EP1865189A2 - Injecteur de carburant doté d'un actionnement piézo-électrique installé du côté basse pression - Google Patents

Injecteur de carburant doté d'un actionnement piézo-électrique installé du côté basse pression Download PDF

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Publication number
EP1865189A2
EP1865189A2 EP07106975A EP07106975A EP1865189A2 EP 1865189 A2 EP1865189 A2 EP 1865189A2 EP 07106975 A EP07106975 A EP 07106975A EP 07106975 A EP07106975 A EP 07106975A EP 1865189 A2 EP1865189 A2 EP 1865189A2
Authority
EP
European Patent Office
Prior art keywords
pressure
valve
fuel injector
actuator
chamber
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
EP07106975A
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German (de)
English (en)
Other versions
EP1865189B1 (fr
EP1865189A3 (fr
Inventor
Hans-Christoph Magel
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Robert Bosch GmbH
Original Assignee
Robert Bosch GmbH
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Filing date
Publication date
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Publication of EP1865189A2 publication Critical patent/EP1865189A2/fr
Publication of EP1865189A3 publication Critical patent/EP1865189A3/fr
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Publication of EP1865189B1 publication Critical patent/EP1865189B1/fr
Ceased legal-status Critical Current
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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • 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
    • F02M57/00—Fuel-injectors combined or associated with other devices
    • F02M57/02—Injectors structurally combined with fuel-injection pumps
    • F02M57/022—Injectors structurally combined with fuel-injection pumps characterised by the pump drive
    • F02M57/025—Injectors structurally combined with fuel-injection pumps characterised by the pump drive hydraulic, e.g. with pressure amplification
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M63/00—Other fuel-injection apparatus having pertinent characteristics not provided for in groups F02M39/00 - F02M57/00 or F02M67/00; Details, component parts, or accessories of fuel-injection apparatus, not provided for in, or of interest apart from, the apparatus of groups F02M39/00 - F02M61/00 or F02M67/00; Combination of fuel pump with other devices, e.g. lubricating oil pump
    • F02M63/0012—Valves
    • F02M63/0014—Valves characterised by the valve actuating means
    • F02M63/0015—Valves characterised by the valve actuating means electrical, e.g. using solenoid
    • F02M63/0026—Valves characterised by the valve actuating means electrical, e.g. using solenoid using piezoelectric or magnetostrictive actuators
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M63/00—Other fuel-injection apparatus having pertinent characteristics not provided for in groups F02M39/00 - F02M57/00 or F02M67/00; Details, component parts, or accessories of fuel-injection apparatus, not provided for in, or of interest apart from, the apparatus of groups F02M39/00 - F02M61/00 or F02M67/00; Combination of fuel pump with other devices, e.g. lubricating oil pump
    • F02M63/0012—Valves
    • F02M63/0031—Valves characterized by the type of valves, e.g. special valve member details, valve seat details, valve housing details
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M63/00—Other fuel-injection apparatus having pertinent characteristics not provided for in groups F02M39/00 - F02M57/00 or F02M67/00; Details, component parts, or accessories of fuel-injection apparatus, not provided for in, or of interest apart from, the apparatus of groups F02M39/00 - F02M61/00 or F02M67/00; Combination of fuel pump with other devices, e.g. lubricating oil pump
    • F02M63/0012—Valves
    • F02M63/0031—Valves characterized by the type of valves, e.g. special valve member details, valve seat details, valve housing details
    • F02M63/0045—Three-way valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M2200/00—Details of fuel-injection apparatus, not otherwise provided for
    • F02M2200/70—Linkage between actuator and actuated element, e.g. between piezoelectric actuator and needle valve or pump plunger
    • F02M2200/701—Linkage between actuator and actuated element, e.g. between piezoelectric actuator and needle valve or pump plunger mechanical
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M2547/00—Special features for fuel-injection valves actuated by fluid pressure
    • F02M2547/001—Control chambers formed by movable sleeves

Definitions

  • DE 102 47 903 A1 refers to a pressure-boosted fuel injector with internal control line.
  • the fuel injection device comprises a multipart injector body, in which a pressure booster is received.
  • the pressure booster can be actuated via a differential pressure chamber and comprises a pressure booster piston which separates a working space from the differential pressure chamber.
