EP2737196A1 - Orifices d'étranglement optimisés en termes de cavitation - Google Patents

Orifices d'étranglement optimisés en termes de cavitation

Info

Publication number
EP2737196A1
EP2737196A1 EP12740278.2A EP12740278A EP2737196A1 EP 2737196 A1 EP2737196 A1 EP 2737196A1 EP 12740278 A EP12740278 A EP 12740278A EP 2737196 A1 EP2737196 A1 EP 2737196A1
Authority
EP
European Patent Office
Prior art keywords
inlet
throttle
pressure
section
outlet
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Withdrawn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
EP12740278.2A
Other languages
German (de)
English (en)
Inventor
Heinrich Werger
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 EP2737196A1 publication Critical patent/EP2737196A1/fr
Withdrawn legal-status Critical Current

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
    • 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
    • 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

Definitions

  • the invention relates to an injection nozzle for injecting fuel into the combustion chamber of an internal combustion engine comprising an axially displaceable nozzle needle which can be acted upon to control its opening and closing movement of the pressure prevailing in a fuel-filled control chamber pressure in the axial direction, wherein the control chamber with a a Inlet restrictor having supply line and an outlet drainage having derivative is in communication and at least one inlet or outlet channel opening or closing control valve is provided with which the pressure in the control chamber is controlled.
  • injectors devices are often used for common rail systems for injecting diesel fuel into the combustion chamber of diesel engines and are usually designed so that the opening and closing of the injection cross sections through a nozzle needle which is longitudinally displaceable with a shaft in a nozzle body is guided.
  • the control of the movement of the nozzle needle is carried out via a solenoid valve.
  • the nozzle needle is acted upon on both sides with the fuel pressure and by a pressure spring acting in the closing direction.
  • a control chamber is provided, in which fuel under pressure the nozzle needle is acted upon in the closing direction and thus presses the nozzle needle onto the needle seat or the valve seat.
  • the control valve which may be formed as a solenoid valve, for example, releases a derivative of the control chamber derivative, so that the fuel pressure decreases upon actuation of the control valve in the control chamber, whereupon the nozzle needle is lifted against the force of the spring from pending on the other side fuel pressure from its seat and thus releases the passage of fuel to the injection ports.
  • the opening speed of the nozzle needle is through determines the difference between the flow in the supply line to the control room and the flow in the discharge from the control room, wherein both in the supply and in the discharge, a throttle is turned on, which determines the maximum flow respectively.
  • the nozzle needle is thus moved by pressure differences between the control chamber and the high-pressure chamber above the nozzle seat.
  • the control chamber is either directly connected to the nozzle needle or it can also be an actuator interposed.
  • a mass flow is realized via the inlet throttle (s) from the rail to the control chamber and further via the outlet throttle (s) to the open control valve. From there, this mass flow usually flows into the leakage circuit.
  • the pressure drop is realized by a lower mass flow through the inlet throttle than through the outlet throttle.
  • the injection nozzle of the aforementioned type according to the invention substantially further developed such that the inlet and / or the outlet throttle has a extending over at least a partial length of the throttle section with decreasing in the flow direction cross section and that the inlet edge of the inlet or outlet throttle is formed rounded.
  • the invention thus relates to the shape of the throttle bores. Compared with the conventional form of a nearly cylindrical throttle bore, it can be conical, ie tapered in the direction of flow, and with a rounded edge, so that the vapor pressure does not drop below the length of the throttle bore, thus establishing a cavitation-free flow , The rounding at the inlet edge and the conicity both reduce the cavitation tendency and have a complementary effect.
  • the flow conditions at the inlet into the throttle bore can be represented as follows with regard to the cavitation problem. Cavitation areas usually arise at the points where the static pressure in a flow field is minimal, the speed according to the Bernoulli equation is therefore maximal. This is achieved in the area of the narrowest flow cross-section, which is located immediately after the inlet edge to the throttle bore. In addition to high speeds and strong deflections of the flow lead to high pressure losses. In fact, to maintain fluid particles in a curved path, despite their inertia, a pressure gradient is required. Thus, the static pressure on the inside of the curve, ie on the Side of the flow-carrying wall, less than on the outside.
