WO2004057177A1 - Fuel-injection device for an internal combustion engine - Google Patents

Fuel-injection device for an internal combustion engine Download PDF

Info

Publication number
WO2004057177A1
WO2004057177A1 PCT/DE2003/004156 DE0304156W WO2004057177A1 WO 2004057177 A1 WO2004057177 A1 WO 2004057177A1 DE 0304156 W DE0304156 W DE 0304156W WO 2004057177 A1 WO2004057177 A1 WO 2004057177A1
Authority
WO
WIPO (PCT)
Prior art keywords
fuel
pump
fuel injection
combustion engine
internal combustion
Prior art date
Application number
PCT/DE2003/004156
Other languages
German (de)
French (fr)
Inventor
Carlos Alvarez-Avila
Dieter Aulich
Claus Westphal
Alexander Redlich
Joerg-Peter Fischer
Régis BLANC
Original Assignee
Robert Bosch Gmbh
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Robert Bosch Gmbh filed Critical Robert Bosch Gmbh
Publication of WO2004057177A1 publication Critical patent/WO2004057177A1/en

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M57/00—Fuel-injectors combined or associated with other devices
    • F02M57/02—Injectors structurally combined with fuel-injection pumps
    • F02M57/022—Injectors structurally combined with fuel-injection pumps characterised by the pump drive
    • F02M57/023—Injectors structurally combined with fuel-injection pumps characterised by the pump drive mechanical
    • 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
    • F02M59/44—Details, components parts, or accessories not provided for in, or of interest apart from, the apparatus of groups F02M59/02 - F02M59/42; Pumps having transducers, e.g. to measure displacement of pump rack or piston
    • 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
    • F02M59/44—Details, components parts, or accessories not provided for in, or of interest apart from, the apparatus of groups F02M59/02 - F02M59/42; Pumps having transducers, e.g. to measure displacement of pump rack or piston
    • F02M59/442—Details, components parts, or accessories not provided for in, or of interest apart from, the apparatus of groups F02M59/02 - F02M59/42; Pumps having transducers, e.g. to measure displacement of pump rack or piston means preventing fuel leakage around pump plunger, e.g. fluid barriers
    • 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
    • F02M59/44—Details, components parts, or accessories not provided for in, or of interest apart from, the apparatus of groups F02M59/02 - F02M59/42; Pumps having transducers, e.g. to measure displacement of pump rack or piston
    • F02M59/445—Selection of particular materials
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B53/00—Component parts, details or accessories not provided for in, or of interest apart from, groups F04B1/00 - F04B23/00 or F04B39/00 - F04B47/00
    • F04B53/14—Pistons, piston-rods or piston-rod connections
    • 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
    • F02M2200/00—Details of fuel-injection apparatus, not otherwise provided for
    • F02M2200/80—Fuel injection apparatus manufacture, repair or assembly
    • F02M2200/8069—Fuel injection apparatus manufacture, repair or assembly involving removal of material from the fuel apparatus, e.g. by punching, hydro-erosion or mechanical operation
    • 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
    • F02M2200/00—Details of fuel-injection apparatus, not otherwise provided for
    • F02M2200/90—Selection of particular materials
    • F02M2200/9038—Coatings
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M47/00—Fuel-injection apparatus operated cyclically with fuel-injection valves actuated by fluid pressure
    • F02M47/02—Fuel-injection apparatus operated cyclically with fuel-injection valves actuated by fluid pressure of accumulator-injector type, i.e. having fuel pressure of accumulator tending to open, and fuel pressure in other chamber tending to close, injection valves and having means for periodically releasing that closing pressure
    • F02M47/027—Electrically actuated valves draining the chamber to release the closing pressure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M59/00—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps
    • F02M59/20—Varying fuel delivery in quantity or timing
    • F02M59/36—Varying fuel delivery in quantity or timing by variably-timed valves controlling fuel passages to pumping elements or overflow passages
    • F02M59/366—Valves being actuated electrically