  • the fuel injection device comprises a switching valve arranged above the injector body, via which the fuel injection device can be actuated.
  • a pressure change in the differential pressure chamber of the pressure booster via a central control line which extends through the pressure booster piston of the pressure booster.
  • the solution shown is the actuator in the form of an electromagnetic switching valve outside of the injector body.
  • DE 103 35 340 A1 refers to a control valve for a fuel injector containing a pressure booster.
  • Out DE 103 35 340 A1 shows that a servo valve is used to actuate a pressure booster which is accommodated in the fuel injector.
  • the pressure booster has a working space which is separated by a booster piston from a differential pressure chamber.
  • the control chamber of the servo valve is both connected to a high pressure source and in a low-pressure side return pressure relieved.
  • a pressure stage acting in the closing direction of the valve piston is formed on the valve piston of the servo valve between the control chamber and a hydraulic chamber.
  • the switching valve is an electromagnetic actuator.
  • piezoelectric actuators are used on fuel injectors.
  • a hydraulic coupler is used to achieve a compensation of thermal expansion of the piezoelectric actuator and a stroke ratio of the piezoelectric actuator performing only small strokes. If the piezoelectric actuator thereby the system pressure, i. exposed to the prevailing in a high pressure accumulator pressure level in the order of 1600 bar and more, the sealing of the piezoelectric actuator against the system pressure is required.
  • a coating of the piezoelectric actuator is necessary, which must withstand the permanently high system pressure over the lifetime of the piezoelectric actuator. There is currently no production-ready solution for this.
  • a direct-switching piezoelectric actuator for controlling a fuel injector.
  • This piezoelectric actuator is arranged in the low-pressure region of the fuel injector.
  • no or only very small pressure loads on a protective coating which is attached to the outer surface of the piezoelectric actuator.
  • the prevailing in the low pressure region of a fuel injector pressure is well below the system pressure, which is present for example in the high pressure region of the fuel injector and corresponds to the pressure level with which a high-pressure accumulator chamber (common rail) is acted upon. Due to the non-existent or only very low pressure loads on the Aktorstoffbe Anlagenung a sufficiently high life of such coatings is achieved and thus a series use of such a trained fuel injector, which is controlled by a piezoelectric actuator, achieved.
  • the construction of the switching valve, which is actuated via the piezoelectric actuator is characterized in detail by an at least two-part valve body and a valve needle formed in one piece.
  • a flat seat is preferably formed, which can be produced particularly easily, in particular in the context of a large-scale production.
  • a small-sized and inexpensive piezoelectric actuator can be used, the valve piston unit of the actuated by the piezo actuator switching valve is completely or almost completely pressure-balanced.
  • existing pressure level In order to ensure the pressure balance of the switching valve, which is used in the receiving space in which the piezoelectric actuator is arranged in the low pressure region of the fuel injector, existing pressure level.
  • a small pressure stage is formed in the region of the switching valve on the valve piston thereof, which is designed such that the valve seat is loaded by hydraulic pressure forces in the closed state. This improves the tightness of the preferably designed as a flat seat sealing seat of the switching valve.
  • the valve function can then be realized by dispensing with springs and in particular the force required for sealing must not be applied by the piezoelectric actuator. If the sealing force to be applied by the piezoelectric actuator becomes smaller, then a piezoactuator which is in particular smaller in size and less expensive can be used, since the switching valve to be actuated in the piezoelectric actuator can be designed in a smaller height, which on the one hand saves installation space and on the other hand the costs - as mentioned above - reduced.
  • Figure 1 shows a first embodiment of a fuel injector with a recorded in the low pressure region of the fuel injector piezo actuator and a 3/2-way valve and with a pressure booster.
  • a fuel injector 10 is supplied with fuel under system pressure via a high-pressure reservoir 12 (common rail).
  • the system pressure within the high pressure reservoir 12 is generated by a high pressure source such as a high pressure pump.
  • the system pressure level in the high-pressure reservoir 12 (common rail) is between 1600 and 2000 bar.
  • the fuel injector 10 is connected via a high-pressure line 14 to the high-pressure reservoir 12.
  • the high-pressure line 14 opens in the area of a valve body 96 in the fuel injector 10.
  • a working space 22 of a pressure booster 18, which is accommodated in an injector body 16 is subjected to system pressure.
