EP3112662A1 - Injecteur de carburant - Google Patents

Injecteur de carburant Download PDF

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Publication number
EP3112662A1
EP3112662A1 EP16176738.9A EP16176738A EP3112662A1 EP 3112662 A1 EP3112662 A1 EP 3112662A1 EP 16176738 A EP16176738 A EP 16176738A EP 3112662 A1 EP3112662 A1 EP 3112662A1
Authority
EP
European Patent Office
Prior art keywords
measuring device
housing
region
fuel injector
fuel
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Withdrawn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
EP16176738.9A
Other languages
German (de)
English (en)
Inventor
Dieter Junger
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 EP3112662A1 publication Critical patent/EP3112662A1/fr
Withdrawn legal-status Critical Current

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    • 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
    • F02M57/005—Fuel-injectors combined or associated with other devices the devices being sensors
    • 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
    • F02M2200/24—Fuel-injection apparatus with sensors
    • F02M2200/247—Pressure sensors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M2200/00—Details of fuel-injection apparatus, not otherwise provided for
    • F02M2200/80—Fuel injection apparatus manufacture, repair or assembly
    • F02M2200/8038—Fuel injection apparatus manufacture, repair or assembly the assembly involving use of adhesives, glue or the like
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M2200/00—Details of fuel-injection apparatus, not otherwise provided for
    • F02M2200/80—Fuel injection apparatus manufacture, repair or assembly
    • F02M2200/8084—Fuel injection apparatus manufacture, repair or assembly involving welding or soldering

