connected to the injectors of the internal combustion engine.
  • the booster piston 21, 22 moves against the biasing force of the spring 29, 30 from the primary side 23, 24 to the secondary side 27, 28 of the cylinder 19, 20.
  • the actuating device 7 switches , 8, and the valve member 9, 10 moves from the second valve seat 13, 14 to the first valve seat 11, 12.
  • the valve member 9, 10 is in contact with the first valve seat 11, 12, the line 17, 18 with a fuel drain 15, 16 in connection. In this valve position, the fuel contained in the fuel line 17, 18 can escape into the fuel outlet 15, 16.
  • the associated pressure loss in the line 17, 18 and the biasing force of the spring 29, 30 ensure that the booster piston moves from the secondary side 27, 28 to the primary side 23, 24 of the cylinder 19, 20.
  • the movement of the two booster pistons 21, 22 is coordinated via a control device (not shown) in such a way that the booster piston 22 delivers first. Shortly before the booster piston 22 reaches its stroke stop, the booster piston 21 begins to deliver.
  • the coordination of the delivery and suction stroke movement of the booster pistons 21, 22 ensures that a sufficient amount of fuel is continuously supplied with high pressure and delivered to the high pressure accumulator 41.
  • the booster pistons 21, 22 ensure that high pressure is generated on the secondary side 27, 28 from the low pressure on the primary side 23, 24.
  • the check valve 37, 38 is used for refilling.
  • the check valves 39, 40 serve to maintain the pressure in the high-pressure fuel accumulator 41.

Abstract

The invention relates to a common-rail fuel injection system for internal combustion engines. The inventive system comprises a high-pressure fuel accumulator (41) for supplying several injectors which serve for injecting fuel into the combustion chamber of the internal combustion engine. The aim of the invention is to reduce strain of the high-pressure pump in conventional common-rail fuel injection systems. To this end, the high-pressure fuel accumulator (41) is hydraulically coupled to a low-pressure accumulator (3) by means of a hydraulic intensification device (17, 19).