Definitions

  • the invention is based on one
  • Fuel injection device for an internal combustion engine according to the preamble of claim 1.
  • Such a fuel injection device is known from EP 0 987 431 A.
  • This fuel injection device each has a high-pressure fuel pump and a fuel injection valve connected to it for each cylinder of the internal combustion engine.
  • the high-pressure fuel pump has a pump piston which is tightly guided in a cylinder bore and which delimits a pump work space in the cylinder bore and is connected to the fuel injection valve.
  • the pump piston is driven by a cam drive of the internal combustion engine in one stroke.
  • the cam drive also causes transverse forces on the pump piston, which can lead to seizure and therefore heavy wear on the pump piston and the cylinder bore due to insufficient lubrication of the pump piston.
  • the function of the fuel injection device is impaired, since the pump working chamber can no longer be reliably sealed by the pump piston and fuel can escape from the pump working chamber.
  • the fuel injection device according to the invention with the features according to claim 1 has the advantage over the that the lubrication of the pump piston is improved by the micro-depressions and thus an increased wear resistance of the pump piston and the cylinder bore is achieved.
  • micro-depressions of the pump piston also reduce the leakage of fuel from the pump work space, as a result of which dilution of the lubricating oil of the internal combustion engine can be reduced in the case of a cam drive which is lubricated according to claim 2.
  • the wear resistance of the pump piston can be further improved.
  • FIG. 1 shows a detail of an internal combustion engine with a fuel injection device in a schematic representation
  • FIG. 2 shows a detail of the surface of a pump piston of the fuel injection device in an enlarged representation according to a first exemplary embodiment
  • FIG. 3 shows the pump piston surface according to a second exemplary embodiment
  • FIG. 4 shows the pump piston surface according to a third exemplary embodiment
  • FIG 5 shows the pump piston surface according to a fourth exemplary embodiment.
  • FIG. 1 shows a detail of an internal combustion engine of a motor vehicle, only a part of it a cylinder of the internal combustion engine is shown.
  • the internal combustion engine is preferably a self-igniting internal combustion engine and has one or more cylinders.
  • a fuel injection device is provided, which is preferably designed as a so-called pump-nozzle unit and which has a high-pressure fuel pump 10 and a fuel injection valve 12 connected to it for each cylinder of the internal combustion engine, which form a common structural unit.
  • the fuel injection device is provided, which is preferably designed as a so-called pump-nozzle unit and which has a high-pressure fuel pump 10 and a fuel injection valve 12 connected to it for each cylinder of the internal combustion engine, which form a common structural unit.
  • the fuel injection device is provided, which is preferably designed as a so-called pump-nozzle unit and which has a high-pressure fuel pump 10 and a fuel injection valve 12 connected to it for each cylinder of the internal combustion engine, which form a common structural unit.
  • Fuel injection device can also be designed as a so-called pump-line nozzle system, in which the high-pressure fuel pump and the fuel injection valve of each cylinder are arranged separately from one another and are connected to one another via a line.
  • High-pressure fuel pump 10 has a pump body 14 with a cylinder bore 16, in which a pump piston 18 is tightly guided.
  • the pump piston 18 is at least indirectly by a cam 20 of a camshaft 21 of the internal combustion engine against the force of a return spring
  • a rocker arm 23 can be arranged, which on the one hand on the cam
  • the pump piston 18 delimits a pump working chamber 22 in the cylinder bore 16, in which fuel is compressed under high pressure during the pumping stroke of the pump piston 18.
  • the pump work chamber 22 is supplied with fuel from a fuel reservoir 24 of the motor vehicle, for example by means of a delivery pump 25.
  • the fuel injection valve 12 has a valve body 26 which is connected to the pump body 14 and which can be constructed in several parts, and in which at least one injection valve member 28 in a bore 30 is guided slidably.
  • the valve body 26 has at least one, preferably a plurality of injection openings 32 at its end region facing the combustion chamber of the cylinder of the internal combustion engine.
  • the injection valve member 28 has, for example, an approximately conical sealing surface 34 on its end region facing the combustion chamber, which cooperates with a valve seat 36 formed in the valve body 26 in its end region facing the combustion chamber, from or after which the injection openings 32 lead away.
  • valve body 26 there is an annular space 38 between the injection valve member 28 and the bore 30 towards the valve seat 36, which in its end region facing away from the valve seat 36 merges into a pressure space 40 surrounding the injection valve member 28 by a radial expansion of the bore 30.
  • the injection valve member 28 has a pressure shoulder 42 at the level of the pressure chamber 40 due to a reduction in cross section.
  • a prestressed closing spring 44 engages, by means of which the injection valve member 28 is pressed toward the valve seat 36.
  • the closing spring 44 is arranged in a spring chamber 46 of the valve body 26, which adjoins the bore 30. It can be provided that the first injection valve member 28 of the fuel injection valve 12 is hollow and a second injection valve member is slidably guided therein, by means of which at least one second injection opening is controlled.
  • a further bore 48 in which a control piston 50 is tightly connected, which is connected to the injection valve member 28.
  • the bore 48 is made smaller in diameter than the spring chamber 46.
  • the control piston 50 is connected to the piston rod 51 via a piston rod 51 which is smaller in diameter than the latter
  • the control piston 50 can be formed in one piece with the injection valve member 28, but is preferably connected to the injection valve member 28 as a separate part for reasons of assembly.
  • a channel 60 leads from the pump work chamber 22 through the pump body 14 and the valve body 26 to the pressure chamber 40 of the fuel injection valve 12.
  • a channel 62 leads from the pump work chamber 22 or from the channel 60 to the control pressure chamber 52.
  • a channel 64 which connects, also flows into the control pressure chamber 52 forms a relief area than that at least indirectly can serve the fuel reservoir 24 or another area in which a low pressure prevails.
  • a connection 66 leads from the pump work chamber 22 or from the channel 60 to a relief region 24, which can serve at least indirectly as the fuel reservoir 24, which is controlled by a first electrically operated control valve 68.
  • the control valve 68 can be designed as a 2/2-way valve, as shown in FIG. 1.
  • connection 64 of the control pressure chamber 52 to the relief area 24 is controlled by a second electrically operated control valve 70, which can be designed as a 2/2-way valve.
  • a throttle point 63 is provided in the connection 62 between the control pressure chamber 52 and the pump work chamber 22, and there is one in the connection between the control pressure chamber 52 and the relief chamber 24
  • Throttle point 65 provided.
  • the inflow of fuel from the pump work chamber 22 into the control pressure chamber 52 and the outflow of fuel from the control pressure chamber 52 can be adjusted to a required extent by suitable dimensioning of the throttle points 63, 65.
  • a sufficient inflow of fuel into the control pressure chamber 52 is required for a quick closing of the fuel injection valve 12 and a sufficient outflow of fuel from the control pressure chamber 52 is required for a quick opening of the fuel injection valve 12.
  • Control valves 68, 70 can be an electromagnetic actuator or have a piezo actuator and are controlled by an electronic control device 72.
  • the pressure in the control pressure chamber 52 is controlled by the second control valve 70, wherein when the control valve 70 is closed, at least approximately the same pressure is established in the control pressure chamber 52 as in the pump work chamber 22, while when the control valve 70 is open, a lower pressure in the control pressure chamber 52 results due to the connection to the relief region 24 sets as in the pump work space 22.
  • the total closing force acting on the injection valve member 28 is therefore dependent on the force of the closing spring 44 and on the pressure prevailing in the control pressure chamber 52, which pressure is controlled by the second control valve 70.
  • the control pressure chamber 52 and the second control valve 70 can also be omitted, so that the
  • Opening pressure of the fuel injection valve 12 is determined only by the closing spring 44.
  • the pump piston 18 of the high-pressure pump 10 is shown enlarged in each case in FIGS. 2 to 5.
  • the pump piston 18 is provided with a plurality of micro-depressions 80 at least in a partial area of its surface which is tightly guided in the cylinder bore 16.
  • the width of the micro-depressions 80 is, for example, between approximately 10 ⁇ m and approximately 30 ⁇ m, their depth is, for example, between approximately 2 ⁇ m and approximately 30 ⁇ m and their distance from one another is, for example, between approximately 30 ⁇ m and approximately 150 ⁇ m.
  • the micro-depressions 80 are preferably distributed uniformly over the surface of the pump piston 18.
  • the micro-recesses 80 of the pump piston 18 Fuel that acts as a lubricant is stored and enables good lubrication and thus low friction between the pump piston 18 and the cylinder bore 16.
  • the micro-depressions 80 also act as a labyrinth seal, so that little or no fuel from the pump working chamber 22 between the pump piston 18 and the cylinder bore 16 can emerge and reach the cam drive 20, 21, 23 of the internal combustion engine. This avoids dilution of the lubricating oil of the internal combustion engine.
  • the micro-depressions 80 are designed as cups.
  • the micro-depressions 80 are designed as grooves which can run in the longitudinal direction or in the transverse direction or at any inclination over the circumference of the pump piston 18.
  • the micro-depressions 80 are designed as intersecting grooves.
  • the micro-depressions 80 are designed as grooves running spirally over the circumference of the pump piston 18.
  • the micro-depressions 80 can be introduced into the surface of the pump piston 18, for example by means of laser processing, hard turning, spark erosion or by means of a lithopraphic method.
  • the pump piston 18 and the cylinder bore 16 can be machined by pairing loops.
  • the pump piston 18 can be in addition to the micro-depressions 80 at least in a partial area of it in the Cylinder bore 16 tightly guided surface may be provided with a coating 82 made of wear-resistant material.
  • the coating 82 can in particular consist of carbon or carbon compounds which have a high hardness.
  • first control valve 68 When the first control valve 68 is open, pump piston 18 is supplied with fuel from the fuel reservoir 24 by means of the feed pump 25. When the pump piston 18 moves, the fuel injection begins with a pre-injection, the first control valve 68 being closed by the control device 72, so that the pump working chamber 22 is separated from the relief region 24 and high pressure builds up in the pump working chamber 22 with the pump piston 18 pumping stroke.
  • the second control valve 70 is also closed by the control device 72, so that the control pressure chamber 52 is separated from the relief region 24. In this case, high pressure builds up in the control pressure chamber 52 at least approximately as in the pump work chamber 22.
  • a fuel injection cycle begins with a pre-injection of a small amount of fuel.
  • the second control valve 70 is opened by the control device 72 so that the control pressure chamber 52 with the relief area 24 is connected. Fuel can then flow out of the control pressure chamber 52 via the throttle point 65 to the relief region 24, so that the pressure in the control pressure chamber 52 drops.
  • the injection valve member 28 moves in the opening direction 29 and releases the at least one injection opening 32.
  • the control device 72 closes the second control valve 70, so that the control pressure chamber 52 is separated from the relief region 24.
  • the first control valve 68 remains in its closed position. High pressure builds up in the control pressure chamber 52 as in the pump work chamber 22, so that a large pressure force acts on the control piston 50 in the closing direction. Since the force acting on the injection valve member 28 in the opening direction 29 is now less than that
  • the fuel injection valve 12 closes the sum of the force of the closing spring 44 and the pressure force on the control piston 50. Several successive pre-injections of fuel can also be provided.
  • the second control valve 70 is in turn opened by the control device 72 at a certain point in time and for a certain period of time, so that the pressure in the control pressure chamber 52 drops.
  • the fuel injection valve 12 then opens due to the reduced pressure force on the control piston 50 and the injection valve member 28 moves in the opening direction 29.
  • the second control valve 70 is open, a small amount of fuel flows through the throttle points 63, 65 to the relief chamber 24, but the throttle points can
  • 63,65 are formed with a small flow cross-section, so that the outflowing fuel quantity and the reduction in pressure in the pump work chamber 22 is small.
  • Control valve 70 through the control device 72 in its brought closed switching position, so that the control pressure chamber 52 is separated from the relief region 24 and 52 high pressure builds up in the control pressure chamber. Due to the high pressure in the control pressure chamber 52 and the closing spring 44, a greater force then acts on the injection valve member 28 in the closing direction than in the opening direction 29 and the fuel injection valve 12 closes.
  • the first control valve 68 may be in its open or closed position to complete the main injection. Subsequent to the main injection, a post-injection can be carried out at
  • Fuel injection cycle take place.
  • the second control valve 70 is opened again by the control device 72 at a time determined by this, so that the fuel injection valve 12 opens as a result of the falling pressure in the control pressure chamber 52.
  • the control device 72 opens the first control valve 68 and / or closes the second control valve 70 so that the fuel injection valve 12 closes.