  • Cavitation areas are therefore found mainly in the vicinity of the throttle bore inlet in the aforementioned throttle bores. Since these cavitation films emanate from the edges of the flow area, a narrowing of the cross-section through which the gas flows flows through in the throttle bore. Further downstream, the flow again abuts against the wall of the throttle bore and occupies the entire available cross-section. The static pressure rises again to the level of the back pressure and the flow velocity drops accordingly. However, if the critical pressure falls short enough, the cavitation films can also reach the outlet of the throttle bore. In the cavitation-free flow through the throttle bore which can be achieved according to the invention, a slight intermeshing of the flow cross-section can likewise result from detachment in the inlet region. However, the pressure loss is not large enough to be below the critical value.
  • the cross-sectional reduction is provided only in a part of the inflow and / or outlet throttle immediately adjacent to the rounded inlet edge.
  • the rounding of the inlet edge has a radius of curvature of 50 ⁇ to ⁇ on.
  • the taper of the decreasing cross-section formed portion of the inlet or outlet throttle ⁇ to 30 ⁇ is preferred.
  • FIG. 1 and 2 show the basic structure of an injector for a common-rail injection system of large diesel engines
  • FIG. 3 shows a detailed view of the supply or discharge with throttle.
  • FIG. 1 and 2 show an injector 1 comprising an injector body 2, a valve body 3, an intermediate plate 4 and an injector nozzle 5, which are held together by a nozzle retaining nut 6.
  • the injector nozzle 5 comprises a nozzle needle 7 which is longitudinally displaceably guided in the nozzle body of the injector nozzle 5 and has a plurality of free surfaces through which fuel can flow from the nozzle front chamber 8 to the needle tip. During the opening movement of the nozzle needle 7, the fuel is injected via a plurality of injection openings 9 into the combustion chamber of the internal combustion engine.
  • the control sleeve 11, the upper end face of the nozzle needle 7 and the underside of the intermediate plate 4 define a control chamber 12.
  • the pressure prevailing in the control chamber 12 pressure is decisive for the control of the movement of the nozzle needle.
  • the fuel pressure on the one hand in the nozzle front chamber 8 is effective where it exerts a force in the opening direction of the nozzle needle 7 via the pressure shoulder of the nozzle needle 7.
  • it acts via the inlet channel 14 and an inlet throttle 15 having supply line 24 in the control chamber 12 and holds, supported by the force of the compression spring 10, the nozzle needle 7 in its closed position.
  • the magnet armature 17 together with the valve needle 18 connected to it is raised and the valve seat 19 of the control valve is opened.
  • the fuel from the control chamber 12 flows through the one flow restrictor 20th having discharge line 23 and the open valve seat 19 in the non-pressurized drain passage 21, which leads to the lowering of the hydraulic force on the upper end face of the nozzle needle 7 for opening the nozzle needle 7.
  • the fuel now passes through the injection openings 9 in the combustion chamber of the engine, not shown.
  • high-pressure fuel simultaneously flows through the inlet throttle 15 into the control chamber 12 and, via the outlet throttle 20, discharges a slightly greater amount.
  • the so-called control amount is discharged without pressure into the discharge channel 21, that is, it is removed from the rail in addition to the injection quantity.
  • the opening speed of the nozzle needle 7 is determined by the flow difference between the inlet and outlet throttle 15 and 20.
  • the magnet armature 17 is pressed by the force of the compression spring 22 down and the valve needle 18 closes via the valve seat 19, the drainage path of the fuel through the outlet throttle 20.
  • the fuel pressure is rebuilt in the control chamber 12 and generates a closing force which reduces the hydraulic force on the pressure shoulder of the nozzle needle 7 and exceeds the force of the compression spring 10.
  • the nozzle needle 7 closes the way to the injection openings 9 and terminates the injection process.
  • the inlet throttle 15 is now enlarged and shown schematically.
  • the supply line section 24 has a diameter D 1, which corresponds to a multiple of the diameter D 2 of the inlet throttle 15. Typically, the diameter Dl corresponds to 2 to 4 times the diameter D2.
  • the supply line section tapers continuously at 27 in the direction of the inlet throttle 15, wherein a curved wall region is formed.
  • the inflow edge 25 shown by dashed lines is located. This inflow edge is rounded according to the invention as shown at 26.
  • the inlet throttle 15 has a taper following rounding 26 so that the diameter decreases from D2 to D3.
  • the throttle bore 15 is preferably conical or frusto-conical, ie the generatrices are formed by straight lines.
  • the cross section of the throttle bore 15 in each section of the throttle bore 15 is increasingly formed.
  • the cross-section of the throttle bore 15 is therefore designed either decreasing or uniform over the entire length of the throttle bore 15.
  • the cross-sectional taper extends over the entire length of the throttle bore 15, i. from the beginning of the throttle bore 15 directly after the inlet edge rounding to the end of the throttle bore 15 before a possible rounding of the outlet edge.
  • the outlet throttle 20 may be formed in a conventional manner.
  • the outlet throttle may be configured as shown in FIG. 3 on the basis of the inlet throttle 15.