Description

Common-Rail -KraftStoffeinspritzsysteCommon rail fuel injection system
Stand der TechnikState of the art
Die Erfindung betrifft ein Common-Rail - Kraftstoffeinspritzsystem für Brennkraftmaschinen, mit einem Kraftstoffhochdruckspeicher zur Versorgung mehrerer Injektoren, die dazu dienen, Kraftstoff in den Brennraum der Brennkraftmaschine einzuspritzen.The invention relates to a common rail fuel injection system for internal combustion engines, with a high-pressure fuel reservoir for supplying a plurality of injectors which are used to inject fuel into the combustion chamber of the internal combustion engine.
Ein derartiges Common-Rail -Kraftstoffeinspritzsystem ist z.B. in der DE 197 28 111 beschrieben. In herkömmlichen Common-Rail-Einspritzsystemen fördert eine Hochdruckpumpe, eventuell unter Zuhilfenahme einer Vorförderpumpe, den einzuspritzenden Kraftstoff aus einem Tank in den zentralen Kraftstoffhochdruckspeicher, der als Common-Rail bezeichnet wird. Von dem Rail führen Kraftstoffleitungen zu den einzelnen Injektoren, die den Zylindern derSuch a common rail fuel injection system is e.g. described in DE 197 28 111. In conventional common-rail injection systems, a high-pressure pump, possibly with the aid of a prefeed pump, conveys the fuel to be injected from a tank into the central high-pressure fuel reservoir, which is referred to as a common rail. Fuel lines run from the rail to the individual injectors, which are the cylinders of the
Brennkraftmaschine zugeordnet sind. Die Injektoren werden in Abhängigkeit von den Betriebsparametern der Brennkraftmaschine einzeln von der Motorelektronik angesteuert, um Kraftstoff in den Brennraum der Brennkraftmaschine einzuspritzen. Durch denInternal combustion engine are assigned. Depending on the operating parameters of the internal combustion engine, the injectors are individually controlled by the engine electronics in order to inject fuel into the combustion chamber of the internal combustion engine. By the
Kraftstoffhochdruckspeicher sind die Druckerzeugung und die Einspritzung voneinander entkoppelt. Aufgabe der Erfindung ist es, das bekannte Common-Rail - Kraftstoffeinspritzsystem dahingehend zu verbessern, dass die Beanspruchung der Hochdruckpumpe reduziert wird. Außerdem soll das erfindungsgemäße Common-Rail - Kraftstoffeinspritzsystem einfach aufgebaut und kostengünstig herstellbar sein.High-pressure fuel accumulators separate the pressure generation and the injection from each other. The object of the invention is to improve the known common rail fuel injection system in such a way that the stress on the high pressure pump is reduced. In addition, the common rail fuel injection system according to the invention should be simple in construction and inexpensive to manufacture.
Die Aufgabe ist bei einem Com on-Rail-The task is with a Com on Rail
Kraftstoffeinspritzsystem für Brennkraftmaschinen, mit einem Kraftstoffhochdruckspeicher zur Versorgung mehrerer Injektoren, die dazu dienen, Kraftstoff in den Brennraum der Brennkraftmaschine einzuspritzen, dadurch gelöst, dass der Kraftstoffhochdruckspeicher über eine hydraulische Übersetzungseinrichtung mit einem Niederdruckspeicher hydraulisch gekoppelt ist. Durch dieFuel injection system for internal combustion engines, with a high-pressure fuel reservoir for supplying a plurality of injectors which serve to inject fuel into the combustion chamber of the internal combustion engine, in that the high-pressure fuel reservoir is hydraulically coupled to a low-pressure reservoir via a hydraulic transmission device. Through the
Übersetzungseinrichtung kann der Niederdruckspeicher zur Kraftstoffhochdruckerzeugung verwendet werden. Auf eine Hochdruckpumpe, wie sie in herkömmlichen Common-Rail - Kraftstoffeinspritzsystemen verwendet wird, kann ganz verzichtet werden.The low-pressure accumulator can be used to generate high-pressure fuel. A high-pressure pump, as used in conventional common rail fuel injection systems, can be dispensed with entirely.