Landscapes

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

Abstract

The invention relates to a fuel-injection device comprising a respective high-pressure fuel pump (10) and a fuel-injection valve (12), connected to the latter, for each cylinder of the internal combustion engine. Said high-pressure fuel pump (10) has a pump plunger (18), which is guided in a precision fit in a cylinder bore (16) and delimits a pump working chamber (22) in the cylinder bore (16), said chamber being connected to the fuel-injection valve (12). The pump plunger (18) is driven by a cam drive (20, 21, 23) of the internal combustion engine to produce a stroke motion. The pump plunger (18) comprises a plurality of micro-depressions (80), at least on one section of the surface that is guided in a precision fit in the cylinder bore (16).

Description

Kraftstoffeinspritzeinrichtung für eine BrennkraftmaschineFuel injection device for an internal combustion engine
Stand der TechnikState of the art
Die Erfindung geht aus von einerThe invention is based on one
Kraftstoffeinspritzeinrichtung für eine Brennkraftmaschine nach der Gattung des Anspruchs 1.Fuel injection device for an internal combustion engine according to the preamble of claim 1.
Eine solche Kraftstoffeinspritzeinrichtung ist durch die EP 0 987 431 A bekannt. Diese Kraftstoffeinspritzeinrichtung weist jeweils eine Kraftstoffhochdruckpumpe und ein mit dieser verbundenes Kraftstoffeinspritzventil für jeweils einen Zylinder der Brennkraftmaschine auf. Die Kraftstoffhochdruckpumpe weist einen in einer Zylinderbohrung dicht geführten Pumpenkolben auf, der in der Zylinderbohrung einen Pumpenarbeitsraum begrenzt, der mit dem Kraftstoffeinspritzventil verbunden ist. Der Pumpenkolben wird durch einen Nockentrieb der Brennkraftmaschine in einer Hubbewegung angetrieben. Durch den Nockentrieb werden dabei auch Querkrafte auf den Pumpenkolben verursacht, die infolge unzureichender Schmierung des Pumpenkolbens zu einem Fressen und daher starkem Verschleiß des Pumpenkolbens und der Zylinderbohrung fuhren können. Hierdurch wird die Funktion der Kraftstoffeinspritzeinrichtung beeinträchtigt, da der Pumpenarbeitsraum durch den Pumpenkolben nicht mehr zuverlässig abgedichtet werden kann und Kraftstoff aus dem Pumpenarbeitsraum austreten kann.Such a fuel injection device is known from EP 0 987 431 A. This fuel injection device each has a high-pressure fuel pump and a fuel injection valve connected to it for each cylinder of the internal combustion engine. The high-pressure fuel pump has a pump piston which is tightly guided in a cylinder bore and which delimits a pump work space in the cylinder bore and is connected to the fuel injection valve. The pump piston is driven by a cam drive of the internal combustion engine in one stroke. The cam drive also causes transverse forces on the pump piston, which can lead to seizure and therefore heavy wear on the pump piston and the cylinder bore due to insufficient lubrication of the pump piston. As a result, the function of the fuel injection device is impaired, since the pump working chamber can no longer be reliably sealed by the pump piston and fuel can escape from the pump working chamber.
Vorteile der ErfindungAdvantages of the invention
Die erfindungsgemaße Kraftstoffeinspritzeinrichtung mit den Merkmalen gemäß Anspruch 1 hat demgegenüber den Vorteil, dass die Schmierung des Pumpenkolbens durch die Mikrovertiefungen verbessert ist und somit eine erhöhte Verschleißbestandigkeit des Pumpenkolbens und der Zylinderbohrung erreicht ist.The fuel injection device according to the invention with the features according to claim 1 has the advantage over the that the lubrication of the pump piston is improved by the micro-depressions and thus an increased wear resistance of the pump piston and the cylinder bore is achieved.
In den abhangigen Ansprüchen sind vorteilhafte Ausgestaltungen und Weiterbildungen der erfindungsgemaßen Kraftstoffeinspritzeinrichtung angegeben. Durch die Mikrovertiefungen des Pumpenkolbens wird auch die Leckage von Kraftstoff aus dem Pumpenarbeitsraum verringert, wodurch eine Verdünnung des Schmieröls der Brennkraftmaschine bei einem gemäß Anspruch 2 olgeschmierten Nockentrieb verringert werden kann. Durch die Weiterbildung gemäß Anspruch 7 kann die Verschleißbestandigkeit des Pumpenkolbens weiter verbessert werden.Advantageous refinements and developments of the fuel injection device according to the invention are specified in the dependent claims. The micro-depressions of the pump piston also reduce the leakage of fuel from the pump work space, as a result of which dilution of the lubricating oil of the internal combustion engine can be reduced in the case of a cam drive which is lubricated according to claim 2. Through the development according to claim 7, the wear resistance of the pump piston can be further improved.
Zeichnungdrawing
Ein Ausfuhrungsbeispiel der Erfindung ist in der Zeichnung dargestellt und in der nachfolgenden Beschreibung naher erläutert. Es zeigen Figur 1 ausschnittsweise eine Brennkraftmaschine mit einer Kraftstoffeinspritzeinrichtung in schematischer Darstellung, Figur 2 ausschnittsweise die Oberflache eines Pumpenkolbens der Kraftstoffeinspritzeinrichtung in vergrößerter Darstellung gemäß einem ersten Ausfuhrungsbeispiel, Figur 3 die Pumpenkolbenoberflache gemäß einem zweiten Ausfuhrungsbeispiel, Figur 4 die Pumpenkolbenoberflache gemäß einem dritten Ausfuhrungsbeispiel und Figur 5 die Pumpenkolbenoberflache gemäß einem vierten Ausfuhrungsbeispiel .An exemplary embodiment of the invention is shown in the drawing and explained in more detail in the following description. 1 shows a detail of an internal combustion engine with a fuel injection device in a schematic representation, FIG. 2 shows a detail of the surface of a pump piston of the fuel injection device in an enlarged representation according to a first exemplary embodiment, FIG. 3 shows the pump piston surface according to a second exemplary embodiment, FIG. 4 shows the pump piston surface according to a third exemplary embodiment and FIG 5 shows the pump piston surface according to a fourth exemplary embodiment.
Beschreibung der AusfuhrungsbeispieleDescription of the exemplary embodiments
In Figur 1 ist ausschnittsweise eine Brennkraftmaschine eines Kraftfahrzeugs dargestellt, wobei lediglich ein Teil eines Zylinders der Brennkraftmaschine dargestellt ist. Die Brennkraftmaschine ist vorzugsweise eine selbstzundende Brennkraftmaschine und weist einen oder mehrere Zylinder auf. Für jeden Zylinder der Brennkraftmaschine ist eine Kraftstoffeinspritzeinrichtung vorgesehen, die vorzugsweise als sogenannte Pumpe-Duse-Einheit ausgebildet ist und die für jeden Zylinder der Brennkraftmaschine jeweils eine Kraftstoffhochdruckpumpe 10 und ein mit dieser verbundenes Kraftstoffeinspritzventil 12 aufweist, die eine gemeinsame Baueinheit bilden. Alternativ kann dieFIG. 1 shows a detail of an internal combustion engine of a motor vehicle, only a part of it a cylinder of the internal combustion engine is shown. The internal combustion engine is preferably a self-igniting internal combustion engine and has one or more cylinders. For each cylinder of the internal combustion engine, a fuel injection device is provided, which is preferably designed as a so-called pump-nozzle unit and which has a high-pressure fuel pump 10 and a fuel injection valve 12 connected to it for each cylinder of the internal combustion engine, which form a common structural unit. Alternatively, the