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Fuel-Injection Apparatus (AREA)

Abstract

L'invention concerne un injecteur (1) servant à l'injection de carburant dans la chambre de combustion d'un moteur à combustion interne, comprenant une aiguille d'injection (6) mobile axialement qui, pour la commande de son mouvement d'ouverture et de fermeture, peut être soumise en direction axiale à une pression présente dans une chambre de commande (12) remplie d'un carburant, la chambre de commande (12) étant en communication avec une conduite d'entrée (24) comportant un étranglement d'entrée (15) et avec une conduite de sortie (23) comportant un étranglement de sortie (20). Au moins une soupape de commande (16) qui commande la pression dans la chambre de commande (12) ouvre ou ferme le canal d'entrée ou de sortie. Selon l'invention, l'étranglement d'entrée et/ou l'étranglement de sortie (15, 20) comportent un tronçon qui s'étend sur au moins sur une partie de la longueur de l'étranglement (15, 20) et dont la section transversale diminue dans le sens de l'écoulement. Le bord d'entrée (25) de l'étranglement d'entrée ou de sortie (15, 20) est arrondi (26).
EP12740278.2A 2011-07-29 2012-06-26 Orifices d'étranglement optimisés en termes de cavitation Withdrawn EP2737196A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
AT11102011A AT511731B1 (de) 2011-07-29 2011-07-29 Kavitationsoptimierte drosselbohrungen
PCT/AT2012/000174 WO2013016745A1 (fr) 2011-07-29 2012-06-26 Orifices d'étranglement optimisés en termes de cavitation

Publications (1)

Publication Number Publication Date
EP2737196A1 true EP2737196A1 (fr) 2014-06-04

Family

ID=46582466

Family Applications (1)

Application Number Title Priority Date Filing Date
EP12740278.2A Withdrawn EP2737196A1 (fr) 2011-07-29 2012-06-26 Orifices d'étranglement optimisés en termes de cavitation

Country Status (3)

Country Link
EP (1) EP2737196A1 (fr)
AT (1) AT511731B1 (fr)
WO (1) WO2013016745A1 (fr)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102015204255A1 (de) * 2015-03-10 2016-09-15 Robert Bosch Gmbh Kraftstoffinjektor für ein Kraftstoffeinspritzsystem

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102005060663A1 (de) * 2005-12-19 2007-06-21 Robert Bosch Gmbh Pumpe-Düse-Einrichtung für eine Brennkraftmaschine, insbesondere für ein Kraftfahrzeug

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10123775B4 (de) * 2001-05-16 2005-01-20 Robert Bosch Gmbh Kraftstoff-Einspritzvorrichtung für Brennkraftmaschinen, insbesondere Common-Rail-Injektor, sowie Kraftstoffsystem und Brennkraftmaschine
DE10152173A1 (de) * 2001-10-23 2003-04-30 Bosch Gmbh Robert Magnetventil zur Steuerung eines Einspritzventils
JP2007009899A (ja) * 2005-05-31 2007-01-18 Denso Corp 燃料噴射弁
GB2428002B (en) * 2005-07-06 2008-05-21 Vanessa Robyn Blake Support cushion
DE102009046373A1 (de) * 2009-11-04 2011-05-05 Robert Bosch Gmbh Magnetventil sowie Kraftstoff-Injektor mit einem Magnetventil

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102005060663A1 (de) * 2005-12-19 2007-06-21 Robert Bosch Gmbh Pumpe-Düse-Einrichtung für eine Brennkraftmaschine, insbesondere für ein Kraftfahrzeug

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of WO2013016745A1 *

Also Published As

Publication number Publication date
AT511731A1 (de) 2013-02-15
WO2013016745A1 (fr) 2013-02-07
AT511731B1 (de) 2014-10-15

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