Eine besondere Ausführungsart der Erfindung ist dadurch gekennzeichnet, dass die hydraulische Übersetzungseinrichtung mindestens einen Übersetzerkolben umfasst, dessen Stirnfläche auf der mit Niederdruck beaufschlagten Primärseite größer ist als dessen Stirnfläche auf der entgegengesetzten Sekundärseite. Der Übersetzerkolben stellt eine einfach aufgebaute Übersetzungseinrichtung dar, durch die der Kraftstoff mit Hochdruck beaufschlagt werden kann. Durch den Übersetzerkolben ist die Niederdruckseite des erfindungsgemäßen Common-Rail -Kraftstoffeinspritzsyste s von der Hochdruckseite getrennt.A special embodiment of the invention is characterized in that the hydraulic transmission device comprises at least one transmission piston, the end face of which is larger on the primary side subjected to low pressure than the end face of which is on the opposite secondary side. The booster piston is a simply constructed booster device through which the fuel can be subjected to high pressure. The low pressure side of the common rail fuel injection system according to the invention is separated from the high pressure side by the booster piston.
Eine weitere besondere Ausführungsart der Erfindung ist dadurch gekennzeichnet, dass die Sekundärseite des Übersetzerkolbens unter Zwischenschaltung eines ersten Rückschlagventils mit einem Kraftstoffzulauf und unter Zwischenschaltung eines zweiten Rückschlagventils mit dem Kraftstoffhochdruckspeicher in Verbindung steht. Im Saughub des Übersetzerkolbens wird über das erste Rückschlagventil auf der Sekundärseite Kraftstoff aus dem Kraf stoffzulauf angesaugt. Der angesaugte Kraftstoff wird im Förderhub des Übersetzerkolbens mit Hochdruck beaufschlagt und gelangt über das zweite Rückschlagventil in den Kraftstoffhochdruckspeicher.Another special embodiment of the invention is characterized in that the secondary side of the Translator piston with the interposition of a first check valve with a fuel inlet and with the interposition of a second check valve with the high-pressure fuel accumulator in connection. In the suction stroke of the booster piston, fuel is drawn from the fuel supply via the first check valve on the secondary side. The fuel drawn in is subjected to high pressure in the delivery stroke of the booster piston and reaches the high-pressure fuel reservoir via the second check valve.
Eine weitere besondere Ausführungsart der Erfindung ist dadurch gekennzeichnet, dass mehrere Übersetzerkolben parallel geschaltet sind, wobei zwischen den Übersetzerkolben und dem Niederdruckspeicher jeweils eine Stelleinrichtung angeordnet ist. Mit mehreren Übersetzerkolben kann eine größere Kraftstoffmenge mit Hochdruck beaufschlagt werden. Durch die Stelleinrichtung wird die Förderarbeit der Übersetzerkolben koordiniert.A further special embodiment of the invention is characterized in that a plurality of booster pistons are connected in parallel, an actuating device being arranged between the booster piston and the low-pressure accumulator. With several booster pistons, a large amount of fuel can be subjected to high pressure. The conveying work of the translation pistons is coordinated by the actuating device.
Eine weitere besondere Ausführungsart der Erfindung ist dadurch gekennzeichnet, dass die Stelleinrichtung von einem 3/2 -Wegeventil gebildet wird, das die Primärseite des zugehörigen Übersetzerkolbens in der ersten Schaltstellung mit dem Niederdruckspeicher und in der zweitenA further special embodiment of the invention is characterized in that the actuating device is formed by a 3/2 way valve, which forms the primary side of the associated booster piston in the first switching position with the low-pressure accumulator and in the second
Schaltstellung mit einem Kraftstoffablauf verbindet. In der ersten Schaltstellung wird die Primärseite des zugehörigen Übersetzerkolbens mit Niederdruck beaufschlagt, und der Förderhub erfolgt . In der zweiten Schaltstellung der Stelleinrichtung bewegt sich der zugehörigeSwitch position connects with a fuel drain. In the first switching position, the primary side of the associated booster piston is subjected to low pressure and the delivery stroke is carried out. In the second switching position of the adjusting device, the associated one moves
