WO2021198015A1 - Injecteur de carburant - Google Patents

Injecteur de carburant Download PDF

Info

Publication number
WO2021198015A1
WO2021198015A1 PCT/EP2021/057747 EP2021057747W WO2021198015A1 WO 2021198015 A1 WO2021198015 A1 WO 2021198015A1 EP 2021057747 W EP2021057747 W EP 2021057747W WO 2021198015 A1 WO2021198015 A1 WO 2021198015A1
Authority
WO
WIPO (PCT)
Prior art keywords
base part
injector
housing base
clamping nut
nozzle clamping
Prior art date
Application number
PCT/EP2021/057747
Other languages
German (de)
English (en)
Inventor
Norbert SCHÖFBÄNKER
Richard Pirkl
Verena KÖGEL
Original Assignee
Liebherr-Components Deggendorf 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 Liebherr-Components Deggendorf Gmbh filed Critical Liebherr-Components Deggendorf Gmbh
Priority to EP21716287.4A priority Critical patent/EP4111047A1/fr
Publication of WO2021198015A1 publication Critical patent/WO2021198015A1/fr

Links

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
    • 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
    • F02M61/168—Assembling; Disassembling; Manufacturing; Adjusting
    • 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
    • F02M55/00—Fuel-injection apparatus characterised by their fuel conduits or their venting means; Arrangements of conduits between fuel tank and pump F02M37/00
    • F02M55/004—Joints; Sealings
    • 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
    • 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
    • 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
    • F02M2200/25—Fuel-injection apparatus with heat-expansible 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
    • F02M2200/80—Fuel injection apparatus manufacture, repair or assembly
    • F02M2200/8076—Fuel injection apparatus manufacture, repair or assembly involving threaded members