Kraftstoffeinspritzeinrichtung auch als sogenanntes Pumpe- Leitung-Duse-System ausgebildet sein, bei dem die Kraftstoffhochdruckpumpe und das Kraftstoffeinspritzventil jedes Zylinders getrennt voneinander angeordnet und über eine Leitung miteinander verbunden sind. DieFuel injection device can also be designed as a so-called pump-line nozzle system, in which the high-pressure fuel pump and the fuel injection valve of each cylinder are arranged separately from one another and are connected to one another via a line. The
Kraftstoffhochdruckpumpe 10 weist einen Pumpenkorper 14 mit einer Zylinderbohrung 16 auf, in der ein Pumpenkolben 18 dicht gefuhrt ist. Der Pumpenkolben 18 wird zumindest mittelbar durch einen Nocken 20 einer Nockenwelle 21 der Brennkraftmaschine entgegen der Kraft einer RuckstellfederHigh-pressure fuel pump 10 has a pump body 14 with a cylinder bore 16, in which a pump piston 18 is tightly guided. The pump piston 18 is at least indirectly by a cam 20 of a camshaft 21 of the internal combustion engine against the force of a return spring
19 in einer Hubbewegung angetrieben wird. Zwischen dem Nocken 20 und dem Pumpenkolben 18 kann beispielsweise ein Kipphebel 23 angeordnet sein, der einerseits auf dem Nocken19 is driven in one stroke. Between the cam 20 and the pump piston 18, for example, a rocker arm 23 can be arranged, which on the one hand on the cam
20 ablauft und der andererseits zumindest mittelbar am Pumpenkolben 18 angreift. Der Pumpenkolben 18 begrenzt in der Zylinderbohrung 16 einen Pumpenarbeitsraum 22, in dem beim Forderhub des Pumpenkolbens 18 Kraftstoff unter Hochdruck verdichtet wird. Dem Pumpenarbeitsraum 22 wird Kraftstoff aus einem Kraftstoffvorratsbehalter 24 des Kraftfahrzeugs zugeführt, beispielsweise mittels einer Forderpumpe 25.20 expires and which, on the other hand, acts at least indirectly on the pump piston 18. The pump piston 18 delimits a pump working chamber 22 in the cylinder bore 16, in which fuel is compressed under high pressure during the pumping stroke of the pump piston 18. The pump work chamber 22 is supplied with fuel from a fuel reservoir 24 of the motor vehicle, for example by means of a delivery pump 25.
Das Kraftstoffeinspritzventil 12 weist einen mit dem Pumpenkorper 14 verbundenen Ventilkorper 26 auf, der mehrteilig ausgebildet sein kann, und in dem wenigstens ein Einspritzventilglied 28 in einer Bohrung 30 langsverschiebbar gefuhrt ist. Der Ventilkorper 26 weist an seinem dem Brennraum des Zylinders der Brennkraftmaschine zugewandten Endbereich wenigstens eine, vorzugsweise mehrere Einspritzoffnungen 32 auf. Das Einspritzventilglied 28 weist an seinem dem Brennraum zugewandten Endbereich eine beispielsweise etwa kegelförmige Dichtflache 34 auf, die mit einem im Ventilkorper 26 in dessen dem Brennraum zugewandtem Endbereich ausgebildeten Ventilsitz 36 zusammenwirkt, von dem oder nach dem die Einspritzoffnungen 32 abfuhren. Im Ventilkorper 26 ist zwischen dem Einspritzventilglied 28 und der Bohrung 30 zum Ventilsitz 36 hin ein Ringraum 38 vorhanden, der in seinem dem Ventilsitz 36 abgewandten Endbereich durch eine radiale Erweiterung der Bohrung 30 in einen das Einspritzventilglied 28 umgebenden Druckraum 40 übergeht. Das Einspritzventilglied 28 weist auf Hohe des Druckraums 40 durch eine Querschnittsverringerung eine Druckschulter 42 auf. Am dem Brennraum abgewandten Ende des Einspritzventilglieds 28 greift eine vorgespannte Schließfeder 44 an, durch die das Einspritzventilglied 28 zum Ventilsitz 36 hin gedruckt wird. Die Schließfeder 44 ist in einem Federraum 46 des Ventilkorpers 26 angeordnet, der sich an die Bohrung 30 anschließt. Es kann vorgesehen sein, daß das erste Einspritzventilglied 28 des Kraftstoffeinspritzventils 12 hohl ausgebildet ist und in diesem ein zweites Einspritzventilglied verschiebbar gefuhrt ist, durch das wenigstens eine zweite Einspritzoffnung gesteuert wird.The fuel injection valve 12 has a valve body 26 which is connected to the pump body 14 and which can be constructed in several parts, and in which at least one injection valve member 28 in a bore 30 is guided slidably. The valve body 26 has at least one, preferably a plurality of injection openings 32 at its end region facing the combustion chamber of the cylinder of the internal combustion engine. The injection valve member 28 has, for example, an approximately conical sealing surface 34 on its end region facing the combustion chamber, which cooperates with a valve seat 36 formed in the valve body 26 in its end region facing the combustion chamber, from or after which the injection openings 32 lead away. In the valve body 26 there is an annular space 38 between the injection valve member 28 and the bore 30 towards the valve seat 36, which in its end region facing away from the valve seat 36 merges into a pressure space 40 surrounding the injection valve member 28 by a radial expansion of the bore 30. The injection valve member 28 has a pressure shoulder 42 at the level of the pressure chamber 40 due to a reduction in cross section. At the end of the injection valve member 28 facing away from the combustion chamber, a prestressed closing spring 44 engages, by means of which the injection valve member 28 is pressed toward the valve seat 36. The closing spring 44 is arranged in a spring chamber 46 of the valve body 26, which adjoins the bore 30. It can be provided that the first injection valve member 28 of the fuel injection valve 12 is hollow and a second injection valve member is slidably guided therein, by means of which at least one second injection opening is controlled.
An den Federraum 46 kann sich an dessen der Bohrung 30 abgewandtem Ende im Ventilkorper 26 eine weitere Bohrung 48 anschließen, in der ein Steuerkolben 50 dicht gefuhrt ist, der mit dem Einspritzventilglied 28 verbunden ist. Die Bohrung 48 ist im Durchmesser kleiner ausgebildet als der Federraum 46. Der Steuerkolben 50 ist über eine gegenüber diesem im Durchmesser kleinere Kolbenstange 51 mit demAt the end of the bore 30 facing away from the bore 30 in the valve body 26 there can be a further bore 48, in which a control piston 50 is tightly connected, which is connected to the injection valve member 28. The bore 48 is made smaller in diameter than the spring chamber 46. The control piston 50 is connected to the piston rod 51 via a piston rod 51 which is smaller in diameter than the latter
