EP1088986A1 - Fuel injector - Google Patents

Fuel injector Download PDF

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Publication number
EP1088986A1
EP1088986A1 EP00120863A EP00120863A EP1088986A1 EP 1088986 A1 EP1088986 A1 EP 1088986A1 EP 00120863 A EP00120863 A EP 00120863A EP 00120863 A EP00120863 A EP 00120863A EP 1088986 A1 EP1088986 A1 EP 1088986A1
Authority
EP
European Patent Office
Prior art keywords
shutter unit
tubular body
pipe
magnetic
fuel injector
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP00120863A
Other languages
German (de)
English (en)
French (fr)
Inventor
Maurizio Boaro
Fabio Cernoia
Marcello Cristiani
Massimo Neretti
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.)
Marelli Europe SpA
Original Assignee
Magneti Marelli SpA
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 Magneti Marelli SpA filed Critical Magneti Marelli SpA
Publication of EP1088986A1 publication Critical patent/EP1088986A1/en
Withdrawn legal-status Critical Current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
    • F02M51/061—Injectors peculiar thereto with means directly operating the valve needle using electromagnetic operating means
    • F02M51/0625—Injectors peculiar thereto with means directly operating the valve needle using electromagnetic operating means characterised by arrangement of mobile armatures
    • F02M51/0664—Injectors peculiar thereto with means directly operating the valve needle using electromagnetic operating means characterised by arrangement of mobile armatures having a cylindrically or partly cylindrically shaped armature, e.g. entering the winding; having a plate-shaped or undulated armature entering the winding
    • F02M51/0667—Injectors peculiar thereto with means directly operating the valve needle using electromagnetic operating means characterised by arrangement of mobile armatures having a cylindrically or partly cylindrically shaped armature, e.g. entering the winding; having a plate-shaped or undulated armature entering the winding the armature acting as a valve or having a short valve body attached 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
    • 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
    • F02M61/166—Selection of particular materials

