EP1252433A2 - Fuel injection valve for internal combustion engines - Google Patents

Fuel injection valve for internal combustion engines

Info

Publication number
EP1252433A2
EP1252433A2 EP00993183A EP00993183A EP1252433A2 EP 1252433 A2 EP1252433 A2 EP 1252433A2 EP 00993183 A EP00993183 A EP 00993183A EP 00993183 A EP00993183 A EP 00993183A EP 1252433 A2 EP1252433 A2 EP 1252433A2
Authority
EP
European Patent Office
Prior art keywords
control valve
valve member
control
pressure chamber
fuel injection
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
EP00993183A
Other languages
German (de)
French (fr)
Other versions
EP1252433B1 (en
Inventor
Friedrich Boecking
Wolfgang Stoecklein
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
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 EP1252433A2 publication Critical patent/EP1252433A2/en
Application granted granted Critical
Publication of EP1252433B1 publication Critical patent/EP1252433B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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
    • 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
    • F02M59/46—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
    • F02M45/00—Fuel-injection apparatus characterised by having a cyclic delivery of specific time/pressure or time/quantity relationship
    • F02M45/02—Fuel-injection apparatus characterised by having a cyclic delivery of specific time/pressure or time/quantity relationship with each cyclic delivery being separated into two or more parts
    • F02M45/04—Fuel-injection apparatus characterised by having a cyclic delivery of specific time/pressure or time/quantity relationship with each cyclic delivery being separated into two or more parts with a small initial part, e.g. initial part for partial load and initial and main part for full load
    • F02M45/08—Injectors peculiar thereto
    • 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
    • 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
    • F02M47/025—Hydraulically 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
    • 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
    • F02M2200/00—Details of fuel-injection apparatus, not otherwise provided for
    • F02M2200/21—Fuel-injection apparatus with piezoelectric or magnetostrictive elements
    • 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