Einspritzventilglied 28 verbunden. Der Steuerkolben 50 kann einstuckig mit dem Einspritzventilglied 28 ausgebildet sein, ist jedoch aus Gründen der Montage vorzugsweise als separates Teil mit dem Einspritzventilglied 28 verbunden.Injection valve member 28 connected. The control piston 50 can be formed in one piece with the injection valve member 28, but is preferably connected to the injection valve member 28 as a separate part for reasons of assembly.
Vom Pumpenarbeitsraum 22 fuhrt durch den Pumpenkorper 14 und den Ventilkorper 26 ein Kanal 60 zum Druckraum 40 des Kraftstoffeinspritzventils 12. Vom Pumpenarbeitsraum 22 oder vom Kanal 60 fuhrt ein Kanal 62 zum Steuerdruckraum 52. In den Steuerdruckraum 52 mundet außerdem ein Kanal 64, der eine Verbindung zu einem Entlastungsbereich bildet, als der zumindest mittelbar der Kraftstoffvorratsbehalter 24 oder ein anderer Bereich dienen kann, in dem ein geringer Druck herrscht. Vom Pumpenarbeitsraum 22 oder vom Kanal 60 fuhrt eine Verbindung 66 zu einem Entlastungsbereich 24 ab, als der zumindest mittelbar der Kraftstoffvorratsbehalter 24 dienen kann, die durch ein erstes elektrisch betätigtes Steuerventil 68 gesteuert wird. Das Steuerventil 68 kann wie in Figur 1 dargestellt als 2/2-Wegeventil ausgebildet sein. Die Verbindung 64 des Steuerdruckraums 52 mit dem Entlastungsbereich 24 wird durch ein zweites elektrisch betätigtes Steuerventil 70 gesteuert, das als 2/2-Wegeventil ausgebildet sein kann. In der Verbindung 62 des Steuerdruckraums 52 mit dem Pumpenarbeitsraum 22 ist eine Drosselstelle 63 vorgesehen und in der Verbindung des Steuerdruckraums 52 mit dem Entlastungsraum 24 ist eineA channel 60 leads from the pump work chamber 22 through the pump body 14 and the valve body 26 to the pressure chamber 40 of the fuel injection valve 12. A channel 62 leads from the pump work chamber 22 or from the channel 60 to the control pressure chamber 52. A channel 64, which connects, also flows into the control pressure chamber 52 forms a relief area than that at least indirectly can serve the fuel reservoir 24 or another area in which a low pressure prevails. A connection 66 leads from the pump work chamber 22 or from the channel 60 to a relief region 24, which can serve at least indirectly as the fuel reservoir 24, which is controlled by a first electrically operated control valve 68. The control valve 68 can be designed as a 2/2-way valve, as shown in FIG. 1. The connection 64 of the control pressure chamber 52 to the relief area 24 is controlled by a second electrically operated control valve 70, which can be designed as a 2/2-way valve. A throttle point 63 is provided in the connection 62 between the control pressure chamber 52 and the pump work chamber 22, and there is one in the connection between the control pressure chamber 52 and the relief chamber 24
Drosselstelle 65 vorgesehen. Durch geeignete Dimensionierung der Drosselstellen 63,65 kann der Zufluß von Kraftstoff aus dem Pumpenarbeitsraum 22 in den Steuerdruckraum 52 und der Abfluß von Kraftstoff aus dem Steuerdruckraum 52 in einem erforderlichen Umfang eingestellt werden. Ein ausreichender Zufluß von Kraftstoff in den Steuerdruckraum 52 ist für ein schnelles Schließen des Kraftstoffeinspritzventils 12 erforderlich und ein ausreichender Abfluß von Kraftstoff aus dem Steuerdruckraum 52 ist für ein schnelles Offnen des Kraftstoffeinspritzventils 12 erforderlich. DieThrottle point 65 provided. The inflow of fuel from the pump work chamber 22 into the control pressure chamber 52 and the outflow of fuel from the control pressure chamber 52 can be adjusted to a required extent by suitable dimensioning of the throttle points 63, 65. A sufficient inflow of fuel into the control pressure chamber 52 is required for a quick closing of the fuel injection valve 12 and a sufficient outflow of fuel from the control pressure chamber 52 is required for a quick opening of the fuel injection valve 12. The
Steuerventile 68,70 können einen elektromagnetischen Aktor oder einen Piezoaktor aufweisen und werden durch eine elektronische Steuereinrichtung 72 angesteuert.Control valves 68, 70 can be an electromagnetic actuator or have a piezo actuator and are controlled by an electronic control device 72.
Durch den im Steuerdruckraum 52 herrschenden Druck wird über die diesen begrenzende Stirnflache des Steuerkolbens 50 eine die Schließfeder 44 unterstutzende Kraft in Schließrichtung auf das Einspritzventilglied 28 erzeugt. Durch das zweite Steuerventil 70 wird der Druck im Steuerdruckraum 52 gesteuert, wobei sich bei geschlossenem Steuerventil 70 zumindest annähernd derselbe Druck im Steuerdruckraum 52 einstellt wie im Pumpenarbeitsraum 22 wahrend sich bei geöffnetem Steuerventil 70 infolge der Verbindung mit dem Entlastungsbereich 24 ein geringerer Druck im Steuerdruckraum 52 einstellt als im Pumpenarbeitsräum 22. Die auf das Einspritzventilglied 28 in der Summe wirkende Schließkraft ist somit abhangig von der Kraft der Schließfeder 44 und von dem im Steuerdruckraum 52 herrschenden Druck, der durch das zweite Steuerventil 70 gesteuert wird. Der Steuerdruckraum 52 und das zweite Steuerventil 70 können auch entfallen, so dass derDue to the pressure prevailing in the control pressure chamber 52, a force supporting the closing spring 44 in the closing direction on the injection valve member 28 is generated via the end face of the control piston 50 delimiting it. The pressure in the control pressure chamber 52 is controlled by the second control valve 70, wherein when the control valve 70 is closed, at least approximately the same pressure is established in the control pressure chamber 52 as in the pump work chamber 22, while when the control valve 70 is open, a lower pressure in the control pressure chamber 52 results due to the connection to the relief region 24 sets as in the pump work space 22. The total closing force acting on the injection valve member 28 is therefore dependent on the force of the closing spring 44 and on the pressure prevailing in the control pressure chamber 52, which pressure is controlled by the second control valve 70. The control pressure chamber 52 and the second control valve 70 can also be omitted, so that the
Offnungsdruck des Kraftstoffeinspritzventils 12 nur durch die Schließfeder 44 bestimmt wird.Opening pressure of the fuel injection valve 12 is determined only by the closing spring 44.