Definitions

  • the present invention relates to a fuel injector.
  • the present invention relates to a fuel injector for internal-combustion engines, to which the following description specifically refers, without detracting from generality.
  • the fuel injectors for internal-combustion engines which are commercially available at present comprise: a main tubular body, which is provided with a central through pipe, which ends at an axial end of the tubular body, in a spray nozzle, which can project outside the injector a jet of finely sprayed fuel; a shutter unit, which is fitted such as to be axially mobile inside the central pipe, from and towards the position of closure, in which it closes the spray nozzle, such as to prevent discharge of the fuel; and a contrast spring which can maintain the shutter unit in the said position of closure.
  • the fuel injectors additionally comprise a coil made of electrically conductive material, which, when electric current is passed through it, can generate a magnetic field which can overcome the resilient force of the spring, such as to move the shutter unit away temporarily from the position of closure, so as to permit controlled discharge of the fuel.
  • the central portion of the main tubular body and the shutter unit are made from ferro-magnetic material, and are disposed aligned one in front of the other, such that the magnetic field produced by the coil of electrically conductive material tends to bring the shutter unit into contact with the central portion of the main tubular body, thus overcoming the resilient force of the spring.
  • the central portion of the main tubular body and the shutter unit define the fixed part and the mobile part of the magnetic core of the coil of the fuel injector.
  • the highly-resistant material for example chromium
  • the highly-resistant material which is deposited on the surface of the two components has non-magnetic or diamagnetic properties, and when it is diffused on the interior, it contaminates the ferro-magnetic material of which the two components are made, thus reducing their ferro-magnetic properties. In turn, this reduction gives rise to deterioration of the performance of the magnetic surface of the injector.
  • the above-described surface treatment has high costs, which affect significantly the overall production costs of the above-described fuel injectors.
  • the object of the present invention is to provide a fuel injector for internal-combustion engines, which is free from the above-described disadvantages.
  • a fuel injector which comprises a main tubular body, which has at least one through pipe which ends in a spray nozzle, which can spray to the exterior the fuel which is present inside the through pipe, and a shutter unit, which is mobile inside the through pipe, from and towards a position of closure, in which it abuts the spray nozzle, and seals it in a fluid-tight manner;
  • the shutter unit being made of ferro-magnetic material, and the injector additionally comprising a coil which can generate selectively a magnetic field, which can displace the shutter unit from the said position of closure;
  • a portion of the said main tubular body in turn being made of ferro-magnetic material, such as to define together with the said shutter unit respectively the fixed part and the mobile part of a magnetic core made of ferro-magnetic material;
  • the said fuel injector being characterised in that the portion of the main tubular body which defines the fixed part of the magnetic core is not provided with any surface treatment.
  • the number 1 indicates as a whole a fuel injector which is particularly suitable for being fitted onto internal-combustion engines of a known type.
  • the injector 1 comprises a main tubular body 2, which is provided with a through pipe 3 with a variable diameter, into which pressurised fuel is supplied.
  • This through pipe 3 extends co-axially relative to the longitudinal axis A of the tubular body 2, and ends at an axial end 2a of the tubular body 2, in a spray nozzle 4, which can project outside the injector 1 itself a finely sprayed jet of fuel.
  • the injector 1 additionally comprises a shutter unit 5, which is made at least partially of ferro-magnetic material, and is fitted such as to be axially mobile inside an end portion of the through pipe 3, from and towards a position of closure, in which the shutter unit 5 itself shuts the spray nozzle 4, such as to prevent discharge of the fuel; a contrast spring 6, which can maintain the shutter unit 5 in the said position of closure; and a coil 7 of electrically conductive material, which can displace the shutter unit 5 by command from the position of closure, thus overcoming the resilient force of the contrast spring 6.
  • a shutter unit 5 which is made at least partially of ferro-magnetic material, and is fitted such as to be axially mobile inside an end portion of the through pipe 3, from and towards a position of closure, in which the shutter unit 5 itself shuts the spray nozzle 4, such as to prevent discharge of the fuel
  • a contrast spring 6, which can maintain the shutter unit 5 in the said position of closure
  • a coil 7 of electrically conductive material which can displace the shutter unit 5 by command from the position
  • the coil 7 is fitted onto the tubular body 2 upstream from the shutter unit 5, and, when electric current is passed through it, it can generate a magnetic field which can overcome the resilient force of the contrast spring 6, and displace the shutter unit 5 axially, thus moving it away from the position of closure.
  • the central portion of the tubular body 2 onto which the coil 7 is fitted, and which is aligned with the shutter unit 5, is made of ferro-magnetic material, such as to intensify the magnetic field which acts on the shutter unit 5.
