EP2249024A1 - Fuel injector - Google Patents

Fuel injector Download PDF

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Publication number
EP2249024A1
EP2249024A1 EP10156162A EP10156162A EP2249024A1 EP 2249024 A1 EP2249024 A1 EP 2249024A1 EP 10156162 A EP10156162 A EP 10156162A EP 10156162 A EP10156162 A EP 10156162A EP 2249024 A1 EP2249024 A1 EP 2249024A1
Authority
EP
European Patent Office
Prior art keywords
valve
valve piston
nozzle needle
chamber
injector
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP10156162A
Other languages
German (de)
French (fr)
Other versions
EP2249024B1 (en
Inventor
Michael Kurz
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Robert Bosch GmbH
Original Assignee
Robert Bosch GmbH
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Filing date
Publication date
Application filed by Robert Bosch GmbH filed Critical Robert Bosch GmbH
Publication of EP2249024A1 publication Critical patent/EP2249024A1/en
Application granted granted Critical
Publication of EP2249024B1 publication Critical patent/EP2249024B1/en
Not-in-force legal-status Critical Current
Anticipated expiration legal-status Critical

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M63/00—Other fuel-injection apparatus having pertinent characteristics not provided for in groups F02M39/00 - F02M57/00 or F02M67/00; Details, component parts, or accessories of fuel-injection apparatus, not provided for in, or of interest apart from, the apparatus of groups F02M39/00 - F02M61/00 or F02M67/00; Combination of fuel pump with other devices, e.g. lubricating oil pump
    • F02M63/0012—Valves
    • F02M63/0031—Valves characterized by the type of valves, e.g. special valve member details, valve seat details, valve housing details
    • F02M63/0049—Combined valve units, e.g. for controlling pumping chamber and injection valve
    • 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
    • F02M51/00—Fuel-injection apparatus characterised by being operated electrically
    • F02M51/06—Injectors peculiar thereto with means directly operating the valve needle
    • F02M51/0603—Injectors peculiar thereto with means directly operating the valve needle using piezoelectric or magnetostrictive operating means
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M63/00—Other fuel-injection apparatus having pertinent characteristics not provided for in groups F02M39/00 - F02M57/00 or F02M67/00; Details, component parts, or accessories of fuel-injection apparatus, not provided for in, or of interest apart from, the apparatus of groups F02M39/00 - F02M61/00 or F02M67/00; Combination of fuel pump with other devices, e.g. lubricating oil pump
    • F02M63/0012—Valves
    • F02M63/0014—Valves characterised by the valve actuating means
    • F02M63/0015—Valves characterised by the valve actuating means electrical, e.g. using solenoid
    • F02M63/0026—Valves characterised by the valve actuating means electrical, e.g. using solenoid using piezoelectric or magnetostrictive actuators
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M63/00—Other fuel-injection apparatus having pertinent characteristics not provided for in groups F02M39/00 - F02M57/00 or F02M67/00; Details, component parts, or accessories of fuel-injection apparatus, not provided for in, or of interest apart from, the apparatus of groups F02M39/00 - F02M61/00 or F02M67/00; Combination of fuel pump with other devices, e.g. lubricating oil pump
    • F02M63/0012—Valves
    • F02M63/0031—Valves characterized by the type of valves, e.g. special valve member details, valve seat details, valve housing details
    • F02M63/0033—Lift valves, i.e. having a valve member that moves perpendicularly to the plane of the valve seat
    • F02M63/0035—Poppet valves, i.e. having a mushroom-shaped valve member that moves perpendicularly to the plane of the valve seat
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M63/00—Other fuel-injection apparatus having pertinent characteristics not provided for in groups F02M39/00 - F02M57/00 or F02M67/00; Details, component parts, or accessories of fuel-injection apparatus, not provided for in, or of interest apart from, the apparatus of groups F02M39/00 - F02M61/00 or F02M67/00; Combination of fuel pump with other devices, e.g. lubricating oil pump
    • F02M63/0012—Valves
    • F02M63/0031—Valves characterized by the type of valves, e.g. special valve member details, valve seat details, valve housing details
    • F02M63/004—Sliding valves, e.g. spool valves, i.e. whereby the closing member has a sliding movement along a seat for opening and closing
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M63/00—Other fuel-injection apparatus having pertinent characteristics not provided for in groups F02M39/00 - F02M57/00 or F02M67/00; Details, component parts, or accessories of fuel-injection apparatus, not provided for in, or of interest apart from, the apparatus of groups F02M39/00 - F02M61/00 or F02M67/00; Combination of fuel pump with other devices, e.g. lubricating oil pump
    • F02M63/0012—Valves
    • F02M63/0031—Valves characterized by the type of valves, e.g. special valve member details, valve seat details, valve housing details
    • F02M63/004—Sliding valves, e.g. spool valves, i.e. whereby the closing member has a sliding movement along a seat for opening and closing
    • F02M63/0042—Sliding valves, e.g. spool valves, i.e. whereby the closing member has a sliding movement along a seat for opening and closing combined with valve seats of the lift valve type
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M63/00—Other fuel-injection apparatus having pertinent characteristics not provided for in groups F02M39/00 - F02M57/00 or F02M67/00; Details, component parts, or accessories of fuel-injection apparatus, not provided for in, or of interest apart from, the apparatus of groups F02M39/00 - F02M61/00 or F02M67/00; Combination of fuel pump with other devices, e.g. lubricating oil pump
    • F02M63/0012—Valves
    • F02M63/0031—Valves characterized by the type of valves, e.g. special valve member details, valve seat details, valve housing details
    • F02M63/0045—Three-way valves
    • 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
    • F02M2200/70—Linkage between actuator and actuated element, e.g. between piezoelectric actuator and needle valve or pump plunger
    • F02M2200/703—Linkage between actuator and actuated element, e.g. between piezoelectric actuator and needle valve or pump plunger hydraulic
    • 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
    • F02M2200/70—Linkage between actuator and actuated element, e.g. between piezoelectric actuator and needle valve or pump plunger
    • F02M2200/703—Linkage between actuator and actuated element, e.g. between piezoelectric actuator and needle valve or pump plunger hydraulic
    • F02M2200/704—Linkage between actuator and actuated element, e.g. between piezoelectric actuator and needle valve or pump plunger hydraulic with actuator and actuated element moving in different directions, e.g. in opposite directions
    • 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
    • F02M2547/00—Special features for fuel-injection valves actuated by fluid pressure
    • F02M2547/001—Control chambers formed by movable sleeves