Der Pumpenkolben 18 der Hochdruckpumpe 10 ist in den Figuren 2 bis 5 jeweils ausschnittsweise vergrößert dargestellt. Der Pumpenkolben 18 ist zumindest in einem Teilbereich seiner in der Zylinderbohrung 16 dicht geführten Oberflache mit einer Vielzahl von Mikrovertiefungen 80 versehen. Die Breite der Mikrovertiefungen 80 betragt beispielsweise zwischen etwa 10 μm und etwa 30 um, deren Tiefe betragt beispielsweise zwischen etwa 2 μm und etwa 30 μm und deren Abstand voneinander betragt beispielsweise zwischen etwa 30 μm und etwa 150 μm. Die Mikrovertiefungen 80 sind vorzugsweise gleichmäßig über die Oberflache des Pumpenkolbens 18 verteilt. Beim Betrieb der Kraftstoffeinspritzeinrichtung wird in den Mikrovertiefungen 80 des Pumpenkolbens 18 der als Schmierstoff wirkende Kraftstoff eingelagert und ermöglicht eine gute Schmierung und damit eine geringe Reibung zwischen dem Pumpenkolben 18 und der Zylinderbohrung 16. Die Mikrovertiefungen 80 wirken ausserdem als eine Labyrinthdichtung, so dass kein oder nur sehr wenig Kraftstoff aus dem Pumpenarbeitsraum 22 zwischen dem Pumpenkolben 18 und der Zylinderbohrung 16 austreten und zum Nockentrieb 20,21,23 der Brennkraftmaschine gelangen kann. Hierdurch wird eine Verdünnung des Schmieröls der Brennkraftmaschine vermieden.The pump piston 18 of the high-pressure pump 10 is shown enlarged in each case in FIGS. 2 to 5. The pump piston 18 is provided with a plurality of micro-depressions 80 at least in a partial area of its surface which is tightly guided in the cylinder bore 16. The width of the micro-depressions 80 is, for example, between approximately 10 μm and approximately 30 μm, their depth is, for example, between approximately 2 μm and approximately 30 μm and their distance from one another is, for example, between approximately 30 μm and approximately 150 μm. The micro-depressions 80 are preferably distributed uniformly over the surface of the pump piston 18. When the fuel injector is in operation, the micro-recesses 80 of the pump piston 18 Fuel that acts as a lubricant is stored and enables good lubrication and thus low friction between the pump piston 18 and the cylinder bore 16. The micro-depressions 80 also act as a labyrinth seal, so that little or no fuel from the pump working chamber 22 between the pump piston 18 and the cylinder bore 16 can emerge and reach the cam drive 20, 21, 23 of the internal combustion engine. This avoids dilution of the lubricating oil of the internal combustion engine.
Bei einem in Figur 2 dargestellten ersten Ausfuhrungsbeispiel sind die Mikrovertiefungen 80 als Napfchen ausgebildet. Bei einem in Figur 3 dargestellten zweiten Ausfuhrungsbeispiel sind die Mikrovertiefungen 80 als Nuten ausgebildet, die in Längsrichtung oder in Querrrichtung oder beliebig geneigt über den Umfang des Pumpenkolbens 18 verlaufen können. Bei einem in Figur 4 dargestellten dritten Ausfuhrungsbeispiel sind die Mikrovertiefungen 80 als sich uberkreuzende Nuten ausgebildet. Bei einem in Figur 5 dargestellten vierten Ausfuhrungsbeispiel sind die Mikrovertiefungen 80 als spiralförmig über den Umfang des Pumpenkolbens 18 verlaufende Nuten ausgebildet.In a first exemplary embodiment shown in FIG. 2, the micro-depressions 80 are designed as cups. In a second exemplary embodiment shown in FIG. 3, the micro-depressions 80 are designed as grooves which can run in the longitudinal direction or in the transverse direction or at any inclination over the circumference of the pump piston 18. In a third exemplary embodiment shown in FIG. 4, the micro-depressions 80 are designed as intersecting grooves. In a fourth exemplary embodiment shown in FIG. 5, the micro-depressions 80 are designed as grooves running spirally over the circumference of the pump piston 18.
Die Mikrovertiefungen 80 können in die Oberflache des Pumpenkolbens 18 beispielsweise mittels Laserbearbeitung, Hartdrehen, Funkenerosion oder mittels eines lithopraphischen Verfahrens eingebracht werden. Um ein möglichst geringes Spiel zwischen dem Pumpenkolben 18 und der Zylinderbohrung 16 zu erreichen können der Pumpenkolben 18 und die Zylinderbohrung 16 durch Paarungsschleifen bearbeitet werden.The micro-depressions 80 can be introduced into the surface of the pump piston 18, for example by means of laser processing, hard turning, spark erosion or by means of a lithopraphic method. In order to achieve as little play as possible between the pump piston 18 and the cylinder bore 16, the pump piston 18 and the cylinder bore 16 can be machined by pairing loops.
Der Pumpenkolben 18 kann zusatzlich zu den Mikrovertiefungen 80 zumindest in einem Teilbereich seiner in der Zylinderbohrung 16 dicht geführten Oberflache mit einer Beschichtung 82 aus verschleißbestandigem Material versehen sein. Die Beschichtung 82 kann insbesondere aus Kohlenstoff oder Kohlenstoffverbindungen bestehen, die eine hohe Harte besitzen.The pump piston 18 can be in addition to the micro-depressions 80 at least in a partial area of it in the Cylinder bore 16 tightly guided surface may be provided with a coating 82 made of wear-resistant material. The coating 82 can in particular consist of carbon or carbon compounds which have a high hardness.
Nachfolgend wird die Funktion derThe function of
Kraftstoffeinspritzeinrichtung erläutert. Beim Saughub desFuel injector explained. During the suction stroke of the
Pumpenkolbens 18 wird diesem bei geöffnetem erstem Steuerventil 68 Kraftstoff aus dem Kraftstoffvorratsbehalter 24 mittels der Forderpumpe 25 zugeführt. Beim Forderhub des Pumpenkolbens 18 beginnt die Kraftstoffeinspritzung mit einer Voreinspritzung, wobei das erste Steuerventil 68 durch die Steuereinrichtung 72 geschlossen wird, so daß der Pumpenarbeitsraum 22 vom Entlastungsbereich 24 getrennt ist und sich im Pumpenarbeitsraum 22 mit dem Forderhub des Pumpenkolbens 18 zunehmend Hochdruck aufbaut. Durch die Steuereinrichtung 72 wird außerdem das zweite Steuerventil 70 geschlossen, so daß der Steuerdruckraum 52 vom Entlastungsbereich 24 getrennt ist. In diesem Fall baut sich im Steuerdruckraum 52 Hochdruck zumindest annähernd wie im Pumpenarbeitsraum 22 auf. Ein Kraftstoffeinspritzzyklus beginnt mit einer Voreinspritzung einer geringen Kraftstoffmenge. Zu einem von der Steuereinrichtung 72 abhangig von Betriebsparametern der Brennkraftmaschine, wie beispielsweise Drehzahl, Last, Temperatur und anderen, bestimmten Zeitpunkt und für eine bestimmte Zeitdauer wird zur Voreinspritzung das zweite Steuerventil 70 durch die Steuereinrichtung 72 geöffnet, so daß der Steuerdruckraum 52 mit dem Entlastungsbereich 24 verbunden ist. Aus dem Steuerdruckraum 52 kann dann Kraftstoff über die Drosselstelle 65 zum Entlastungsbereich 24 abströmen, so dass der Druck im Steuerdruckraum 52 sinkt. Wenn der Druck im Pumpenarbeitsraum 22 und damit im Druckraum 40 des Kraftstoffeinspritzventils 12 so groß ist, dass die durch diesen über die Druckschulter 42 auf das Einspritzventilglied 28 ausgeübte Druckkraft großer ist als die Summe der Kraft der Schließfeder 44 und der auf den Steuerkolben 50 durch den im Steuerdruckraum 52 wirkenden Restdruck wirkenden Druckkraft, so bewegt sich das Einspritzventilglied 28 in Offnungsrichtung 29 und gibt die wenigstens eine Einspritzoffnung 32 frei. Zur Beendigung der Voreinspritzung wird durch die Steuereinrichtung 72 das zweite Steuerventil 70 