Definitions

  • the present invention relates to a fuel injector for injecting fuel into a combustion chamber.
  • fuel is usually injected into a combustion chamber via an injector in a certain amount and for a certain period of time. Because of the very short injection times, which are in the microsecond range, it is necessary to open or close the outlet opening of the injector at a very high frequency.
  • Such an injector typically has a nozzle needle (also: injector needle) which allows a fuel to which a high pressure is applied to escape when an outlet hole of the injector is opened.
  • this nozzle needle acts like a plug which, when it is lifted, enables the fuel to escape. Accordingly, it is necessary to lift this needle at relatively short time intervals and to slide it back into the outlet opening again after a short time.
  • Hydraulic servo valves can be used to trigger this movement.
  • Such valves are made using a Solenoid controlled.
  • a piezo element can be used, which reacts faster than the valve controlled by means of an electromagnet.
  • servo valves which control the nozzle needle and are themselves controlled via an electromagnetic valve or piezo valve.
  • a pressure level is built up in a control chamber that interacts with the nozzle needle with the aid of the fuel available under high pressure, which pressure level acts on the nozzle needle in the closing direction.
  • This control chamber or this control valve is typically connected to the high-pressure region of the fuel via an inlet throttle.
  • this control chamber has a small, closable outlet throttle which is arranged in the seat plate and from which the fuel can escape to a low-pressure area.
  • the pressure in the control chamber and the closing force acting on the nozzle needle are reduced, since the fuel in the control chamber, which is under high pressure, can flow off in the direction of the armature lifted by the solenoid valve. This leads to a movement of the nozzle needle, which releases the outlet opening at the injector tip.
  • the outlet throttle of the valve is either closed or opened with the help of an anchor element.
  • the control chamber below is filled with fuel under high pressure via an inlet, so that the nozzle needle is forced into its closed position.
  • the anchor element lifts from a through opening, the fuel stored under high pressure flows out and reduces the force acting on the nozzle needle, so that it lifts from its outlet openings and fuel can flow out as a result.
  • the solenoid valve has to be integrated into the cylinder head bore so that it has to be made very small and the fuel to be dispensed by the injector has to be guided through the solenoid valve or past the solenoid valve down to the nozzle. Since the control valve of the injector is integrated into the injector as an independent assembly, but requires a sealing connection to the adjacent injector body above (compared to the fuel pressurized with a pressure of up to 3000 bar), there are very large ones in the lower area of the injector Areas that are loaded with floch pressure.
  • the aim of the present invention is to create an injector which, despite its compact dimensions and the high axial forces required for tightness, enables the nozzle clamping nut to be loosened without being damaged.
  • the fuel injector comprises an elongated housing base part, which preferably has a connection for supplying fuel, a housing tip section for receiving a nozzle needle, which is to be arranged sealingly on an end face of the housing base part, and a nozzle clamping nut which is designed to be used with the To cooperate housing base part and to urge the housing tip section against the end face of the housing base part, wherein the injector is characterized in that the nozzle clamping nut is an expansion sleeve which is deformable in its longitudinal direction.
  • the required sealing forces are applied by the nozzle clamping nut, which is designed as an expansion sleeve. So it happens when fastening the nozzle lock nut to the housing base part, during the the housing tip portion of the nozzle lock nut against the
  • Housing base part is pushed into an expansion process of the
  • Nozzle clamping nut whereby a sufficiently high force can be applied to press the housing tip section against an end face of the housing base part.
  • the expansion deformation can promote the application of very high axial pretensioning forces, so that there is better contact pressure between the housing base part and the housing tip section.
  • Another advantage is the very constant axial force from injector to injector, with the axial force being less dependent on thread friction.
  • the nozzle clamping nut has a sleeve-like structure and is provided with an inwardly protruding stop flange which interacts with a section of the housing tip section in order to urge it against the end face of the housing base part.
  • the sleeve has an inwardly projecting flange which, towards its center, defines an opening from which a part of the housing tip section protrudes.
  • Housing tip section urged in the direction of the housing base part, so that a sealing connection is created in the contact area of the housing base part and the surface of the housing tip section facing the housing base part.
  • the nozzle clamping nut has a fastening means for fastening to the housing base part and for urging the
  • nozzle clamping nut has housing tip section against the end face of the housing base part, in particular a thread, for example an internal thread, which cooperates with an associated fastening means, in particular a thread, on the housing base part.
  • the nozzle clamping nut can thus be moved towards the housing base part, so that the desired clamping of the housing tip section takes place.
  • this is achieved with an external thread on the housing base part and a matching internal thread on the nozzle clamping nut.
  • the internal thread or the fastening means of the nozzle clamping nut is located on the longitudinal end area opposite to the passage of the housing tip section, so that an expansion deformation occurring near the inwardly protruding flange has no effect on the fastening to the housing base part.
  • the fastening means of the nozzle clamping nut is a fine thread of the M19.5 x 1.5 or M19.3 x 1.5 type and the associated fastening means of the housing base part is a correspondingly designed mating thread.
  • the fastening means of the nozzle clamping nut is a thread with a pitch of 0.75 mm. It can further be provided that the thread diameter can also be significantly larger and take on dimensions up to M30.
  • the fastening means of the nozzle clamping nut can be arranged at the end opposite to the receiving of the housing tip section.
  • an expansion area for expanding the nozzle clamping nut in its longitudinal direction is arranged in the longitudinal half facing away from the housing base part, the expansion area preferably being arranged in the longitudinal third or even longitudinal quarter facing away from the housing base part.
  • the expansion area can be a section in the nozzle clamping nut which has a minimal wall thickness.
  • the expansion takes place in an area that is least stable compared to the other areas. This is the expansion area with a minimum wall thickness of the nozzle clamping nut, which can extend over a certain longitudinal extent.
  • the expansion area is located at the level of a receptacle for the control valve and / or the nozzle needle.
  • expansion does not have a negative effect on the fastening means.
  • the fastening means in particular a threaded area, so that the fastening means can still be released even with a very high axial preload achieved by the expansion.