  • the working space 22 of the pressure booster 18 is separated by a pressure booster piston 20 from a pressure-relieving differential pressure chamber 24.
  • the pressure amplifier 18 further comprises a compression space 26, in which a pressure level corresponding to the transmission ratio of the pressure intensifier 18 is increased.
  • a piston spring 28 is further included, which the pressure booster piston 20 after actuation of the same, i. a pressure relief of the differential pressure chamber 24, returns to its rest position.
  • a compression channel 30, in which a first throttle point 36 is formed extends to a control chamber 40.
  • a differential pressure chamber 24 also extends a line to the control chamber 40, in which a second throttle body 38 is formed.
  • a preferably needle-shaped injection valve member 50 is acted upon in the closing direction acting spring 42.
  • a compression line 32 connects the compression space 26 formed in the injector body 16 with a nozzle chamber 46, which is formed in the nozzle body 44 and the preferably needle-shaped injection valve member 50 surrounds annular.
  • the injection valve member 50 has a pressure stage 52 in the region in which it is enclosed by the nozzle chamber 46. Below the seat of the preferably needle-shaped injection valve member 50 there is at least one injection opening 54, via which fuel is injected into a combustion space 56 when the injection valve member 50 is open.
  • the fuel injector 10 according to the first embodiment variant shown in FIG. 1 furthermore comprises a piezoelectric actuator 70, which has a number of piezoelectric elements forming a piezocrystal stack 72, which are arranged stacked one above the other.
  • the piezoelectric actuator 70 is received in the low-pressure region 80 of the fuel injector 10, which is filled with fuel.
  • the piezoelectric actuator 70 is surrounded by a coating 74 to the piezocrystal stack 72 against the prevailing in the low pressure region 80 of the fuel injector 10 residual pressure, i. the low pressure, protect.
  • the piezoelectric actuator 70 is surrounded by an actuator spring 78, which is preferably designed as a tubular spring.
  • the piezoelectric actuator 70 of the fuel injector 10 is an inversely driven piezoelectric actuator, which in the closed state of the injection valve member 50, i. is energized when the injection openings 54 closed at the combustion chamber end of the fuel injector 10. To effect an opening of the preferably needle-shaped injection valve member 50, the energization of the inversely driven piezoelectric actuator 70 is released.
  • electrical connections 76 are formed in the head region of the piezoelectric actuator 70, which are guided via a first housing part 84 to the outside. From the low pressure region 80, within which the piezoelectric actuator 70 is arranged in a cavity 88, a low-pressure side return 82 branches off.
  • the cavity 88 is delimited by the first housing part 84 and a second housing part 86 laterally delimiting the cavity 88.
  • a further housing part 90 can be used to support the same.
  • the piezoelectric actuator 70 is in direct contact with a valve piston 94 with its underside.
  • the valve piston 94 is surrounded by the valve body 96.
  • the valve piston 94 is part of a switching valve, which is designed as a 3/2 valve.
  • Below the valve body 96 of the switching valve 92 is an intermediate disc 98, in which a hydraulic chamber 100 is formed.
  • the hydraulic chamber 100 communicates via an overflow line 102 with the low-pressure region 80 of the fuel injector 10 formed cavity 88 in connection.
  • the switching valve 92 includes a first valve seat 104, which can be opened or closed by the valve piston 94 upon actuation of the piezo actuator 70.
  • the valve piston 94 comprises a second valve seat 106.
  • the valve piston 94 is guided in a piston guide 108 in the valve body 96.
  • the diameter of the valve piston 94 is indicated by reference numeral 110
  • the diameter of the first valve seat 104 in the valve body 96 is identified by reference numeral 112.
  • the diameter 112 of the first valve seat 104 corresponds to the diameter of the piston guide 108, ie, the diameter 110 of the valve piston 94.
  • the switching valve 92 further includes a first valve space 114 and a second valve space 116, in which a control line 34 for pressure relief of the differential pressure chamber 24 of the pressure booster 18 opens.
  • a control line 34 for pressure relief of the differential pressure chamber 24 of the pressure booster 18 opens.
  • Within the valve body 96 of the switching valve 92 which is preferably designed as a 3/2 valve, branches off from the high pressure line 14 from a branch 118, which opens into the first valve chamber 114 of the switching valve 92.
  • the piezoelectric actuator 70 is arranged directly between the valve piston 94 and the insert 90 and is prestressed by means of the spring 78.