Übersetzerkolben, z.B. unterstützt durch die Vorspannkraft einer Feder, in seine Ausgangsstellung zurück. Dabei kann der im Saughub auf der Primärseite des zugehörigen Übersetzerkolbens verdrängte Kraftstoff über den Kra tstoffablauf entweichen. Eine weitere besondere Ausführungsart der Erfindung ist dadurch gekennzeichnet, dass die Stelleinrichtungen so gesteuert werden, dass sich mindestens ein Übersetzerkolben ständig im Förderhub befindet. Dadurch ist gewährleistet, dass in dem erfindungsgemäßen Common-Rail-The booster piston, for example supported by the biasing force of a spring, returns to its starting position. The fuel displaced in the suction stroke on the primary side of the associated booster piston can escape via the fuel outlet. A further special embodiment of the invention is characterized in that the actuating devices are controlled in such a way that at least one booster piston is constantly in the delivery stroke. This ensures that in the common rail according to the invention
Kraftstoffeinspritzsystem kontinuierlich Druck und Menge gefördert werden.Fuel injection system pressure and quantity are continuously promoted.
Eine weitere besondere Ausführungsart der Erfindung ist dadurch gekennzeichnet, dass der Niederdruckspeicher über eine Förderpumpe mit Öl versorgt wird. Das hat den Vorteil, dass das Fördermedium auch zur Schmierung der Förderpumpe verwendet werden kann. Ein separater Schmierkreislauf ist nicht erforderlich.Another particular embodiment of the invention is characterized in that the low-pressure accumulator is supplied with oil via a feed pump. This has the advantage that the pumped medium can also be used to lubricate the pump. A separate lubrication circuit is not necessary.
Eine weitere besondere Ausführungsart der Erfindung ist dadurch gekennzeichnet, dass an den Niederdruckspeicher weitere hydraulisch betätigbare Komponenten, wie Bremseinrichtungen, hydraulische Ventilsteuerungen usw., angeschlossen sind. Das erfindungsgemäße Common-Rail-A further special embodiment of the invention is characterized in that further hydraulically actuable components, such as braking devices, hydraulic valve controls, etc., are connected to the low-pressure accumulator. The common rail according to the invention
Kraftstoffeinspritzsystem kann auf diese Art und Weise in das Öl -Hydraulik-Management der Brennkraftmaschine integriert werden.In this way, the fuel injection system can be integrated into the oil hydraulic management of the internal combustion engine.
Weitere Vorteile, Merkmale und Einzelheiten der Erfindung ergeben sich aus der nachfolgenden Beschreibung, in der unter Bezugnahme auf die Zeichnung ein Ausführungsbeispiel der Erfindung im Einzelnen beschrieben ist. Dabei können die in den Ansprüchen und in der Beschreibung erwähnten Merkmale jeweils einzeln für sich oder in beliebiger Kombination erfindungswesentlich sein.Further advantages, features and details of the invention result from the following description, in which an embodiment of the invention is described in detail with reference to the drawing. The features mentioned in the claims and in the description can each be essential to the invention individually or in any combination.
In Fig. 1 ist ein Hydraulikschaltplan in vereinfachter Form dargestellt, um das erfindungsgemäße Common-Rail - Kraftstoffeinspritzsystem zu verdeutlichen. EineA hydraulic circuit diagram is shown in simplified form in FIG. 1 in order to illustrate the common rail fuel injection system according to the invention. A
Förderpumpe 1 saugt aus einem (nicht dargestellten) Vorratsbehälter Hydrauliköl an. Das angesaugte Hydrauliköl wird von der Förderpumpe 1 über eine Leitung 2 in einen Niederdruckspeicher 3 gefördert . Über eine beispielhaft dargestellte Leitung 4 ist der Niederdruckspeicher 3 mit einer hydraulischen Ventilsteuerung (nicht dargestellt) verbunden. In dem Niederdruckspeicher 3 herrscht ein Druck von 100 - 300 bar. Selbstverständlich kann der Niederdruckspeicher 3 auch mit einem hydraulischen Bremssystem in Verbindung stehen.Feed pump 1 sucks from a (not shown) Hydraulic oil reservoir on. The suctioned hydraulic oil is conveyed by the feed pump 1 via a line 2 into a low-pressure accumulator 3. The low-pressure accumulator 3 is connected to a hydraulic valve control (not shown) via a line 4 shown as an example. A pressure of 100-300 bar prevails in the low-pressure accumulator 3. Of course, the low pressure accumulator 3 can also be connected to a hydraulic brake system.