Definitions

  • the invention relates to a fuel injection valve for internal combustion engines according to the preamble of claim 1.
  • Such a fuel injection valve is known from DE 198 13 983 AI.
  • This fuel injection valve is part of a storage fuel injection system and has an injection valve member through which at least one injection opening is controlled and which has a pressure shoulder delimiting a pressure chamber.
  • Fuel under pressure can be supplied to the pressure chamber from a high-pressure fuel source via a pressure line, through which the injection valve member can be raised against a closing force to open the at least one injection opening from a valve seat.
  • the movement of the injector member is influenced by a control valve which is one by one
  • Piezoaktor Generated actuating force has movable control valve member which controls the pressure prevailing in a control pressure chamber connected to a pressure source, which acts on the injection valve member in its closing direction.
  • the control pressure chamber can be connected to a relief chamber by the control valve member, as a result of which the pressure in the control pressure chamber drops and the injection valve member can be moved in the opening direction.
  • the control valve member interacts with a sealing surface arranged on this with a valve seat.
  • the fuel injector according to the invention with the features according to claim 1 has the advantage that the control valve member with a movement from one valve seat to the other valve seat without
  • FIG. 1 shows a storage fuel injection system in a schematic representation
  • Figure 2 shows a fuel injection valve
  • Figure 3 shows the fuel injection valve in longitudinal section according to a modified embodiment
  • Figure 4 shows the fuel injection valve in longitudinal section according to a second embodiment.
  • Storage fuel injection system has a high-pressure pump 10, through which fuel is conveyed from a storage tank 12 under high pressure into a storage 14.
  • the memory 14 is designed as a so-called rail, from which lines lead to fuel injection valves 16 which are arranged on an internal combustion engine.
  • Fuel injection valve 16 has a control valve 18, by means of which the opening and closing of the fuel injection valve 16 is controlled.
  • the storage fuel injection system also has one
  • Control device 20 to which signals are supplied via various operating parameters of the internal combustion engine and by means of which the control valves 18 of the fuel injection valves 16 are controlled to open or close them.
  • FIG. 2 shows a fuel injection valve 16 with an associated control valve 18 according to a first exemplary embodiment.
  • the fuel injection valve 16 has a valve body 22 on, in which an injection valve member 24 is guided axially.
  • the valve body 22 has at least one, preferably a plurality of injection openings 26 at its end region facing the combustion chamber of the internal combustion engine.
  • the injection valve member 24 has at its
  • End area facing the combustion chamber has, for example, an approximately conical sealing surface 28 which interacts with a valve seat 30 formed in the valve body 22, from which the injection openings 26 lead away.
  • a valve seat 30 formed in the valve body 22, from which the injection openings 26 lead away.
  • annular space 32 is formed surrounding the injection valve member 24, which is connected to a pressure chamber 34, which in turn is connected to the accumulator 14, so that the pressure generated by the high pressure pump 10 prevails in the pressure chamber 34.
  • the injection valve member 24 has a pressure shoulder 36 arranged in the pressure chamber 34, via which the pressure prevailing in the pressure chamber 34 exerts a force acting on the injection valve member 24 in the opening direction 38 of the latter.
  • a pre-tensioned closing spring 40 acts on the injection valve member 24, by means of which the injection valve member 24 is acted upon in the closing direction against the force acting in the pressure chamber 34 in the opening direction 38 in the closing direction. Due to the pressure prevailing in the pressure chamber 34, the injection valve member 24 can be moved in the opening direction 38 against the force of the closing spring 40 and thereby gives the
  • Injection openings 26 are free, through which fuel is injected into the combustion chamber of the internal combustion engine.
  • the injection valve member 24 is pressed with its sealing surface 28 into the valve seat 30 on the valve body 22 in the closing direction, so that the injection openings 26 are closed.
  • a closing piston 42 which is part of the control valve 18, is arranged in the region of the end of the injection valve member 24 facing away from the combustion chamber.
  • the Locking piston 42 can be made in one piece with the
  • Injection valve member 24 may be formed or as a separate part.
  • the closing piston 42 is arranged at least approximately coaxially with the injection valve member 24 and is axially displaceably guided in a bore 44 in a housing part 46 of the control valve 18.
  • the closing piston 42 delimits a control pressure chamber 48 in the bore 44, which is connected to the accumulator 14 via a channel 49 in which a throttle 50 is arranged.
  • the bore 44 facing away from the locking piston 42 is stepped and has a section 44a with a reduced diameter and then a section 44b with an enlarged diameter.
  • a socket 52 is inserted into the sections 44a, b of the bore 44, which has a substantially smaller diameter than the section 44a of the bore and is arranged with its end region in the section 44a.
  • the socket 52 is arranged at least approximately coaxially with the closing piston 42.
  • the nozzle 52 has an annular collar 53, the diameter of which is slightly smaller than the diameter of the section 44b of the bore 44 and which is arranged in the section 44b.
  • the connecting piece 52 lies with its annular collar 53 against the annular shoulder formed at the transition between the sections 44a and 44b of the bore 44 and is thus fixed in the direction of its longitudinal axis towards the control pressure chamber 48.
  • An intermediate disk 54 adjoins the housing part 46 and has a bore 55, the diameter of which is larger than the diameter of the connecting piece 52 but smaller than the diameter of the collar 53.
  • the intermediate disk 54 is clamped between the housing part 46 and a further housing part 56, so that the connecting piece 52 is also fixed away from the control pressure chamber 48 via its annular collar 53 in the direction of its longitudinal axis.
  • a flow channel 58 is formed in the nozzle 52, which extends from the front end of the nozzle 52 which delimits the control pressure chamber 48 and opens at the lateral surface of the nozzle 52 close to the end thereof which faces away from the control pressure chamber 48.
  • the flow channel 58 has, for example, a section 58a which runs approximately parallel to the longitudinal axis of the connection piece 52 and a section 58b which extends approximately at right angles to this and which opens out on the lateral surface of the connection piece 52.
  • Flow channel 58 may have a throttle 59 arranged to limit the flow.
  • the nozzle 52 At its end area facing away from the control pressure chamber 48, the nozzle 52 has, for example, a conical bevel 60, which serves as a first valve seat of the control valve 18.
  • the housing part 56 of the control valve 18 has a bore 61, into which the connection piece 52 projects with its area facing away from the control pressure chamber 48.
  • a control valve member 62 is guided tightly displaceably as a
  • the control valve member 62 has a bore 63 towards the intermediate disk 54, the diameter of which is only slightly larger than the diameter of the connecting piece 52 passing through the bore 63.
  • a pressure chamber 64 which is widened in relation to the bore 63 is formed in the control valve member 62, in which the flow channel 58 of the nozzle 52 opens. At the pressure chamber 64, a bore 65 with a smaller one is closed in the control valve member 62
  • Diameter than the bore 63 which opens at the end of the control valve member 62 facing away from the intermediate disk 54.
  • the transition from the pressure chamber 64 to the bore 65 runs, for example, with a conical bevel 66.
  • the bore 63, the pressure chamber 64 and the Bore 65 in the control valve member 62 are arranged at least approximately coaxially with one another.
  • the chamfer 66 serves as the first sealing surface of the control valve member 62, which cooperates with the chamfer 60 on the nozzle 52 as the first valve seat.
  • the bore 65 forms an outflow channel through which the pressure chamber 64 is connected to the outside of the control valve member 62.
  • the control valve member 62 has, at its end area facing away from the intermediate disk 54, a shoulder 68 which is reduced in diameter compared to the diameter of the area of the control valve member 62 guided in the bore 61 and which tapers towards its end with, for example, a conical bevel 69 which has a second sealing surface forms on the control valve member 62.
  • a reduced shoulder 68 is formed on the control valve member 62, an annular shoulder 70.
  • the bore 61 is designed as a blind bore and a prestressed return spring 72 is arranged between the bottom 71 of the bore 61 and the annular shoulder 70 of the control valve member 62, through which the control valve member 62 is pressed toward the intermediate disk 54.
  • the bottom 71 of the bore 61 has a recess 73 which is arranged at least approximately coaxially with the control valve member 62, the edge 74 is, for example, beveled conically and forms a second valve seat with which the bevel 69 forming the second sealing surface cooperates on the control valve member 62.
  • an annular space 75 is delimited in the bore 61, which is connected via a channel 76 to a relief space, which, for example, the storage tank 12 can serve.
  • the diameters of the first valve seat 60 and the second valve seat 74, at which the control valve member 62 has its first sealing surface 66 and its second, respectively Sealing surface 69 comes to rest, are at least approximately the same size.
  • a working space 78 is delimited in the bore 61 towards the intermediate disk 54 by the control valve member 62.
  • the diameter of the bore 61 in the area of the annular space 75 and / or in the area of the work space 78 can be somewhat enlarged compared to the area in which the control valve member 62 is guided in the bore 61.
  • the work space 78 is connected to a piezo actuator 80 via a hydraulic transmission.
  • the piezo actuator 80 is controlled by the control device 20 and changes its length depending on an electrical voltage applied to it.
  • the piezo actuator 80 is arranged in a cylinder 81 and, when it changes in length, compresses or relaxes a hydraulic volume arranged in the cylinder 81.
  • the hydraulic translation is achieved in that the hydraulic volume influenced by the piezo actuator 80 acts on a piston 82 which is smaller in diameter than the piezo actuator 80 and which, when the length of the piezo actuator 80 changes, increases the stroke by the ratio of the diameter of the piezo actuator 80 to the diameter of the piston 82 performs.
  • the piston 82 is arranged at least approximately coaxially with the piezo actuator 80 and is displaceably guided in a cylinder 83 corresponding in diameter.
  • a working space 84 is delimited by the piston 82 and is connected to the working space 78 via a channel 85 with a smaller diameter in the housing part 56.
  • the piezo actuator 80 and the piston 82 can be arranged anywhere on the circumference of the housing part 56 of the control valve 18 and can be inclined with their longitudinal axes approximately perpendicular to the longitudinal axis of the control valve 18 or, as shown in FIG. 2, to the longitudinal axis of the control valve.
  • the function of the fuel injection valve 16 and the control valve 18 is explained below. If the piezo actuator 80 is not activated, there is a low pressure in the working space 78 and the control valve member 62 is held by the return spring 72 with its first sealing surface 66 in contact with the first valve seat 60 on the nozzle 52. The control valve member 62 is in a first closed position.
  • the pressure chamber 64 in the control valve member 62 is thus separated from the relief chamber, which is formed by the storage tank 12, and no fuel can flow out of the control pressure chamber 48 through the channel 58 and the pressure chamber 64. For this reason, the same pressure prevails in the control pressure chamber 48 as in the accumulator 14, which acts on the closing piston 42 and acts on the injection valve member 24 via it and keeps it in its closed position, in which the injection valve member 24 rests with its sealing surface 28 on the valve seat 30 and which Injection openings 28 closes so that no fuel is injected.
  • the piezo actuator 80 When the piezo actuator 80 is controlled by the control device 20, its length increases and the piston 82 displaces hydraulic volume from the working space 84 via the channel 85 into the working space 78, where the pressure rises until it reaches the control valve member 62 Exerted force can overcome the bias of the return spring 72 and the control valve member 62 is moved away from the intermediate plate 54.
  • the first sealing surface 66 of the control valve member 62 lifts from the first valve seat 60 on the nozzle 52, so that the pressure chamber 64 in the control valve member 62 is connected to the bore 65.
  • the second sealing surface 69 on the control valve member 62 is then not yet in contact with the second valve seat 74, so that the bore 65 of the control valve member 62 is connected to the annular space 75 and via this to the storage tank 12 serving as a relief space.
  • fuel can flow through the flow channel 58, the pressure chamber 64 and the bore 65 serving as the outflow channel into the relief chamber, as a result of which the pressure in the control pressure chamber 48 drops.
  • the injection valve member 24 can be moved in the opening direction 38 by the pressure of the accumulator 14 acting on its pressure shoulder 36 against the force of the closing spring 40 and against the force generated by the reduced pressure prevailing in the control pressure chamber 48, and gives the
  • Injection ports 28 free so that fuel is injected.
  • Control valve member 62 moved further until it comes to rest with its second sealing surface 69 on the second valve seat 74 on the bottom 71 of the bore 61.
  • the control valve member 62 is in a second closed position.
  • the bore 65 in the control valve member 62 is separated from the annular space 75, so that fuel can flow out of the control valve member 62 through the bore 65 and the high pressure of the accumulator 14 prevails in the control pressure chamber 48, through which the injection valve member 24 passes through the closing piston 42 is moved into its closed position and is held in this.
  • the pressure in the working space 78 can be set such that the control valve 18 is held in its open position, in which it is not in contact with the first valve seat 60 on the nozzle 52 with its first sealing surface 66 nor with its second sealing surface 69 rests on the second valve seat 74 on the bottom 71 of the bore 61 and thus the fuel injection valve 16 remains open.
  • the control valve member 62 is moved from its first closed position into its second closed position or vice versa by corresponding activation of the piezo actuator 80 without interruption of movement.
  • the control valve member 62 moves, there is no reversal of the direction of movement, but this is only moved in one direction.
  • the control valve 18 is only opened briefly, so that the fuel injection valve 16 is accordingly only opened briefly. This enables, for example
  • Fuel pre-injection in which a small amount of fuel is injected before the actual fuel injection.
  • the timing of the opening, the duration of the opening and the size of the opening stroke of the fuel injection valve 16 can be determined by correspondingly controlling the piezo actuator 78 of the control valve 18 via the control device 20.
  • the fuel injection valve can initially only be opened briefly and / or with a small opening stroke for the pre-injection, then closed and then opened for the main injection for a longer time and / or with a larger opening stroke.
  • a specific course of the injection can also be achieved, in which, for example, the fuel injection valve is initially only opened with a small opening stroke and then opened with a larger opening stroke. Any other course of injection can also be achieved.
  • the pressure acts at the front end of the control valve member 62 next to the bore 65 on an annular surface of the same size as within the control valve member 62 next to the bore 65, so that the pressure forces arising thereby equalize.
  • a movement of the control valve member 62 by the pressure generated by the piezo actuator 80 in the working space 78 does not have to take place against the pressure in the control pressure space 48, so that only relatively small actuating forces need to be generated by the piezo actuator 80 and the piezo actuator 80 and the hydraulic translation with small dimensions can be executed.
  • control valve 18 is shown according to a modified version compared to the above-described first embodiment, the basic structure of the control valve 18 according to the modified embodiment is the same as in the first embodiment and only the additional ones below
  • the connecting piece 52 is guided as tightly as possible in the bore 63 of the control valve member 62, so that the bore 63 represents a sealing area through which the pressure chamber 64 in the control valve member 62 is separated from the working chamber 78.
  • the control valve member 62 has in its
  • Bore 63 has a circumferential annular groove 88 which is connected via one or more approximately radial bores 89 to an annular groove 90 formed in the outer jacket of the control valve member 62.
  • a groove formed in the outer jacket of the control valve member 62 leads from the annular groove 90 for example, approximately axially extending groove 91 in the annular space 75, via which a connection to the relief space in the form of the storage tank is made.
  • the groove 91 can also be formed in the bore 61 of the housing part 56 instead of in the outer jacket of the control valve member 62.
  • the working spaces 78 and 84 of the hydraulic transmission of the control valve 18 can also be filled via the annular grooves 88 and 90.
  • control valve 18 is shown according to a second embodiment, in which the basic structure is again the same as in the first
  • the control valve member 162 has the bore 63 through which the connection piece 52 projects into the pressure chamber 64, from which the bore 65 leads away.
  • the recess 73 is formed on the bottom 71 of the bore 161 and the control valve member 162 has the extension 68.
  • the bore 161 is designed as a stepped bore and has a section 161a with a larger diameter towards the intermediate disk 54 and a section 161b with a smaller one towards its base 71
  • control valve member 162 is also stepped in its outer diameter and has an area 162a with a larger diameter, which is arranged in the section 161a of the bore 161, and an area 162b with a smaller diameter, which is in the section 161b of the bore 161 is arranged.
  • a prestressed return spring 172 is arranged between an annular shoulder 170 formed by a shoulder on the control valve member 162 and the intermediate disk 54, by means of which the control valve member 162 is pressed toward the bottom 71 of the bore 161.
  • a working space 178 is delimited in section 161a of bore 161 by region 162a of control valve member 162, which is larger in diameter and which is connected via a channel 185 to the hydraulic transmission of piezo actuator 80.
  • control valve 18 The function of the control valve 18 according to the second exemplary embodiment is explained below. If the piezo actuator 80 is not activated by the control device 20, the return spring 172 presses the control valve member 162 with its second sealing surface 69 against the second valve seat 74 at the bottom 71 of the bore and is in its second closed position. When the piezo actuator 80 is activated, the increased pressure in the working space 178 displaces the control valve member 162 toward the intermediate disk 54 against the bias of the return spring 172. If the pressure in the working space 178 is sufficiently high, the control valve member 162 comes into contact with the first valve seat 60 with its first sealing surface 66 and is held in its first closed position.
  • the volume of the bore 65 in the control valve member 162 is also acted upon by the high pressure in the control pressure chamber 48.
  • the control valve member 62 according to the first exemplary embodiment is located when the piezo actuator is not activated 80 in its first closed position, in which only the pressure chamber 64 in the control valve member 62 is acted upon by the high pressure in the control pressure chamber 48, while the volume of the bore 65 is connected to the relief chamber. Due to the larger volume present in the control valve 18 according to the second exemplary embodiment, which is acted upon by the high pressure in the control pressure chamber 48, the dynamic behavior of the control valve 18 can be influenced, in particular with short pre-injection times.

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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

The inventive fuel injection valve (16) comprises an injection valve element (24) via which at least one injection opening (26) is controlled. The movement of the injection valve element (24) is influenced by a control valve (18) which comprises a control valve element (62), said control valve element controlling the pressure in a control pressure space (48), and which can be moved by an adjusting force generated by a piezo actuator (80) thus controlling a connection of the control pressure space (48) to a pressure release space (12). The control valve (18) comprises two valve seats (60, 74) which are interspaced in the direction of movement of the control valve element (62), and with which the control valve element (62) interacts via a respective sealing surface (66, 69) arranged thereon so that the control valve element (62) has two closing positions in which the control pressure space (48) is separated from the pressure release space (12). When the control valve element (62) is not located in one of both closing positions, the control pressure space (48) is connected to the pressure release space (12). The fuel injection valve (16) can be momentarily opened by moving the control valve element (62) between both closing positions thereof.