Definitions

  • the invention relates to a fuel injector, in particular common-rail injector, according to the preamble of claim 1.
  • Such a fuel injector is from the post-published DE 10 2015 211 186 A1 the applicant known.
  • the known fuel injector has a measuring device which has a piezoelectric element as well as insulating layers on both sides of the piezoelectric element, wherein such a measuring device can be produced as a prefabricatable module.
  • Such a trained, especially in advance with regard to their functions testable measuring device is housed within a dome-shaped, made of metal housing, wherein the measuring device on the one hand at the bottom of the housing of the housing and on the other hand directly to the deformation region, in each case over one of the insulation layers, rests.
  • the connection between the housing and the deformation region in the region of the injector housing is effected by means of a welded connection.
  • the housing has a circumferential flange region, in the region of which the weld seam, preferably in the form of a laser weld seam, is arranged. From the cited document, it is also possible to remove that the measuring device consisting of the piezoelectric element and the insulation layers rests under axial prestress against the deformation region of the injector housing. This is done in that the addressed assembly has a height which is slightly larger than the depth of the receptacle for the assembly in the housing.
  • a welding gap is formed between the housing on the side facing the deformation region, in particular also in the region of the flange region, such that by applying an axial biasing force to the housing in the region of the flange with simultaneous formation of the welded joint, the desired biasing force on the measuring device can be generated.
  • the housing for receiving the measuring device is made of stiffness reasons or to produce the desired axial preload force of a relatively hard material, in particular Invar®.
  • Invar® has a low temperature expansion coefficient for the Glaseinschmelzen.
  • the axial preload on the sensor device is very much dependent on the size of the welding gap and the welding parameters. Overall, this makes the setting of the desired biasing force on the piezoelectric element or the measuring device relatively expensive.
  • the present invention seeks to further develop a fuel injector according to the preamble of claim 1 such that a simplified manufacturability, in particular with regard to the setting of the desired axial biasing force on the measuring device or the piezoelectric element is enabled ,
  • the connection between the housing for receiving the measuring device and the injector to be high quality, also considered over the life of the fuel injector.
  • a low susceptibility to cracking should be made possible.
  • a high signal gradient is desired, that is, even relatively small deformations lead to a relatively high voltage signal of the piezoelectric element.
  • a fuel injector with the characterizing features of claim 1, characterized in that the measuring device rests with the interposition of a rigid, in particular made of metal washer on the deformation region.
  • the use according to the invention of an intermediate plate makes it possible, depending on the individually determined height of the measuring device (consisting of the piezoelectric element and the insulating layers) and the depth of the receptacle in the housing by using a correspondingly thick intermediate disc, the desired welding gap between the housing and the deformation region to adjust the formation of the weld with high accuracy. This makes it possible for the manufacture of the measuring device and the housing increased tolerance values are made possible because the tolerances on an individually or in certain thickness gradations provided intermediate disc be compensated.
  • the intermediate disk consists of a rigid material, ie has a very high modulus of elasticity, a deformation of the deformation region of the injector housing leads to a relatively high useful signal at the measuring device.
  • the use of an intermediate disc makes it possible to use a material with a relatively low coefficient of thermal expansion and little hardness or austenite for the steel housings. This makes it possible to achieve a high quality of the welded connection between the housing and the injector housing.
  • a particularly protected or robust construction of the measuring device is made possible by the intermediate disc, since it is now mechanically protected inside the housing not only by the housing itself but also in the intermediate disc.
  • the measuring device rests on the side facing away from the intermediate disc with an end face on the bottom of the receptacle, and that the receptacle has a depth which is less than the sum of the thickness to achieve an axial biasing force on the measuring device the measuring device and the washer.
  • the desired (axial) pretensioning force can be adjusted to the measuring device or the piezoelectric element via a corresponding selection of the thickness of the intermediate plate.
  • Such a biasing force on the piezoelectric element has proven to be advantageous on the one hand in practice for the life of such a piezoelectric element, since such a piezoelectric element is very insensitive to compressive stresses, as well as a balancing of shape and parallelism errors allows a proportional useful signal.
  • the housing is hood-shaped with a bottom portion and a radially encircling outer wall that protrudes from the outer wall, a flange radially outwardly, in the region of the welded joint is formed, that the housing has an area aligned with the outer wall, in that the housing bears directly against the deformation region, and that a welding gap is formed between the flange and the deformation region in the region outside the region where the housing bears against the deformation region.
  • the weld is formed as a laser weld.
  • the material of the washer so matched to the measuring device and the material of the housing is that at least approximately the same thermal expansions arise for the composite of intermediate disc and measuring device as for the housing.
  • the measuring device and the washer are connected to each other.
  • connection between the measuring device and the washer that the washer rests directly on the measuring device, and in that the connection between the intermediate disk and the measuring device is formed by an adhesive connection which is arranged between a peripheral surface of the intermediate disk and an end face of the measuring device.
  • the intermediate disk has a recess for the adhesive, at least in the region of two opposite corners, in the region of which Measuring device covers the washer.
  • the Indian Fig. 1 fuel injector 10 shown greatly simplified is designed as a so-called common rail injector, and is used to inject fuel into the combustion chamber, not shown, of an internal combustion engine, in particular a self-igniting internal combustion engine.
  • the fuel injector 10 has an injector housing 11, which consists essentially of metal and may have a multi-part design, in which at least one, preferably a plurality of injection openings 12 for injecting the fuel into the combustion chamber are arranged on the side facing the combustion chamber of the internal combustion engine.
  • this has a high pressure chamber 15, in which a nozzle needle 16 serving as an injection member is arranged in a liftable manner in the direction of the double arrow 17.
  • lowered position of the nozzle needle 16 this forms together with the inner wall of the high-pressure chamber 15 and the injector 11 a sealing seat, so that the injection openings 12 are at least indirectly closed, such that injecting fuel from the high-pressure chamber 15 in the Combustion chamber of the internal combustion engine is prevented.
  • lifted from the sealing seat position of the nozzle needle 16 this releases the injection openings 12 for injecting the fuel into the combustion chamber of the internal combustion engine.
  • the movement of the nozzle needle 16, in particular for releasing the injection openings 12, takes place in a manner known per se by means of an actuator, not shown, which can be actuated via a voltage supply line 18 by a control device of the internal combustion engine.