  • the undamaged fastening means enables reusability of the housing base part, since after removing the nozzle clamping nut, the housing-side fastening means can again interact with an intact nozzle clamping nut.
  • a deformation occurring in the area of the fastening means almost always leads to damage which occurs when the nozzle clamping nut is removed from the housing base part and which no longer allows a nozzle clamping nut to be re-applied.
  • the nozzle clamping nut is made of a material which has a lower strength than the material from which the housing base part is made.
  • the nozzle clamping nut consists of a highly compressed tempered steel 42CrMo4, preferably with its tensile strength in a range of 1450-1550 N / mm 2 , preferably in a range of 1475-1525 N / mm 2 .
  • the yield strength of the high-density quenched and tempered steel 42CrMo4 is in a range between 1250 - 1350 N / mm 2 , preferably in a range between 1275 - 1325 N / mm 2 and preferably in a range between 1295 - 1305 N / mm 2 , each with an elongation at break of> 10%.
  • the exact yield strength of 1300N / mm 2 is also covered by the invention and represents an advantageous value for the high-density quenched and tempered steel 42CrMo4.
  • the advantage of designing the nozzle clamping nut as a highly compressed heat-treatable steel is that the compression process at high temperature and subsequent controlled cooling creates a very fine-grain structure that achieves significantly higher strength values.
  • the guaranteed elongation at break with increased strength is an advantage, since a material that is only highly tempered has a significantly lower elongation at break of less than 6% and breaks under load.
  • the design of the nozzle clamping nut as highly compressed tempered steel 42CrMo4 is significantly more resilient and has an improved elongation at break. With such a nozzle clamping nut, a particularly good expansion sleeve can be produced, which can introduce high axial forces into the housing tip section.
  • the housing base part is made of a highly compressed heat-treated steel 50CrMo4 consists, preferably with its tensile strength in a range of 1550-1650 N / mm 2 , preferably in a range of 1575-1625 N / mm 2 .
  • the yield point of the highly compressed heat-treated steel 50CrMo4 is in a range between 1300-1400 N / mm 2 , preferably in a range between 1325-1375 N / mm 2 and preferably in a range between 1345-1355 N / mm 2 , each with an elongation at break of> 10%.
  • the exact yield strength of 1350N / mm 2 is also covered by the invention and represents an advantageous value for the highly compressed heat-treated steel 50CrMo4.
  • the stronger material of the housing base part prevents plastic deformation of the fastening means on the housing side, for example a thread. Furthermore, by using 50CrMo4, the autofrettage usually required to achieve the fatigue strength of the housing base part can be dispensed with, so that production is also simplified.
  • the housing is protected by the difference in strength between the housing base part and the nozzle clamping nut, so that at least the housing can be reused.
  • the yield strength and / or the tensile strength of the nozzle clamping nut is lower than the yield strength and / or the tensile strength of the housing base part.
  • the housing base part has not been subjected to autofrettage in order to achieve its fatigue strength.
  • the nozzle clamping nut has a phosphating.
  • the phosphating serves as a separating layer in the fastening means, for example the thread flanks and can also prevent local overheating due to thread friction during screwing.
  • the invention also relates to a method for producing a fuel injector, preferably a fuel injector according to one of the preceding claims, wherein the housing base part is not subjected to autofrettage before being connected to the nozzle clamping nut.
  • the complex step of an autofrettage i.e. the application of an internal pressure to the housing base part, which is above the later operating pressure and above the yield point and leads to plasticization in the inner circumference area, can be omitted.
  • the method according to the invention can provide that the nozzle clamping nut is first phosphated and then oiled before it is connected to the housing base part, so that the phosphating acts as a separating layer in a threaded connection between the housing base part and the nozzle clamping nut.
  • FIG. 1 a a schematic sectional illustration of an inventive
  • Fig. 1b a cross-sectional view corresponding to the plane AA shown in Fig. 1a.
  • 1a shows a longitudinal sectional view of an injector 1 according to the invention, which is provided with a nozzle clamping nut 5 at its distal end region.
  • This nozzle clamping nut 5 interacts via a fastening means 7 with a housing base part 2 of the injector 1 and has the primary task of pressing a housing tip section 4 in a sealing manner against an end face 8 of the housing base part 2.
  • the control valve (not shown) and the nozzle needle (not shown) which can be moved in the longitudinal direction of the injector are arranged within the housing tip section 4.
  • the nozzle needle If the nozzle needle is in a raised state, it releases injection holes and fuel under high pressure flows from connection 3 through the fuel channel 10 located in the housing base part 2 into the housing tip section 4. There the fuel flows past the control valve and the raised nozzle needle and then occurs to the outside via the injection holes. For a smooth process, it can be seen that the contact between the housing tip section 4 and the housing base part 2 is tight, since otherwise undesirable leakage of fuel can occur.
  • the fastening means 7 is a threaded connection with an internal thread arranged on the nozzle clamping nut 5 and an associated external thread arranged on the housing base part 2.
  • the thread on the clamping nut side is located at the end opposite to the reception of the housing tip section, so that an expansion of the nozzle clamping nut advantageously taking place at a distance therefrom does not have any negative effects on the threaded connection.
  • the nozzle clamping nut 5 has an inwardly projecting circumferential flange 6, in the center of which an opening is arranged through which a part of the housing tip section 4 passes. With this flange 6, the housing tip section 4 is correspondingly shaped The outer contour is pressed in the direction of the housing base part 2, so that a contact pressure is created on the contact area that is to be kept tight, which also corresponds to the highest tightness requirements. It is advantageous here if the nozzle clamping nut 5 has a section 11 provided for expansion or longitudinal expansion in one area over its longitudinal extent, the wall thickness of which is reduced compared to adjoining or adjacent areas.
  • this section 11 is an area with a minimum wall thickness of the nozzle clamping nut.
  • This section 11 can advantageously be arranged in the longitudinal half spaced apart from the housing base part 2, preferably the distal longitudinal third or even longitudinal quarter of the nozzle clamping nut 5.
  • Nozzle clamping nut 5 as an expansion sleeve ensures the necessary increase in the pressing force, so that even very high fuel pressures can be sealed over a large area.
  • FIG. 1b shows a cross-sectional view along the plane represented by A-A in FIG. 1.
  • Housing tip section 4 runs around the nozzle clamping nut 5, which over the inwardly protruding flange element 6 urges the housing tip section 4 against the housing base part 2.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Fuel-Injection Apparatus (AREA)