Definitions

  • the invention relates to an actuator-controlled fuel injector.
  • Fuel injectors in which a nozzle needle is actuated by an actuator to open and close an injection port are known in the art.
  • such injectors In order to realize the necessary stroke of the nozzle needle, such injectors must have a certain minimum length, which can not be fallen below. Such a minimum length limits the capabilities of the injector and causes increased manufacturing and assembly costs.
  • injectors In order to reduce the length at a given stroke of the nozzle needle, injectors are known in which two actuators are connected in series. Injectors with multiple actuators connected in series are complex and expensive to manufacture.
  • An object of the invention is to provide a simple and inexpensive to produce injector, which has the shortest possible length with the largest possible stroke of the nozzle needle.
  • An injector according to the invention for injecting fuel into a combustion chamber of an internal combustion engine has a valve group which is located between a nozzle needle and an actuator, wherein a valve piston bore is formed in the valve group; a valve piston disposed in the valve piston bore that passes through the actuator between a closed position and at least one injection position is movable; a nozzle needle control space whose volume is variable by moving the valve piston; a valve space formed between the valve piston and the valve group and connected to the nozzle needle control space via a servo bore formed in the valve piston; an inlet and a drain, which open into the valve chamber, wherein the mouth of the drain is closed in the valve chamber by the valve piston when the valve piston is in the closed position and wherein the mouth of the drain is open, when the valve piston in a Injection position is located.
  • the necessary stroke of the nozzle needle can be realized with an actuator whose length is significantly reduced compared to a conventional injector.
  • the costs for the actuator can therefore be significantly reduced.
  • the drain can be made smaller than in a conventional injector, so that the control amount can be reduced.
  • the valve piston bore has a lower portion facing the nozzle needle and an upper portion facing the actuator, the lower portion having a larger cross-section than the upper portion.
  • the valve piston has a lower portion facing the nozzle needle and an upper portion facing the actuator, wherein the lower portion has a larger cross section than the upper portion and is fitted in the lower portion of the valve piston bore, that between the lower portion of the valve piston and the valve group is formed a second control chamber.
  • the second control chamber has a larger cross-section than the nozzle needle control chamber.
  • a control chamber bore is formed in the valve piston, which hydraulically connects the nozzle needle control chamber with the second control chamber.
  • a control chamber bore allows effective pressure equalization between the nozzle needle control chamber and the second control chamber.
  • valve space between the nozzle needle and the valve piston is arranged.
  • valve space is formed radially around the valve piston in the valve piston bore. This allows a particularly simple arrangement of the valve chamber and an easy-to-implement design of the inlet and outlet, which open into the valve piston bore.
  • valve piston when the valve piston is in an injection position, the valve piston closes the mouth of the inlet into the valve chamber, and the mouth of the inlet is opened when the valve piston is in the closed position.
  • the inlet is closed when the valve piston is in the injection position, the pressure in the valve chamber during the injection process drops very quickly. This causes a particularly fast movement of the nozzle needle when opening the injection openings and allows very short switching and injection times.
  • a servo box is formed in the servo bore.
  • an inlet or outlet throttle is formed in the inlet and / or in the outlet.
  • the actuator facing the end of the valve piston is connected to a coupler piston.
  • the coupler piston is fitted into a coupler sleeve connected to the actuator such that between the coupler piston and the coupler sleeve is formed a coupler space.
  • the coupler space makes it possible to compensate for temperature-induced changes in length of the components.
  • the actuator is a piezoelectric actuator.
  • Piezoelectric actuators are particularly reliable and have particularly short reaction times, which enable particularly fast injection processes with short switching times.
  • FIG. 1 shows a section through an embodiment of an injector 7 according to the invention.
  • FIG. 2 shows an enlarged view of the valve group of in FIG. 1 shown injector 7 in the closed state.
  • FIG. 3 shows an enlarged view of the valve group in an open state.
  • An inventive injector 7 has a in the FIG. 1 Shown above cylindrical injector body 4 and in the FIG. 1 shown below cylindrical nozzle module 1, which are clamped by a hydraulic nozzle lock nut 58 hydraulically tight.
  • the connection between the nozzle retaining nut 58 and the injector body 4 is additionally sealed by a sealing ring 60.
  • a nozzle needle chamber 56 and a fuel chamber 52 are formed, which are hydraulically connected to each other via at least one connecting bore 54.
  • Two injection openings 8 connect the fuel chamber 52 with a combustion chamber 5, which surrounds the lower end of the nozzle module 1.
  • a nozzle needle 6 is arranged in the nozzle needle chamber 56 and in the fuel chamber 52, which is movable parallel to a longitudinal axis A of the nozzle module 1 between a lower closure position and at least one upper injection position.
  • a lower closing end 10 of the nozzle needle 6 closes the injection openings 8 when the nozzle needle 6 is in the lower closing position, and releases the injection openings 8 when the nozzle needle 6 is in an upper injection position.
  • the nozzle needle chamber 56 and the fuel chamber 52 are filled with pressurized fuel. When the injection openings 8 are released, the fuel flows from the fuel chamber 52 through the injection openings 8 into the combustion chamber 5.
  • An upper control end 6a of the nozzle needle 6 is movably arranged in a control chamber sleeve 15.
  • a nozzle needle spring 12 is arranged around an upper region of the nozzle needle 6 and is supported, on the one hand, on a shoulder 11 formed on the circumference of the nozzle needle 6 and, on the other hand, on the control chamber sleeve 15.
  • the nozzle needle 6 is mounted elastically movable parallel to the longitudinal axis A in the nozzle module 1 and is pressed by the nozzle needle spring 12 in the lower closure position in which it closes the injection openings 8.
  • a valve group 2 is pressure-tight in the nozzle retaining nut 58 fitted.
  • a valve piston bore 32 is formed, in which a valve piston 16 is inserted so that it is movable parallel to the longitudinal axis A of the injector 7.
  • a nozzle needle control chamber 14 is formed, which is bounded on the one hand by the nozzle needle 6, on the other hand by the valve piston 16 and the volume of both by moving the nozzle needle 6 as well can be varied by moving the valve piston 16 parallel to the longitudinal axis A of the injector 7.
  • the valve piston 16 has a lower portion 16a facing the nozzle needle 6 and an upper portion 16b facing away from the nozzle needle 6.
  • the lower portion 16 a of the valve piston 16 in a plane which is aligned at right angles to the longitudinal axis A of the injector 7, a larger cross-section than the upper portion 16 b of the valve piston 16 and is fitted in such a manner in the lower portion of the valve piston bore 32 that on from the nozzle needle 6 side facing away from the lower portion 16a of the valve piston 16 between the valve piston 16 and the valve group 2, a second control chamber 22 is formed, the volume of which is variable by moving the valve piston 16 parallel to the longitudinal axis A.
  • the second control chamber 22 is hydraulically connected to the nozzle needle control chamber 14 through a control chamber bore 20 which extends through the lower portion 16 a of the valve piston 16.
  • valve space 24 is formed between the valve piston 16 and the valve group 2 in the valve piston bore 32, which radially surrounds the valve piston 16.
  • the valve chamber 24 is hydraulically connected to the nozzle needle control chamber 14 by a servo bore 18 formed in the valve piston 16.
  • An inlet 25 hydraulically connected to a fuel feed line 38 opens below valve space 24 in the valve piston bore 32.
  • the fuel feed line 38 is connected to a fuel pump 39, which feeds fuel under high pressure via the fuel feed line 38 into the inlet 25 and via a bore formed in the nozzle module 43 the nozzle needle chamber 56 and through the connecting bore 54 and the fuel chamber 52 filled with fuel.
  • a drain 27 connected to a fuel drain passage 34 terminates above the valve space 24 in the valve piston bore 32.
  • the fuel drain passage 34 is configured to discharge fuel from the injector 7 into a fuel intake device 36.
  • a sealing seat 30 is formed below the mouth of the drain 27 into the valve piston bore 32, which can be opened and closed by moving the valve piston 16 parallel to the longitudinal axis A of the injector 7 and so that by moving the valve piston 16, a hydraulic connection between the drain 27 and the valve chamber 24 can be produced and closed.
  • the hydraulic connection between the valve chamber 24 and the drain 27 is closed when the valve piston 16 is in the upper, closed position and the hydraulic connection is opened when the valve piston 16 is in a lower injection position.
  • a recess 17 is formed around its circumference such that the inlet 25 is hydraulically connected to the valve space 24 when the valve piston 16 is in the upper, closed position, and the valve space 24 hydraulically from the inlet 25 is disconnected when the valve piston 16 is in a lower injection position.
  • a coupler piston 48 is mounted, which is fitted in such a manner arranged above the valve group 2 coupler 44, that between the coupler piston 48 and the coupler 44, a coupler 46 is formed in the Operation is filled with fuel.
  • the volume of the coupler space is variable by moving the coupler piston 48 and / or by moving the coupler sleeve 44.
  • the coupler sleeve 44 is surrounded by a coupler spring 50, which supports the coupler sleeve 44 elastically and parallel to the longitudinal axis A movable on the valve group 2.
  • the coupler sleeve 44 is mechanically coupled to an actuator module 3, which is arranged on the side facing away from the valve group 2 side of the coupler sleeve 44, such that the coupler sleeve 44 by pressing the actuator module 3 against the force of the coupler spring 50 is movable parallel to the longitudinal axis A of the injector 7.
  • the actuator 3 In the closed state of the injector 7, i. if no fuel is to be injected into the combustion chamber 5, the actuator 3 is de-energized.
  • the coupler sleeve 44, the coupler piston 48 and the valve piston 16 are each in an upper position.
  • the sealing seat 30 between the valve chamber 24 and the drain 27 is closed.
  • the valve chamber 24 is in hydraulic communication with the inlet 25, so that in the valve chamber 24, the high system pressure of the fuel system prevails.
  • the valve chamber 24 is in hydraulic communication with the nozzle needle control chamber 14 via the servo bore 18, so that the high fuel pressure also prevails in the nozzle needle control chamber 14.
  • the nozzle needle 6 is pressed by the nozzle needle spring 12 and the pressure prevailing in the nozzle needle control chamber 14 fuel pressure in the lower, closed position in which the nozzle seat 10, the injection ports 8 closes and no fuel from the fuel chamber 52 flows into the combustion chamber 5.
  • the actuator 3 is activated by applying an electrical voltage to an electrical connection 40.
  • the actuator 3 extends and pushes the coupler piston 44 against the force of the coupler spring 50 in the direction of the valve group 2 down.
  • the coupler piston 48 is also pressed in the direction of the valve group 2.
  • the coupler piston 48 pushes the valve piston 16 within the valve piston bore 32 in the direction of the nozzle needle 6 down.
  • the volume of the nozzle needle control chamber 14 is reduced, on the other hand, the volume of the second control chamber 22 is increased.
  • the cross section A1 of the second control chamber 22 is greater than the cross section A2 of the nozzle needle control chamber 14, and the second control chamber 22 is hydraulically connected to the nozzle needle chamber 14 through the control chamber bore 20, the total volume, ie the sum of the volumes of the two control chambers 14, increases , 22, so that the pressure of the fuel in the two control chambers 14, 22 decreases.
  • the reduced pressure in the nozzle needle control chamber 14 is insufficient to keep the nozzle needle 6 in the lower, closed position against a force of the fuel in the fuel chamber 52 acting on a pressure stage 9 formed in the lower portion of the nozzle needle 6.
  • the nozzle needle 6 moves upward under the influence of the force acting on the pressure stage 9.
  • the nozzle seat 10 is opened and fuel from the fuel chamber 52 flows through the injection openings 8 into the combustion chamber 5.
  • the opening of the drain 27 and the closing of the inlet 25 causes, in addition to the previously described increase in the total volume of the control chambers 14 and 22, a further reduction in the pressure in the nozzle needle control chamber 14, whereby an additional upward force acts on the nozzle needle 6.
  • This additional force accelerates the nozzle needle 6 in addition to the direct stroke dNH, which results from the volume change of the control chambers 14, 22, so that the injection openings 8 are opened further and faster. As a result, shorter injection times can be realized.
  • the voltage applied to the actuator 3 is turned off.
  • the length of the actuator 3 decreases and the coupler sleeve 44 is pressed by the coupler spring 50 against the shortened actuator 3 upwards in the direction of the shortened actuator 3.
  • the pressure in the coupler chamber 46 decreases, and the coupler piston 48 and the valve piston 16 connected to it move upwards in the direction of the actuator 3.
  • the increased pressure in the nozzle needle control chamber 14 causes a downward force on the nozzle needle 6, which is sufficient to press the nozzle needle 6 against the force acting on the pressure step 9 upward force in the nozzle seat 10 and to close the injection openings 8. No further Fuel flows through the injection openings 8 from the fuel chamber 52 into the combustion chamber 5 and the injection process is completed.
  • the opening speed and the closing speed of the nozzle needle 6 can be adjusted as required.
  • FIG. 4 shows an alternative embodiment of the valve assembly according to the invention.
  • the inlet 25 opens directly into the valve chamber 24.
  • the hydraulic connection of the inlet 25 with the valve chamber 24 is not interrupted during the injection process.
  • the inlet throttle 26 By a suitable dimensioning of the inlet throttle 26 so the opening speed of the nozzle needle 6 can be adjusted.
  • the nozzle needle 6 can be braked when opening, to prevent the nozzle needle 6 opens faster than desired.
  • FIG. 5 shows a further alternative embodiment of the valve group 2 according to the invention, wherein in the servo bore 18 of the valve piston, a servo throttle 19 is formed.
  • a servo throttle 19 By suitable dimensioning of the servo throttle 19, the servo influence on the direct needle stroke dNH, which results from the change in the volume of the nozzle needle control chamber 14 and the second control chamber 22, can be superimposed with a time delay.
  • a better injection quality is achieved, in particular when injecting small amounts, in which a high injection tolerance and a fast switching is required. This leads to lower exhaust emissions and reduced consumption.