  • the piezo plate 70 may either be fixedly connected to the valve piston 94 and the insert 90 or be clamped only by the actuator spring 78.
  • the compensation of temperature-induced expansions of the piezoelectric actuator 70 takes place mechanically via compensation elements produced, for example, from Invar, such as, for example, the first housing part 84 and the second housing part 86 and optionally via an insert part 90 made of suitable material.
  • the first valve chamber 114 is acted upon by the branch 118 with system pressure.
  • the piezo actuator 70 is charged and assumes its nominal length.
  • the second valve seat 106 is closed above the hydraulic chamber 100.
  • the piezoelectric actuator 70 is discharged via the electrical connections 76, as a result of which the piezocrystal stack 72 of the piezoelectric actuator 70 is shortened.
  • the shortening of the piezocrystal stack 72 causes a movement of the valve piston 94 in its second switching position, in which the first valve seat 104 is opened and the second valve seat 106 is closed.
  • the pressure booster piston 20 enters the compression space 26, from which the compression line 32 branches off to the nozzle chamber 46.
  • the injection valve member 50 opens against the action of the recorded in the control chamber 40 spring 42 and releases the opening into the combustion chamber 56 of the internal combustion engine injection openings 54.
  • a refilling of the differential pressure chamber 24 via the control line 34; the compression space 26 is refilled via the lines with the throttling points 36 and 38.
  • the piezoelectric actuator 70 When the piezoelectric actuator 70 is recharged via the electrical connections 76, the piezoelectric actuator 70 is deflected, as a result of which the valve piston 94 from the first valve seat 104 returns into the second valve seat 106, i. the upper plan side of the washer 98, is turned on. As a result, the pressure relief of the differential pressure chamber 24 is released and supported by the piston spring 28 takes the pressure booster piston 20 of the booster 18 back to its rest position.
  • the piezoelectric actuator 70 has "buried" electrical terminals 76, whereby the electrical contact layers against the surrounding medium, i. the low-pressure fuel, are protected and damage due to electrical short circuits is excluded.
  • FIG. 2 shows an embodiment variant using the example of a stroke-controlled fuel injector with a piezoelectric actuator arranged in its low-pressure region, but without a pressure booster.
  • a stroke-controlled fuel injector 130 shown in FIG. 2 comprises the piezoelectric actuator 70, which is likewise received in the low-pressure region 80 of the stroke-controlled fuel injector 130 analogously to the embodiment variant shown in FIG.
  • the low-pressure region 80 in particular the cavity 88 formed in the latter, is delimited by the first housing part 84 and by the second housing part 86.
  • the insert part 90 located above the piezoelectric actuator 70, the insert part 90, which is also made of a strain due to temperature compensating material.
  • the piezocrystal stack 72 of the piezoelectric actuator 70 is enclosed by the coating 74.
  • the piezo actuator 70 which is also operated inversely, biased by the actuator spring 78.
  • the actuator spring 78 is preferably designed as a tubular spring.
  • a temperature compensation element 134 Between the piezo plate 70 and the valve piston 94 which is guided in the valve body 96, there is a temperature compensation element 134.
  • the valve piston 94 and the piezo actuator 70 is formed as two separate components.
  • the piezoelectric actuator 70 is clamped between the insert part 90 and the temperature compensation element 134.
  • Below the valve body 96 is the washer 98, in which the hydraulic chamber 100 is formed.
  • a first compression spring element 132 In the hydraulic chamber 100 is a first compression spring element 132, which supports the opening movement of the valve piston 94 when canceling the energization of the inversely controlled piezoelectric actuator 70, ie when its shortening.
  • the stroke-controlled fuel injector 130 is acted upon by the system pressure applied to the high-pressure accumulator chamber 12 (common rail) and the high-pressure line 14 branching from this system pressure.
  • the system pressure is also present in the first valve chamber 114 of the switching valve 92 via the branch 118 branching off from the high-pressure line 14.
  • the high pressure line 14 opens into a hydraulic space of the stroke-controlled fuel injector 130.
  • the control chamber 40 is pressurized with system pressure via a pressure line in which the first throttle point 36 is formed.