Description

Kraftstoffeinspritzventil für BrennkraftmaschinenFuel injection valve for internal combustion engines
Stand der TechnikState of the art
Die Erfindung geht aus von einem Kraftstoffeinspritzventil für Brennkraf maschinen nach der Gattung des Anspruchs 1.The invention relates to a fuel injection valve for internal combustion engines according to the preamble of claim 1.
Ein solches Kraftstoffeinspritzventil ist durch die DE 198 13 983 AI bekannt. Dieses Kraftstoffeinspritzventil ist Bestandteil eines Speicherkraftstoffeinspritzsystems und weist ein Einspritzventilglied auf, durch das wenigstens eine Einspritzöffnung gesteuert wird und das eine einen Druckraum begrenzenden Druckschulter aufweist . Dem Druckraum ist unter Druck stehender Kraftstoff von einer Kraftstoffhochdruckquelle über eine Druckleitung zuführbar, durch den das Einspritzventilglied entgegen einer Schließkraft zur Öffnung der wenigstens einen Einspritzöffnung von einem Ventilsitz abhebbar ist. Die Bewegung des Einspritzventilglieds wird durch ein Steuerventil beeinflußt, das ein durch eine von einemSuch a fuel injection valve is known from DE 198 13 983 AI. This fuel injection valve is part of a storage fuel injection system and has an injection valve member through which at least one injection opening is controlled and which has a pressure shoulder delimiting a pressure chamber. Fuel under pressure can be supplied to the pressure chamber from a high-pressure fuel source via a pressure line, through which the injection valve member can be raised against a closing force to open the at least one injection opening from a valve seat. The movement of the injector member is influenced by a control valve which is one by one
Piezoaktor .erzeugte Stellkraft bewegbares Steuerventilglied aufweist, das den in einem mit einer Druckquelle verbundenen Steuerdruckraum herrschenden Druck steuert, der das Einspritzventilglied in dessen Schließrichtung beaufschlagt. Durch das Steuerventilglied ist der Steuerdruckraum mit einem Entlastungsraum verbindbar, wodurch der Druck im Steuerdruckraum absinkt und das Einspritzventilglied in Öffnungsrichtung bewegt werden kann. Das Steuerventilglied wirkt mit einer an diesem angeordneten Dichtfläche mit einem Ventilsitz zusammen. Zu einem schnellen Öffnen und Schließen des Kraftstoffeinspritzventils, wie dies beispielsweise zur Erzielung einer Voreinspritzung erforderlich ist, sind hohe Stellkräfte für das Steuerventilglied notwendig, die vom Piezoaktor erzeugt werden müssen, um das Steuerventilglied vom Ventilsitz abzuheben und nach dessen Bewegungsrichtungsumkehr wieder auf den Ventilsitz zurückzuführen. Die Bewegung des Steuerventilglieds durch die vom Piezoaktor erzeugte Stellkraft muß außerdem gegen den im Steuerdruckraum herrschenden Druck erfolgen, so daß ein großer Kraftaufwand zu dessen Bewegung erforderlich ist. Aus diesen Gründen ist ein Piezoaktor mit großen Abmessungen erforderlich.Piezoaktor. Generated actuating force has movable control valve member which controls the pressure prevailing in a control pressure chamber connected to a pressure source, which acts on the injection valve member in its closing direction. The control pressure chamber can be connected to a relief chamber by the control valve member, as a result of which the pressure in the control pressure chamber drops and the injection valve member can be moved in the opening direction. The control valve member interacts with a sealing surface arranged on this with a valve seat. For a quick opening and closing of the fuel injection valve, as is necessary, for example, to achieve a pre-injection, high actuating forces for the control valve member are necessary, which are from Piezoactuators must be generated in order to lift the control valve member from the valve seat and to return it to the valve seat after the direction of movement is reversed. The movement of the control valve member by the actuating force generated by the piezo actuator must also take place against the pressure prevailing in the control pressure chamber, so that a great effort is required to move it. For these reasons, a piezo actuator with large dimensions is required.
Vorteile der ErfindungAdvantages of the invention
Das erfindungsgemäße Kraftstoffeinspritzventil mit den Merkmalen gemäß Anspruch 1 hat demgegenüber den Vorteil, daß durch das Steuerventilglied mit einer Bewegung vom einen Ventilsitz zum anderen Ventilsitz ohneThe fuel injector according to the invention with the features according to claim 1 has the advantage that the control valve member with a movement from one valve seat to the other valve seat without
Bewegungsrichtungsumkehr ein sehr schnelles Öffnen und Schließen des Kraftstoffeinspritzventils erreicht werden kann, wozu außerdem nur eine geringe vom Piezoaktor zu erzeugende Stellkraft erforderlich ist, so daß dieser mit geringen Abmessungen ausgeführt werden kann.Reversal of direction of movement a very quick opening and closing of the fuel injector can be achieved, for which purpose only a small actuating force to be generated by the piezo actuator is required, so that it can be carried out with small dimensions.
In den abhängigen Ansprüchen sind vorteilhafte Ausgestaltungen und Weiterbildungen des erfindungsgemäßen Kraftstoffeinspritzventils angegeben. Durch die Ausbildung gemäß Anspruch 2 ergibt sich auf das Steuerventilglied keine Kraft durch den Druck im Steuerdruckraum, wodurch nur eine geringe vom Piezoaktor zu erzeugende Stellkraft für die Bewegung des Steuerventilglieds erforderlich ist und der Piezoaktor mit geringen Abmessungen ausgeführt werden kann. Die Ausbildung gemäß Anspruch 3 ermöglicht einen kompakten Aufbau des Steuerventils.Advantageous refinements and developments of the fuel injection valve according to the invention are specified in the dependent claims. Due to the design according to claim 2, there is no force on the control valve member due to the pressure in the control pressure chamber, as a result of which only a small actuating force to be generated by the piezo actuator is required for the movement of the control valve member and the piezo actuator can be designed with small dimensions. The design according to claim 3 enables a compact structure of the control valve.
Zeichnung Zwei Ausführungsbeispiele der Erfindung sind in der Zeichnung dargestellt und in der nachfolgenden Beschreibung näher erläutert . Es zeigen Figur 1 ein Speicherkraftstoffeinspritzsystem in schematischer Darstellung, Figur 2 ein Kraftstoffeinspritzventil desdrawing Two embodiments of the invention are shown in the drawing and explained in more detail in the following description. 1 shows a storage fuel injection system in a schematic representation, Figure 2 shows a fuel injection valve
Speicherkraftstoffeinspritzsystems in einem Längsschnitt gemäß einem ersten Ausführungsbeispiel, Figur 3 das Kraftstoffeinspritzventil im Längsschnitt gemäß einer modifizierten Ausführung und Figur 4 das Kraftstoffeinspritzventil im Längsschnitt gemäß einem zweiten Ausführungsbeispiel .Storage fuel injection system in a longitudinal section according to a first embodiment, Figure 3 shows the fuel injection valve in longitudinal section according to a modified embodiment and Figure 4 shows the fuel injection valve in longitudinal section according to a second embodiment.
Beschreibung des AusführungsbeispielsDescription of the embodiment
Ein in Figur 1 schematisch dargestelltesA schematically shown in Figure 1
Speicherkraftstoffeinspritzsystem weist eine Hochdruckpumpe 10 auf, durch die Kraftstoff aus einem Vorratstank 12 unter Hochdruck in einen Speicher 14 gefördert wird. Der Speicher 14 ist als sogenanntes Rail ausgebildet, von dem Leitungen zu Kraftstoffeinspritzventilen 16 abführen, die an einer Brennkraftmaschine angeordnet sind. JedesStorage fuel injection system has a high-pressure pump 10, through which fuel is conveyed from a storage tank 12 under high pressure into a storage 14. The memory 14 is designed as a so-called rail, from which lines lead to fuel injection valves 16 which are arranged on an internal combustion engine. each
Kraftstoffeinspritzventil 16 weist ein Steuerventil 18 auf, durch das das Öffnen und Schließen des Kraftstoffeinspritzventils 16 gesteuert wird. Das Speicherkraftstoffeinspritzsystem weist außerdem eineFuel injection valve 16 has a control valve 18, by means of which the opening and closing of the fuel injection valve 16 is controlled. The storage fuel injection system also has one
Steuereinrichtung 20 auf, der Signale über verschiedene Betriebsparameter der Brennkraftmaschine zugeführt werden und durch die abhängig hiervon die Steuerventile 18 der Kraftstoffeinspritzventile 16 zu deren Öffnen oder Schließen angesteuert werden.Control device 20, to which signals are supplied via various operating parameters of the internal combustion engine and by means of which the control valves 18 of the fuel injection valves 16 are controlled to open or close them.
In Figur 2 ist ein Kraftstoffeinspritzventil 16 mit zugehörigem Steuerventil 18 gemäß einem ersten Ausführungsbeispiel dargestellt. Das Kraftstoffeinspritzventil 16 weist einen Ventilkörper 22 auf, in dem ein Einspritzventilglied 24 axial verschiebbar geführt ist. Der Ventilkörper 22 weist an seinem dem Brennraum der Brennkraftmaschine zugewandten Endbereich wenigstens eine, vorzugsweise mehrere Einspritzöffnungen 26 auf. Das Einspritzventilglied 24 weist an seinem demFIG. 2 shows a fuel injection valve 16 with an associated control valve 18 according to a first exemplary embodiment. The fuel injection valve 16 has a valve body 22 on, in which an injection valve member 24 is guided axially. The valve body 22 has at least one, preferably a plurality of injection openings 26 at its end region facing the combustion chamber of the internal combustion engine. The injection valve member 24 has at its
