EP3139028A1 - Zweiseitig gesockelte koppler für stellantrieb - Google Patents

Zweiseitig gesockelte koppler für stellantrieb Download PDF

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Publication number
EP3139028A1
EP3139028A1 EP15183646.7A EP15183646A EP3139028A1 EP 3139028 A1 EP3139028 A1 EP 3139028A1 EP 15183646 A EP15183646 A EP 15183646A EP 3139028 A1 EP3139028 A1 EP 3139028A1
Authority
EP
European Patent Office
Prior art keywords
actuator
actuator assembly
reaction chamber
plug
fluid
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.)
Withdrawn
Application number
EP15183646.7A
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English (en)
French (fr)
Inventor
Michael Cooke
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.)
Delphi International Operations Luxembourg SARL
Original Assignee
Delphi International Operations Luxembourg SARL
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 Delphi International Operations Luxembourg SARL filed Critical Delphi International Operations Luxembourg SARL
Priority to EP15183646.7A priority Critical patent/EP3139028A1/de
Publication of EP3139028A1 publication Critical patent/EP3139028A1/de
Withdrawn legal-status Critical Current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
    • F02M51/00—Fuel-injection apparatus characterised by being operated electrically
    • F02M51/06—Injectors peculiar thereto with means directly operating the valve needle
    • F02M51/0603—Injectors peculiar thereto with means directly operating the valve needle using piezoelectric or magnetostrictive operating means
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M61/00—Fuel-injectors not provided for in groups F02M39/00 - F02M57/00 or F02M67/00
    • F02M61/04—Fuel-injectors not provided for in groups F02M39/00 - F02M57/00 or F02M67/00 having valves, e.g. having a plurality of valves in series
    • F02M61/08—Fuel-injectors not provided for in groups F02M39/00 - F02M57/00 or F02M67/00 having valves, e.g. having a plurality of valves in series the valves opening in direction of fuel flow
    • 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
    • F02M61/00—Fuel-injectors not provided for in groups F02M39/00 - F02M57/00 or F02M67/00
    • F02M61/16—Details not provided for in, or of interest apart from, the apparatus of groups F02M61/02 - F02M61/14
    • F02M61/167—Means for compensating clearance or thermal expansion