  • the central portion of the tubular body 2, and the shutter unit 5 define respectively the fixed part and the mobile part of a magnetic core made of ferro-magnetic material, which is disposed co-axially relative to the coil 7, in order to intensity the magnetic field produced by the latter.
  • the shutter unit 5 is subjected to surface treatment, which consists of depositing on part or all of its outer surface a layer of highly-resistant material which preferably, but not necessarily, has non-magnetic or diamagnetic characteristics.
  • the shutter unit 5 is subjected to galvanic treatment, which, by means of electro-plating, is designed to produce a layer of chromium on the entire outer surface of the shutter unit 5 (see figure 2). It will be appreciated that this layer of chromium can optionally be produced only on the part of the outer surface of the shutter unit 5 which is subjected directly to the mechanical stresses.
  • the central portion of the tubular body 2, i.e. the fixed part of the magnetic core of the coil 7, is on the other hand not provided with any surface treatment.
  • the tubular body 2 consists of three tubular segments, which are connected to one another in a telescopic manner, such as to permit easy, quick assembly of the injector 1.
  • the first tubular segment which is indicated hereinafter by the number 8 defines the end portion of the tubular body 2, inside which the shutter unit 5 is mobile axially;
  • the second tubular segment which is indicated hereinafter by the number 9, defines the initial portion of the tubular body 2, through which the pressurised fuel enters the through pipe 3;
  • the third tubular segment which is indicated hereinafter by the number 10, connects the tubular segments 8 and 9 to one another, and defines the housing for the coil 7.
  • the fixed part of the magnetic core of the coil 7, i.e. the central portion of the tubular body 2, onto which the coil 2 is fitted, and which is simultaneously aligned with the shutter unit 5, consists of an end portion of the tubular segment 9, which is thus made of ferro-magnetic material, and is obviously not provided with any surface treatment.
  • the shutter unit 5 consists of a cup-type body with a cylindrical shape, which is fitted such as to slide axially inside the pipe 3, with its own end facing the spray nozzle, such that, when it is in the position of closure, it can be positioned with its base abutting a sealing surface 11 provided on the spray nozzle 4 itself, in order to provide the hydraulic sealing.
  • This sealing surface 11, is preferably, but not necessarily flat.
  • the spray nozzle 4 consists of a disc with a calibrated central hole, which is fitted onto the axial end 2a of the tubular body 2, i.e. onto the tubular segment 8, such as to be perpendicular to the longitudinal axis A of the tubular body 2 itself.
  • the surface of the disc which faces the through pipe 3 defines the sealing surface 11, whereas the surface of the disc which faces in the direction opposite the through pipe 3, has, in the example illustrated, a frusto-conical flare, which serves the purpose of guaranteeing improved spraying and diffusion of the jet of fuel.
  • the shutter unit 5 consists of a cylindrical tubular element 12 made of ferro-magnetic material, and a sealing disc 13 made of highly-resistant material, which is welded to an axial end of the cylindrical tubular element 12, such as to define the base of the cup-type body.
  • this sealing disc 13 On its own outer flat surface 13a, i.e. on its surface which does not face the cylindrical tubular element 12, this sealing disc 13 has two concentric annular projections 14 and 15, which are co-axial relative to the axis A, each of which can abut the spray nozzle 4, i.e. the sealing surface 11, such as to surround the calibrated central hole, so as to form the hydraulic seal.
  • the sealing disc 13 has a plurality of through holes 16, which can permit passage of the fuel from the interior of the cup-type body, i.e. inside the shutter unit 5, towards the outer flat surface 13a of the disc, at the area delimited by the two annular projections 14 and 15.
  • the contrast spring 6 is disposed inside the pipe 3, co-axially relative to the axis A, with a first end abutting the base of the shutter unit 5, i.e. the sealing disc 13, and a second end abutting a shoulder provided inside the pipe 3.
  • this shoulder is defined by the axial end of a spring-thrust body 17 inserted inside the pipe 3, immediately upstream from the section of the through pipe 3 in which the shutter unit 5 is mobile, i.e. inside the tubular segment 9.
  • This spring-thrust body 17 constitutes an integral part of the tubular body 2, has a cylindrical tubular shape, and is preferably, but not necessarily, made of ferro-magnetic material. The position of the spring-thrust body 17 inside the pipe 3 can be adjusted during fitting of the injector 1, such as to regulate the compression of the contrast spring 6.
  • the coil 7, which is made of electrically conductive material, is fitted on the tubular segment 10 of the tubular body 2, inside an outer annular seat 18 provided on the tubular segment 10 itself, and has an outer protective housing 19 fitted onto the coil 7, such as to close the latter onto the tubular body 2.
  • an electrical connector 20 by means of which it is possible to convey the electric current to the coil 7.
  • a further advantage of the injector 1 is that there is reduction of the thickness of the gap which exists between the fixed part and the mobile part of the magnetic core, thus improving the efficiency of the magnetic circuit, and reducing the dispersion of the functional characteristics.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Fuel-Injection Apparatus (AREA)
EP00120863A 1999-09-28 2000-09-25 Fuel injector Withdrawn EP1088986A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
ITBO990521 1999-09-28
IT1999BO000521A IT1310497B1 (it) 1999-09-28 1999-09-28 Iniettore carburante.