Brennraum zugewandten Endbereich eine beispielsweise etwa kegelförmige Dichtfläche 28 auf, die mit einem im Ventilkörper 22 ausgebildeten Ventilsitz 30 zusammenwirkt, von dem aus die Einspritzöffnungen 26 abführen. Im Ventilkörper 22 ist ein das Einspritzventilglied 24 umgebender Ringraum 32 ausgebildet, der mit einem Druckraum 34 verbunden ist, der wiederum mit dem Speicher 14 verbunden ist, so daß im Druckraum 34 der von der Hochdruckpumpe 10 erzeugte Druck herrscht. Das Einspritzventilglied 24 weist eine im Druckraum 34 angeordnete Druckschulter 36 auf, über die der im Druckraum 34 herrschende Druck eine in Öffnungsrichtung 38 des Einspritzventilglieds 24 wirkende Kraft auf dieses ausübt. Am Einspritzventilglied 24 greift eine vorgespannte Schließfeder 40 an, durch die das Einspritzventilglied 24 entgegen der durch den im Druckraum 34 herrschenden Druck auf dieses in Öffnungsrichtung 38 wirkenden Kraft in Schließrichtung beaufschlagt ist. Durch den im Druckraum 34 herrschenden Druck ist das Einspritzventilglied 24 gegen die Kraft der Schließfeder 40 in Öffnungsrichtung 38 bewegbar und gibt dabei dieEnd area facing the combustion chamber has, for example, an approximately conical sealing surface 28 which interacts with a valve seat 30 formed in the valve body 22, from which the injection openings 26 lead away. In the valve body 22 an annular space 32 is formed surrounding the injection valve member 24, which is connected to a pressure chamber 34, which in turn is connected to the accumulator 14, so that the pressure generated by the high pressure pump 10 prevails in the pressure chamber 34. The injection valve member 24 has a pressure shoulder 36 arranged in the pressure chamber 34, via which the pressure prevailing in the pressure chamber 34 exerts a force acting on the injection valve member 24 in the opening direction 38 of the latter. A pre-tensioned closing spring 40 acts on the injection valve member 24, by means of which the injection valve member 24 is acted upon in the closing direction against the force acting in the pressure chamber 34 in the opening direction 38 in the closing direction. Due to the pressure prevailing in the pressure chamber 34, the injection valve member 24 can be moved in the opening direction 38 against the force of the closing spring 40 and thereby gives the
Einspritzöffnungen 26 frei, durch die Kraftstoff in den Brennraum der Brennkraf maschine eingespritzt wird. Zur Beendung der Einspritzung wird das Einspritzventilglied 24 in Schließrichtung mit seiner Dichtfläche 28 in den Ventilsitz 30 am Ventilkörper 22 gepresst, so daß die Einspritzöffnungen 26 verschlossen werden.Injection openings 26 are free, through which fuel is injected into the combustion chamber of the internal combustion engine. To end the injection, the injection valve member 24 is pressed with its sealing surface 28 into the valve seat 30 on the valve body 22 in the closing direction, so that the injection openings 26 are closed.
Im Bereich des dem Brennraum abgewandten Endes des Einspritzventilglieds 24 ist ein Schließkolben 42 angeordnet, der Teil des Steuerventils 18 ist. Der Schließkolben 42 kann einstückig mit demA closing piston 42, which is part of the control valve 18, is arranged in the region of the end of the injection valve member 24 facing away from the combustion chamber. The Locking piston 42 can be made in one piece with the
Einspritzventilglied 24 ausgebildet sein oder als separates Teil. Der Schließkolben 42 ist zumindest annähernd koaxial zum Einspritzventilglied 24 angeordnet und in einer Bohrung 44 in einem Gehäuseteil 46 des Steuerventils 18 axial verschiebbar geführt .Injection valve member 24 may be formed or as a separate part. The closing piston 42 is arranged at least approximately coaxially with the injection valve member 24 and is axially displaceably guided in a bore 44 in a housing part 46 of the control valve 18.
Der Schließkolben 42 begrenzt in der Bohrung 44 einen Steuerdruckraum 48, der über einen Kanal 49, in dem eine- Drossel 50 angeordnet ist, mit dem Speicher 14 verbunden ist. Dem Schließkolben 42 abgewandt ist die Bohrung 44 gestuft ausgebildet und weist einen Abschnitt 44a mit verringertem Durchmesser und an diesen anschließend wieder einen Abschnitt 44b mit vergrößertem Durchmesser auf. Von der dem Steuerdruckraum 48 abgewandten Seite her ist in die Abschnitte 44a,b der Bohrung 44 ein Stutzen 52 eingesetzt, der im wesentlichen einen etwas kleineren Durchmesser als der Abschnitt 44a der Bohrung aufweist und mit seinem Endbereich im Abschnitt 44a angeordnet ist. Der Stutzen 52 ist zumindest annähernd koaxial zum Schließkolben 42 angeordnet. Der Stutzen 52 weist einen Ringbund 53 auf, dessen Durchmesser etwas kleiner ist als der Durchmesser des Abschnitts 44b der Bohrung 44 und der im Abschnitt 44b angeordnet ist. Der Stutzen 52 liegt mit seinem Ringbund 53 an der am Übergang zwischen den Abschnitten 44a und 44b der Bohrung 44 gebildeten Ringschulter an und ist damit in Richtung seiner Längsachse zum Steuerdruckraum 48 hin festgelegt. An das Gehäuseteil 46 schließt sich eine Zwischenscheibe 54 an, die eine Bohrung 55 aufweist, deren Durchmesser größer als der Durchmesser des Stutzens 52 jedoch kleiner als der Durchmesser des Ringbunds 53 ist. Die Zwischenscheibe 54 ist zwischen dem Gehäuseteil 46 und einem weiteren Gehäuseteil 56 eingespannt, so daß durch diese der Stutzen 52 über seinen Ringbund 53 in Richtung seiner Längsachse auch vom Steuerdruckraum 48 weg festgelegt ist. Im Stutzen 52 ist ein Strömungskanal 58 ausgebildet, der von dem den Steuerdruckraum 48 begrenzenden Stirnende des Stutzens 52 ausgeht und an der Mantelfläche des Stutzens 52 nahe von dessen dem Steuerdruckraum 48 abgewandten Ende mündet. Der Strömungskanal 58 weist beispielsweise ausgehend vom Stirnende des Stutzens 52 einen etwa parallel zur Längsachse des Stutzens 52 verlaufenden Abschnitt 58a und einen etwa rechtwinklig zu diesem verlaufenden Abschnitt 58b auf, der an der Mantelfläche des Stutzens 52 mündet. ImThe closing piston 42 delimits a control pressure chamber 48 in the bore 44, which is connected to the accumulator 14 via a channel 49 in which a throttle 50 is arranged. The bore 44 facing away from the locking piston 42 is stepped and has a section 44a with a reduced diameter and then a section 44b with an enlarged diameter. From the side facing away from the control pressure chamber 48, a socket 52 is inserted into the sections 44a, b of the bore 44, which has a substantially smaller diameter than the section 44a of the bore and is arranged with its end region in the section 44a. The socket 52 is arranged at least approximately coaxially with the closing piston 42. The nozzle 52 has an annular collar 53, the diameter of which is slightly smaller than the diameter of the section 44b of the bore 44 and which is arranged in the section 44b. The connecting piece 52 lies with its annular collar 53 against the annular shoulder formed at the transition between the sections 44a and 44b of the bore 44 and is thus fixed in the direction of its longitudinal axis towards the control pressure chamber 48. An intermediate disk 54 adjoins the housing part 46 and has a bore 55, the diameter of which is larger than the diameter of the connecting piece 52 but smaller than the diameter of the collar 53. The intermediate disk 54 is clamped between the housing part 46 and a further housing part 56, so that the connecting piece 52 is also fixed away from the control pressure chamber 48 via its annular collar 53 in the direction of its longitudinal axis. A flow channel 58 is formed in the nozzle 52, which extends from the front end of the nozzle 52 which delimits the control pressure chamber 48 and opens at the lateral surface of the nozzle 52 close to the end thereof which faces away from the control pressure chamber 48. Starting from the front end of the connection piece 52, the flow channel 58 has, for example, a section 58a which runs approximately parallel to the longitudinal axis of the connection piece 52 and a section 58b which extends approximately at right angles to this and which opens out on the lateral surface of the connection piece 52. in the
Strömungskanal 58 kann eine Drossel 59 angeordnet sein, um den Durchfluß zu begrenzen. An seinem dem Steuerdruckraum 48 abgewandten Endbereich weist der Stutzen 52 eine beispielsweise konische Anschrägung 60 auf, die als ein erster Ventilsitz des Steuerventils 18 dient.Flow channel 58 may have a throttle 59 arranged to limit the flow. At its end area facing away from the control pressure chamber 48, the nozzle 52 has, for example, a conical bevel 60, which serves as a first valve seat of the control valve 18.
Das Gehäuseteil 56 des Steuerventils 18 weist eine Bohrung 61 auf, in die der Stutzen 52 mit seinem dem Steuerdruckraum 48 abgewandten Bereich hineinragt. In der Bohrung 61 ist ein Steuerventilglied 62 dicht verschiebbar geführt, das als einThe housing part 56 of the control valve 18 has a bore 61, into which the connection piece 52 projects with its area facing away from the control pressure chamber 48. In the bore 61, a control valve member 62 is guided tightly displaceably as a
Hohlkolben ausgebildet ist, in den der Stutzen 52 hineinragt. Das Steuerventilglied 62 weist zur Zwischenscheibe 54 hin eine Bohrung 63 auf, deren Durchmesser nur wenig größer ist als der Durchmesser des durch die Bohrung 63 hindurchtretenden Stutzens 52. An die Bohrung 63 anschließend ist im Steuerventilglied 62 ein gegenüber der Bohrung 63 erweiterter Druckraum 64 ausgebildet, in dem der Strömungskanal 58 des Stutzens 52 mündet. An den Druckraum 64 schließt sich im Steuerventilglied 62 eine Bohrung 65 mit kleineremHollow piston is formed, into which the nozzle 52 protrudes. The control valve member 62 has a bore 63 towards the intermediate disk 54, the diameter of which is only slightly larger than the diameter of the connecting piece 52 passing through the bore 63. A pressure chamber 64 which is widened in relation to the bore 63 is formed in the control valve member 62, in which the flow channel 58 of the nozzle 52 opens. At the pressure chamber 64, a bore 65 with a smaller one is closed in the control valve member 62