Definitions

  • the present invention relates to an actuator assembly for a fuel injector and more particularly to servo actuator provided with an integral hydraulic lash adjuster.
  • injection events are indirectly commanded by energizing an actuator displacing a valve opening a spill orifice.
  • an actuator displacing a valve opening a spill orifice.
  • a spring displaces the valve closing said orifice.
  • Servo actuators such as piezo or magneto-restrictive actuators, require hydraulic lash adjuster, hereafter HLA, also called “coupler” in order to adapt to slow variations of the lengths of the parts caused by temperature changes and wear.
  • HLA hydraulic lash adjuster
  • DE102010029106 , DE102009000203 , EP1519037 , WO2013053594 , WO2013053594 disclose examples of such injectors.
  • the working volume of the HLA becomes pressurized when control valve is opened as the actuator is energized, but after an injection, inertia of the moving parts and the fluid leaked out during operation can cause cavities to form in the working fluid, meaning that motion of the parts is only well controlled in the compression direction.
  • the actuator assembly has an elongated body provided with an internal bore extending from an opening to a bottom face and wherein a servo actuator member is arranged to extend and retract in order to cooperate with a valve member.
  • the actuator assembly further comprises a hydraulic lash adjuster (hereafter HLA) filled with fluid, the HLA being provided with a first reaction chamber wherein pressure rises when the actuator member extends and wherein pressure drops when the actuator member retracts and, a second reaction chamber wherein pressure drops when the actuator member extends and wherein pressure rises when the actuator member retracts so that, the HLA is adapted to resist both the extensions and the contractions of the servo actuator member.
  • HLA hydraulic lash adjuster
  • first reaction chamber and the second reaction chamber are in fluid communication with each other.
  • the first reaction chamber of the HLA is defined between a first inner shoulder face of the bore and a first outer shoulder face of the actuator member.
  • the second reaction chamber of the HLA is defined between a second inner shoulder face of the bore and a second outer shoulder face of the actuator member.
  • the actuator assembly may further comprise an annular reacting plug arranged in the bore and fixed to the actuator body.
  • the plug locally restricts the section of the bore, the first inner shoulder face and the second inner shoulder face being integral to said annular plug.
  • the actuator member has a thin head portion extending with clearance fit through a central opening of the annular plug and protruding in a secondary chamber defined between said second inner shoulder face and the bottom face of the bore.
  • the actuator assembly may further comprise an annular collar engaged and fixed to the thin head portion protruding in a secondary chamber, the second outer shoulder face being integral to said collar.
  • the annular collar may be threaded onto the head portion of the actuator member so that the volume of the second reaction chamber can be chosen by adjusting the axial position of the collar on the head portion.
  • the actuator assembly may further comprise a locking screw adapted to lock the position of the annular collar over the head portion.
  • the actuator assembly may further comprise a fluid absorbing member arranged in said secondary chamber, said fluid absorbing member being made of a material such as felt or sponge which by capillary action can attract the fluid ensuring that there is fluid present in the first reaction chamber and in the second reaction chamber irrespective of the orientation of the assembly.
  • the actuator assembly may further comprise at least one securing member, such as a screw, securing the reacting plug to the actuator body.
  • the fluid may be high viscosity silicone oil.
  • the invention also extends to a fuel injector comprising an actuator assembly as described above.
  • the actuator assembly 12 of a fuel injector 10 comprising an actuator body 14 extending along a longitudinal axis X1, drawn vertical on the figures the top-down arbitrary orientation of the figures being utilized to ease, simplify and clarify the present description without any intention to limit the invention.
  • the actuator body 14 extends from an upper region 16, top of the figures, where can be placed an electrical connector not represented, to a lower transverse face 18 adapted to be in sealing surface contact against the top face of a control valve assembly not represented.
  • the body 14 is also provided with an internal cylindrical cavity 20 extending inside the body 14 along a cavity axis X2 parallel to the longitudinal axis X1.
  • the cavity 20 comprises a large bore 22 upwardly extending from an opening 24 in the lower transverse face 18, up to a bottom face 26 wherefrom a thinner conduit 28 upwardly extends toward the upper region 16.
  • annular reacting plug 30 fixed to the body 14 the reacting plug 30 having a peripheral cylindrical face 32 that is in contact with the inner wall of the large bore, a first inner shoulder face 34, or lower face 34, a second inner shoulder face 36, or upper face 36 and, a central axial aperture 37 defining an inner cylindrical face.
  • the cross section of the annular plug 30 is an isosceles trapezium, first 34 and second 36 shoulder faces being conical and symmetrical. The advantages attached to such embodiment are detailed below but alternatively, any other cross section would fit the purpose of the invention and in particular, acute or obtuse, symmetric or non-symmetric, trapezium sections.
