EP1063422B1 - Injecteur de combustible - Google Patents

Injecteur de combustible Download PDF

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Publication number
EP1063422B1
EP1063422B1 EP20000305328 EP00305328A EP1063422B1 EP 1063422 B1 EP1063422 B1 EP 1063422B1 EP 20000305328 EP20000305328 EP 20000305328 EP 00305328 A EP00305328 A EP 00305328A EP 1063422 B1 EP1063422 B1 EP 1063422B1
Authority
EP
European Patent Office
Prior art keywords
fuel
bore
valve needle
guide member
needle
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.)
Expired - Lifetime
Application number
EP20000305328
Other languages
German (de)
English (en)
Other versions
EP1063422A1 (fr
Inventor
Rao Kunkulagunta Koteswara
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 Technologies Inc
Original Assignee
Delphi Technologies Inc
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 Technologies Inc filed Critical Delphi Technologies Inc
Publication of EP1063422A1 publication Critical patent/EP1063422A1/fr
Application granted granted Critical
Publication of EP1063422B1 publication Critical patent/EP1063422B1/fr
Anticipated expiration legal-status Critical
Expired - Lifetime 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
    • 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
    • F02M61/10—Other injectors with elongated valve bodies, i.e. of needle-valve type
    • F02M61/12—Other injectors with elongated valve bodies, i.e. of needle-valve type characterised by the provision of guiding or centring means for valve bodies