Durchmesser als die Bohrung 63 an, die an dem der Zwischenscheibe 54 abgewandten Stirnende des Steuerventilglieds 62 mündet. Der Übergang vom Druckraum 64 zur Bohrung 65 verläuft mit einer beispielsweise konischen Anschrägung 66. Die Bohrung 63, der Druckraum 64 und die Bohrung 65 im Steuerventilglied 62 sind zumindest annähernd koaxial zueinander angeordnet. Die Anschrägung 66 dient als erste Dichtfläche des Steuerventilglieds 62, die mit der Anschrägung 60 am Stutzen 52 als erstem Ventilsitz zusammenwirkt. Die Bohrung 65 bildet einen Abströmkanal, durch den der Druckraum 64 mit der Außenseite des Steuerventilglieds 62 verbunden ist.Diameter than the bore 63, which opens at the end of the control valve member 62 facing away from the intermediate disk 54. The transition from the pressure chamber 64 to the bore 65 runs, for example, with a conical bevel 66. The bore 63, the pressure chamber 64 and the Bore 65 in the control valve member 62 are arranged at least approximately coaxially with one another. The chamfer 66 serves as the first sealing surface of the control valve member 62, which cooperates with the chamfer 60 on the nozzle 52 as the first valve seat. The bore 65 forms an outflow channel through which the pressure chamber 64 is connected to the outside of the control valve member 62.
Das Steuerventilglied 62 weist an seinem der Zwischenscheibe 54 abgewandten Endbereich einen gegenüber dem Durchmesser des in der Bohrung 61 geführten Bereichs der Steuerventilglieds 62 im Durchmesser verringerten Ansatz 68 auf, der sich zu seinem Ende hin mit einer beispielsweise konischen Anschrägung 69 verjüngt, die eine zweite Dichtfläche am Steuerventilglied 62 bildet. Durch den imThe control valve member 62 has, at its end area facing away from the intermediate disk 54, a shoulder 68 which is reduced in diameter compared to the diameter of the area of the control valve member 62 guided in the bore 61 and which tapers towards its end with, for example, a conical bevel 69 which has a second sealing surface forms on the control valve member 62. Through the im
Durchmesser verringerten Ansatz 68 ist am Steuerventilglied 62 eine Ringschulter 70 gebildet. Die Bohrung 61 ist als Sackbohrung ausgebildet und zwischen dem Boden 71 der Bohrung 61 und der Ringschulter 70 des Steuerventilglieds 62 ist eine vorgespannte Rückstellfeder 72 angeordnet, durch die das Steuerventilglied 62 zur Zwischenscheibe 54 hin gedrückt wird. Der Boden 71 der Bohrung 61 weist eine zumindest annähernd koaxial zum Steuerventilglied 62 angeordnete Vertiefung 73 auf, der Rand 74 beispielsweise konisch angeschrägt ausgebildet ist und einen zweiten Ventilsitz bildet, mit dem die die zweite Dichtfläche bildende /Anschrägung 69 am Steuerventilglied 62 zusammenwirkt. Durch das Steuerventilglied 62 mit dessen Ansatz 68 wird in der Bohrung 61 ein Ringraum 75 begrenzt, der über einen Kanal 76 mit einem Entlastungsraum verbunden ist, als der beispielsweise der Vorratstank 12 dienen kann.A reduced shoulder 68 is formed on the control valve member 62, an annular shoulder 70. The bore 61 is designed as a blind bore and a prestressed return spring 72 is arranged between the bottom 71 of the bore 61 and the annular shoulder 70 of the control valve member 62, through which the control valve member 62 is pressed toward the intermediate disk 54. The bottom 71 of the bore 61 has a recess 73 which is arranged at least approximately coaxially with the control valve member 62, the edge 74 is, for example, beveled conically and forms a second valve seat with which the bevel 69 forming the second sealing surface cooperates on the control valve member 62. Through the control valve member 62 with its extension 68, an annular space 75 is delimited in the bore 61, which is connected via a channel 76 to a relief space, which, for example, the storage tank 12 can serve.
Die Durchmesser des ersten Ventilsitzes 60 und des zweiten Ventilsitzes 74, an denen das Steuerventilglied 62 mit seiner ersten Dichtfläche 66 bzw. mit seiner zweiten Dichtfläche 69 zur Anlage kommt, sind zumindest annähernd gleich groß.The diameters of the first valve seat 60 and the second valve seat 74, at which the control valve member 62 has its first sealing surface 66 and its second, respectively Sealing surface 69 comes to rest, are at least approximately the same size.
Durch das Steuerventilglied 62 wird in der Bohrung 61 zur Zwischenscheibe 54 hin ein Arbeitsraum 78 begrenzt. Die Bohrung 61 kann im Bereich des Ringraums 75 und/oder im Bereich des Arbeitsraums 78 im Durchmesser etwas vergrößert sein gegenüber dem Bereich, in dem das Steuerventilglied 62 in der Bohrung 61 geführt ist. Der Arbeitsraum 78 ist über eine hydraulische Übersetzung mit einem Piezoaktor 80 verbunden. Der Piezoaktor 80 wird von der Steuereinrichtung 20 angesteuert und ändert abhängig von einer an diesem anliegenden elektrischen Spannung seine Länge. Der Piezoaktor 80 ist in einem Zylinder 81 angeordnet und bewirkt bei seiner Längenänderung eine Verdichtung bzw. Entspannung eines im Zylinder 81 angeordneten Hydraulikvolumens. Die hydraulische Übersetzung ist dadurch erreicht, daß das vom Piezoaktor 80 beeinflußte Hydraulikvolumen auf einen im Durchmesser gegenüber dem Piezoaktor 80 verkleinerten Kolben 82 wirkt, der bei einer Längenänderung des Piezoaktors 80 einen um das Verhältnis des Durchmessers des Piezoaktors 80 zum Durchmesser des Kolbens 82 vergrößerten Hub ausführt. Der Kolben 82 ist zumindest annähernd koaxial zum Piezoaktor 80 angeordnet und in einem im Durchmesser entsprechenden Zylinder 83 verschiebbar geführt. Durch den Kolben 82 wird ein Arbeitsraum 84 begrenzt, der über einen im Durchmesser kleineren Kanal 85 im Gehäuseteil 56 mit dem Arbeitsraum 78 verbunden ist. Der Piezoaktor 80 sowie der Kolben 82 können beliebig am Umfang des Gehäuseteils 56 des Steuerventils 18 angeordnet sein und mit ihren Längsachsen etwa senkrecht zur Längsachse des Steuerventils 18 oder wie in Figur 2 dargestellt beliebig zur Längsachse des Steuerventils geneigt . Nachfolgend wird die Funktion des Kraftstoffeinspritzventils 16 und des Steuerventils 18 erläutert. Wenn der Piezoaktor 80 nicht aktiviert ist, so herrscht im Arbeitsraum 78 ein geringer Druck und das Steuerventilglied 62 wird durch die Rückstellfeder 72 mit seiner ersten Dichtfläche 66 in Anlage am ersten Ventilsitz 60 am Stutzen 52 gehalten. Das Steuerventilglied 62 befindet sich hierbei in einer ersten Schließstellung. Der Druckraum 64 im Steuerventilglied 62 ist somit vom Entlastungsraum, der durch den Vorratstank- 12 gebildet ist, getrennt und aus dem Steuerdruckraum 48 kann durch den Kanal 58 und den Druckraum 64 kein Kraftstoff abströmen. Aus diesem Grund herrscht im Steuerdruckraum 48 derselbe Druck wie im Speicher 14, der auf den Schließkolben 42 wirkt und über diesen auf das Einspritzventilglied 24 wirkt und dieses in seiner Schließstellung hält, in der das Einspritzventilglied 24 mit seiner Dichtfläche 28 am Ventilsitz 30 anliegt und die Einspritzöffnungen 28 verschließt, so daß kein Kraftstoff eingespritzt wird.A working space 78 is delimited in the bore 61 towards the intermediate disk 54 by the control valve member 62. The diameter of the bore 61 in the area of the annular space 75 and / or in the area of the work space 78 can be somewhat enlarged compared to the area in which the control valve member 62 is guided in the bore 61. The work space 78 is connected to a piezo actuator 80 via a hydraulic transmission. The piezo actuator 80 is controlled by the control device 20 and changes its length depending on an electrical voltage applied to it. The piezo actuator 80 is arranged in a cylinder 81 and, when it changes in length, compresses or relaxes a hydraulic volume arranged in the cylinder 81. The hydraulic translation is achieved in that the hydraulic volume influenced by the piezo actuator 80 acts on a piston 82 which is smaller in diameter than the piezo actuator 80 and which, when the length of the piezo actuator 80 changes, increases the stroke by the ratio of the diameter of the piezo actuator 80 to the diameter of the piston 82 performs. The piston 82 is arranged at least approximately coaxially with the piezo actuator 80 and is displaceably guided in a cylinder 83 corresponding in diameter. A working space 84 is delimited by the piston 82 and is connected to the working space 78 via a channel 85 with a smaller diameter in the housing part 56. The piezo actuator 80 and the piston 82 can be arranged anywhere on the circumference of the housing part 56 of the control valve 18 and can be inclined with their longitudinal axes approximately perpendicular to the longitudinal axis of the control valve 18 or, as shown in FIG. 2, to the longitudinal axis of the control valve. The function of the fuel injection valve 16 and the control valve 18 is explained below. If the piezo actuator 80 is not activated, there is a low pressure in the working space 78 and the control valve member 62 is held by the return spring 72 with its first sealing surface 66 in contact with the first valve seat 60 on the nozzle 52. The control valve member 62 is in a first closed position. The pressure chamber 64 in the control valve member 62 is thus separated from the relief chamber, which is formed by the storage tank 12, and no fuel can flow out of the control pressure chamber 48 through the channel 58 and the pressure chamber 64. For this reason, the same pressure prevails in the control pressure chamber 48 as in the accumulator 14, which acts on the closing piston 42 and acts on the injection valve member 24 via it and keeps it in its closed position, in which the injection valve member 24 rests with its sealing surface 28 on the valve seat 30 and which Injection openings 28 closes so that no fuel is injected.