geschlossen, so dass der Steuerdruckraum 52 vom Entlastungsbereich 24 getrennt ist. Das erste Steuerventil 68 bleibt in seiner geschlossenen Stellung. Im Steuerdruckraum 52 baut sich dabei Hochdruck wie im Pumpenarbeitsraum 22 auf, so dass auf den Steuerkolben 50 eine große Druckkraft in Schließrichtung wirkt. Da nunmehr die auf das Einspritzventilglied 28 in Offnungsrichtung 29 wirkende Kraft geringer ist als dieWhen the first control valve 68 is open, pump piston 18 is supplied with fuel from the fuel reservoir 24 by means of the feed pump 25. When the pump piston 18 moves, the fuel injection begins with a pre-injection, the first control valve 68 being closed by the control device 72, so that the pump working chamber 22 is separated from the relief region 24 and high pressure builds up in the pump working chamber 22 with the pump piston 18 pumping stroke. The second control valve 70 is also closed by the control device 72, so that the control pressure chamber 52 is separated from the relief region 24. In this case, high pressure builds up in the control pressure chamber 52 at least approximately as in the pump work chamber 22. A fuel injection cycle begins with a pre-injection of a small amount of fuel. At a certain point in time and for a certain period of time, which is dependent on operating parameters of the internal combustion engine, for example speed, load, temperature and other, for pilot injection, the second control valve 70 is opened by the control device 72 so that the control pressure chamber 52 with the relief area 24 is connected. Fuel can then flow out of the control pressure chamber 52 via the throttle point 65 to the relief region 24, so that the pressure in the control pressure chamber 52 drops. If the pressure in the pump work chamber 22 and thus in the pressure chamber 40 of the fuel injection valve 12 is so great that the pressure on the pressure shoulder 42 leads to it Injection valve member 28 is greater than the sum of the force of the closing spring 44 and the pressure force acting on the control piston 50 by the residual pressure acting in the control pressure chamber 52, the injection valve member 28 moves in the opening direction 29 and releases the at least one injection opening 32. To end the pilot injection, the control device 72 closes the second control valve 70, so that the control pressure chamber 52 is separated from the relief region 24. The first control valve 68 remains in its closed position. High pressure builds up in the control pressure chamber 52 as in the pump work chamber 22, so that a large pressure force acts on the control piston 50 in the closing direction. Since the force acting on the injection valve member 28 in the opening direction 29 is now less than that
Summe der Kraft der Schließfeder 44 und der Druckkraft auf den Steuerkolben 50 schließt das Kraftstoffeinspritzventil 12. Es können auch mehrere aufeinander folgende Voreinspritzungen von Kraftstoff vorgesehen sein.The fuel injection valve 12 closes the sum of the force of the closing spring 44 and the pressure force on the control piston 50. Several successive pre-injections of fuel can also be provided.
Für eine nachfolgende Haupteinspritzung wird das zweite Steuerventil 70 durch die Steuereinrichtung 72 wiederum zu einem von dieser bestimmten Zeitpunkt und für eine bestimmte Zeitdauer geöffnet, so daß der Druck im Steuerdruckraum 52 sinkt. Das Kraftstoffeinspritzventil 12 öffnet dann infolge der reduzierten Druckkraft auf den Steuerkolben 50 und das Einspritzventilglied 28 bewegt sich in Offnungsrichtung 29. Bei geöffnetem zweitem Steuerventil 70 fließt eine geringe Kraftstoffmenge über die Drosselstellen 63,65 zum Entlastungsraum 24 ab, jedoch können die DrosselstellenFor a subsequent main injection, the second control valve 70 is in turn opened by the control device 72 at a certain point in time and for a certain period of time, so that the pressure in the control pressure chamber 52 drops. The fuel injection valve 12 then opens due to the reduced pressure force on the control piston 50 and the injection valve member 28 moves in the opening direction 29. When the second control valve 70 is open, a small amount of fuel flows through the throttle points 63, 65 to the relief chamber 24, but the throttle points can
63,65 mit kleinem Durchflußquerschnitt ausgebildet werden, so daß die abströmende Kraftstoffmenge und die Verringerung des Drucks im Pumpenarbeitsraum 22 gering ist.63,65 are formed with a small flow cross-section, so that the outflowing fuel quantity and the reduction in pressure in the pump work chamber 22 is small.
Zur Beendigung der Haupteinspritzung wird das zweiteTo finish the main injection, the second one
Steuerventil 70 durch die Steuereinrichtung 72 in seine geschlossene Schaltstellung gebracht, so daß der Steuerdruckraum 52 vom Entlastungsbereich 24 getrennt ist und sich im Steuerdruckraum 52 Hochdruck aufbaut. Auf das Einspritzventilglied 28 wirkt dann bedingt durch den Hochdruck im Steuerdruckraum 52 und die Schließfeder 44 in Schließrichtung eine größere Kraft als in Offnungsrichtung 29 und das Kraftstoffeinspritzventil 12 schließt. Das erste Steuerventil 68 kann sich zur Beendigung der Haupteinspritzung in seiner geöffneten oder geschlossenen Stellung befinden. Anschließend an die Haupteinspritzung kann noch eine Nacheinspritzung beimControl valve 70 through the control device 72 in its brought closed switching position, so that the control pressure chamber 52 is separated from the relief region 24 and 52 high pressure builds up in the control pressure chamber. Due to the high pressure in the control pressure chamber 52 and the closing spring 44, a greater force then acts on the injection valve member 28 in the closing direction than in the opening direction 29 and the fuel injection valve 12 closes. The first control valve 68 may be in its open or closed position to complete the main injection. Subsequent to the main injection, a post-injection can be carried out at
Kraftstoffeinspritzzyklus erfolgen. Zur Nacheinspritzung wird das zweite Steuerventil 70 durch die Steuereinrichtung 72 zu einem durch diese bestimmten Zeitpunkt nochmals geöffnet, so daß das Kraftstoffeinspritzventil 12 infolge des sinkenden Drucks im Steuerdruckraum 52 öffnet. Zur Beendigung der Nacheinspritzung wird durch die Steuereinrichtung 72 das erste Steuerventil 68 geöffnet und/oder das zweite Steuerventil 70 geschlossen, so dass das Kraftstoffeinspritzventil 12 schließt. Fuel injection cycle take place. For post-injection, the second control valve 70 is opened again by the control device 72 at a time determined by this, so that the fuel injection valve 12 opens as a result of the falling pressure in the control pressure chamber 52. To end the post-injection, the control device 72 opens the first control valve 68 and / or closes the second control valve 70 so that the fuel injection valve 12 closes.