  • the actuator may, for example, be a magnetic actuator or a piezoactuator.
  • the supply bore 19 is also connected via a fuel connection, not shown, with a fuel line 22, which in turn is coupled to a fuel reservoir 25 (rail).
  • a blind hole-shaped recess 24 is formed, so that the wall thickness of the injector 11 is reduced in the region of the recess 24.
  • the injector housing 11 may also have a flattening, in the region of which the wall thickness of the injector housing 11 is reduced.
  • the newly formed base 26 of the recess 24 forms part of a deformation region 27.
  • a branch 28 which opens in the region of the deformation region 27.
  • the fuel pressure prevailing in the supply bore 19 or the branch 28 also acts on the side of the deformation region 27 facing away from the recess 24. Since the wall thickness of the injector housing 11 is reduced in the region of the recess 24, the deformation region 27 of the injector housing 11 acts on the Recess 24 facing side in the manner of an elastically deformable membrane, wherein the deformation, which forms as a curvature, the greater, the higher the fuel pressure in the supply hole 19.
  • the fuel injector 10 To detect the time course of the fuel pressure in the supply bore 19 and thus also in the high-pressure chamber 15, which is used as an indication of the instantaneous position of the nozzle needle 16 for driving the nozzle needle 16, the fuel injector 10 has a measuring device 30 whose signals to a not shown control unit for at least indirect control of the fuel injector 10 are supplied.
  • the measuring device 30 has according to the representation of Fig. 2 a preferably made of metal, in particular NiFe with a coefficient of thermal expansion between 4.5 (10 -6 K -1 ) and 6.5 (10 -6 K -1 ) existing, produced by deep-drawing process housing 35.
  • the lid or hood-shaped housing 35 has a peripheral flange 36, in the region of which a weld seam 38, in particular designed as a laser welding connection, serves to connect the housing 35 of the measuring device 30 to the injector housing 11 in the region of the recess 24.
  • a weld gap 40 may be formed between the base 26 of the recess 24 and the facing surface of the flange 36 in regions.
  • the measuring device 30 comprises a piezoelectric element 41 designed as a sensor element.
  • the piezoelectric element 41 is preferably accommodated in a receptacle 43 of the housing 35 while forming a radial gap 42.
  • the piezo element 41 has a first insulation layer 44, a first electrode layer 45, a piezoceramic layer 46, a second electrode layer 47 and a second insulation layer 48.
  • the layers 44 to 48 described so far are sandwiched one over the other and in contact with each other, wherein the piezoceramic layer 46 is arranged between the two electrode layers 45 and 47, and wherein the two insulation layers 44, 48 on the side facing away from the respective electrode layer 45, 47 of the piezoceramic layer 46 are arranged.
  • the two insulating layers 44, 48 are preferably made of unpolarized piezoceramics (alternatively also of aluminum oxide).
  • the layers 44 to 48 form, with a suitable material selection, a module 50 which can be produced in the sintering process and can be tested in advance.
  • the assembly 50 is in the region of the two insulating layers 44, 48 are processed on their opposite sides to achieve low roughness and flat surfaces, preferably by grinding.
  • the assembly 50 described so far is arranged in operative connection with an intermediate disc 52, which rests directly on the base 26 of the recess 24. Furthermore, the assembly 50 faces the end face 53 of the intermediate disc 52 directly on the facing end face 54 of the insulating layer 44 at. Both the assembly 50 and washer 52 and the receptacle 43 in the housing 35 are each formed in cross section in each case approximately rectangular, which is particularly apparent from the Fig. 3 is recognizable. Furthermore, the base surface of the assembly 50 and the washer 52 at least substantially the same size, except in the region of at least two diametrically opposite corners of the washer 52, at the area of the intermediate disc 52 is provided with a preferably concave recess 55, the over the entire height of the washer 52 extends.
  • the intermediate plate 52 is connected to the assembly 50 by means of an adhesive bond 56.
  • the adhesive bond 56 is arranged between the peripheral surface 57 of the intermediate disk 52 in the region of the recess 55 and the (lower) end surface 54 of the assembly 50 facing the intermediate disk 52.
  • the thickness D 2 of the intermediate disc 52 is, for example, and not limiting, between 0.7mm and 0.9mm. Furthermore, the thickness D of the assembly 50 or the measuring device 30 is typically, and not limited, between 1.1 mm and 1.3 mm.
  • the intermediate disk 52 consists of a metal having a high temperature expansion coefficient and a high modulus of elasticity, for example stainless steel 1.4310. It is also essential that the mentioned welding gap 40 between the housing 35 and the base 26 of the recess 24 is formed only over a portion of the recess 24 facing end face 59 of the housing 35.
  • the welding gap 40 is formed only in the region of the flange 36, while the aligned with the outer wall 61 of the housing 35 or formed in extension of the outer wall 61 portion 62 of the end face 59 of the housing 35 directly, ie without welding gap 40, at the base 26 of Recess 24 is present.
  • the depth T of the receptacle 43 between the base 51 of the receptacle 43, in the region of which the measuring device 30 is preferably fully applied, and the end face 59 in the region 62 is slightly less than the sum of the thickness D. 1 of the measuring device 30 and the thickness D 2 of the intermediate disc 52nd
  • two electrical connection lines 63, 64 in the form of connecting wires.
  • two blind-hole-shaped, preferably produced by a laser machining holes 65, 66 are formed.
  • the two bores 65, 66 respectively penetrate the second insulation layer 48, wherein the bore 66 completely penetrates the piezoceramic layer 46 and projects into the first insulation layer 44, while the bore 65 merely protrudes into the piezoceramic layer 45. In other words, this means that the two bores 65, 66 completely penetrate the two electrode layers 45, 47 and are continued in the direction of the injector housing 11.
  • the two connecting lines 63, 64 are formed in particular in the form of an enameled wire. Furthermore, the holes 65, 66 in the region of the housing 35 have a larger diameter or cross-section than in the region of the measuring device 30 or the module 50.
  • the connecting lines 63, 64 have in the region of the housing 35 has a first portion 67, in whose Area of the cross-section or diameter of the connecting lines 63, 64 is greater than in the region of the measuring device 30 and the assembly 50, where the connecting lines 63, 64 form a second portion 68. Between the bottom of the respective bore 65, 66 and the free end of the second portion 68 of the respective connecting line 63, 64 an axial distance is formed.
  • connection between the second portion 68 of the connecting line 63, 64 and the respective electrode layer 45, 47 is effected by a solder joint 69, 70, which also the axial gap between the free end of the second portion 68 of the connecting line 63, 64 and the bottom of the bore 65, 66 bridges or fills. Furthermore, the annular space 75 between the bore 65, 66 in the region of the housing 35 and the connecting line 63, 64 filled by an insulating material 76 in the form of a glass fusion 77.
  • a washer 52 is selected whose thickness D 2 is chosen so the intermediate disk 52 protrudes slightly beyond the plane of the housing 35 in the region 62.
  • the housing 35 with an axial or biasing force F is subjected to force in the region of the flange 36 in the direction of the base 26 of the depression 24 until the region 62 of the flange 36 bears against the base 26 of the recess 24 and finally the weld seam 38 is formed in the region of the flange 36.
  • the fuel injector 10 described so far can be modified or modified in many ways, without departing from the spirit of the invention.
  • the footprint of the measuring device 30 is not limited to rectangular shapes.
EP16176738.9A 2015-06-30 2016-06-28 Injecteur de carburant Withdrawn EP3112662A1 (fr)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE102015212187.9A DE102015212187A1 (de) 2015-06-30 2015-06-30 Kraftstoffinjektor