Der Niederdruckspeicher 3 steht über zwei Leitungen 5, 6 mit zwei Stelleinrichtungen 7, 8 in Verbindung. Bei den Stelleinrichtungen 7, 8 handelt es sich um 3/2 -Wegeventile .The low-pressure accumulator 3 is connected to two actuating devices 7, 8 via two lines 5, 6. The actuating devices 7, 8 are 3/2 directional valves.
In den Stelleinrichtungen 7, 8 ist jeweils ein Ventilglied 9, 10 hin- und herbewegbar aufgenommen. Das Ventilglied 9, 10 ist zwischen einem ersten Ventilsitz 11, 12 und einem zweiten Ventilsitz 13, 14 verschiebbar.In the actuating devices 7, 8, a valve member 9, 10 is received in a reciprocating manner. The valve member 9, 10 is displaceable between a first valve seat 11, 12 and a second valve seat 13, 14.
Wenn sich das Ventilglied 9, 10 an seinem zweitenIf the valve member 9, 10 on its second
Ventilsitz 13, 14 in Anlage befindet, ist die von dem Niederdruckspeicher 3 kommende Leitung 5, 6 mit einer Leitung 17, 18 verbunden. Die Leitung 17, 18 mündet in einen Zylinder 19, 20.Valve seat 13, 14 is in contact, the line 5, 6 coming from the low-pressure accumulator 3 is connected to a line 17, 18. The line 17, 18 opens into a cylinder 19, 20.
In dem Zylinder 19, 20 ist ein Übersetzerkolben 21, 22 hin- und herbewegbar aufgenommen. Auf der Primärseite 23, 24 des Zylinders 19, 20 ist eine Stirnfläche 25, 26 des Übersetzerkolbens 21, 22 mit Niederdruck beaufschlagt. Auf der Sekundärseite 27, 28 des Zylinders 19, 20 ist eineIn the cylinder 19, 20, a booster piston 21, 22 is received in a reciprocating manner. On the primary side 23, 24 of the cylinder 19, 20, an end face 25, 26 of the booster piston 21, 22 is subjected to low pressure. On the secondary side 27, 28 of the cylinder 19, 20 is one
Feder 29, 30 gegen den Übersetzerkolben 21, 22 vorgespannt. Außerdem ist auf der Sekundärseite 27, 28 des Zylinders 19, 20 an dem Übersetzerkolben 21, 22 ein Stößel 31, 32 ausgebildet. Der Stößel 31, 32 ragt in eine Kraftstoffleitung 33, 34. Die primärseitige Stirnfläche 25, 26 des Übersetzerkolbens 21, 22 ist ebenso wie die sekundärseitige Stirnfläche 45, 46 des Stößels 31, 32 kreisförmig. Allerdings ist die primärseitige Stirnfläche 25, 26 des Übersetzerkolbens 21, 22 deutlich größer als die sekundärseitige Stirnfläche 45, 46 des Stößels 31, 32. Dadurch wird erreicht, dass der auf der Primärseite 23, 24 herrschende Niederdruck in auf der Sekundärseite 27, 28 herrschenden Hochdruck übersetzt wird.Spring 29, 30 biased against the booster piston 21, 22. In addition, a plunger 31, 32 is formed on the secondary side 27, 28 of the cylinder 19, 20 on the booster piston 21, 22. The plunger 31, 32 projects into a fuel line 33, 34. The primary-side end surface 25, 26 of the booster piston 21, 22, like the secondary-side end surface 45, 46 of the plunger 31, 32, is circular. However, the primary end face 25, 26 of the booster piston 21, 22 is significantly larger than the secondary end face 45, 46 of the tappet 31, 32. This ensures that the low pressure prevailing on the primary side 23, 24 prevails in the secondary side 27, 28 High pressure is translated.
Wenn der Druck auf der Sekundärseite 27, 28 einen vorgegebenen Grenzwert überschreitet, öffnet ein am Ende der Kraftstoffleitung 33, 34 angeordnetes Rückschlagventil 39, 40, und der mit Hochdruck beaufschlagte Kraftstoff gelangt in einen Kraftstoffhochdruckspeicher 41. Der Kraftstoffhochdruckspeicher 41 wiederum ist überIf the pressure on the secondary side 27, 28 exceeds a predetermined limit value, a check valve 39, 40 arranged at the end of the fuel line 33, 34 opens, and the high-pressure fuel reaches a high-pressure fuel reservoir 41. The high-pressure fuel reservoir 41 is in turn over
KraftstoffHochdruckleitungen 42 mit den Injektoren der Brennkraftmaschine verbunden.High-pressure fuel lines 42 connected to the injectors of the internal combustion engine.