Definitions

  • This invention relates to a fuel injector for use in delivering fuel under high pressure to a combustion space of an associated compression ignition internal combustion engine.
  • a typical fuel injector comprises a valve needle slidable within a bore formed in a nozzle body and engageable with a seating to control fuel delivery through one or more outlet openings which communicate with the bore downstream of the seating. Movement of the valve needle occurs rapidly, in use, the periods during which fuel injection occurs being of short duration. Further, in order to reduce the levels of noise and particulate contaminants produced by an engine, in some applications the injector may be required to open to deliver a small, pilot injection of fuel, to close, and to open after a short delay to deliver a main injection. It has been found that some fuel injectors are unable to operate sufficiently quickly for use in such applications.
  • US-A-4,570,853 discloses a fuel injector comprising a nozzle body having a bore which defines a seating.
  • a valve needle is reciprocable within the bore, the valve needle being provided with a further bore, extending upwardly from its tip, within which an abutment body is slidable.
  • the abutment body is spring biased into engagement with a set of nozzle openings to control delivery of fuel from the injector.
  • DE 37 36 700A discloses a fuel injection nozzle having a nozzle body defining a bore.
  • a securing component is disposed within the bore and a valve needle is slidable therein, the securing component ensuring that the valve needle is spaced from the bore of the nozzle body.
  • the valve needle is engageable with an outlet to control fuel delivery therethrough.
  • GB 2 204 357 discloses a fuel injector in which an inner valve pin is movable within an outer valve needle.
  • the outer valve needle controls fuel injection through a set of injector outlets.
  • the inner valve pin remains seated against its seating and defines a relatively narrow clearance which then restricts the flow of fuel past the outer valve needle to the outlets.
  • the outer valve needle is moved through a further amount, the inner valve pin is caused to lift with the outer needle so that the clearance to fuel flow to the outlets is opened up.
  • the restriction to fuel flowing to the outlets thus depends on how far the outer valve needle lifts.
  • EP 0 878 623 describes an injector of the type having two valve needles, an inner valve needle controlling fuel delivery through a first set of injector outlets and an outer valve needle controlling fuel delivery through a second set of injector outlets.
  • a fuel injector comprising a plurality of outlet openings and a nozzle body provided with a first bore defining a seating, a valve needle being reciprocable within the bore and engageable with the seating to control the delivery of fuel through all of the plurality of outlet openings.
  • the fuel injector further comprises an elongate guide member mounted within the bore, the guide member being provided with a second bore within which at least a part of the valve needle is received to guide the valve needle for movement within the first bore.
  • the second bore provided in the guide member defines a shoulder with which the valve needle is engageable to limit the distance through which the valve needle can lift away from the seating, in use.
  • valve needle can be of relatively small dimensions and low mass.
  • the inertia of the valve needle can thus be reduced, resulting in improved responsiveness.
  • the guide member may define, with the nozzle body, a flow path for fuel flowing towards the plurality of outlet openings.
  • the guide member may be provided with formations forming a restriction to fuel flow along the flow path.
  • valve needle conveniently defines, with the guide member, a control chamber, the guide member further defining a passage whereby fuel can be supplied to or vented from the control chamber to vary the fuel pressure within the control chamber.
  • Figure 1 is a sectional view of part of a fuel injector in accordance with an embodiment of the invention.
  • the fuel injector illustrated, in part, in Figure 1 comprises a largely typical nozzle body 10 provided with a blind bore 11, the blind end of which defines a seating 12. Downstream of the seating 12, a plurality of outlet openings 13 of small diameter communicate with the bore 11.
  • the bore 11 is shaped to include a region of enlarged diameter defining an annular gallery 14 which communicates with a drilling 15 forming part of a supply passage for supplying fuel to the bore 11, in use.
  • the guide member 16 Located within the bore 11 is a guide member 16 of elongate form.
  • the guide member 16 includes, at its upper end in the orientation illustrated, a region of enlarged diameter, this region being of diameter substantially equal to the diameter of the adjacent part of the bore 11 and forming a substantially fluid tight seal between the guide member 16 and the upper end of the bore 11.
  • the lower end of the guide member 16 is also of diameter substantially equal to that of the bore 11, and is provided with flute formations 17 permitting fuel from the supply passage to flow along a flow path defined by the bore 11 towards the seating 12.
  • the guide member 16 is provided with an axially extending through bore 18 of stepped form.
  • the lower end of the bore 18 is of relatively large diameter and serves to guide a valve needle 19 for reciprocating movement within the bore 18, the valve needle 19 being engageable with the seating 12 to control by opening and closing the supply of fuel from the bore 11 to the outlet openings 13, thus controlling fuel delivery from the injector.
  • the bore 18 defines a step or shoulder 20 against which the upper end of the needle 19 is engageable to limit the distance through which the needle 19 is movable, in use.
  • the guide member 16 further defines a second step 21 which serves as a spring abutment for a spring 22 located between the spring abutment and the upper end surface of the needle 19, the spring 22 applying a biasing force to the needle 19 urging the needle 19 towards the seating 12.
  • the upper end of the bore 18 communicates through passages (not shown) provided in other parts of the fuel injector with a source of fuel under low pressure, for example the fuel reservoir or tank associated with the engine.
  • the supply passage of which the drilling 15 forms part may be connected to an outlet of a rotary distributor pump.
  • the supply passage is at relatively low pressure, then the bore 11 will be at low pressure, and the force applied by the fuel within the bore 11 to the exposed angled thrust surfaces 19a of the needle 19 will be relatively low.