  • the first throttle point 36 acts as an inlet throttle. From the control chamber 40, which is delimited by a sealing sleeve 140, runs a Ab Kunststofftechnisch in which a discharge throttle 138 is formed and which opens in the second valve chamber 116 of the switching valve 92.
  • the sealing sleeve 140 is acted upon by a compression spring, which in turn is supported on a collar 146 of the preferably needle-shaped injection valve member 50. At its circumference there is at least one bevel 142, via which fuel injection ports 54 flow under system pressure, and is injected via the injection openings 94 opened with the injection valve member 50 open into the combustion chamber 46 of the internal combustion engine.
  • the operation of the switching valve 92 corresponds to the operation of the switching valve 92 described in connection with Figure 1, the valve piston 94 is formed in the diameter 110, which corresponds to the inner diameter of the piston guide 108.
  • a pressure relief of the control chamber 40 and thus an actuation of the preferably needle-shaped injection valve member 50 takes place upon cancellation of the energization of the inversely driven piezoelectric actuator 70.
  • the closed in the closed position of the injection valve member 50 second valve seat 106 is when canceling the energization of the piezoelectric actuator 70 due to the shortening of the piezocrystal stack 72nd , supported by the spring force of the first compression spring element 132, opened, whereas the first valve seat 104 in the valve body 96 is closed.
  • FIG. 3 shows a further, second embodiment of a fuel injector with arranged in the low pressure region piezoelectric actuator, which is driven inversely, wherein the fuel injector includes a pressure booster.
  • the second embodiment of the fuel injector 10 as shown in Figure 3 can be removed that the fuel injector 10 is supplied via the high-pressure accumulator chamber 12 (common rail) with fuel under system pressure.
  • the fuel under system pressure is passed from the high-pressure accumulator chamber 12 via the high-pressure line 14 into the working chamber 22 of the pressure intensifier 18, which is located in the injector body 16.
  • the pressure booster 18 includes the pressure booster piston 20, which separates the working space 22 from the differential pressure space 24.
  • the fuel under system pressure is compressed to an elevated pressure level corresponding to the transmission ratio of the pressure booster 18. From the compression space 26, the fuel under elevated pressure flows via the compression line 32 to the nozzle chamber 46, which encloses a preferably needle-shaped injection valve member 50.
  • the pressure stage 52 is located in the region which is preferably needle-shaped.
  • the injection valve member 50 In the combustion chamber end of the injection valve member 50, there is at least one injection opening 54, via which fuel, which is under increased pressure when the injection valve member 50 is open Combustion chamber 56 of the internal combustion engine is injected.
  • the pressure relief of the differential pressure chamber 24 via the control line 34 in which a discharge line 164 opens, in which there is a throttle point and extending from a hydraulic space.
  • the second throttle body 38 which serves as a drain throttle.
  • a guided in the injector body 16 piston member is acted upon, which has a passage 158 and at the preferably needle-shaped injection valve member 50 facing end face is provided with a convex contour 162.
  • the end face of the preferably needle-shaped injection valve member 50 is designated by reference numeral 160.
  • the control line 34 opens into the second valve chamber 116 of the switching valve 92 for pressure relief of the differential pressure chamber 24 and for pressure relief of the control chamber 40.
  • the switching valve 92 includes the valve piston 94, which is guided in the piston guide 108 in the valve body 96.
  • Below the valve body 96 is the intermediate disc 98, in which the hydraulic chamber 100 is formed and which receives the first compression spring element 132, which causes a closing force on the valve piston 94 with respect to the sealing of the second valve seat 106.
  • the valve piston 94 is formed within the piston guide 108 in diameter 110.
  • the first valve seat 104 in the valve body 96 is formed in a diameter 112.
  • the valve piston 94 On the end face facing away from the first compression spring element 132, the valve piston 94 has a trough-shaped depression 154.
  • a piezoelectric crystal stack 72 is also housed in the low pressure region 80 of the fuel injector 10.
  • the formed in the low pressure region 80 cavity 88 is bounded by the first housing part 84 and the second housing part 86.
  • the piezoelectric actuator 70 has the coating 74 for protecting the piezocrystal stack 72 and is charged or discharged via electrical connections 76.
  • the piezoelectric actuator 70 according to FIG. 3 is a piezoelectric actuator 70 that is not driven inversely. This means that the piezoelectric actuator 70 is not charged in the quiescent state and therefore assumes its normal length.