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

Abstract

Fuel injector (7) comprises a valve group (2) arranged between a nozzle needle (6) and an actuator (3), a valve piston (16) arranged in a hole (32) for moving between a closed and an injection position, a control space (14) for moving the valve piston, a valve chamber (24) arranged between the valve piston and the valve group and an inlet (25) and an outlet (27) opening into the valve chamber. Preferred Features: The actuator is a piezo-electric actuator. The valve chamber is formed in the valve hole radially around the valve piston.

Description

Die Erfindung betrifft einen aktorgesteuerten Kraftstoffinjektor.The invention relates to an actuator-controlled fuel injector.

Stand der TechnikState of the art

Kraftstoffinjektoren, in denen eine Düsennadel durch einen Aktor betätigt wird, um eine Einspritzöffnung zu öffnen und zu verschließen, sind im Stand der Technik bekannt. Um den notwendigen Hub der Düsennadel zu verwirklichen, müssen solche Injektoren eine gewisse Mindestbaulänge aufweisen, die nicht unterschritten werden kann. Eine solche Mindestbaulänge beschränkt die Einsatzmöglichkeiten des Injektors und verursacht erhöhte Fertigungs- und Montagekosten.Fuel injectors in which a nozzle needle is actuated by an actuator to open and close an injection port are known in the art. In order to realize the necessary stroke of the nozzle needle, such injectors must have a certain minimum length, which can not be fallen below. Such a minimum length limits the capabilities of the injector and causes increased manufacturing and assembly costs.

Um die Baulänge bei vorgegebenem Hub der Düsennadel zu reduzieren, sind Injektoren bekannt, bei denen zwei Aktoren in Reihe geschaltet sind. Injektoren mit mehreren in Reihe geschalteten Aktoren sind in der Herstellung aufwändig und teuer.In order to reduce the length at a given stroke of the nozzle needle, injectors are known in which two actuators are connected in series. Injectors with multiple actuators connected in series are complex and expensive to manufacture.

Offenbarung der ErfindungDisclosure of the invention

Eine Aufgabe der Erfindung ist es, einen einfach und kostengünstig herstellbaren Injektor bereitzustellen, der bei größtmöglichem Hub der Düsennadel eine möglichst geringe Baulänge aufweist.An object of the invention is to provide a simple and inexpensive to produce injector, which has the shortest possible length with the largest possible stroke of the nozzle needle.

Die Aufgabe wird durch den Gegenstand des unabhängigen Anspruchs gelöst. Vorteilhafte Weiterbildungen ergeben sich aus den abhängigen Ansprüchen.The object is solved by the subject matter of the independent claim. Advantageous developments emerge from the dependent claims.

Ein erfindungsgemäßer Injektor zum Einspritzen von Kraftstoff in einen Brennraum einer Verbrennungskraftmaschine hat eine Ventilgruppe, die sich zwischen einer Düsennadel und einem Aktor befindet, wobei in der Ventilgruppe eine Ventilkolben-Bohrung ausgebildet ist; einen in der Ventilkolben-Bohrung angeordneten Ventilkolben, der durch den Aktor zwischen einer geschlossenen Position und wenigstens einer Einspritzposition bewegbar ist; einen Düsennadelsteuerraum, dessen Volumen durch Bewegen des Ventilkolbens variierbar ist; einen Ventilraum, der zwischen dem Ventilkolben und der Ventilgruppe ausgebildet ist und der über eine in dem Ventilkolben ausgebildete Servobohrung mit dem Düsennadelsteuerraum verbunden ist; einen Zulauf und einen Ablauf, die in den Ventilraum münden, wobei die Mündung des Ablaufs in den Ventilraum durch den Ventilkolben verschlossen ist, wenn sich der Ventilkolben in der geschlossenen Position befindet und wobei die Mündung des Ablaufs geöffnet ist, wenn sich der Ventilkolben in einer Einspritzposition befindet.An injector according to the invention for injecting fuel into a combustion chamber of an internal combustion engine has a valve group which is located between a nozzle needle and an actuator, wherein a valve piston bore is formed in the valve group; a valve piston disposed in the valve piston bore that passes through the actuator between a closed position and at least one injection position is movable; a nozzle needle control space whose volume is variable by moving the valve piston; a valve space formed between the valve piston and the valve group and connected to the nozzle needle control space via a servo bore formed in the valve piston; an inlet and a drain, which open into the valve chamber, wherein the mouth of the drain is closed in the valve chamber by the valve piston when the valve piston is in the closed position and wherein the mouth of the drain is open, when the valve piston in a Injection position is located.

In einem solchen erfindungsgemäßen Injektor kann der notwendige Hub der Düsennadel mit einem Aktor realisiert werden, dessen Länge gegenüber einem herkömmlichen Injektor deutlich reduziert ist. Die Kosten für den Aktor können daher deutlich gesenkt werden. Auch kann der Ablauf kleiner als in einem herkömmlichen Injektor dimensioniert werden, so dass die Steuermenge reduziert werden kann.In such an injector according to the invention, the necessary stroke of the nozzle needle can be realized with an actuator whose length is significantly reduced compared to a conventional injector. The costs for the actuator can therefore be significantly reduced. Also, the drain can be made smaller than in a conventional injector, so that the control amount can be reduced.

In einer Ausführungsform hat die Ventilkolben-Bohrung einen der Düsennadel zugewandten unteren Bereich und einen dem Aktor zugewandten oberen Bereich, wobei der untere Bereich einen größeren Querschnitt als der obere Bereich hat. Der Ventilkolben hat einen der Düsennadel zugewandten unteren Bereich und einem dem Aktor zugewandten oberen Bereich, wobei der untere Bereich einen größeren Querschnitt als der obere Bereich hat und so in den unteren Bereich der Ventilkolben-Bohrung eingepasst ist, dass zwischen dem unteren Bereich des Ventilkolbens und der Ventilgruppe ein zweiter Steuerraum ausgebildet ist.In one embodiment, the valve piston bore has a lower portion facing the nozzle needle and an upper portion facing the actuator, the lower portion having a larger cross-section than the upper portion. The valve piston has a lower portion facing the nozzle needle and an upper portion facing the actuator, wherein the lower portion has a larger cross section than the upper portion and is fitted in the lower portion of the valve piston bore, that between the lower portion of the valve piston and the valve group is formed a second control chamber.

In einer Ausführungsform hat der zweite Steuerraum einen größeren Querschnitt als der Düsennadelsteuerraum. Durch einen solchen Aufbau lässt sich einfach und zuverlässig eine Bewegungsumkehr zwischen dem Aktor und der Düsennadel erreichen, so dass der Aktor während des Einspritzvorgangs aktiviert, d.h. ausgelängt ist. Ein solcher, direktgesteuerter Injektor hat eine gute Haltbarkeit und eine geringe Drift des Aktohubes.In one embodiment, the second control chamber has a larger cross-section than the nozzle needle control chamber. By such a structure can be easily and reliably achieve a reversal of motion between the actuator and the nozzle needle, so that the actuator is activated during the injection process, that is lengthened. Such a direct-acting injector has a good durability and a low drift of the Aktohubes.

In einer Ausführungsform ist in dem Ventilkolben eine Steuerraumbohrung ausgebildet, die den Düsennadelsteuerraum hydraulisch mit dem zweiten Steuerraum verbindet. Eine solche Steuerraumbohrung ermöglicht einen effektiven Druckausgleich zwischen dem Düsennadelsteuerraum und dem zweiten Steuerraum.In one embodiment, a control chamber bore is formed in the valve piston, which hydraulically connects the nozzle needle control chamber with the second control chamber. Such a control chamber bore allows effective pressure equalization between the nozzle needle control chamber and the second control chamber.