  • the spring 22 will apply a sufficient force to the needle 19 to ensure that the needle 19 remains in engagement with the seating 12.
  • the fuel pressure within the bore 11 will rise, thus the magnitude of the force applied to the valve needle 19 urging the valve needle 19 away from the seating 12 will rise, and a point will be reached beyond which the valve needle 19 will be able to move against the action of the spring 22, thereby lifting away from the seating 12 and allowing fuel to flow from the bore 11 to the outlet openings 13 to be delivered into the combustion space of the engine with which the injector is associated.
  • the needle 19 moves, fuel within the bore 18 is displaced towards the low pressure reservoir. The movement of the needle 19 is limited by the step 20.
  • the flutes 17 are of sufficient dimensions such that the rate at which fuel is able to flow along the flow path towards the seating 12 is not significantly restricted.
  • the guide member 16 which is held in a substantially concentric position within the bore 11, guides the movement of the needle 19, ensuring that the needle 19 remains substantially concentric with the bore 11 whilst lifted away from the seating 12, permitting uniform fuel flow to all of the outlet openings 13.
  • the fuel pressure within the bore 11 is reduced. This may be achieved simply by terminating the supply of fuel to the bore 11, the continued delivery of fuel through the outlet openings 13 gradually causing the fuel pressure within the bore 11 to fall. Alternatively, the fuel pressure may be allowed to fall by opening a spill valve to vent fuel from the bore 11, thereby relieving the fuel pressure applied to the thrust surfaces 19a of the valve needle 19. Regardless as to how the fuel pressure within the bore 11 is reduced, the reduction in fuel pressure reduces the magnitude of the force urging the valve needle 19 away from the seating 12, and a point will be reached beyond which the valve needle 19 is returned into engagement with the seating 12 under the action of the spring 22. Once such engagement has been achieved, fuel is no longer able to flow to the outlet openings 13, thus fuel injection is terminated.
  • the injector is described with reference to a fuel system incorporating a rotary distributor pump, it will be appreciated that the injector could be used with other types of fuel system in which the timing of fuel injection is controlled by controlling the magnitude of the fuel pressure applied to the bore 11.
  • the injector may alternatively be used in, for example, a common rail fuel system.
  • the drilling 15 is connected ,through the supply passage, with a source of fuel under high pressure.
  • the bore 11 is therefore supplied, continuously, with fuel under high pressure, thus the force applied to the valve needle 19 urging the valve needle 19 away from the seating 12 is high.
  • the upper end surface of the needle 19 defines, with the bore 18, a control chamber, the fuel pressure within which applies a force to the needle 19 urging the needle 19 towards the seating 12.
  • the fuel pressure within the control chamber is controlled by controlling the fuel pressure applied to the bore 18, for example using an electro-magnetically actuable valve or using a piezo-electric actuator arrangement (not shown).
  • the fuel pressure within the control chamber is high and a relatively large magnitude downward force is applied to the needle 19 assisting the spring 22 in ensuring that the needle 19 remains in engagement with the seating 12.
  • the effective area of the needle 19 exposed to the fuel pressure within the control chamber is greater than that exposed to the fuel pressure within the bore 11, and this difference assists in ensuring that the needle 19 remains in engagement with the seating 12.
  • the fuel pressure within the control chamber is vented, for example, by opening an electro-magnetically actuable valve or by appropriate control of a piezo-electric actuator arrangement. The reduction in the fuel pressure within the control chamber reduces the magnitude of the downward force applied to the needle 19, and a point will be reached beyond which the needle 19 is able to lift away from the seating 12 thus permitting fuel to flow to the outlet openings 13.
  • control chamber is repressurised.
  • the injector is controlled using an electro-magnetically actuable valve
  • this may be achieved by closing the valve, fuel flowing to the control chamber through a restricted passage which connects the bore 18 to the supply passage.
  • a valve may be provided instead of the restricted passage. The repressurisation of the control chamber increases the magnitude of the downward force applied to the needle 19, and a point will be reached beyond which the valve needle 19 returns into engagement with the seating 12, thus terminating injection.
  • the guide member 16 is provided with formations defining flutes 17 which do not form a significant restriction to fuel flow within the bore 11, if desired the guide member 16 may be provided with formations which, in combination with the nozzle body 10, form a restriction to fuel flow along the flow path.
  • the rate at which fuel is able to flow to the part of the bore 11 downstream of the guide member 16 is restricted, thus the fuel pressure within this region falls during injection and the magnitude of the force applied to the valve needle 19 urging the valve needle 19 away from the seating 12 reduces. This may be advantageous as it may result in more rapid movement of the needle 19 towards the seating 12 when injection is to be terminated, resulting in the fuel injector being of improved responsiveness.
  • the responsiveness of the injector is improved as the needle 19 is of relatively small dimensions and low mass compared to a typical valve needle, and as a result is of reduced inertia compared to typical arrangements. Rapid movement of the needle 19 can therefore be achieved.
  • the injector is therefore suitable for use in fuel systems of the type in which a pilot injection is to be made, the pilot injection of fuel being followed, after a short delay, by a main injection of fuel. In such a fuel system, the valve needle is caused to reciprocate rapidly within the bore in a very short period of time.
  • a further advantage of the arrangement described hereinbefore is that the guide member 16 forms a substantially fluid tight seal with the nozzle body 10.
  • the requirement of typical arrangements for the needle to form a substantially fluid tight seal with the nozzle body is removed.
  • a small clearance can be formed between the needle and the bore within which the needle is to be slidable, such a clearance reducing the risk of seizure of the needle, in use.