Publications (1)

Publication Number Publication Date
EP3112662A1 true EP3112662A1 (fr) 2017-01-04

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ID=56289387

Family Applications (1)

Application Number Title Priority Date Filing Date
EP16176738.9A Withdrawn EP3112662A1 (fr) 2015-06-30 2016-06-28 Injecteur de carburant

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EP (1) EP3112662A1 (fr)
DE (1) DE102015212187A1 (fr)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3018339A1 (fr) * 2014-11-07 2016-05-11 Robert Bosch Gmbh Injecteur
EP3018338A1 (fr) * 2014-11-07 2016-05-11 Robert Bosch Gmbh Injecteur de carburant et procede de fabrication d'un injecteur de carburant
EP3018336A1 (fr) * 2014-11-07 2016-05-11 Robert Bosch Gmbh Injecteur de carburant

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102015211186A1 (de) 2015-04-30 2016-11-03 Robert Bosch Gmbh Kraftstoffinjektor

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3018339A1 (fr) * 2014-11-07 2016-05-11 Robert Bosch Gmbh Injecteur
EP3018338A1 (fr) * 2014-11-07 2016-05-11 Robert Bosch Gmbh Injecteur de carburant et procede de fabrication d'un injecteur de carburant
EP3018336A1 (fr) * 2014-11-07 2016-05-11 Robert Bosch Gmbh Injecteur de carburant

Also Published As

Publication number Publication date
DE102015212187A1 (de) 2017-01-05

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