Im sogenannten Förderhub bewegt sich der Übersetzerkolben 21, 22 entgegen der Vorspannkraft der Feder 29, 30 von der Primärseite 23, 24 zur Sekundärseite 27, 28 des Zylinders 19, 20. Wenn der Förderhub des Übersetzerkolbens 21, 22 beendet ist, schaltet die Stelleinrichtung 7, 8, und das Ventilglied 9, 10 verschiebt sich von dem zweiten Ventilsitz 13, 14 an den ersten Ventilsitz 11, 12. Wenn sich das Ventilglied 9, 10 an dem ersten Ventilsitz 11, 12 in Anlage befindet, steht die Leitung 17, 18 mit einem Kraftstoffablauf 15, 16 in Verbindung. In dieser Ventilstellung kann der in der Kraftstoffleitung 17, 18 enthaltene Kraftstoff in den Kraftstoffablauf 15, 16 entweichen. Der damit verbundene Druckverlust in der Leitung 17, 18 und die Vorspannkraft der Feder 29, 30 sorgen dafür, dass sich der Übersetzerkolben von der Sekundärseite 27, 28 zur Primärseite 23, 24 des Zylinders 19, 20 bewegt. Bei dieser sogenannten Saughubbewegung des Übersetzerkolbens 21, 22 wird Kraftstoff aus dem KraftstoffZulauf 35, 36 über das Rückschlagventil 37, 38 in die Kraftstoffleitung 33, 34 angesaugt. Wenn die Saughubbewegung des Übersetzerkolbens 21, 22 beendet ist, schaltet die Stelleinrichtung 7, 8, so dass das Ventilglied 9, 10 wieder an dem zweiten Ventilsitz 13, 14 in Anlage kommt .In the so-called delivery stroke, the booster piston 21, 22 moves against the biasing force of the spring 29, 30 from the primary side 23, 24 to the secondary side 27, 28 of the cylinder 19, 20. When the delivery stroke of the booster piston 21, 22 has ended, the actuating device 7 switches , 8, and the valve member 9, 10 moves from the second valve seat 13, 14 to the first valve seat 11, 12. When the valve member 9, 10 is in contact with the first valve seat 11, 12, the line 17, 18 with a fuel drain 15, 16 in connection. In this valve position, the fuel contained in the fuel line 17, 18 can escape into the fuel outlet 15, 16. The associated pressure loss in the line 17, 18 and the biasing force of the spring 29, 30 ensure that the booster piston moves from the secondary side 27, 28 to the primary side 23, 24 of the cylinder 19, 20. During this so-called suction stroke movement of the booster piston 21, 22, fuel is released from the Fuel inlet 35, 36 is sucked into the fuel line 33, 34 via the check valve 37, 38. When the suction stroke movement of the booster piston 21, 22 has ended, the actuating device 7, 8 switches, so that the valve member 9, 10 comes into contact with the second valve seat 13, 14 again.
Über eine (nicht dargestellte) Steuereinrichtung wird die Bewegung der beiden Übersetzerkolben 21, 22 so koordiniert, dass zuerst der Übersetzerkolben 22 fördert. Kurz bevor der Übersetzerkolben 22 seinen Hubanschlag erreicht, beginnt der Übersetzerkolben 21 zu fördern. Durch die Koordination der Förder- und Saughubbewegung der Übersetzerkolben 21, 22 wird erreicht, dass koninuierlich eine ausreichende Menge Kraftstoff mit Hochdruck beaufschlagt und in den Hochdruckspeicher 41 gefördert wird.The movement of the two booster pistons 21, 22 is coordinated via a control device (not shown) in such a way that the booster piston 22 delivers first. Shortly before the booster piston 22 reaches its stroke stop, the booster piston 21 begins to deliver. The coordination of the delivery and suction stroke movement of the booster pistons 21, 22 ensures that a sufficient amount of fuel is continuously supplied with high pressure and delivered to the high pressure accumulator 41.
Die Übersetzerkolben 21, 22 sorgen dafür, dass aus dem Niederdruck auf der Primärseite 23, 24 Hochdruck auf der Sekundärseite 27, 28 erzeugt wird. Das Rückschlagventil 37, 38 dient zur Wiederbefüllung. Die Rückschlagventile 39, 40 dienen dazu, den Druck in dem Kraftstoffhochdruckspeicher 41 zu halten. The booster pistons 21, 22 ensure that high pressure is generated on the secondary side 27, 28 from the low pressure on the primary side 23, 24. The check valve 37, 38 is used for refilling. The check valves 39, 40 serve to maintain the pressure in the high-pressure fuel accumulator 41.