In einer Ausführungsform ist der Ventilraum zwischen der Düsennadel und dem Ventilkolben angeordnet. Insbesondere ist der Ventilraum radial um den Ventilkolben in der Ventilkolbenbohrung ausgebildet. Dies ermöglicht eine besonders einfache Anordnung des Ventilraums und eine einfach zu realisierende Ausbildung des Zu- und Ablaufs, die in die Ventilkolbenbohrung münden.In one embodiment, the valve space between the nozzle needle and the valve piston is arranged. In particular, the valve space is formed radially around the valve piston in the valve piston bore. This allows a particularly simple arrangement of the valve chamber and an easy-to-implement design of the inlet and outlet, which open into the valve piston bore.

In einer Ausführungsform verschließt der Ventilkolben die Mündung des Zulaufs in den Ventilraum, wenn sich der Ventilkolben in einer Einspritzposition befindet, und die Mündung des Zulaufs ist geöffnet, wenn sich der Ventilkolben in der geschlossenen Position befindet. Dadurch, dass der Zulauf geschlossen ist, wenn der Ventilkolben in der Einspritzposition ist, fällt der Druck im Ventilraum während des Einspritzvorgangs besonders schnell ab. Dies bewirkt eine besonders schnelle Bewegung der Düsennadel beim Öffnen der Einspritzöffnungen und ermöglicht besonders kurze Schalt- und Einspritzzeiten.In one embodiment, when the valve piston is in an injection position, the valve piston closes the mouth of the inlet into the valve chamber, and the mouth of the inlet is opened when the valve piston is in the closed position. Characterized in that the inlet is closed when the valve piston is in the injection position, the pressure in the valve chamber during the injection process drops very quickly. This causes a particularly fast movement of the nozzle needle when opening the injection openings and allows very short switching and injection times.

In einer Ausführungsform ist in der Servobohrung eine Servodossel ausgebildet ist. In einer weiteren Ausführungsform ist in dem Zulauf und/oder in dem Ablauf eine Zulauf- bzw. Ablaufdrossel ausgebildet. Durch solche Drosseln lässt sich ein gewünschtes Öffnungs- und Schließverhalten der Düsennadel besonders gut einstellen. Durch eine geeignete Servodrossel in der Servobohrung lässt sich der Servoeinfluss auf den direkten Nadelhub zeitverzögert überlagern. Dadurch wird insbesondere beim Einspritzen von Kleinstmengen, bei denen eine hohe Einspritztoleranz und ein schnelles Schalten erforderlich ist, eine bessere Einspritzgüte erreicht. Die führt zu geringeren Abgasemissionen und einem verringerten Verbrauch.In one embodiment, a servo box is formed in the servo bore. In a further embodiment, an inlet or outlet throttle is formed in the inlet and / or in the outlet. By means of such throttles, a desired opening and closing behavior of the nozzle needle can be adjusted particularly well. A suitable servo throttle in the servo bore allows the servo influence to be superimposed on the direct needle stroke with a time delay. As a result, a better injection quality is achieved, in particular when injecting small amounts, in which a high injection tolerance and a fast switching is required. This leads to lower exhaust emissions and reduced consumption.

In einer Ausführungsform ist das dem Aktor zugewandte Ende des Ventilkolbens mit einem Kopplerkolben verbunden. Der Kopplerkolben ist so in eine mit dem Aktor verbundene Kopplerhülse eingepasst, dass zwischen dem Kopplerkolben und der Kopplerhülse ein Kopplerraum ausgebildet ist. Der Kopplerraum ermöglicht es, temperaturbedingte Längenänderungen der Bauteile zu kompensieren.In one embodiment, the actuator facing the end of the valve piston is connected to a coupler piston. The coupler piston is fitted into a coupler sleeve connected to the actuator such that between the coupler piston and the coupler sleeve is formed a coupler space. The coupler space makes it possible to compensate for temperature-induced changes in length of the components.

In einer Ausführungsform ist der Aktor eine piezo-elektrischer Aktor. Piezo-elektrischer Aktoren sind besonders zuverlässig und weisen besonders geringe Reaktionszeiten auf, die besonders schnelle Einspritzvorgänge mit kurzen Schaltzeiten ermöglichen.In one embodiment, the actuator is a piezoelectric actuator. Piezoelectric actuators are particularly reliable and have particularly short reaction times, which enable particularly fast injection processes with short switching times.

Der Aufbau und die Funktionsweise eines erfindungsgemäßen Injektors wird im Folgenden anhand der in den beigefügten Figuren näher beschriebenen Ausführungsbeispiele näher erläutert. Dabei zeigt:

  • Figur 1 zeigt einen Schnitt durch ein Ausführungsbeispiel eines erfindungsgemäßen Injektors.
  • Figur 2 zeigt die Ventilgruppe des Injektors aus Figur 1 im geschlossenen Zustand.
  • Figur 3 zeigt die Ventilgruppe des Injektors aus Figur 1 in einem geöffnetem Zustand.
  • Figur 4 zeigt ein alternatives Ausführungsbeispiel der Ventilgruppe, bei der der Zulauf stets geöffnet ist.
  • Figur 5 zeigt ein weiteres Ausführungsbeispiel der Ventilgruppe mit einer zusätzlichen Servodrossel.
The structure and operation of an injector according to the invention will be explained in more detail below with reference to the embodiments described in more detail in the accompanying figures. Showing:
  • FIG. 1 shows a section through an embodiment of an injector according to the invention.
  • FIG. 2 shows the valve group of the injector FIG. 1 in the closed state.
  • FIG. 3 shows the valve group of the injector FIG. 1 in an open state.
  • FIG. 4 shows an alternative embodiment of the valve group, in which the inlet is always open.
  • FIG. 5 shows a further embodiment of the valve group with an additional servo throttle.

Der Aufbau und die Funktionsweise eines ersten Ausführungsbeispiels eines erfindungsgemäßen Injektors werden im Folgenden anhand der Figuren 1 bis 3 näher erläutert.The structure and operation of a first embodiment of an injector according to the invention are described below with reference to FIGS. 1 to 3 explained in more detail.

Figur 1 zeigt einen Schnitt durch ein Ausführungsbeispiel eines erfindungsgemäßen Injektors 7. Figur 2 zeigt eine vergrößerte Darstellung der Ventilgruppe des in Figur 1 gezeigten Injektors 7 im geschlossenen Zustand. Figur 3 zeigt eine vergrößerte Darstellung der Ventilgruppe in einem geöffnetem Zustand. FIG. 1 shows a section through an embodiment of an injector 7 according to the invention. FIG. 2 shows an enlarged view of the valve group of in FIG. 1 shown injector 7 in the closed state. FIG. 3 shows an enlarged view of the valve group in an open state.

Ein erfindungsgemäßer Injektor 7 weist einen in der Figur 1 oben dargestellten zylindrischen Injektorkörper 4 und ein in der Figur 1 unten dargestelltes zylindrisches Düsenmodul 1 auf, die mittels einer Düsenspannmutter 58 hydraulisch dicht verspannt sind. Die Verbindung zwischen der Düsenspannmutter 58 und dem Injektorkörper 4 ist zusätzlich durch einen Dichtungsring 60 abgedichtet.An inventive injector 7 has a in the FIG. 1 Shown above cylindrical injector body 4 and in the FIG. 1 shown below cylindrical nozzle module 1, which are clamped by a hydraulic nozzle lock nut 58 hydraulically tight. The connection between the nozzle retaining nut 58 and the injector body 4 is additionally sealed by a sealing ring 60.

In dem Düsenmodul 1 sind ein Düsennadelraum 56 und eine Kraftstoffkammer 52 ausgebildet, die über wenigstens eine Verbindungsbohrung 54 hydraulisch miteinander verbunden sind. Zwei Einspritzöffnungen 8 verbinden die Kraftstoffkammer 52 mit einem Brennraum 5, der das untere Ende des Düsenmoduls 1 umgibt. Entlang einer Längsachse A des Düsenmoduls 1 ist in dem Düsennadelraum 56 und in der Kraftstoffkammer 52 eine Düsennadel 6 angeordnet, die parallel zu einer Längsachse A des Düsenmoduls 1 zwischen einer unteren Verschlussposition und wenigstens einer oberen Einspritzposition bewegbar ist. Ein unteres Verschlussende 10 der Düsennadel 6 verschließt die Einspritzöffnungen 8, wenn sich die Düsennadel 6 in der unteren Verschlussposition befindet, und gibt die Einspritzöffnungen 8 frei, wenn sich die Düsennadel 6 in einer oberen Einspritzposition befindet. Im Betrieb sind der Düsennadelraum 56 und die Kraftstoffkammer 52 mit unter Druck stehendem Kraftstoff gefüllt. Bei freigegebenen Einspritzöffnungen 8 strömt der Kraftstoff aus der Kraftstoffkammer 52 durch die Einspritzöffnungen 8 in den Brennraum 5.In the nozzle module 1, a nozzle needle chamber 56 and a fuel chamber 52 are formed, which are hydraulically connected to each other via at least one connecting bore 54. Two injection openings 8 connect the fuel chamber 52 with a combustion chamber 5, which surrounds the lower end of the nozzle module 1. Along a longitudinal axis A of the nozzle module 1, a nozzle needle 6 is arranged in the nozzle needle chamber 56 and in the fuel chamber 52, which is movable parallel to a longitudinal axis A of the nozzle module 1 between a lower closure position and at least one upper injection position. A lower closing end 10 of the nozzle needle 6 closes the injection openings 8 when the nozzle needle 6 is in the lower closing position, and releases the injection openings 8 when the nozzle needle 6 is in an upper injection position. In operation, the nozzle needle chamber 56 and the fuel chamber 52 are filled with pressurized fuel. When the injection openings 8 are released, the fuel flows from the fuel chamber 52 through the injection openings 8 into the combustion chamber 5.