  • a reacting plug 30 having parallel plane upper and lower faces could also be chosen.
  • the reacting plug 30 divides said large bore 22 into a main chamber 38, extending below the reacting plug 30 toward the opening 24 in the lower transverse face and, a secondary chamber 40 extending above the reacting plug 30 to the bottom face 26 of the large bore 22.
  • the reacting plug 30 may be fixed in the large bore 22 by press-fit, as represented on figure 1 , or via securing members 42 such as pressing-screws 42, represented on figures 2 and 4 , said screws being radially threaded in the wall of the body 14, the sealing of the threaded holes being ensured after assembly with tightening glue or sealing paste.
  • said bore 22 may be provided with a small pressing step 44 so that the section of the main chamber 38 below said step 44 is slightly enlarged facilitating the insertion of the plug 30.
  • a servo actuator member 46 such as a piezo-electric or a magneto restrictive actuator, which has a large cylindrical actuation portion 48, a thinner head portion 50 and a first outer shoulder face 52 in-between them.
  • the actuation portion 48 extends in the main chamber 38 from a lower face 54 to the first outer shoulder face 52 which faces the first inner shoulder face 34 of the reacting plug 30 then, the thinner head portion 50 upwardly extending from said first outer shoulder face 52 engages through the central opening 37 of the plug and protrudes on the opposite side in the secondary chamber 40.
  • a male actuation pin 56 protrudes from the lower face 54 and, electrical wires departing from the thinner head portion 50 upwardly extend in the thinner conduit 28, toward the electrical connector.
  • the collar 60 In the secondary chamber 40 is arranged with clearance fit a collar 60 that is fixed on the protruding portion of the head portion 50, the collar 60 having a lower face 62, or second outer shoulder face 62, arranged facing the second inner shoulder face 36 of the reacting plug, the two shoulder faces 36, 62, having complementary parallel profiles and, in the chosen illustrated example the lower face 62 is conical.
  • the collar 60 has right-angled trapezium cross section, the lower face 62 being the sloped leg of the trapezium opposed to a transverse upper face 64 that is the right angle leg above which, in the secondary chamber 40, an actuator spring 66 compressed between said upper face 64 and the bottom face 26 of the large bore permanently downwardly solicits the actuator member 46.
  • the collar 60 is provided on its upper face with a recess in which is arranged an absorbing member 68 made of a material such as felt or sponge.
  • the absorbing member 68 is a thick washer above which a closing washer 70 closes the recess and receives the actuator spring 66, the axial force of the spring 66 being transmitted from the closing washer 70 to the collar 60 via an inner tubular spacer 72 through which is engaged the head portion 50.
  • the spacer 72 can be integral to the collar 60, as represented on the figure, or can be provided separately as an independent component.
  • a resilient sealing assembly 74 comprising a resilient sealing member 76 provided with a central aperture 78 through which extends the actuation pin 56, said sealing assembly 74 sealingly closing the cavity 20, thanks to an O-ring 80 arranged in the central aperture 78 and radially compressed between the sealing member 76 and the actuation pin 56.
  • the actuator member 46 is arranged in the cavity 20 so that its lower face 54 remains inside the cavity 20 at a distance of the sealing member 76 defining between them a reservoir 82.
  • the actuator member 46 is immersed in high viscosity fluid F such as silicone oil having typically a viscosity in the 1,000-800,000 centistokes range, said fluid F filling a fluid filling volume VF comprising all available spaces of the cavity 20, all said spaces being in fluid communication with each other.
  • the fluid filling volume VF comprises the main chamber 38, the reservoir 82, the secondary chamber 40 wherein the fluid F is absorbed and captured in the absorbing washer 68 and also, the clearances for instance between the inner and outer shoulder faces.
  • the fluid F may fill part of the secondary chamber, half for instance, so that said secondary chamber may act as a compensation reservoir ensuring that fluid is always present in the rest of the filling volume VF even if the actuator assembly is arranged in a slightly non vertical way, and also to allow for thermal expansion and contraction of the fluid.
  • the actuation portion 48 of the actuator member comprises a piezo stack 84 axially compressed in a very stiff cage spring 86 having a tubular body provided with a plurality of regularly spaced transverse apertures 88 providing to the tubular body the required axial stiffness.
  • the silicone oil F having a high dielectric strength of around 10-15kV/mm, and variants being compatible with silicone coatings often used to passivate the piezo stack, it is acceptable to have the oil F flowing through the transverse apertures 88 and to be in direct contact with the piezo stack 84 without generating dielectric breakdown.
  • the clearance C is to be distinguished in several portions each varying in thickness.
  • a large clearance C1 of few tens of microns is between first inner and first outer shoulder faces 34, 52, defining there between a first reaction chamber 90 and, similar large clearance C1 is also between the second inner and second outer shoulder faces 36, 62, defining there between a second reaction chamber 92.