Claims

Ansprüche Expectations
1. Common-Rail-Kraftstoffeinspritzsystem für Brennkraftmaschinen, mit einem Kraftstoffhochdruckspeicher1. Common rail fuel injection system for internal combustion engines, with a high-pressure fuel reservoir
(41) zur Versorgung mehrerer Injektoren, die dazu dienen, Kraftstoff in den Brennraum der Brennkrafcmaschine einzuspritzen, dadurch gekennzeichnet, dass der Kraftstoffhochdruckspeicher (41) über eine hydraulische Übersetzungseinrichtung (17, 19) mit einem Niederdruckspeicher (3) hydraulisch gekoppelt ist.(41) for supplying a plurality of injectors which serve to inject fuel into the combustion chamber of the internal combustion engine, characterized in that the high-pressure fuel accumulator (41) is hydraulically coupled to a low-pressure accumulator (3) via a hydraulic transmission device (17, 19).
2. Common-Rail-Kraftstoffeinspritzsystem nach Anspruch 1, dadurch gekennzeichnet, dass die hydraulische Übersetzungseinrichtung (17, 19) mindestens einen Übersetzerkolben (21, 22) umfasst, dessen Stirnfläche (25, 26) auf der mit Niederdruck beaufschlagten Primärseite (23, 24) größer ist als dessen Stirnfläche (45, 46) auf der entgegengesetzten Sekundärseite (27, 28).2. Common rail fuel injection system according to claim 1, characterized in that the hydraulic transmission device (17, 19) comprises at least one transmission piston (21, 22), the end face (25, 26) of which is acted upon by the low pressure primary side (23, 24 ) is larger than its end face (45, 46) on the opposite secondary side (27, 28).
3. Common-Rail-Kraftstoffeinspritzsystem nach Anspruch 2, dadurch gekennzeichnet, dass die Sekundärseite (27, 28) des3. Common rail fuel injection system according to claim 2, characterized in that the secondary side (27, 28) of the
Übersetzerkolbens (21, 22) unter Zwischenschaltung eines ersten Rückschlagventils (37, 38) mit einemBooster piston (21, 22) with the interposition of a first check valve (37, 38) with a
Kraftstoffzulauf (35, 36) und unter Zwischenschaltung eines zweiten Rückschlagventils (39, 40) mit dem Kraftstoffhochdruckspeicher (41) in Verbindung steht. Fuel inlet (35, 36) and with the interposition of a second check valve (39, 40) with the high-pressure fuel reservoir (41) in connection.
4. Common-Rail-Kraftstoffeinspritzsystem nach Anspruch 3, dadurch gekennzeichnet, dass mehrere Übersetzerkolben (21, 22) parallel geschaltet sind, wobei zwischen den Übersetzerkolben (21, 22) und dem Niederdruckspeicher (3) jeweils eine Stelleinrichtung (7, 8) angeordnet ist.4. Common-rail fuel injection system according to claim 3, characterized in that a plurality of booster pistons (21, 22) are connected in parallel, an adjusting device (7, 8) being arranged between the booster pistons (21, 22) and the low-pressure accumulator (3) is.
5. Common-Rail -Kraftstoffeinspritzsystem nach Anspruch 4, dadurch gekennzeichnet, dass die Stelleinrichtung (7, 8) von einem 3/2-Wegeventil gebildet wird, das die Primärseite (23, 24) des zugehörigen Übersetzerkolbens (21, 22) in der ersten Schaltstellung mit dem Niederdruckspeicher (3) und in der zweiten Schaltstellung mit einem Kraftstoffablauf (15, 16) verbindet.5. Common rail fuel injection system according to claim 4, characterized in that the actuating device (7, 8) is formed by a 3/2-way valve which the primary side (23, 24) of the associated booster piston (21, 22) in the connects the first switching position with the low pressure accumulator (3) and in the second switching position with a fuel outlet (15, 16).
6. Common-Rail-Kraftstoffeinspritzsystem nach Anspruch 4 oder 5, dadurch gekennzeichnet, dass die Stelleinrichtungen (7, 8) so gesteuert werden, dass sich mindestens ein Übersetzerkolben (21, 22) ständig im Förderhub befindet.6. Common rail fuel injection system according to claim 4 or 5, characterized in that the adjusting devices (7, 8) are controlled so that at least one booster piston (21, 22) is constantly in the delivery stroke.
7. Common-Rail-Kraftstoffeinspritzsystem nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass der Niederdruckspeicher (3) über eine Förderpumpe (1) mit Öl - versorgt wird.7. Common rail fuel injection system according to one of the preceding claims, characterized in that the low-pressure accumulator (3) is supplied with oil via a feed pump (1).
8. Common-Rail -Kraftstoffeinspritzsystem nach Anspruch 7, dadurch gekennzeichnet, dass an den Niederdruckspeicher (3) weitere hydraulisch betätigbare Komponenten, wie Bremseinrichtungen, hydraulische Ventilsteuereinrichtungen usw. , angeschlossen sind. 8. Common rail fuel injection system according to claim 7, characterized in that to the low-pressure accumulator (3) further hydraulically actuated components, such as braking devices, hydraulic valve control devices, etc., are connected.
PCT/DE2000/003242 1999-10-08 2000-09-19 Common-rail fuel injection system WO2001027464A1 (en)