Ein oberes Steuerende 6a der Düsennadel 6 ist beweglich in einer Steuerraumhülse 15 angeordnet. Eine Düsennadelfeder 12 ist um einen oberen Bereich der Düsennadel 6 angeordnet und stützt sich einerseits an einem am Umfang der Düsennadel 6 ausgebildeten Absatz 11 und andererseits an der Steuerraumhülse 15 ab. So ist die Düsennadel 6 parallel zur Längsachse A elastisch beweglich in dem Düsenmodul 1 gelagert und wird von der Düsennadelfeder 12 in die untere Verschlussposition gedrückt, in der sie die Einspritzöffnungen 8 verschließt.An upper control end 6a of the nozzle needle 6 is movably arranged in a control chamber sleeve 15. A nozzle needle spring 12 is arranged around an upper region of the nozzle needle 6 and is supported, on the one hand, on a shoulder 11 formed on the circumference of the nozzle needle 6 and, on the other hand, on the control chamber sleeve 15. Thus, the nozzle needle 6 is mounted elastically movable parallel to the longitudinal axis A in the nozzle module 1 and is pressed by the nozzle needle spring 12 in the lower closure position in which it closes the injection openings 8.

Oberhalb des Düsenmoduls 1 ist eine Ventilgruppe 2 druckdicht in die Düsenspannmutter 58 eingepasst. In der Ventilgruppe 2 ist eine Ventilkolbenbohrung 32 ausgebildet, in die ein Ventilkolben 16 so eingeführt ist, dass er parallel zur Längsachse A des Injektors 7 beweglich ist.Above the nozzle module 1, a valve group 2 is pressure-tight in the nozzle retaining nut 58 fitted. In the valve group 2, a valve piston bore 32 is formed, in which a valve piston 16 is inserted so that it is movable parallel to the longitudinal axis A of the injector 7.

Der Ventilkolben 16 begrenzt das von der Düsennadel 6 abgewandte Ende der Steuerraumhülse 15. Innerhalb der Steuerraumhülse 15 ist ein Düsennadelsteuerraum 14 ausgebildet, der einerseits von der Düsennadel 6, andererseits von dem Ventilkolben 16 begrenzt ist und dessen Volumen sowohl durch Bewegen der Düsennadel 6 als auch durch Bewegen des Ventilkolbens 16 parallel zur Längsachse A des Injektors 7 variierbar ist.Within the control chamber sleeve 15, a nozzle needle control chamber 14 is formed, which is bounded on the one hand by the nozzle needle 6, on the other hand by the valve piston 16 and the volume of both by moving the nozzle needle 6 as well can be varied by moving the valve piston 16 parallel to the longitudinal axis A of the injector 7.

Der Ventilkolben 16 hat einen der Düsennadel 6 zugewandten unteren Bereich 16a und einen von der Düsennadel 6 abgewandten oberen Bereich 16b. Der untere Bereich 16a des Ventilkolbens 16 weist in einer Ebene, die rechtwinklig zur Längsachse A des Injektors 7 ausgerichtet ist, einen größeren Querschnitt als der obere Bereich 16b des Ventilkolbens 16 auf und ist derart in den unteren Bereich der Ventilkolbenbohrung 32 eingepasst, dass auf der von der Düsennadel 6 abgewandten Seite des unteren Bereichs 16a des Ventilkolbens 16 zwischen dem Ventilkolben 16 und der Ventilgruppe 2 ein zweiter Steuerraum 22 ausgebildet ist, dessen Volumen durch Bewegen des Ventilkolbens 16 parallel zur Längsachse A variierbar ist. Der zweite Steuerraum 22 ist durch eine Steuerraumbohrung 20, die durch den unteren Bereich 16a des Ventilkolbens 16 verläuft, hydraulisch mit dem Düsennadelsteuerraum 14 verbunden.The valve piston 16 has a lower portion 16a facing the nozzle needle 6 and an upper portion 16b facing away from the nozzle needle 6. The lower portion 16 a of the valve piston 16, in a plane which is aligned at right angles to the longitudinal axis A of the injector 7, a larger cross-section than the upper portion 16 b of the valve piston 16 and is fitted in such a manner in the lower portion of the valve piston bore 32 that on from the nozzle needle 6 side facing away from the lower portion 16a of the valve piston 16 between the valve piston 16 and the valve group 2, a second control chamber 22 is formed, the volume of which is variable by moving the valve piston 16 parallel to the longitudinal axis A. The second control chamber 22 is hydraulically connected to the nozzle needle control chamber 14 through a control chamber bore 20 which extends through the lower portion 16 a of the valve piston 16.

Um den oberen Bereich 16b des Ventilkolbens 16 ist zwischen dem Ventilkolben 16 und der Ventilgruppe 2 in der Ventilkolbenbohrung 32 ein Ventilraum 24 ausgebildet, der den Ventilkolben 16 radial umgibt. Der Ventilraum 24 ist durch eine in dem Ventilkolben 16 ausgebildete Servobohrung 18 hydraulisch mit dem Düsennadelsteuerraum 14 verbunden. Ein mit einer Kraftstoffzulaufleitung 38 hydraulisch verbundener Zulauf 25 mündet unterhalb Ventilraums 24 in die Ventilkolbenbohrung 32. Die Kraftstoffzulaufleitung 38 ist mit einer Kraftstoffpumpe 39 verbunden, die Kraftstoff unter hohem Druck über die Kraftstoffzulaufleitung 38 in den Zulauf 25 einspeist und über eine in dem Düsenmodul ausgebildete Bohrung 43 den Düsennadelraum 56 und durch die Verbindungsbohrung 54 auch die Kraftstoffkammer 52 mit Kraftstoff befüllt.Around the upper region 16b of the valve piston 16, a valve space 24 is formed between the valve piston 16 and the valve group 2 in the valve piston bore 32, which radially surrounds the valve piston 16. The valve chamber 24 is hydraulically connected to the nozzle needle control chamber 14 by a servo bore 18 formed in the valve piston 16. An inlet 25 hydraulically connected to a fuel feed line 38 opens below valve space 24 in the valve piston bore 32. The fuel feed line 38 is connected to a fuel pump 39, which feeds fuel under high pressure via the fuel feed line 38 into the inlet 25 and via a bore formed in the nozzle module 43 the nozzle needle chamber 56 and through the connecting bore 54 and the fuel chamber 52 filled with fuel.

Ein mit einem Kraftstoffablaufkanal 34 verbundener Ablauf 27 mündet oberhalb des Ventilraums 24 in die Ventilkolbenbohrung 32. Der Kraftstoffablaufkanal 34 ist ausgebildet, Kraftstoff aus dem Injektor 7 in eine Kraftstoffaufnahmevorrichtung 36 abzuführen.A drain 27 connected to a fuel drain passage 34 terminates above the valve space 24 in the valve piston bore 32. The fuel drain passage 34 is configured to discharge fuel from the injector 7 into a fuel intake device 36.

Unterhalb der Mündung des Ablaufs 27 in die Ventilkolbenbohrung 32 ist ein Dichtsitz 30 ausgebildet, der durch Bewegen des Ventilkolbens 16 parallel zur Längsachse A des Injektors 7 öffenbar und und verschließbar ist, so dass durch Bewegen des Ventilkolbens 16 eine hydraulische Verbindung zwischen dem Ablauf 27 und dem Ventilraum 24 herstellbar und verschließbar ist. Die hydraulische Verbindung zwischen dem Ventilraum 24 und dem Ablauf 27 ist verschlossen, wenn sich der Ventilkolben 16 in der oberen, geschlossenen Position befindet und die hydraulische Verbindung ist geöffnet, wenn sich der Ventilkolben 16 in einer unteren Einspritzposition befindet.Below the mouth of the drain 27 into the valve piston bore 32, a sealing seat 30 is formed, which can be opened and closed by moving the valve piston 16 parallel to the longitudinal axis A of the injector 7 and so that by moving the valve piston 16, a hydraulic connection between the drain 27 and the valve chamber 24 can be produced and closed. The hydraulic connection between the valve chamber 24 and the drain 27 is closed when the valve piston 16 is in the upper, closed position and the hydraulic connection is opened when the valve piston 16 is in a lower injection position.

Im oberen Bereich 16b des Ventilkolbens 16 ist um dessen Umfang eine Ausnehmung 17 derart ausgebildet, dass der Zulauf 25 hydraulisch mit dem Ventilraum 24 verbunden ist, wenn sich der Ventilkolben 16 in der oberen, geschlossenen Position befindet, und der Ventilraum 24 hydraulisch von dem Zulauf 25 getrennt ist, wenn sich der Ventilkolben 16 in einer unteren Einspritzposition befindet.In the upper area 16b of the valve piston 16, a recess 17 is formed around its circumference such that the inlet 25 is hydraulically connected to the valve space 24 when the valve piston 16 is in the upper, closed position, and the valve space 24 hydraulically from the inlet 25 is disconnected when the valve piston 16 is in a lower injection position.