  • the piezoelectric actuator 70 is charged via the electrical connections 76, there is a longitudinal expansion of the piezoelectric crystal stack 72 and thus the actuation of a disc-shaped insert 150, on which a journal is formed approximately centrally.
  • the disc-shaped insert 150 is acted upon by a second compression spring element 152, which is supported in the cavity 88 at a stage of the second housing part 86.
  • the pin which contacts the planing side of the disc-shaped insert 150, which faces in the valve piston 94, contacts the trough-shaped recess 154 of the valve piston 94 directly without the formation of a gap.
  • the piezosteller 70 If, on the other hand, the piezosteller 70 is charged, the piezocrystal stack 72 experiences an expansion, so that the disc-shaped insertion part 150 with pins formed thereon is set against the trough-shaped recess 154 and the valve piston 94 in the vertical direction moved down. As a result, the first valve seat 104 is closed, whereas the second valve seat 106 opens. Now there is a hydraulic connection between the differential pressure chamber 24 of the pressure booster 18, the discharge line 34, the second valve chamber 116 and the opening surrounding the pin to form an annular gap, the cavity 88 in the low-pressure side return 82.
  • the pressure booster piston 20 moves due to the pressure relief of the differential pressure chamber 24 in the compression space 26, so that fuel under maximum pressure flows with closed filling valve 166 via the compression line 82 to the nozzle chamber 46. Due to the pending in the nozzle chamber 46 maximum pressure level 50 of the needle-shaped preferably injection valve member 50 is opened by the pressure stage and the opening into the combustion chamber 56 injection openings 54 are released.
  • the length of the piezocrystal stack 72 is shortened.
  • the valve piston 94 is moved vertically upward by the first compression spring element 132, so that the second valve seat 106 closes and the first valve seat 104 opens, as shown in FIG. Characterized the discharge line 34 is separated from the low-pressure side return 82 and the pressure booster piston 20 is moved from the compression chamber 26 supported by the piston spring 28 in its rest position.
  • the compression chamber 26 is refilled via the filling valve 166, which branches off from a hydraulic space and flows through in the filling direction of the compression chamber 26.
  • the control quantity flowing out of the control chamber 40 upon actuation of the injection valve member 50 is controlled via the second throttling point 38 and the discharge line 164 Disabled via the control line 34.
  • the piezo plate 70 has, above the insert part 90, a coupler space 156 which serves to compensate for the temperature-induced expansion of the piezo plate 70.
  • the piezoelectric actuator 70 is placed in its rest position via the second compression spring element 152, which is supported in the second housing part 86.
  • the piezoelectric actuator 70 is located directly in the low-pressure region 80 of the fuel injector 10 and is protected by the coating 74 against the fuel present in the cavity 88. Since the piezocrystal stack 72 of the piezoelectric actuator 70 is only subjected to low pressure, the loads and requirements for the coating 74 decrease accordingly, so that it has a sufficient service life.
  • the electrical connections 76 of the piezoelectric actuator 70 are preferably formed as buried electrodes, whereby the electrical contact layers are protected against the surrounding medium and damage due to electrical short circuits can be excluded.
  • FIG. 4 shows a variant of the embodiment of the fuel injector shown in FIG.
  • FIG. 4 shows the fuel injector according to FIG. 3 only above the injector body 16.
  • the injector body 16, the pressure booster 18 and the injection valve member 50 and its actuating mechanism are constructed analogously to the embodiment according to Figure 3 and require no further description.
  • the piezo-actuator 70 or the insert part 90 is accommodated in an actuator guide 174 cooperating with the first housing part 84.
  • the actuator guide 174 is protected against the located in the cavity 88, under low pressure fuel by means of a membrane 170.
  • the membrane 170 may be bellows-type.
  • Within the membrane 170 is a first guide member 76 which is connected to the first housing part 84 and at this possibly spring-loaded trained second guide member 178.
  • the second guide member 178 is fixedly connected to the insert part 90.
  • the membrane 170 encapsulates a separate hydraulic coupler module, formed by the actuator guide 174. In the area enclosed by the membrane 170, a foreign medium may also be present. If a seal is provided between the circumference of the disk-shaped insert part 150 and the second housing part 86, the cavity 88 can be completely dry, with the low-pressure side return line 82 branching off in the lower region of the second housing part 86 in this case.