Wenn der Piezoaktor 80 von der Steuereinrichtung 20 angesteuert wird, so vergrößert sich dessen Länge und durch den Kolben 82 wird Hydraulikvolumen aus dem Arbeitsraum 84 über den Kanal 85 in den Arbeitsraum 78 verdrängt, wo der Druck ansteigt, bis die von diesem auf das Steuerventilglied 62 ausgeübte Kraft die Vorspannung der Rückstellfeder 72 überwinden kann und das Steuerventilglied 62 von der Zwischenscheibe 54 weg bewegt wird. Die erste Dichtfläche 66 des Steuerventilglieds 62 hebt dabei vom ersten Ventilsitz 60 am Stutzen 52 ab, so daß der Druckraum 64 im Steuerventilglied 62 mit der Bohrung 65 verbunden ist. Die zweite Dichtfläche 69 am Steuerventilglied 62 befindet sich dann noch nicht in Anlage am zweiten Ventilsitz 74, so daß die Bohrung 65 des Steuerventilglieds 62 mit dem Ringraum 75 und über diesen mit dem als Entlastungsraum dienenden Vorratstank 12 verbunden ist. Aus dem Steuerdruckraum 48 kann in dieser geöffneten Stellung des Steuerventils 18 Kraftstoff durch den Strömungskanal 58, den Druckraum 64 und die als Abströmkanal dienende Bohrung 65 in den Entlastungsraum abströmen, wodurch der Druck im Steuerdruckraum 48 sinkt. Das Einspritzventilglied 24 kann in diesem Fall durch den auf seine Druckschulter 36 wirkenden Druck des Speichers 14 gegen die Kraft der Schließfeder 40 und gegen die von dem im Steuerdruckraum 48 herrschenden verringerten Druck erzeugte Kraft in Öffnungsrichtung 38 bewegt werden und gibt dieWhen the piezo actuator 80 is controlled by the control device 20, its length increases and the piston 82 displaces hydraulic volume from the working space 84 via the channel 85 into the working space 78, where the pressure rises until it reaches the control valve member 62 Exerted force can overcome the bias of the return spring 72 and the control valve member 62 is moved away from the intermediate plate 54. The first sealing surface 66 of the control valve member 62 lifts from the first valve seat 60 on the nozzle 52, so that the pressure chamber 64 in the control valve member 62 is connected to the bore 65. The second sealing surface 69 on the control valve member 62 is then not yet in contact with the second valve seat 74, so that the bore 65 of the control valve member 62 is connected to the annular space 75 and via this to the storage tank 12 serving as a relief space. From the control pressure chamber 48 In this open position of the control valve 18, fuel can flow through the flow channel 58, the pressure chamber 64 and the bore 65 serving as the outflow channel into the relief chamber, as a result of which the pressure in the control pressure chamber 48 drops. In this case, the injection valve member 24 can be moved in the opening direction 38 by the pressure of the accumulator 14 acting on its pressure shoulder 36 against the force of the closing spring 40 and against the force generated by the reduced pressure prevailing in the control pressure chamber 48, and gives the
Einspritzöffnungen 28 frei, so daß Kraftstoff eingespritzt wird.Injection ports 28 free so that fuel is injected.
Wenn der durch den Piezoaktor 80 erzeugte Druck im Arbeitsraum 78 weiter erhöht wird, so wird dasIf the pressure generated by the piezo actuator 80 in the working space 78 is increased further, then this becomes
Steuerventilglied 62 weiter verschoben, bis es mit seiner zweiten Dichtfläche 69 am zweiten Ventilsitz 74 am Boden 71 der Bohrung 61 zur Anlage kommt. Das Steuerventilglied 62 befindet sich hierbei in einer zweiten Schließstellung. In diesem Fall ist die Bohrung 65 im Steuerventilglied 62 vom Ringraum 75 getrennt, so daß aus dem Steuerventilglied 62 durch die Bohrung 65 kann Kraftstoff abströmen kann und im Steuerdruckraum 48 der hohe Druck des Speichers 14 herrscht, durch den über den Schließkolben 42 das Einspritzventilglied 24 in seine Schließstellung bewegt wird und in dieser gehalten wird.Control valve member 62 moved further until it comes to rest with its second sealing surface 69 on the second valve seat 74 on the bottom 71 of the bore 61. The control valve member 62 is in a second closed position. In this case, the bore 65 in the control valve member 62 is separated from the annular space 75, so that fuel can flow out of the control valve member 62 through the bore 65 and the high pressure of the accumulator 14 prevails in the control pressure chamber 48, through which the injection valve member 24 passes through the closing piston 42 is moved into its closed position and is held in this.
Durch entsprechende Ansteuerung des Piezoaktors 80 über die Steuereinrichtung 20 kann der Druck im Arbeitsraum 78 derart eingestellt werden, daß das Steuerventil 18 in seiner geöffneten Stellung gehalten wird, in der dieses weder mit seiner ersten Dichtfläche 66 am ersten Ventilsitz 60 am Stutzen 52 anliegt noch mit seiner zweiten Dichtfläche 69 am zweiten Ventilsitz 74 am Boden 71 der Bohrung 61 anliegt und somit das Kraf stoffeinspritzventil 16 geöffnet bleibt. Es kann auch vorgesehen werden, daß durch entsprechende Aktivierung des Piezoaktors 80 das Steuerventilglied 62 ohne Bewegungsunterbrechung von seiner ersten Schließstellung in seine zweite Schließstellung bewegt wird oder umgekehrt. Bei der Bewegung des Steuerventilglieds 62 erfolgt dabei keine Bewegungsrichtungsumkehr, sondern dieses wird nur in einer Richtung bewegt. Das Steuerventil 18 wird dabei nur kurzzeitig geöffnet, so daß entsprechend auch das Kraftstoffeinspritzventil 16 nur kurzzeitig geöffnet wird. Dies ermöglicht beispielsweise eineBy appropriate control of the piezo actuator 80 via the control device 20, the pressure in the working space 78 can be set such that the control valve 18 is held in its open position, in which it is not in contact with the first valve seat 60 on the nozzle 52 with its first sealing surface 66 nor with its second sealing surface 69 rests on the second valve seat 74 on the bottom 71 of the bore 61 and thus the fuel injection valve 16 remains open. It can also be provided that the control valve member 62 is moved from its first closed position into its second closed position or vice versa by corresponding activation of the piezo actuator 80 without interruption of movement. When the control valve member 62 moves, there is no reversal of the direction of movement, but this is only moved in one direction. The control valve 18 is only opened briefly, so that the fuel injection valve 16 is accordingly only opened briefly. This enables, for example
Kraftstoffvoreinspritzung, bei der eine geringe KraftStoffmenge vor der eigentlichen Kraftstoffeinspritzung eingespritzt wird. Durch entsprechende Ansteuerung des Piezoaktors 78 des Steuerventils 18 über die Steuereinrichtung 20 kann der Zeitpunkt der Öffnung, die Dauer der Öffnung und die Größe des Öffnungshubs des Kraftstoffeinspritzventils 16 bestimmt werden. Das Kraftstoffeinspritzventil kann zunächst nur kurzzeitig und/oder mit geringem Öffnungshub geöffnet werden für die Voreinspritzung, danach geschlossen werden und anschließend für die Haupteinspritzung für längere Zeit und/oder mit größerem Öffnungshub geöffnet werden. Es kann auch ein bestimmter Verlauf der Einspritzung erzielt werden, bei der beispielsweise das Kraftstoffeinspritzventil zunächst nur mit einem geringen Öffnungshub geöffnet wird und anschließend mit einem größeren Öffnungshub geöffnet wird. Es kann auch ein beliebiger anderer Verlauf der Einspritzung erzielt werden.Fuel pre-injection, in which a small amount of fuel is injected before the actual fuel injection. The timing of the opening, the duration of the opening and the size of the opening stroke of the fuel injection valve 16 can be determined by correspondingly controlling the piezo actuator 78 of the control valve 18 via the control device 20. The fuel injection valve can initially only be opened briefly and / or with a small opening stroke for the pre-injection, then closed and then opened for the main injection for a longer time and / or with a larger opening stroke. A specific course of the injection can also be achieved, in which, for example, the fuel injection valve is initially only opened with a small opening stroke and then opened with a larger opening stroke. Any other course of injection can also be achieved.
Wenn sich das Steuerventilglied 62 in seiner erstenWhen the control valve member 62 is in its first
Schließstellung befindet, in der dessen erste Dichtfläche 66 am ersten Ventilsitz 60 am Stutzen 52 anliegt, so wirkt der Druck des Steuerdruckraums 48 im Druckraum 64, wobei sich jedoch keine resultierende Kraft auf das Steuerventilglied 62 ergibt, da der Druck allseitig den Druckraum 64 beaufschlagt. Wenn sich das Steuerventilglied 62 in seiner zweiten Schließstellung befindet, in der dessen zweite Dichtfläche 69 am zweiten Ventilsitz 74 am Boden 71 der Bohrung 61 anliegt, so ergibt sich durch den im Druckraum 64 und der Bohrung 65 herrschenden Druck des Steuerdruckraums 48 ebenfalls keine resultierende Kraft, da die Durchmesser der beiden Ventilsitze 60 und 74 gleich groß sind. Der Druck wirkt am Stirnende des Steuerventilglieds 62 neben der Bohrung 65 auf eine gleich große Ringfläche wie innerhalb des Steuerventilglieds 62 neben der Bohrung 65, so daß sich die hierbei entstehenden Druckkräfte ausgleichen. Eine Bewegung des Steuerventilglieds 62 durch den vom Piezoaktor 80 erzeugten Druck im Arbeitsraum 78 muß somit nicht gegen den Druck im Steuerdruckraum 48 erfolgen, so daß vom Piezoaktor 80 nur relativ geringe Stellkräfte erzeugt zu werden brauchen und der Piezoaktor 80 sowie die hydraulische Übersetzung mit geringen Abmessungen ausgeführt werden können.In the closed position, in which its first sealing surface 66 abuts the nozzle 52 on the first valve seat 60, the pressure of the control pressure chamber 48 acts in the pressure chamber 64, but there is no resultant force on the control valve member 62, since the pressure on all sides of the pressure chamber 64 applied. If the control valve member 62 is in its second closed position, in which its second sealing surface 69 bears against the second valve seat 74 at the bottom 71 of the bore 61, the pressure of the control pressure chamber 48 prevailing in the pressure chamber 64 and the bore 65 likewise does not result in any force , since the diameters of the two valve seats 60 and 74 are the same size. The pressure acts at the front end of the control valve member 62 next to the bore 65 on an annular surface of the same size as within the control valve member 62 next to the bore 65, so that the pressure forces arising thereby equalize. A movement of the control valve member 62 by the pressure generated by the piezo actuator 80 in the working space 78 does not have to take place against the pressure in the control pressure space 48, so that only relatively small actuating forces need to be generated by the piezo actuator 80 and the piezo actuator 80 and the hydraulic translation with small dimensions can be executed.