Das obere, von der Düsennadel 6 abgewandte Ende des Ventilkolbens 16 ragt über das obere, von der Düsennadel 6 abgewandte Ende der Ventilgruppe 2 hinaus. An einer oberen, von der Düsennadel 6 abgewandten Stirnseite des Ventilkolbens 16 ist ein Kopplerkolben 48 angebracht, der derart in eine oberhalb der Ventilgruppe 2 angeordnete Kopplerhülse 44 eingepasst ist, dass zwischen dem Kopplerkolben 48 und der Kopplerhülse 44 ein Kopplerraum 46 ausgebildet ist, der im Betrieb mit Kraftstoff gefüllt ist. Das Volumen des Kopplerraums ist durch Bewegen des Kopplerkolbens 48 und/oder durch Bewegen der Kopplerhülse 44 variierbar.The upper, remote from the nozzle needle 6 end of the valve piston 16 protrudes beyond the upper, remote from the nozzle needle 6 end of the valve assembly 2 addition. At a top, remote from the nozzle needle 6 end face of the valve piston 16, a coupler piston 48 is mounted, which is fitted in such a manner arranged above the valve group 2 coupler 44, that between the coupler piston 48 and the coupler 44, a coupler 46 is formed in the Operation is filled with fuel. The volume of the coupler space is variable by moving the coupler piston 48 and / or by moving the coupler sleeve 44.

Die Kopplerhülse 44 ist von einer Kopplerfeder 50 umgeben, welche die Kopplerhülse 44 elastisch und parallel zur Längsachse A beweglich auf der Ventilgruppe 2 abstützt.The coupler sleeve 44 is surrounded by a coupler spring 50, which supports the coupler sleeve 44 elastically and parallel to the longitudinal axis A movable on the valve group 2.

Die Kopplerhülse 44 ist mechanisch mit einem Aktormodul 3, das auf der von der Ventilgruppe 2 abgewandten Seite der Kopplerhülse 44 angeordnet ist, derart gekoppelt, dass die Kopplerhülse 44 durch Betätigen des Aktormoduls 3 gegen die Kraft der Kopplerfeder 50 parallel zur Längsachse A des Injektors 7 bewegbar ist.The coupler sleeve 44 is mechanically coupled to an actuator module 3, which is arranged on the side facing away from the valve group 2 side of the coupler sleeve 44, such that the coupler sleeve 44 by pressing the actuator module 3 against the force of the coupler spring 50 is movable parallel to the longitudinal axis A of the injector 7.

Im geschlossenen Zustand des Injektors 7, d.h. wenn kein Kraftstoff in den Brennraum 5 eingespritzt werden soll, ist der Aktor 3 stromlos. Die Kopplerhülse 44, der Kopplerkolben 48 und der Ventilkolben 16 befinden sich jeweils in einer oberen Position. Der Dichtsitz 30 zwischen dem Ventilraum 24 und dem Ablauf 27 ist geschlossen. Der Ventilraum 24 steht in hydraulischer Verbindung mit dem Zulauf 25, so dass im Ventilraum 24 der hohe Systemdruck des Kraftstoffsystems herrscht. Der Ventilraum 24 steht über die Servobohrung 18 in hydraulischer Verbindung mit dem Düsennadelsteuerraum 14, so dass auch im Düsennadelsteuerraum 14 der hohe Kraftstoffdruck herrscht. Die Düsennadel 6 wird durch die Düsennadelfeder 12 und den im Düsennadelsteuerraum 14 herrschenden Kraftstoffdruck in die untere, geschlossene Position gedrückt, in der der Düsensitz 10 die Einspritzöffnungen 8 verschließt und kein Kraftstoff aus der Kraftstoffkammer 52 in den Brennraum 5 strömt.In the closed state of the injector 7, i. if no fuel is to be injected into the combustion chamber 5, the actuator 3 is de-energized. The coupler sleeve 44, the coupler piston 48 and the valve piston 16 are each in an upper position. The sealing seat 30 between the valve chamber 24 and the drain 27 is closed. The valve chamber 24 is in hydraulic communication with the inlet 25, so that in the valve chamber 24, the high system pressure of the fuel system prevails. The valve chamber 24 is in hydraulic communication with the nozzle needle control chamber 14 via the servo bore 18, so that the high fuel pressure also prevails in the nozzle needle control chamber 14. The nozzle needle 6 is pressed by the nozzle needle spring 12 and the pressure prevailing in the nozzle needle control chamber 14 fuel pressure in the lower, closed position in which the nozzle seat 10, the injection ports 8 closes and no fuel from the fuel chamber 52 flows into the combustion chamber 5.

Zum Einleiten eines Einspritzvorgangs wird der Aktor 3 durch Anlegen einer elektrischen Spannung an eine elektrische Anbindung 40 aktiviert. Der Aktor 3 längt aus und drückt den Kopplerkolben 44 gegen die Kraft der Kopplerfeder 50 in Richtung auf die Ventilgruppe 2 nach unten. Durch die auf das Volumen des Kopplerraums 46 ausgeübte Kraft wird auch der Kopplerkolben 48 in Richtung auf die Ventilgruppe 2 gedrückt.To initiate an injection process, the actuator 3 is activated by applying an electrical voltage to an electrical connection 40. The actuator 3 extends and pushes the coupler piston 44 against the force of the coupler spring 50 in the direction of the valve group 2 down. As a result of the force exerted on the volume of the coupler space 46, the coupler piston 48 is also pressed in the direction of the valve group 2.

Der Kopplerkolben 48 drückt den Ventilkolben 16 innerhalb der Ventilkolbenbohrung 32 in Richtung auf die Düsennadel 6 nach unten. Dadurch wird einerseits das Volumen des Düsennadelsteuerraums 14 verringert, andererseits wird das Volumen des zweiten Steuerraums 22 vergrößert. Da, wie insbesondere in der Figur 2 gezeigt, der Querschnitt A1 des zweiten Steuerraums 22 größer als der Querschnitt A2 des Düsennadelsteuerraums 14 ist, und der zweite Steuerraum 22 durch die Steuerraumbohrung 20 hydraulisch mit dem Düsennadelraum 14 verbunden ist, vergrößert sich das Gesamtvolumen, d.h. die Summe der Volumina der beiden Steuerräume 14, 22, sodass sich der Druck des Kraftstoffs in den beiden Steuerräumen 14, 22 verringert.The coupler piston 48 pushes the valve piston 16 within the valve piston bore 32 in the direction of the nozzle needle 6 down. As a result, on the one hand, the volume of the nozzle needle control chamber 14 is reduced, on the other hand, the volume of the second control chamber 22 is increased. There, as in particular in the FIG. 2 1, the cross section A1 of the second control chamber 22 is greater than the cross section A2 of the nozzle needle control chamber 14, and the second control chamber 22 is hydraulically connected to the nozzle needle chamber 14 through the control chamber bore 20, the total volume, ie the sum of the volumes of the two control chambers 14, increases , 22, so that the pressure of the fuel in the two control chambers 14, 22 decreases.

Der verringerte Druck im Düsennadelsteuerraum 14 reicht nicht aus, um die Düsennadel 6 gegen eine Kraft des Kraftstoffs in der Kraftstoffkammer 52, die auf eine im unteren Bereich der Düsennadel 6 ausgebildete Druckstufe 9 wirkt, in der unteren, geschlossenen Position zu halten. Die Düsennadel 6 bewegt sich unter Einfluss der auf die Druckstufe 9 wirkenden Kraft nach oben. Der Düsensitz 10 wird geöffnet und Kraftstoff aus der Kraftstoffkammer 52 strömt durch die Einspritzöffnungen 8 in den Brennraum 5.The reduced pressure in the nozzle needle control chamber 14 is insufficient to keep the nozzle needle 6 in the lower, closed position against a force of the fuel in the fuel chamber 52 acting on a pressure stage 9 formed in the lower portion of the nozzle needle 6. The nozzle needle 6 moves upward under the influence of the force acting on the pressure stage 9. The nozzle seat 10 is opened and fuel from the fuel chamber 52 flows through the injection openings 8 into the combustion chamber 5.

Ist dAH der Hub des Kopplerkolbens 44, A1 der Querschnitt des zweiten Steuerraums 22 und A2 der Querschnitt des Düsennadelsteuerraums 14, so ist der durch die Veränderung des Gesamtvolumens der Steuerräume 14, 22 bewirkte direkte Hub der Düsennadel 6 dNH: dNH = A ⁢ 1 - A ⁢ 2 / A ⁢ 2 * dAH

Figure imgb0001
If dAH is the stroke of the coupler piston 44, A1 is the cross section of the second control chamber 22 and A2 is the cross section of the nozzle needle control chamber 14, the direct stroke of the nozzle needle 6 caused by the change in the total volume of the control chambers 14, 22 is dNH: DNH = A ⁢ 1 - A ⁢ 2 / A ⁢ 2 * dAH
Figure imgb0001

Durch die Wahl der Querschnitte A1 und A2 der Steuerräume 14, 22 ist die Übersetzung dNH/dAH = (A1-A2)/A2 zwischen dem Hub des Kopplerkolbens 44 und dem direkten Hub der Düsennadel 6 bedarfsgemäß einstellbar.By selecting the cross sections A1 and A2 of the control chambers 14, 22, the ratio dNH / dAH = (A1-A2) / A2 between the stroke of the coupler piston 44 and the direct stroke of the nozzle needle 6 is adjusted as needed.