  • FIG. 5 shows a representation of the valve region of the fuel injector in a third embodiment, similar to the second embodiment of the fuel injector described above in connection with FIGS. 3 and 4.
  • the part of the fuel injector 10 lying below the valve body 96 corresponds to the embodiment of the second exemplary embodiment of the fuel injector 10 shown in FIG.
  • valve body 96 of the switching valve 92 opens via the high-pressure line 14, which branches off from the high-pressure reservoir 12 (common rail) via the branch 118 in the first valve chamber 114 of the switching valve 92.
  • the switching valve 92 is preferably designed as a 3/2 valve.
  • Below the valve body 96 is the washer 98, in which the hydraulic chamber 100 is located.
  • the first compression spring element 132 is received, which acts on an end face of the valve piston 94.
  • the valve piston 94 is received in a piston guide 108.
  • the piston guide 108 is formed in an inner diameter corresponding to the diameter 110 of the valve piston 94.
  • first valve seat 104 and the second valve seat 106 are located in the valve body 96 of the switching valve 92.
  • the diameter of the first valve seat 104 in the valve body 96 is substantially equal to the diameter 110 of the valve piston 94.
  • the second valve seat 106 is on the valve piston 94 preferably executed in a slightly larger diameter. By this difference in diameter, a hydraulic closing force is exerted on the second valve seat 106. This supports the closing action of the first compression spring element 132, which is received in the hydraulic chamber 100.
  • valve housing a simple and cost-effective production is achieved, especially when the valve piston 94 sealed by a formed on a second plan side 188 of a disc 184 flat seat can be.
  • the piezoelectric actuator 70 is taken in the illustration of Figure 5 between the insert 90 and the disc-shaped member 150 with pins.
  • the non-inversely operated piezo-actuator 70 is biased by the actuator spring 78, which engages under the component 150.
  • the actuator spring 78 is supported on a first planar side 186 of the disc 184.
  • the pin of the component 150 passes through an opening 182 in the disc 184. Between the end face of the pin and the bottom of the trough-shaped recess 154 is formed when the second valve seat 106 is closed, a gap 180, which serves to compensate for residual tolerances and a safe closing of the valve guaranteed.
  • the compensation of thermal expansion of the piezoelectric actuator 70 takes place mechanically via corresponding expansions of the insert part 90 of the first housing part 84, through which the electrical connections 76 are routed, and by an expansion of the second housing part 86, which delimits the cavity 88.
  • the components 84, 90 and 86 are preferably made of a material such as Invar.
  • the piezo actuator 70 At rest, the piezo actuator 70 is not charged and takes its nominal length.
  • the piezoelectric actuator 70 is charged via the electrical contacts 76, whereby the piezocrystal stack 72, which is enclosed by a coating 74, expands.
  • FIG. 6 shows a modification of the embodiment variant of a stroke-controlled fuel injector shown in FIG.
  • the switching valve 92 is acted upon by the high-pressure line 14 and the branch 118 via the high-pressure reservoir 12 (common rail) with fuel under system pressure.
  • the first valve space 114 of the switching valve 92 is under system pressure.
  • the valve piston 94 of the switching valve 92 is acted upon by the first pressure spring element 132 accommodated in the hydraulic chamber 100, so that the valve piston 94 whose second valve seat 106 delimits the trough-shaped recess 154 is closed.
  • the second valve seat 106 of the valve piston 94 is attached to the second plan side 188, which acts as a flat seat.
  • the disc 184 includes the opening 182 through which a pin of the component 150 protrudes to form an annular gap.
  • the component 150 engaging under the piezocrystal stack 72 is prestressed by the actuator spring 78, which in turn is supported on the first plane side 186 of the disk 184. Between the pin on the component 150 and the bottom of the trough-shaped recess 154 in the region of the second valve seat 106 of the valve piston 94, the gap identified by reference numeral 180 forms.
  • the piezoelectric actuator 70 whose piezoelectric crystal stack 72 is enclosed by the coating 74, is accommodated in the low-pressure region 80, ie in the cavity 88 of the stroke-controlled fuel injector 130. From the cavity 88 branches off a low-pressure side return 82.
  • the diameter ratios of the piston guide 108 of the valve piston 94 and the first valve seat 104 in the valve body 96 correspond to those already described in FIG were.