In Figur 3 ist das Steuerventil 18 gemäß einer gegenüber dem vorstehend erläuterten ersten Ausführungsbeispiel modifizierten Ausführung dargestellt, wobei der grundsätzliche Aufbau des Steuerventils 18 gemäß der modifizierten Ausführung gleich ist wie beim ersten Ausführungsbeispiel und nachfolgend nur die zusätzlichenIn Figure 3, the control valve 18 is shown according to a modified version compared to the above-described first embodiment, the basic structure of the control valve 18 according to the modified embodiment is the same as in the first embodiment and only the additional ones below
Merkmale erläutert werden. Der Stutzen 52 ist in der Bohrung 63 des Steuerventilglieds 62 möglichst dicht geführt, so daß die Bohrung 63 einen Dichtbereich darstellt, durch den der Druckraum 64 im Steuerventilglied 62 vom Arbeitsraum 78 getrennt ist. Das Steuerventilglied 62 weist in seinerFeatures are explained. The connecting piece 52 is guided as tightly as possible in the bore 63 of the control valve member 62, so that the bore 63 represents a sealing area through which the pressure chamber 64 in the control valve member 62 is separated from the working chamber 78. The control valve member 62 has in its
Bohrung 63 eine umlaufende Ringnut 88 auf, die über eine oder mehrere etwa radiale Bohrungen 89 mit einer im Außenmantel des Steuerventilglieds 62 ausgebildete Ringnut 90 verbunden ist. Von der Ringnut 90 führt eine im Außenmantel des Steuerventilglieds 62 ausgebildete beispielsweise etwa axial verlaufende Nut 91 in den Ringraum 75, über den eine Verbindung mit dem Entlastungsraum in Form des Vorratstanks hergestellt ist. Wenn sich das Steuerventilglied 62 in einer seiner Schließstellungen befindet, so herrscht im Druckraum 64 derselbe Hochdruck wie im Steuerdruckraum 48, wobei eventuell durch den zwischen dem Stutzen 52 und der Bohrung 63 vorhandenen Ringspalt Kraftstoff aus dem Druckraum 64 abströmt . Diese abströmende Leckmenge an Kraftstoff wird über die Ringnut 88, die Bohrung 89, die Ringnut 90 und die Nut 91 in denBore 63 has a circumferential annular groove 88 which is connected via one or more approximately radial bores 89 to an annular groove 90 formed in the outer jacket of the control valve member 62. A groove formed in the outer jacket of the control valve member 62 leads from the annular groove 90 for example, approximately axially extending groove 91 in the annular space 75, via which a connection to the relief space in the form of the storage tank is made. When the control valve member 62 is in one of its closed positions, the same high pressure prevails in the pressure chamber 64 as in the control pressure chamber 48, fuel possibly flowing out of the pressure chamber 64 through the annular gap between the nozzle 52 and the bore 63. This outflowing amount of fuel leakage is via the annular groove 88, the bore 89, the annular groove 90 and the groove 91 in the
Entlastungsraum abgeführt und kann nicht in den Arbeitsraum 78 gelangen. Die Nut 91 kann anstelle im Außenmantel des Steuerventilglieds 62 auch in der Bohrung 61 des Gehäuseteils 56 ausgebildet sein. Über die Ringnuten 88 und 90 kann außerdem eine Befüllung der Arbeitsräume 78 und 84 der hydraulischen Übersetzung des Steuerventils 18 erfolgen.Relief chamber removed and can not get into the work space 78. The groove 91 can also be formed in the bore 61 of the housing part 56 instead of in the outer jacket of the control valve member 62. The working spaces 78 and 84 of the hydraulic transmission of the control valve 18 can also be filled via the annular grooves 88 and 90.
In Figur 4 ist das Steuerventil 18 gemäß einem zweiten Ausführungsbeispiel dargestellt, bei dem wiederum der grundsätzliche Aufbau gleich ist wie beim erstenIn Figure 4, the control valve 18 is shown according to a second embodiment, in which the basic structure is again the same as in the first
Ausführungsbeispiel, jedoch die Wirkrichtungen der vom Piezoaktor erzeugten Stellkraft und der Rückstellfeder umgekehrt sind. Das Steuerventilglied 162 weist die Bohrung 63 auf, durch die der Stutzen 52 in den Druckraum 64 ragt, von dem die Bohrung 65 abführt. Am Boden 71 der Bohrung 161 ist die Vertiefung 73 ausgebildet und das Steuerventilglied 162 weist den Ansatz 68 auf. Die Bohrung 161 ist als Stufenbohrung ausgebildet und weist zu der Zwischenscheibe 54 hin einen Abschnitt 161a mit größerem Durchmesser auf und zu ihrem Boden 71 hin einen Abschnitt 161b mit kleineremEmbodiment, but the directions of action of the actuating force generated by the piezo actuator and the return spring are reversed. The control valve member 162 has the bore 63 through which the connection piece 52 projects into the pressure chamber 64, from which the bore 65 leads away. The recess 73 is formed on the bottom 71 of the bore 161 and the control valve member 162 has the extension 68. The bore 161 is designed as a stepped bore and has a section 161a with a larger diameter towards the intermediate disk 54 and a section 161b with a smaller one towards its base 71
Durchmesser. Entsprechend ist das Steuerventilglied 162 in seinem Außendurchmesser ebenfalls gestuft ausgebildet und weist einen Bereich 162a mit größerem Durchmesser auf, der im Abschnitt 161a der Bohrung 161 angeordnet ist und einen Bereich 162b mit kleinerem Durchmesser, der im Abschnitt 161b der Beohrung 161 angeordnet ist. Zwischen einer durch einen Absatz am Steuerventilglied 162 gebildeten Ringschulter 170 und der Zwischenscheibe 54 ist eine vorgespannte Rückstellfeder 172 angeordnet, durch die das Steuerventilglied 162 zum Boden 71 der Bohrung 161 hin gedrückt wird. Durch den im Durchmesser größeren Bereich 162a des Steuerventilglieds 162 wird im Abschnitt 161a der Bohrung 161 ein Arbeitsraum 178 begrenzt, der über einen Kanal 185 mit der hydraulischen Übersetzung des Piezoaktors 80 verbunden ist. Der vom Steuerventilglied 162 im Abschnitt 161a der Bohrung 161 zur Zwischenscheibe 54 hin begrenzte Raum 188, in dem die Rückstellfeder 172 angeordnet ist, ist über einen Kanal 189 mit einem Entlastungsraum, beispielsweise dem Vorratstank 12, verbunden.Diameter. Correspondingly, the control valve member 162 is also stepped in its outer diameter and has an area 162a with a larger diameter, which is arranged in the section 161a of the bore 161, and an area 162b with a smaller diameter, which is in the section 161b of the bore 161 is arranged. A prestressed return spring 172 is arranged between an annular shoulder 170 formed by a shoulder on the control valve member 162 and the intermediate disk 54, by means of which the control valve member 162 is pressed toward the bottom 71 of the bore 161. A working space 178 is delimited in section 161a of bore 161 by region 162a of control valve member 162, which is larger in diameter and which is connected via a channel 185 to the hydraulic transmission of piezo actuator 80. The space 188 delimited by the control valve member 162 in the section 161a of the bore 161 towards the intermediate disk 54, in which the return spring 172 is arranged, is connected via a channel 189 to a relief space, for example the storage tank 12.
Nachfolgend wird die Funktion des Steuerventils 18 gemäß dem zweiten Ausführungsbeispiel erläutert. Wenn der Piezoaktor 80 von der Steuereinrichtung 20 nicht aktiviert ist, so wird durch die Rückstellfeder 172 das Steuerventilglied 162 mit seiner zweiten Dichtfläche 69 gegen den zweiten Ventilsitz 74 am Boden 71 der Bohrung gepresst und befindet sich in seiner zweiten Schließstellung. Wenn der Piezoaktor 80 aktiviert ist, so wird durch den erhöhten Druck im Arbeitsraum 178 das Steuerventilglied 162 gegen die Vorspannung der Rückstellfeder 172 zur Zwischenscheibe 54 hin verschoben. Bei ausreichend hohem Druck im Arbeitsraum 178 gelangt das Steuerventilglied 162 mit seiner ersten Dichtfläche 66 in Anlage am ersten Ventilsitz 60 und wird in seiner ersten Schließstellung gehalten. In seiner zweiten Schließstellung, in der sich das Steuerventilglied 162 bei nicht aktiviertem Piezoaktor 80 befindet, ist das Volumen der Bohrung 65 im Steuerventilglied 162 ebenfalls vom hohen Druck im Steuerdruckraum 48 beaufschlagt. Im Gegensatz hierzu befindet sich das Steuerventilglied 62 gemäß dem ersten Ausführungsbeispiel bei nicht aktiviertem Piezoaktor 80 in seiner ersten Schließstellung, in der nur der Druckraum 64 im Steuerventilglied 62 vom hohen Druck im Steuerdruckraum 48 beaufschlagt ist, während das Volumen der Bohrung 65 mit dem Entlastungsraum verbunden ist. Durch das beim Steuerventil 18 gemäß dem zweiten Ausführungsbeispiel vorhandene größere vom hohen Druck im Steuerdruckraum 48 beaufschlagte Volumen kann das dynamische Verhalten des Steuerventils 18 insbesondere bei kurzen Voreinspritzzeiten beeinflußt werden. The function of the control valve 18 according to the second exemplary embodiment is explained below. If the piezo actuator 80 is not activated by the control device 20, the return spring 172 presses the control valve member 162 with its second sealing surface 69 against the second valve seat 74 at the bottom 71 of the bore and is in its second closed position. When the piezo actuator 80 is activated, the increased pressure in the working space 178 displaces the control valve member 162 toward the intermediate disk 54 against the bias of the return spring 172. If the pressure in the working space 178 is sufficiently high, the control valve member 162 comes into contact with the first valve seat 60 with its first sealing surface 66 and is held in its first closed position. In its second closed position, in which the control valve member 162 is when the piezo actuator 80 is not activated, the volume of the bore 65 in the control valve member 162 is also acted upon by the high pressure in the control pressure chamber 48. In contrast to this, the control valve member 62 according to the first exemplary embodiment is located when the piezo actuator is not activated 80 in its first closed position, in which only the pressure chamber 64 in the control valve member 62 is acted upon by the high pressure in the control pressure chamber 48, while the volume of the bore 65 is connected to the relief chamber. Due to the larger volume present in the control valve 18 according to the second exemplary embodiment, which is acted upon by the high pressure in the control pressure chamber 48, the dynamic behavior of the control valve 18 can be influenced, in particular with short pre-injection times.