Priority Applications (3)

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KR1020017007019A KR20010080693A (en) 1999-10-08 2000-09-19 Common-rail fuel injection system
EP00978945A EP1144856A1 (en) 1999-10-08 2000-09-19 Common-rail fuel injection system
JP2001529578A JP2003511624A (en) 1999-10-08 2000-09-19 Common rail fuel injector

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DE19948464A DE19948464A1 (en) 1999-10-08 1999-10-08 Common rail fuel injection system

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WO2006091392A1 (en) * 2005-02-22 2006-08-31 Siemens Vdo Automotive Corporation Common rail system with pressure amplification
DE102005044046B4 (en) * 2005-09-15 2007-01-18 Adrian Verstallen Device for producing a diesel-oil-water microemulsion and for injecting this emulsion into a diesel engine
CN102619739B (en) * 2012-04-09 2015-04-15 台州巨力工具有限公司 Variable plunger pump

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DE19646581A1 (en) * 1996-11-12 1998-05-14 Bosch Gmbh Robert Fuel injection system
US5823429A (en) * 1996-07-12 1998-10-20 Servojet Products International Hybrid hydraulic electronic unit injector
DE19716221A1 (en) * 1997-04-18 1998-10-22 Bosch Gmbh Robert Fuel injection device with pre and main injection in internal combustion engines, especially for fuels that are difficult to ignite
DE19728111A1 (en) 1997-07-02 1999-01-07 Bosch Gmbh Robert Fuel injection system

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DE3100725A1 (en) * 1980-12-16 1982-07-01 Gebrüder Sulzer AG, 8401 Winterthur Device for the controlled delivery of fuel in an internal combustion engine
DE3133288A1 (en) * 1981-08-22 1983-03-03 M.A.N. Maschinenfabrik Augsburg-Nürnberg AG, 8900 Augsburg Fuel injection system on an internal combustion engine

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US5823429A (en) * 1996-07-12 1998-10-20 Servojet Products International Hybrid hydraulic electronic unit injector
DE19646581A1 (en) * 1996-11-12 1998-05-14 Bosch Gmbh Robert Fuel injection system
DE19716221A1 (en) * 1997-04-18 1998-10-22 Bosch Gmbh Robert Fuel injection device with pre and main injection in internal combustion engines, especially for fuels that are difficult to ignite
DE19728111A1 (en) 1997-07-02 1999-01-07 Bosch Gmbh Robert Fuel injection system

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DE19948464A1 (en) 2001-04-12
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EP1144856A1 (en) 2001-10-17
CZ20011997A3 (en) 2002-05-15

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