Claims (5)

  1. Injecteur de combustible comprenant une pluralité d'ouvertures de sortie (13) et un corps de buse (10) équipé d'un premier alésage (11) définissant un siège (12), une aiguille d'injection (19) pouvant effectuer un mouvement de va et vient à l'intérieur de l'alésage (11) et pouvant s'engager avec le siège (12) pour commander, en ouvrant et en fermant, l'approvisionnement en combustible par toutes les ouvertures de sortie (13), l'injecteur de combustible comprenant en outre un élément de guidage allongé (16) monté à l'intérieur de l'alésage (11), l'élément de guidage (16) étant équipé d'un deuxième alésage (18) dans lequel au moins une partie de l'aiguille d'injection (19) est réceptionnée pour guider l'aiguille d'injection (19) afin qu'elle se déplace à l'intérieur du premier alésage (11) dans lequel le deuxième alésage (18) prévu dans l'élément de guidage (16) définit un épaulement (20) avec lequel l'aiguille d'injection (19) peut s'engager pour limiter la distance à travers laquelle l'aiguille d'injection (19) peut se soulever du siège (12), en service.
  2. Injecteur de combustible selon la revendication 1, dans lequel l'élément de guidage (16) sert de butée de ressort pour un ressort (22) installé pour diriger l'aiguille d'injection (19) vers le siège (12).
  3. Injecteur de combustible selon la revendication 1 ou la revendication 2, dans lequel l'élément de guidage (16) définit, en même temps que le corps de buse (10), un chemin d'écoulement pour le combustible s'écoulant vers la pluralité d'ouvertures de sortie (13).
  4. Injecteur de combustible selon la revendication 3, dans lequel l'élément de guidage (16) est équipé d'au moins une formation (17) qui définit, en même temps que le corps de buse (10), une restriction à l'écoulement du combustible le long du chemin d'écoulement.
  5. Injecteur de combustible selon l'une quelconque des revendications 1 à 4, à utiliser dans un système de combustible de type à rail commun, l'aiguille d'injection (19) définissant, en même temps que l'élément de guidage (16), une chambre de commande pour le combustible, l'élément de guidage (16) définissant en outre un passage à travers lequel le combustible peut être approvisionné ou déchargé de la chambre de commande de manière à faire varier la pression du combustible à l'intérieur de la chambre de commande, en service.
EP20000305328 1999-06-23 2000-06-23 Injecteur de combustible Expired - Lifetime EP1063422B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB9914546 1999-06-23
GBGB9914546.8A GB9914546D0 (en) 1999-06-23 1999-06-23 Fuel injector

Publications (2)

Publication Number Publication Date
EP1063422A1 EP1063422A1 (fr) 2000-12-27
EP1063422B1 true EP1063422B1 (fr) 2005-03-30

Family

ID=10855816

Family Applications (1)

Application Number Title Priority Date Filing Date
EP20000305328 Expired - Lifetime EP1063422B1 (fr) 1999-06-23 2000-06-23 Injecteur de combustible

Country Status (3)

Country Link
EP (1) EP1063422B1 (fr)
DE (1) DE60019026T2 (fr)
GB (1) GB9914546D0 (fr)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10253721A1 (de) * 2002-11-19 2004-06-03 Robert Bosch Gmbh Kraftstoffeinspritzventil für Brennkraftmaschinen

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3236046C2 (de) * 1982-09-29 1986-03-20 Daimler-Benz Ag, 7000 Stuttgart Kraftstoffeinspritzdüse für Brennkraftmaschinen
GB8710976D0 (en) * 1987-05-08 1987-06-10 Lucas Ind Plc Fuel injection nozzle
DE3736700A1 (de) * 1987-10-29 1989-05-11 Inter System Vertrieb Ges Fuer Kraftstoff-einspritzduese fuer eine brennkraftmaschine
GB9709678D0 (en) * 1997-05-14 1997-07-02 Lucas Ind Plc Fuel injector

Also Published As

Publication number Publication date
EP1063422A1 (fr) 2000-12-27
DE60019026D1 (de) 2005-05-04
GB9914546D0 (en) 1999-08-25
DE60019026T2 (de) 2006-01-26

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