Mit dem direkten Hub können insbesondere geringe Hübe zum Einspritzen kleiner Kraftstoffmengen, bei denen es auf eine hohe Einspritztoleranz und kurze Schaltzeiten erforderlich sind, mit hoher Güte realisiert werden. Dies wirkt sich positiv aus die Emissionen und den Verbrauch aus.With the direct stroke in particular small strokes for injecting small amounts of fuel, which require a high injection tolerance and short switching times, can be realized with high quality. This has a positive effect on emissions and consumption.

Wenn sich der Ventilkolben 16 zum Auslösen des Einspritzvorgangs durch den Kopplerkolben 48 in der Ventilkolbenbohrung 32 nach unten bewegt, wird zusätzlich der Dichtsitz 30 zwischen dem Ventilraum 24 und dem Ablauf 27 geöffnet. Kraftstoff aus dem Düsennadelsteuerraum 14 strömt durch die Servobohrung 18, den Ventilraum 24, den geöffneten Dichtsitz 30 und den Ablauf 27 in den Ablaufkanal 34.In addition, when the valve piston 16 moves downward to initiate the injection operation by the coupler piston 48 in the valve piston bore 32, the seal seat 30 between the valve chamber 24 and the drain 27 is opened. Fuel from the nozzle needle control chamber 14 flows through the servo bore 18, the valve chamber 24, the open seal seat 30 and the drain 27 into the drain passage 34.

Sobald sich der Ventilkolben 16 um den Schieberhub SH nach unten bewegt hat, wird die Mündung des Zulaufs 25 in den Ventilraum 24 durch den Ventilkolben 16 verschlossen, sodass kein zusätzlicher Kraftstoff aus der Zulaufleitung 38 in den Ventilraum 24 einströmt.As soon as the valve piston 16 has moved downwards by the slide stroke SH, the mouth of the inlet 25 into the valve chamber 24 is closed by the valve piston 16, so that no additional fuel from the supply line 38 flows into the valve chamber 24.

Das Öffnen des Ablaufs 27 und das Schließen des Zulaufs 25 bewirkt zusätzlich zu der zuvor beschriebenen Vergrößerung der Gesamtvolumens der Steuerräume 14 und 22 eine weitere Verringerung des Drucks im Düsennadelsteuerraum 14, wodurch eine zusätzliche nach oben gerichtete Kraft auf die Düsennadel 6 wirkt. Diese zusätzliche Kraft beschleunigt die Düsennadel 6 zusätzlich zum direkten Hub dNH, der sich aus der Volumenänderung der Steuerräume 14, 22 ergibt, sodass die Einspritzöffnungen 8 weiter und schneller geöffnet werden. Dadurch können kürzere Einspritzzeiten realisiert werden.The opening of the drain 27 and the closing of the inlet 25 causes, in addition to the previously described increase in the total volume of the control chambers 14 and 22, a further reduction in the pressure in the nozzle needle control chamber 14, whereby an additional upward force acts on the nozzle needle 6. This additional force accelerates the nozzle needle 6 in addition to the direct stroke dNH, which results from the volume change of the control chambers 14, 22, so that the injection openings 8 are opened further and faster. As a result, shorter injection times can be realized.

Um den Einspritzvorgang zu beenden, wird die an den Aktor 3 angelegte Spannung abgeschaltet. Die Länge des Aktors 3 verringert sich und die Kopplerhülse 44 wird von der Kopplerfeder 50 gegen den verkürzten Aktor 3 nach oben in Richtung auf den verkürzten Aktor 3 gedrückt. Der Druck im Kopplerraums 46 verringert sich, der Kopplerkolben 48 und der mit ihm verbundene Ventilkolben 16 bewegen sich in Richtung auf den Aktor 3 nach oben.To end the injection process, the voltage applied to the actuator 3 is turned off. The length of the actuator 3 decreases and the coupler sleeve 44 is pressed by the coupler spring 50 against the shortened actuator 3 upwards in the direction of the shortened actuator 3. The pressure in the coupler chamber 46 decreases, and the coupler piston 48 and the valve piston 16 connected to it move upwards in the direction of the actuator 3.

Da durch die Aufwärtsbewegung des Ventilkolbens 16 das Volumen des zweiten Steuerraums 22 stärker verringert wird, als sich das Volumen des Düsennadelsteuerraums 14 vergrößert (direkter Hub dNH), strömt Kraftstoff über die Steuerraumbohrung 20 aus dem zweiten Steuerraum 22 in den Düsennadelsteuerraum 14 und erhöht den Druck im Düsennadelsteuerraum 14.Since the volume of the second control chamber 22 is more reduced by the upward movement of the valve piston 16, as the volume of the Düsennadelsteuerraums 14 increases (direct stroke dNH), fuel flows through the control chamber bore 20 from the second control chamber 22 in the nozzle needle control chamber 14 and increases the pressure in the nozzle needle control room 14.

Durch die Aufwärtsbewegung des Ventilkolbens 16 wird der Dichtsitz 30 in der Ventilkolbenbohrung 32 geschlossen, sodass kein weiterer Kraftstoff durch den Ablauf 27 aus dem Ventilraum 24 in den Ablaufkanal 34 abfließt. Gleichzeitig wird die Mündung des Zulaufs 25 in den Ventilraum 24 geöffnet. Unter hohem Druck stehender Kraftstoff strömt aus der Zulaufleitung 38 in den Ventilraum 24 ein. Über die in dem Ventilkolben 16 ausgebildete Servobohrung 18 gelangt Kraftstoff aus dem Ventilraum 24 in den Düsennadelsteuerraum 14 und erhöht den Druck im Düsennadelsteuerraum 14 zusätzlich.By the upward movement of the valve piston 16, the sealing seat 30 is closed in the valve piston bore 32, so that no further fuel flows through the outlet 27 from the valve chamber 24 into the drainage channel 34. At the same time the mouth of the inlet 25 is opened in the valve chamber 24. Fuel under high pressure flows from the supply line 38 into the valve chamber 24. Via the servo bore 18 formed in the valve piston 16, fuel passes from the valve chamber 24 into the nozzle needle control chamber 14 and additionally increases the pressure in the nozzle needle control chamber 14.

Der erhöhte Druck im Düsennadelsteuerraum 14 bewirkt eine nach unten gerichtete Kraft auf die Düsennadel 6, die ausreicht, um die Düsennadel 6 gegen die auf die Druckstufe 9 wirkende aufwärtsgerichtete Kraft nach unten in den Düsensitz 10 zu drücken und die Einspritzöffnungen 8 zu verschließen. Kein weiterer Kraftstoff strömt durch die Einspritzöffnungen 8 aus der Kraftstoffkammer 52 in den Brennraum 5 und der Einspritzvorgang ist beendet.The increased pressure in the nozzle needle control chamber 14 causes a downward force on the nozzle needle 6, which is sufficient to press the nozzle needle 6 against the force acting on the pressure step 9 upward force in the nozzle seat 10 and to close the injection openings 8. No further Fuel flows through the injection openings 8 from the fuel chamber 52 into the combustion chamber 5 and the injection process is completed.

Durch eine geeignete Dimensionierung einer im Zulauf 25 ausgebildeten Zulaufdrossel 26 und einer im Ablauf 27 ausgebildeten Ablaufdrossel 28 lassen sich die Öffnungsgeschwindigkeit und die Schließgeschwindigkeit der Düsennadel 6 bedarfsgemäß einstellen.By a suitable dimensioning of a feed throttle 26 formed in the inlet 25 and a flow restrictor 28 formed in the drain 27, the opening speed and the closing speed of the nozzle needle 6 can be adjusted as required.

Figur 4 zeigt ein alternatives Ausführungsbeispiel der erfindungsgemäßen Ventilgruppe. Bei diesem Ausführungsbeispiel mündet der Zulauf 25 direkt in den Ventilraum 24. Die hydraulische Verbindung des Zulaufs 25 mit dem Ventilraum 24 wird während des Einspritzvorgangs nicht unterbrochen. Durch eine geeignete Dimensionierung der Zulaufdrossel 26 kann so die Öffnungsgeschwindigkeit der Düsennadel 6 eingestellt werden. Insbesondere kann die Düsennadel 6 beim Öffnen abgebremst werden, um zu verhindern, dass sich die Düsennadel 6 schneller als gewünscht öffnet. FIG. 4 shows an alternative embodiment of the valve assembly according to the invention. In this embodiment, the inlet 25 opens directly into the valve chamber 24. The hydraulic connection of the inlet 25 with the valve chamber 24 is not interrupted during the injection process. By a suitable dimensioning of the inlet throttle 26 so the opening speed of the nozzle needle 6 can be adjusted. In particular, the nozzle needle 6 can be braked when opening, to prevent the nozzle needle 6 opens faster than desired.