Claims

Ansprüche Expectations
1. Kraftstoffeinspritzventil für Brennkraftmaschinen, insbesondere als Bestandteil eines1. Fuel injection valve for internal combustion engines, in particular as part of a
Speicherkraftstoffeinspritzsystems, mit einem axial verschiebbar geführten Einspritzventilglied (24) , durch das wenigstens eine Einspritzöffnung (26) gesteuert wird und das eine einen Druckraum (34) begrenzenden Druckschulter (36) aufweist, wobei dem Druckraum (36) unter Druck stehender Kraftstoff von einer Kraftstoffhochdruckquelle (10; 14) zugeführt wird, durch den das Einspritzventilglied (24) entgegen einer Schließkraft zur Öffnung der wenigstens einen Einspritzöffnung (26) von einem Ventilsitz (30) abhebbar ist, und mit einem die Bewegung des Einspritzventilglieds (24) beeinflussenden Steuerventil (18) , das ein durch eine von einem Piezoaktor (80) erzeugte Stellkraft gegen eine Rückstellkraft bewegbares Steuerventilglied (62; 162) aufweist, das den in einem mit einer Druckquelle (10; 14) verbundenen Steuerdruckraum (48) herrschenden Druck steuert, der das Einspritzventilglied (24) zumindest mittelbar in seiner Schließrichtung beaufschlagt, wobei durch dasStorage fuel injection system, with an axially displaceably guided injection valve member (24) through which at least one injection opening (26) is controlled and which has a pressure shoulder (36) delimiting a pressure chamber (34), the pressure chamber (36) being under pressure from a high-pressure fuel source (10; 14) is supplied, through which the injection valve member (24) can be raised against a closing force to open the at least one injection opening (26) from a valve seat (30), and with a control valve (18) influencing the movement of the injection valve member (24) ) which has a control valve member (62; 162) which can be moved against a restoring force by a positioning force generated by a piezo actuator (80) and which controls the pressure prevailing in a control pressure chamber (48) connected to a pressure source (10; 14) and which controls the injection valve member (24) acted upon at least indirectly in its closing direction, with the
Steuerventilglied (62; 162) der Steuerdruckraum (48) mit einem Entlastungsraum (12) verbindbar ist und das Steuerventilglied (62; 162) mit wenigstens einer Dichtfläche (66,69) mit wenigstens einem Ventilsitz (60,74) zusammenwirkt, über den die Verbindung des Steuerdruckraums (48) mit dem Entlastungsraum (12) gesteuert wird, dadurch gekennzeichnet, daß das Steuerventil (18) zwei in der Bewegungsrichtung des Steuerventilglieds (62; 162) zueinander beabstandete Ventilsitze (60,74) aufweist, daß das Steuerventilglied (62; 162) zwischen zwei Schließstellungen bewegbar ist, in denen es jeweils mit einer Dichtfläche (66,69) an einem der Ventilsitze (60,74) anliegt und der Steuerdruckraum (48) vom Entlastungsraum (12) getrennt ist, und daß bei zwischen seinen beiden Schließstellungen angeordnetem Steuerventilglied (62; 162) der Steuerdruckraum (48) mit dem Entlastungsraum (12) verbunden ist.Control valve member (62; 162) the control pressure chamber (48) can be connected to a relief chamber (12) and the control valve member (62; 162) cooperates with at least one sealing surface (66,69) with at least one valve seat (60,74), via which the Connection of the control pressure chamber (48) to the relief chamber (12) is controlled, characterized in that the control valve (18) has two valve seats (60, 74) spaced apart from one another in the direction of movement of the control valve member (62, 162), that the control valve member (62 ; 162) between two closed positions is movable, in which it rests with a sealing surface (66, 69) on one of the valve seats (60, 74) and the control pressure chamber (48) is separated from the relief chamber (12), and in that the control valve member (62 ; 162) the control pressure chamber (48) is connected to the relief chamber (12).
2. Kraftstoffeinspritzventil nach Anspruch 1, dadurch gekennzeichnet, daß die beiden Ventilsitze (60,74) eine * zumindest annähernd gleich große Querschnittsfläche aufweisen.2. Fuel injection valve according to claim 1, characterized in that the two valve seats (60,74) have an * at least approximately the same cross-sectional area.
3. Kraftstoffeinspritzventil nach Anspruch 1 oder 2, dadurch gekennzeichnet, daß das Steuerventilglied (62; 162) als ein Hohlkolben ausgebildet ist, wobei eine erste Dichtfläche (66) innerhalb des Steuerventilglieds (62; 162) und die zweite Dichtfläche (69) an der Außenseite des Steuerventilglieds (62; 162) angeordnet ist.3. Fuel injection valve according to claim 1 or 2, characterized in that the control valve member (62; 162) is designed as a hollow piston, a first sealing surface (66) within the control valve member (62; 162) and the second sealing surface (69) on the Outside of the control valve member (62; 162) is arranged.
4. Kraftstoffeinspritzventil nach Anspruch 3, dadurch gekennzeichnet, daß in das Steuerventilglied (62; 162) ein Stutzen (52) hineinragt, in dem ein zum Steuerdruckraum (48) führender Kanal (58) ausgebildet ist, der im Steuerventilglied (62; 162) in einem Druckraum (64) mündet, dessen Verbindung mit dem Entlastungsraum (12) durch das Steuerventilglied (62; 162) gesteuert wird.4. Fuel injection valve according to claim 3, characterized in that in the control valve member (62; 162) protrudes a nozzle (52) in which a to the control pressure chamber (48) leading channel (58) is formed, which is in the control valve member (62; 162) opens into a pressure chamber (64), the connection of which to the relief chamber (12) is controlled by the control valve member (62; 162).
5. Kraftstoffeinspritzventil nach Anspruch 4, dadurch gekennzeichnet, daß die innerhalb des Steuerventilglieds (62;162) ausgebildete erste Dichtfläche ( 66 ) mit dem als erstem Ventilsitz (60) dienenden Endbereich des Stutzens (52) zusammenwirkt und durch diese eine Verbindung des Druckraums (64) mit einem im Steuerventilglied (62; 162) ausgebildeten Abströmkanal (65) gesteuert wird. 5. Fuel injection valve according to claim 4, characterized in that the first sealing surface (66) formed within the control valve member (62; 162) cooperates with the end region of the connecting piece (52) serving as the first valve seat (60) and through this a connection of the pressure chamber ( 64) is controlled with an outflow channel (65) formed in the control valve member (62; 162).
6. Kraftstoffeinspritzventil nach Anspruch 5, dadurch gekennzeichnet, daß die an der Außenseite des Steuerventilglieds (62;.162) angeordnete zweite Dichtfläche (69) im Bereich der Mündung des Abströmkanals (65) angeordnet ist und mit dem an einem Gehäuseteil (56) des Steuerventils (16) angeordneten zweiten Ventilsitz (74) zusammenwirkt und durch diese eine Verbindung des Abströmkanals (65) mit dem Entlastungsraum (12) steuert.6. Fuel injection valve according to claim 5, characterized in that the arranged on the outside of the control valve member (62; .162) second sealing surface (69) in the region of the mouth of the outflow channel (65) and with which on a housing part (56) of the Control valve (16) arranged second valve seat (74) cooperates and controls a connection of the outflow channel (65) with the relief chamber (12).
7. Kraftstoffeinspritzventil nach einem der Ansprüche 4 bis 6, dadurch gekennzeichnet, daß die vom Piezoaktor (80) erzeugte Stellkraft durch eine hydraulische Übersetzung verstärkt wird, die einen vom Steuerventilglied (62) begrenzten Arbeitsraum (78) aufweist, daß zwischen dem Stutzen (52) und dem Steuerventilglied (62) ein Dichtbereich (63) vorgesehen ist, durch den der Druckraum (64) vom Arbeitsraum (78) getrennt wird und daß der Dichtbereich (63) eine Verbindung (88,89,90,91) mit einem Entlastungsraum (12) aufweist .7. Fuel injection valve according to one of claims 4 to 6, characterized in that the actuating force generated by the piezo actuator (80) is amplified by a hydraulic transmission which has a working space (78) delimited by the control valve member (62), that between the connecting piece (52 ) and the control valve member (62) a sealing area (63) is provided, through which the pressure chamber (64) is separated from the working space (78) and that the sealing area (63) has a connection (88,89,90,91) with a relief space (12).
8. Kraftstoffeinspritzventil nach einem der Ansprüche 5 bis 7, dadurch gekennzeichnet, daß das Steuerventilglied (62) durch die Rückstellkraft zum ersten Ventilsitz (60) am Stutzen (52) hin beaufschlagt ist.8. Fuel injection valve according to one of claims 5 to 7, characterized in that the control valve member (62) is acted upon by the restoring force to the first valve seat (60) on the connecting piece (52).
9. Kraftstoffeinspritzventil nach /Anspruch 6 oder 7, dadurch gekennzeichnet, daß das Steuerventilglied (162) durch die Rückstellkraft zum zweiten Ventilsitz (74) am Gehäuseteil (56) hin beaufschlagt ist. 9. Fuel injection valve according to / claim 6 or 7, characterized in that the control valve member (162) is acted upon by the restoring force to the second valve seat (74) on the housing part (56).
EP00993183A 1999-11-11 2000-11-10 Fuel injection valve for internal combustion engines Expired - Lifetime EP1252433B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE19954288A DE19954288A1 (en) 1999-11-11 1999-11-11 Fuel injection valve for fitting to internal combustion engines has an injection valve element to control injection openings, a control valve to affect movement in injection valve elements and a valve element for regulating pressure
DE19954288 1999-11-11
PCT/DE2000/004011 WO2001038712A2 (en) 1999-11-11 2000-11-10 Fuel injection valve for internal combustion engines

Publications (2)

Publication Number Publication Date
EP1252433A2 true EP1252433A2 (en) 2002-10-30
EP1252433B1 EP1252433B1 (en) 2005-08-31

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP00993183A Expired - Lifetime EP1252433B1 (en) 1999-11-11 2000-11-10 Fuel injection valve for internal combustion engines

Country Status (7)

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US (1) US6581850B1 (en)
EP (1) EP1252433B1 (en)
JP (1) JP2003515045A (en)
KR (1) KR100717522B1 (en)
CZ (1) CZ295475B6 (en)
DE (2) DE19954288A1 (en)
WO (1) WO2001038712A2 (en)

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Also Published As

Publication number Publication date
JP2003515045A (en) 2003-04-22
WO2001038712A3 (en) 2001-12-27
EP1252433B1 (en) 2005-08-31
CZ20012468A3 (en) 2002-11-13
KR100717522B1 (en) 2007-05-14
US6581850B1 (en) 2003-06-24
KR20010101466A (en) 2001-11-14
CZ295475B6 (en) 2005-08-17
DE50011086D1 (en) 2005-10-06
DE19954288A1 (en) 2001-05-17
WO2001038712A2 (en) 2001-05-31

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