Publications (1)

Publication Number Publication Date
EP1088986A1 true EP1088986A1 (en) 2001-04-04

Family

ID=11344251

Family Applications (1)

Application Number Title Priority Date Filing Date
EP00120863A Withdrawn EP1088986A1 (en) 1999-09-28 2000-09-25 Fuel injector

Country Status (2)

Country Link
EP (1) EP1088986A1 (it)
IT (1) IT1310497B1 (it)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1895218A1 (en) * 2006-09-04 2008-03-05 Magneti Marelli Powertrain S.p.A. Shut-off valve for controlling the flow rate of a fuel pump for an internal combustion engine
WO2015036244A1 (en) * 2013-09-13 2015-03-19 Continental Automotive Gmbh Fluid injector

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4313571A (en) * 1979-10-05 1982-02-02 Weber S.P.A. Electromagnetically actuated injector for internal combustion engine
US4360161A (en) * 1979-01-29 1982-11-23 The Bendix Corporation Electromagnetic fuel injector
US4527744A (en) * 1982-08-19 1985-07-09 Robert Bosch Gmbh Electromagnetically actuatable valve
EP0172591A1 (en) * 1984-07-12 1986-02-26 WEBER S.r.l. Improved electroinjector for feeding fuel to an internal combustion engine
EP0301620A2 (en) * 1987-07-27 1989-02-01 WEBER S.r.l. Electromagnetically controlled fuel injector for feeding fuel to internal combustion engines
DE3810826A1 (de) * 1988-03-30 1989-10-12 Pierburg Gmbh Elektromagnetisches einspritzventil fuer brennkraftmaschinen
EP0536773A1 (en) * 1991-10-11 1993-04-14 MAGNETI MARELLI S.p.A. Electromagnetically actuated fuel atomising and metering valve for a heat engine fuel supply device
DE4421935A1 (de) * 1993-12-09 1995-06-14 Bosch Gmbh Robert Elektromagnetisch betätigbares Ventil

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4360161A (en) * 1979-01-29 1982-11-23 The Bendix Corporation Electromagnetic fuel injector
US4313571A (en) * 1979-10-05 1982-02-02 Weber S.P.A. Electromagnetically actuated injector for internal combustion engine
US4527744A (en) * 1982-08-19 1985-07-09 Robert Bosch Gmbh Electromagnetically actuatable valve
EP0172591A1 (en) * 1984-07-12 1986-02-26 WEBER S.r.l. Improved electroinjector for feeding fuel to an internal combustion engine
EP0301620A2 (en) * 1987-07-27 1989-02-01 WEBER S.r.l. Electromagnetically controlled fuel injector for feeding fuel to internal combustion engines
DE3810826A1 (de) * 1988-03-30 1989-10-12 Pierburg Gmbh Elektromagnetisches einspritzventil fuer brennkraftmaschinen
EP0536773A1 (en) * 1991-10-11 1993-04-14 MAGNETI MARELLI S.p.A. Electromagnetically actuated fuel atomising and metering valve for a heat engine fuel supply device
DE4421935A1 (de) * 1993-12-09 1995-06-14 Bosch Gmbh Robert Elektromagnetisch betätigbares Ventil

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1895218A1 (en) * 2006-09-04 2008-03-05 Magneti Marelli Powertrain S.p.A. Shut-off valve for controlling the flow rate of a fuel pump for an internal combustion engine
US7814886B2 (en) 2006-09-04 2010-10-19 Magneti Marelli Powertrain S.P.A. Shut-off valve for controlling the flow rate of a fuel pump for an internal combustion engine
CN101165334B (zh) * 2006-09-04 2011-06-15 玛涅蒂玛瑞利动力系公开有限公司 用于控制内燃机用燃料泵的流量的截止阀
WO2015036244A1 (en) * 2013-09-13 2015-03-19 Continental Automotive Gmbh Fluid injector
US10309357B2 (en) 2013-09-13 2019-06-04 Continental Automotive Gmbh Fluid injector

Also Published As

Publication number Publication date
ITBO990521A1 (it) 2001-03-28
ITBO990521A0 (it) 1999-09-28
IT1310497B1 (it) 2002-02-18

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