  • the switching valve 92 is used in the illustration according to FIG. 6 for controlling a stroke-controlled fuel injector 130 with a servo-controlled injection valve member 50.
  • the switching valve 92 controls in the embodiment variant shown in Figure 6 instead of the pressure in a differential pressure chamber 24 of a pressure booster of this embodiment, the pressure in the control chamber, which acts on the injection valve member 50 directly.

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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)
EP07106975A 2006-06-07 2007-04-26 Injecteur de carburant doté d'un actionnement piézo-électrique installé du côté basse pression Ceased EP1865189B1 (fr)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE200610026381 DE102006026381A1 (de) 2006-06-07 2006-06-07 Kraftstoffinjektor mit Druckübersetzer und niederdruckseitig angeordnetem Piezosteller

Publications (3)

Publication Number Publication Date
EP1865189A2 true EP1865189A2 (fr) 2007-12-12
EP1865189A3 EP1865189A3 (fr) 2009-10-28
EP1865189B1 EP1865189B1 (fr) 2012-10-03

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Country Link
EP (1) EP1865189B1 (fr)
DE (1) DE102006026381A1 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1900932A2 (fr) 2006-09-11 2008-03-19 Robert Bosch Gmbh Injecteur destiné à la vaporisation de carburant
EP2166218A3 (fr) * 2008-09-17 2010-06-23 Robert Bosch GmbH Soupape d'injection de combustible
EP2333296A1 (fr) * 2009-12-10 2011-06-15 Delphi Technologies Holding S.à.r.l. Élément de soupape pour agencement de vanne de liquide
WO2016120040A1 (fr) * 2015-01-27 2016-08-04 Delphi International Operations Luxembourg S.À R.L. Servo-injecteur

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102010042622A1 (de) 2010-10-19 2012-04-19 Robert Bosch Gmbh Kraftstoffinjektor, inbesondere Common-Rail-Injektor

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19946841A1 (de) * 1999-09-30 2001-05-03 Bosch Gmbh Robert Ventil zum Steuern von Flüssigkeiten
DE10141110A1 (de) * 2001-08-22 2003-03-20 Bosch Gmbh Robert Kraftstoffeinspritzvorrichtung für Brennkraftmaschinen
DE10335059A1 (de) * 2003-07-31 2005-02-17 Robert Bosch Gmbh Schaltventil für einen Kraftstoffinjektor mit Druckübersetzer
DE102004017305A1 (de) * 2004-04-08 2005-10-27 Robert Bosch Gmbh Kraftstoffeinspritzeinrichtung für Brennkraftmaschinen mit direkt ansteuerbaren Düsennadeln
DE102004024215A1 (de) * 2004-05-15 2005-12-08 L'orange Gmbh Steuerventil
DE102004044811A1 (de) * 2004-09-16 2006-03-23 Robert Bosch Gmbh Steuerventil einer Einspritzdüse
DE102005038596A1 (de) * 2005-08-16 2007-02-22 Robert Bosch Gmbh Kraftstoffinjektor für eine selbstzündende Verbrennungskraftmaschine
DE102005039913A1 (de) * 2005-08-24 2007-03-08 Robert Bosch Gmbh Kraftstoffinjektor
EP2333296B1 (fr) * 2009-12-10 2013-04-17 Delphi Technologies Holding S.à.r.l. Élément de soupape pour agencement de vanne de liquide

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1900932A2 (fr) 2006-09-11 2008-03-19 Robert Bosch Gmbh Injecteur destiné à la vaporisation de carburant
EP1900932A3 (fr) * 2006-09-11 2009-11-18 Robert Bosch Gmbh Injecteur destiné à la vaporisation de carburant
EP2166218A3 (fr) * 2008-09-17 2010-06-23 Robert Bosch GmbH Soupape d'injection de combustible
EP2333296A1 (fr) * 2009-12-10 2011-06-15 Delphi Technologies Holding S.à.r.l. Élément de soupape pour agencement de vanne de liquide
WO2016120040A1 (fr) * 2015-01-27 2016-08-04 Delphi International Operations Luxembourg S.À R.L. Servo-injecteur

Also Published As

Publication number Publication date
EP1865189B1 (fr) 2012-10-03
EP1865189A3 (fr) 2009-10-28
DE102006026381A1 (de) 2007-12-13

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