Claims

Ansprüche Expectations
1. Kraftstoffeinspritzeinrichtung für eine Brennkraftmaschine mit jeweils einer Kraftstoff ochdruckpumpe (10) und einem mit dieser verbundenen Kraftstoffeinspritzventil (12) für jeden Zylinder der Brennkraftmaschine, wobei die1. Fuel injection device for an internal combustion engine, each having a fuel high-pressure pump (10) and a fuel injection valve (12) connected thereto for each cylinder of the internal combustion engine, the
Kraftstoff ochdruckpumpe (10) einen in einer Zylinderbohrung (16) dicht geführten Pumpenkolben (18) aufweist, der in der Zylinderbohrung (16) einen Pumpenarbeitsraum (22) begrenzt, der mit dem Kraftstoffeinspritzventil (12) verbunden ist, wobei der Pumpenkolben (18) durch einen Nockentrieb (20,21,23) der Brennkraftmaschine in einer Hubbewegung angetrieben wird, dadurch gekennzeichnet, dass der Pumpenkolben (18) zumindest in einem Teilbereich seiner in der Zylinderbohrung (16) dicht geführten Oberflache eine Vielzahl von Mikrovertiefungen (80) aufweist.High-pressure fuel pump (10) has a pump piston (18) which is tightly guided in a cylinder bore (16) and delimits a pump working chamber (22) in the cylinder bore (16), which is connected to the fuel injection valve (12), the pump piston (18) is driven by a cam drive (20, 21, 23) of the internal combustion engine in a lifting movement, characterized in that the pump piston (18) has a plurality of micro-depressions (80) at least in a partial area of its surface which is tightly guided in the cylinder bore (16).
2. Kraftstoffeinspritzeinrichtung nach Anspruch 1, dadurch gekennzeichnet, dass der Nockentrieb (20,21,23) der2. Fuel injection device according to claim 1, characterized in that the cam drive (20,21,23)
Brennkraftmaschine olgeschmiert ist.Internal combustion engine is lubricated.
3. Kraftstoffeinspritzeinrichtung nach Anspruch 1 oder 2, dadurch gekennzeichnet, dass die Mikrovertiefungen (80) als Napfchen ausgebildet sind.3. Fuel injection device according to claim 1 or 2, characterized in that the microwells (80) are designed as cups.
4. Kraftstoffeinspritzeinrichtung nach Anspruch 1 oder 2, dadurch gekennzeichnet, dass die Mikrovertiefungen (80) als Nuten ausgebildet sind. 4. Fuel injection device according to claim 1 or 2, characterized in that the micro-depressions (80) are designed as grooves.
5. Kraftstoffeinspritzeinrichtung nach Anspruch 4, dadurch gekennzeichnet, dass die Nuten (80) sich kreuzen.5. Fuel injection device according to claim 4, characterized in that the grooves (80) intersect.
6. Kraftstoffeinspritzeinrichtung nach Anspruch 4, dadurch gekennzeichnet, dass die Nuten (80) spiralförmig über die6. Fuel injection device according to claim 4, characterized in that the grooves (80) spiral over the
Oberflache des Pumpenkolbens (18) verlaufen.Run surface of the pump piston (18).
7. Kraftstoffeinspritzeinrichtung nach einem der vorstehenden Ansprüche, dadurch gekennzeichnet, dass der Pumpenkolben (18) zumindest in einem Teilbereich seiner in der Zylinderbohrung (16) dicht geführten Oberflache mit einer Beschichtung (82) aus verschleißbestandigem Material, insbesondere aus Kohlenstoff oder Kohlensstoffverbindungen, versehen ist. 7. Fuel injection device according to one of the preceding claims, characterized in that the pump piston (18) is provided at least in a partial area of its surface in the cylinder bore (16) tightly guided with a coating (82) made of wear-resistant material, in particular carbon or carbon compounds ,
PCT/DE2003/004156 2002-12-20 2003-12-17 Fuel-injection device for an internal combustion engine WO2004057177A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE2002159955 DE10259955A1 (en) 2002-12-20 2002-12-20 Fuel injection device for an internal combustion engine
DE10259955.6 2002-12-20

Publications (1)

Publication Number Publication Date
WO2004057177A1 true WO2004057177A1 (en) 2004-07-08

Family

ID=32519181

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/DE2003/004156 WO2004057177A1 (en) 2002-12-20 2003-12-17 Fuel-injection device for an internal combustion engine

Country Status (2)

Country Link
DE (1) DE10259955A1 (en)
WO (1) WO2004057177A1 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2824311A1 (en) * 2013-07-10 2015-01-14 EFI Hightech AG Piston element assembly, and fuel injector with a piston element assembly
WO2015110242A1 (en) * 2014-01-27 2015-07-30 Robert Bosch Gmbh Electromagnetically controlled valve for a high pressure pump and high pressure pump

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102011082740B4 (en) 2011-09-15 2022-03-03 Robert Bosch Gmbh Method for producing a piston pump with a housing and at least one axially movable piston arranged in a piston guide of the housing
IT201700054112A1 (en) 2017-05-18 2018-11-18 Bosch Gmbh Robert PUMP UNIT FOR FUEL SUPPLY TO AN INTERNAL COMBUSTION ENGINE
DE102021211397A1 (en) * 2021-10-08 2023-04-13 Robert Bosch Gesellschaft mit beschränkter Haftung High-pressure fuel pump for a fuel system of an internal combustion engine

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0823551A2 (en) * 1996-08-08 1998-02-11 Toyota Jidosha Kabushiki Kaisha Roller bush for fuel injection pump
WO1999002852A1 (en) * 1997-07-11 1999-01-21 Robert Bosch Gmbh Piston pump for high pressure fuel supply
EP0967384A2 (en) * 1998-04-24 1999-12-29 Sumitomo Electric Industries, Ltd Fuel injection pump
EP0987431A2 (en) * 1998-09-18 2000-03-22 Lucas Industries Limited Fuel injector

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0823551A2 (en) * 1996-08-08 1998-02-11 Toyota Jidosha Kabushiki Kaisha Roller bush for fuel injection pump
WO1999002852A1 (en) * 1997-07-11 1999-01-21 Robert Bosch Gmbh Piston pump for high pressure fuel supply
EP0967384A2 (en) * 1998-04-24 1999-12-29 Sumitomo Electric Industries, Ltd Fuel injection pump
EP0987431A2 (en) * 1998-09-18 2000-03-22 Lucas Industries Limited Fuel injector

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2824311A1 (en) * 2013-07-10 2015-01-14 EFI Hightech AG Piston element assembly, and fuel injector with a piston element assembly
WO2015110242A1 (en) * 2014-01-27 2015-07-30 Robert Bosch Gmbh Electromagnetically controlled valve for a high pressure pump and high pressure pump

Also Published As

Publication number Publication date
DE10259955A1 (en) 2004-07-15

Similar Documents

Publication Publication Date Title
EP1363015A1 (en) Fuel injection system for an internal combustion engine
EP1490592A1 (en) Fuel injection device for an internal combustion engine
DE10162651A1 (en) Fuel injection device for an internal combustion engine
DE10141678A1 (en) Fuel injection device for an internal combustion engine
EP1456525B1 (en) Fuel injection device for an internal combustion engine
WO2004057177A1 (en) Fuel-injection device for an internal combustion engine
WO2002103197A1 (en) Fuel injection device for an internal combustion engine
EP1260705A1 (en) Fuel injection system for internal combustion engine
DE10207045A1 (en) Fuel injection device for a combustion engine, has a high pressure pump with two pistons one of which can assume a passive position
EP1525390A1 (en) Fuel injection device for an internal combustion engine
DE10154802A1 (en) Fuel injection device for an internal combustion engine
DE10155406A1 (en) Fuel injection device for an internal combustion engine
EP1456528A1 (en) Fuel-injection device for an internal combustion engine
EP1203882A2 (en) Injector
DE10359169A1 (en) Fuel injection device for internal combustion engine, has control valve that closes during small stroke of piston to keep valve component in closed position, and control space separated from operating space during big stroke of piston
EP1430219A1 (en) Fuel injection device for an internal combustion engine
EP1384000A1 (en) Fuel injection device for an internal combustion engine
DE10162384A1 (en) Fuel injection device for an internal combustion engine
DE10224694A1 (en) IC engine with fuel injection system supplied by high pressure pump, has reciprocating piston driven via engine camshaft
DE10337848A1 (en) Fuel injection valve for internal combustion engine has piston controlling connection between fuel-filled chamber, low pressure region so connection is at least approximately closed at start of valve element opening and is then opened up
DE10359170A1 (en) Fuel injection device for a combustion engine has two component injection valve with electrical control valve avoiding need for a further control valve
WO2002086305A2 (en) Fuel injection device for an internal combustion engine
EP1601870A1 (en) Fuel injection valve for an internal combustion engine
WO2003027481A1 (en) Fuel injection device for an internal combustion engine
DE10323562A1 (en) Fuel injection device for an internal combustion engine

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): JP US

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IT LU MC NL PT RO SE SI SK TR

121 Ep: the epo has been informed by wipo that ep was designated in this application
122 Ep: pct application non-entry in european phase
NENP Non-entry into the national phase

Ref country code: JP

WWW Wipo information: withdrawn in national office

Country of ref document: JP