  • a small clearance C2 of few microns separates the head portion 50 of the actuator from the cylindrical wall of the central aperture 37 of the reacting plug.
  • a similar small clearance C2 is also between the collar 60 and the wall of the secondary chamber 40.
  • the first reacting chamber 90 and the second reacting chamber 92 are sloped in order to help evacuating toward the top of the injector any bubble of air that would be captured in the silicone oil F.
  • the fuel injector 10 is connected to a control unit not represented which alternatively energizes or not the actuator member in order to command or to forbid injection events.
  • the actuator member 46 When the actuator assembly 12 is energized, the actuator member 46 axially X2 expands so that the actuation pin 56 solicits and pushes a control valve that opens a spill orifice through which pressurized fuel gushes flowing toward an outlet consequently enabling fuel injection event. While the actuator 46 expands the pressure rises in the first reaction chamber 90 and drops in the second reaction chamber 92.
  • the first reaction chamber 90 acts as a top mounted hydraulic lash adjuster (HLA) resisting and controlling the expansion motions of the actuator member 46.
  • HLA top mounted hydraulic lash adjuster
  • the actuator member 46 retracts to a rest length so the actuation pin 56 lifts off and the control valve closes the spill orifice, as being biased by a spring valve and consequently, fuel injection event is prevented. While the actuator 46 retracts it remains downwardly biased by the actuator spring 66 and, the pressure drops in the first reaction chamber 90 while it rises in the second reaction chamber 92.
  • the second reaction chamber 92 acts as a top mounted hydraulic lash adjuster (HLA) resisting and controlling the contraction motions of the actuator 46.
  • HLA top mounted hydraulic lash adjuster
  • the actuator member 46 is able to accommodate with said dimensions variations.
  • sealing assembly 74 It is important to isolate the silicone oil from exposure to fuel, one reason being that fuel has low viscosity and could affect the HLA performances.
  • the sealing performance of the sealing assembly 74 is assured by the O-ring 80 compressed between the wall of the central aperture 78 of the sealing member 76 and the actuation pin 56.
  • a metal diaphragm or bellows welded to the actuator body 14 and also to the actuation pin 56 could be used, such embodiments being described in application GB1512350 filed 15 July 2015 .
  • a separate filling orifice would be added and would typically be plugged with a metal ball, or a plug, after filling the oil the filling orifice extending in the wall of the actuator body from an opening in the lower transverse face of the body, or alternatively in the outer peripheral face, to another opening inside the cavity.
  • the actuation portion 56 is further provided with a metal encapsulation tube 94 enclosing the cage spring 86 and the piezo stack 84.
  • Said encapsulation tube 94 protects the stack 84 from direct fluid contact and consequent dielectric breakdown. This may occur either if the fluid F has intrinsically a low dielectric strength or, if the sealing performance of the sealing assembly 74 is not sufficient enabling minor fuel leaks inside the cavity.
  • a small clearance similar to the previously described small clearance C1, is reserved between the tubular encapsulation 94 and the cylindrical wall of the main chamber 38 of the large bore 22.
  • the fluid filling volume VF comprises the reservoir 82, said small clearance C1 surrounding the encapsulation tube 94, the first reaction chamber 90 and the second reaction chamber 92 and, the secondary chamber 40 wherein the fluid F is absorbed and captured in the absorbing member 68.
  • the assembly process 110 of this first embodiment depends upon the fixation means of the plug 30 in the body 14.
  • a second embodiment now described in reference to figures 3 and 4 , enables tuning of the resisting force and controlling motion of the actuator member 46 due to its contractions when not energized. Said adjustment is provided with adjusting means for trimming the large clearance C1 of the second reacting chamber 92.
  • the collar 60 is no longer permanently fixed on the head portion 50.
  • the central bore of the collar and the head portion 50 are complementary threaded and so, the collar 60 is screwed onto the head portion 50 to a position where the lower face 62 of the collar is precisely at a desired distance from the upper face 36 of the restricting plug.
  • the collar's position is locked thanks to a locking screw 96 provided with an external thread so that, as visible of the figure, it is engaged and screwed in the central aperture of the collar 60 to the point where said locking screw 96 comes in abutment against the head portion 50 of the actuator member, where it is tightened locking the collar 60 in a fixed position.
  • the locking screw 96 is provided with an axial drive feature such as a slot and, the collar 60 with a radial drive feature such as a hexagon socket, a compact tool 98 can be made which can access both features whilst having room for a bore to pass the actuator electrical connections through.
  • This adjusting means enables to set the collar 60 in an operating assembly and therefore to trim it to provide the same performances of a particular parameter for a given electrical drive signal.
  • this parameter could for example be opening delay, or fuelling.
  • This second embodiment might be easier to assemble should the annular reacting plug 30 be fixed to the body 14 by securing members 42 as shown on figure 4 .
  • the assembly process 110 of this second embodiment comprises the following steps:

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Fuel-Injection Apparatus (AREA)
EP15183646.7A 2015-09-03 2015-09-03 Zweiseitig gesockelte koppler für stellantrieb Withdrawn EP3139028A1 (de)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP15183646.7A EP3139028A1 (de) 2015-09-03 2015-09-03 Zweiseitig gesockelte koppler für stellantrieb

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP15183646.7A EP3139028A1 (de) 2015-09-03 2015-09-03 Zweiseitig gesockelte koppler für stellantrieb

Publications (1)

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EP3139028A1 true EP3139028A1 (de) 2017-03-08

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EP15183646.7A Withdrawn EP3139028A1 (de) 2015-09-03 2015-09-03 Zweiseitig gesockelte koppler für stellantrieb

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Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10039543A1 (de) * 2000-08-12 2002-02-28 Daimler Chrysler Ag Einspritzventil
WO2005026532A1 (de) * 2003-09-12 2005-03-24 Siemens Aktiengesellschaft Dosiervorrichtung
EP1519037A1 (de) 2003-09-29 2005-03-30 Robert Bosch Gmbh Brennstoffeinspritzventil
EP1591656A2 (de) * 2004-04-26 2005-11-02 Isuzu Motors Limited Längen-Ausgleichselement und dieses enthaltendes Kraftstoff-Einspritzventil
DE102005045893A1 (de) * 2005-09-26 2007-04-05 Siemens Ag Hydraulische Kompensationseinrichtung
DE102009000203A1 (de) 2009-01-14 2010-07-15 Robert Bosch Gmbh Hydraulikmodul für einen Kraftstoffinjektor
DE102010029106A1 (de) 2010-05-19 2011-11-24 Robert Bosch Gmbh Steifigkeitsoptimierter Kopplerkörper
WO2013053594A1 (de) 2011-10-14 2013-04-18 Robert Bosch Gmbh Hydraulischer koppler

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10039543A1 (de) * 2000-08-12 2002-02-28 Daimler Chrysler Ag Einspritzventil
WO2005026532A1 (de) * 2003-09-12 2005-03-24 Siemens Aktiengesellschaft Dosiervorrichtung
EP1519037A1 (de) 2003-09-29 2005-03-30 Robert Bosch Gmbh Brennstoffeinspritzventil
EP1591656A2 (de) * 2004-04-26 2005-11-02 Isuzu Motors Limited Längen-Ausgleichselement und dieses enthaltendes Kraftstoff-Einspritzventil
DE102005045893A1 (de) * 2005-09-26 2007-04-05 Siemens Ag Hydraulische Kompensationseinrichtung
DE102009000203A1 (de) 2009-01-14 2010-07-15 Robert Bosch Gmbh Hydraulikmodul für einen Kraftstoffinjektor
DE102010029106A1 (de) 2010-05-19 2011-11-24 Robert Bosch Gmbh Steifigkeitsoptimierter Kopplerkörper
WO2013053594A1 (de) 2011-10-14 2013-04-18 Robert Bosch Gmbh Hydraulischer koppler

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