Figur 5 zeigt ein weiteres alternatives Ausführungsbeispiel der erfindungsgemäßen Ventilgruppe 2, wobei in der Servobohrung 18 des Ventilkolbens eine Servodrossel 19 ausgebildet ist. Durch eine geeignete Dimensionierung der Servodrossel 19 lässt sich der Servoeinfluss auf den direkten Nadelhub dNH, der sich aus der Veränderung des Volumens des Düsennadelsteuerraums 14 und des zweiten Steuerraums 22 ergibt, zeitverzögert überlagern. Dadurch wird insbesondere beim Einspritzen von Kleinstmengen, bei denen eine hohe Einspritztoleranz und ein schnelles Schalten erforderlich ist, eine bessere Einspritzgüte erreicht. Die führt zu geringeren Abgasemissionen und einem verringerten Verbrauch. FIG. 5 shows a further alternative embodiment of the valve group 2 according to the invention, wherein in the servo bore 18 of the valve piston, a servo throttle 19 is formed. By suitable dimensioning of the servo throttle 19, the servo influence on the direct needle stroke dNH, which results from the change in the volume of the nozzle needle control chamber 14 and the second control chamber 22, can be superimposed with a time delay. As a result, a better injection quality is achieved, in particular when injecting small amounts, in which a high injection tolerance and a fast switching is required. This leads to lower exhaust emissions and reduced consumption.

Claims (10)

Injektor (7) zum Einspritzen von Kraftstoff in einen Brennraum (5) einer Verbrennungskraftmaschine, mit
einer Ventilgruppe (2), die sich zwischen einer Düsennadel (6) und einem Aktor (3) befindet, wobei in der Ventilgruppe (2) eine Ventilkolbenbohrung (32) ausgebildet ist;
einem in der Ventilkolbenbohrung (32) angeordneten Ventilkolben (16), der durch den Aktor (3) zwischen einer geschlossenen Position und wenigstens einer Einspritzposition bewegbar ist;
einem Düsennadelsteuerraum (14), dessen Volumen durch Bewegen des Ventilkolbens (16) variierbar ist;
einem Ventilraum (24), der zwischen dem Ventilkolben (16) und der Ventilgruppe (2) ausgebildet ist und der über eine in dem Ventilkolben (16) ausgebildete Servobohrung (18) mit dem Düsennadelsteuerraum (14) verbunden ist,
einem Zulauf (25) und einem Ablauf (27), die in den Ventilraum (24) münden,
wobei die Mündung des Ablaufs (27) in den Ventilraum (24) durch den Ventilkolben (16) verschlossen ist, wenn sich der Ventilkolben (16) in der geschlossenen Position befindet und wobei die Mündung des Ablaufs (27) geöffnet ist, wenn sich der Ventilkolben (16) in einer Einspritzposition befindet.Injector (7) for injecting fuel into a combustion chamber (5) of an internal combustion engine, with
a valve group (2) located between a nozzle needle (6) and an actuator (3), wherein in the valve group (2) a valve piston bore (32) is formed;
a valve piston (16) disposed in the valve piston bore (32) and movable by the actuator (3) between a closed position and at least one injection position;
a nozzle needle control space (14) whose volume is variable by moving the valve piston (16);
a valve space (24), which is formed between the valve piston (16) and the valve group (2) and which is connected to the nozzle needle control chamber (14) via a servo bore (18) formed in the valve piston (16),
an inlet (25) and a drain (27) which open into the valve chamber (24),
wherein the mouth of the drain (27) into the valve space (24) is closed by the valve piston (16) when the valve piston (16) is in the closed position and the mouth of the drain (27) is open when the Valve piston (16) is in an injection position. Injektor (7) nach Anspruch 1,
wobei die Ventilkolbenbohrung (32) einen der Düsennadel (6) zugewandten unteren Bereich und einen dem Aktor (3) zugewandten oberen Bereich hat, wobei der untere Bereich einen größeren Querschnitt als der obere Bereich hat, und
wobei der Ventilkolben (16) einen der Düsennadel (6) zugewandten unteren Bereich und einem dem Aktor (3) zugewandten oberen Bereich hat, wobei der untere Bereich einen größeren Querschnitt als der obere Bereich hat und so in den unteren Bereich der Ventilkolbenbohrung (32) eingepasst ist, so dass zwischen dem unteren Bereich des Ventilkolbens (16) und der Ventilgruppe (2) ein zweiter Steuerraum (22) ausgebildet ist.Injector (7) according to claim 1,
wherein the valve piston bore (32) has a lower portion facing the nozzle needle (6) and an upper portion facing the actuator (3), the lower portion having a larger cross-section than the upper portion, and
wherein the valve piston (16) has a lower region facing the nozzle needle (6) and an upper region facing the actuator (3), the lower region having a larger cross section than the upper region and thus into the lower region of the valve piston bore (32). is fitted, so that between the lower portion of the valve piston (16) and the valve group (2), a second control chamber (22) is formed. Injektor (7) nach Anspruch 2, wobei der zweite Steuerraum (22) einen größeren Querschnitt als der Düsennadelsteuerraum (14) hat.The injector (7) according to claim 2, wherein the second control space (22) has a larger cross section than the nozzle needle control space (14). Injektor (7) nach Anspruch 2 oder 3, wobei im Ventilkolben (16) eine Steuerraumbohrung (20) ausgebildet ist, die den Düsennadelsteuerraum (14) mit dem zweiten Steuerraum (22) verbindet.Injector (7) according to claim 2 or 3, wherein in the valve piston (16) a control chamber bore (20) is formed, which connects the nozzle needle control chamber (14) with the second control chamber (22). Injektor (7) nach einem der Ansprüche 1 bis 4, wobei der Ventilraum (24) zwischen der Düsennadel (6) und dem Ventilkolben (16) ausgebildet ist.Injector (7) according to one of claims 1 to 4, wherein the valve space (24) between the nozzle needle (6) and the valve piston (16) is formed. Injektor (7) nach Anspruch 5, wobei der Ventilraum (24) radial um den Ventilkolben (16) in der Ventilkolbenbohrung (32) ausgebildet ist.Injector (7) according to claim 5, wherein the valve chamber (24) is formed radially around the valve piston (16) in the valve piston bore (32). Injektor (7) nach einem der Ansprüche 1 bis 6, wobei die Mündung des Zulaufs (26) in den Ventilraum (24) durch den Ventilkolben (16) verschlossen ist, wenn sich der Ventilkolben (16) in einer Einspritzposition befindet und wobei die Mündung des Zulaufs (25) geöffnet ist, wenn sich der Ventilkolben (16) in der geschlossenen Position befindet.The injector (7) according to any one of claims 1 to 6, wherein the mouth of the inlet (26) into the valve chamber (24) is closed by the valve piston (16) when the valve piston (16) is in an injection position and wherein the orifice of the inlet (25) is opened when the valve piston (16) is in the closed position. Injektor (7) nach einem der Ansprüche 1 bis 7, wobei in der Servobohrung (17), in dem Zulauf (25) und/oder in dem Ablauf (27) wenigstens eine Drossel (18, 26, 28) ausgebildet ist.Injector (7) according to one of claims 1 to 7, wherein in the servo bore (17), in the inlet (25) and / or in the outlet (27) at least one throttle (18, 26, 28) is formed. Injektor (7) nach einem der Ansprüche 1 bis 8, wobei das dem Aktor (3) zugewandte Ende des Ventilkolbens (16) mit einem Kopplerkolben (48) verbunden ist, der so in eine mit dem Aktor (3) verbundene Kopplerhülse (44) eingepasst ist, dass zwischen dem Kopplerkolben (48) und der Kopplerhülse (44) ein Kopplerraum (46) ausgebildet ist.Injector (7) according to one of claims 1 to 8, wherein the actuator (3) facing the end of the valve piston (16) with a coupler piston (48) is connected, which in such a manner connected to the actuator (3) coupler sleeve (44). is fitted, that between the coupler piston (48) and the coupler sleeve (44) a coupler space (46) is formed. Injektor (7) nach einem der Ansprüche 1 bis 9, wobei der Aktor (3) eine piezo-elektrischer Aktor (3) ist.Injector (7) according to one of claims 1 to 9, wherein the actuator (3) is a piezoelectric actuator (3).
EP10156162A 2009-05-07 2010-03-11 Fuel injector Not-in-force EP2249024B1 (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2871354A1 (en) * 2013-11-06 2015-05-13 Robert Bosch Gmbh Fuel injector valve for combustion engines
JP2019148194A (en) * 2018-02-26 2019-09-05 株式会社Ｓｏｋｅｎ Fuel injection device

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1174615A2 (en) * 2000-07-18 2002-01-23 Delphi Technologies, Inc. Fuel injector
EP1865192A2 (en) * 2006-06-07 2007-12-12 Robert Bosch Gmbh Fuel injector with servo assistance
WO2008017538A1 (en) * 2006-08-07 2008-02-14 Robert Bosch Gmbh Fuel injector with direct needle control and servo valve assistance

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1174615A2 (en) * 2000-07-18 2002-01-23 Delphi Technologies, Inc. Fuel injector
EP1865192A2 (en) * 2006-06-07 2007-12-12 Robert Bosch Gmbh Fuel injector with servo assistance
WO2008017538A1 (en) * 2006-08-07 2008-02-14 Robert Bosch Gmbh Fuel injector with direct needle control and servo valve assistance

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2871354A1 (en) * 2013-11-06 2015-05-13 Robert Bosch Gmbh Fuel injector valve for combustion engines
JP2019148194A (en) * 2018-02-26 2019-09-05 株式会社Ｓｏｋｅｎ Fuel injection device

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