Abstract

L'invention concerne un injecteur de carburant, comprenant une partie de boîtier principale allongée, qui comporte de préférence une connexion pour l'alimentation en carburant, une section de pointe de boîtier destinée à recevoir une aiguille de buse, qui doit être disposée de manière étanche sur une face avant de la partie de boîtier principale, et un écrou de serrage de buse qui est conçu pour coopérer avec la partie de boîtier principale et pour pousser la section de pointe de boîtier contre la face avant de la partie de boîtier principale. L'injecteur est caractérisé en ce que l'écrou de serrage de buse est un manchon expansible qui est déformable à la contrainte dans sa direction longitudinale.
PCT/EP2021/057747 2020-03-31 2021-03-25 Injecteur de carburant WO2021198015A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP21716287.4A EP4111047A1 (fr) 2020-03-31 2021-03-25 Injecteur de carburant

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
DE102020108815.9 2020-03-31
DE102020108815 2020-03-31
DE102020113609.9A DE102020113609A1 (de) 2020-03-31 2020-05-20 Kraftstoffinjektor
DE102020113609.9 2020-05-20

Publications (1)

Publication Number Publication Date
WO2021198015A1 true WO2021198015A1 (fr) 2021-10-07

Family

ID=77658750

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2021/057747 WO2021198015A1 (fr) 2020-03-31 2021-03-25 Injecteur de carburant

Country Status (3)

Country Link
EP (1) EP4111047A1 (fr)
DE (1) DE102020113609A1 (fr)
WO (1) WO2021198015A1 (fr)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102005008697A1 (de) * 2005-02-25 2006-09-07 Vw Mechatronic Gmbh & Co. Kg Kraftstoffinjektor mit Filtereinrichtung
DE102006049532A1 (de) * 2006-10-20 2008-04-24 Robert Bosch Gmbh Schraubverbindung für Kraftstoffinjektor
DE102011086005A1 (de) * 2011-11-09 2013-05-16 Robert Bosch Gmbh Kraftstoffinjektor, Verfahren zur Montage eines Kraftstoffinjektors sowie Spanneinrichtung zur Montage eines Kraftstoffinjektors
DE102017116383A1 (de) 2017-07-20 2019-01-24 Liebherr-Components Deggendorf Gmbh Injektor zum Einspritzen von Krafstoff

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19523243B4 (de) 1995-06-27 2009-04-02 Robert Bosch Gmbh Kraftstoffeinspritzventil für Brennkraftmaschinen mit einer Spannmutter mit konisch ausgebildeter Ringschulter
DE102006052114A1 (de) 2006-11-06 2008-05-08 Robert Bosch Gmbh Verfahren zur Bestimmung der Schichtdicke

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102005008697A1 (de) * 2005-02-25 2006-09-07 Vw Mechatronic Gmbh & Co. Kg Kraftstoffinjektor mit Filtereinrichtung
DE102006049532A1 (de) * 2006-10-20 2008-04-24 Robert Bosch Gmbh Schraubverbindung für Kraftstoffinjektor
DE102011086005A1 (de) * 2011-11-09 2013-05-16 Robert Bosch Gmbh Kraftstoffinjektor, Verfahren zur Montage eines Kraftstoffinjektors sowie Spanneinrichtung zur Montage eines Kraftstoffinjektors
DE102017116383A1 (de) 2017-07-20 2019-01-24 Liebherr-Components Deggendorf Gmbh Injektor zum Einspritzen von Krafstoff

Also Published As

Publication number Publication date
EP4111047A1 (fr) 2023-01-04
DE102020113609A1 (de) 2021-09-30

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