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
  • F02M61/04—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
• • 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

• a fuel injector for internal combustion engines is provided.
• the invention relates to a fuel injector valve for internal combustion engines, including a hollow slide valve guide fixedly disposed in the external housing of the injector and the foremost end of which is designed as an atomizer closed in front and provided with a central bore, said atomizer having in its side wall a number of transversely extending nozzle holes for the injection of atomized fuel, a slide valve axially displaceable in the guide for opening and closing the nozzle holes and having a foremost section with a cylindrical end section carried by a shank and which is journalled with tight fit in the bore of the atomizer in order to close the nozzle holes when the valve is in the closed position; said injector valve having a flow passage through which pressurized fuel may flow past the slide valve and on to the nozzle holes when the slide occupies its opening position in which its end section exposes the holes, and a closure spring acting against the fuel pressure for holding the slide in its closing position.
• DK patent No. 149 141 deals with a fuel injector valve of this type, wherein the slide valve and its foremost section which project down into the atomizer are comparatively rigid in the trans- verse direction, thereby requiring the slide be mounted completely coaxially with the bore in the atomizer. Even a very slight failing alignment between the slide and the atomizer bore may entail failure in the fuel injector valve.
• the rearmost slide valve section journalled in the valve guide has a comparatively large diameter and is ground to size to fit into the valve guide whereas the foremost slide section projecting down into the bore of the atomizer has a smaller diameter and is ground to size so that the cylindrical end section is journalled with tight fit within the atomizer bore.
• the end section In order to ensure tight barring of the nozzle holes, even when the fuel pressure in the flow passage immediately before and after the actual fuel injection attains very high values, such as 800 to 1000 bar, the end section must fit extremely precisely in the atomizer bore and, consequently, the clearance between the end section and the bore typically amounts to 10 to 15 ⁇ m.
• the demand for full coaxiality between the end section of the slide valve and the rearmost section journalled in the valve guide necessitates that the two sections are ground in the same setting-up and, consequently, the connection between the end section and the remainder of the slide valve must have such a high stiffness against transverse bending that the shearing force provided by the cutting force of the grinder does not result in any noticeable bending of the slide valve.
• the slide valve consisting of steel has been hardened to a glass-hard state, meaning that the handling as well as the grinding of the slide valve must be effected very cautiously in order to pre ⁇ vent the slide valve from breaking as a consequence of its brittleness.
• This circumstance in unison with the high demands for coaxiality and tolerances of the ground surfaces result in that the slide valve is expensive to manufacture.
• the entire slide valve has to be exchanged when the end section is worn down. The dispatch and exchange of the slide valve is also difficult due to the brittleness of the slide because even a rather slight transverse impingement may cause breaking of the slide valve.
• the object of the invention to provide a slide valve with a longer lifetime than the prior art slide valve and which is easier to manufacture, handle and exchange.
• the fuel injector valve accord ⁇ ing to the invention is characterized in that the axial length of the end section of the slide valve at most is of the same order of magnitude as the diameter of the bore in the atomizer, and that the length of the shank is at least several times longer than the axial length of the end section.
• the foremost section of the slide valve is so flexible that the bore in the atomizer automatically aligns the end section of the slide valve to its own longitudinal axis so that the end section does not necessarily have to be completely coaxial with the rearmost slide valve sec- tion journalled in the valve guide.
• the wearing of the end section and the atomizer will be diminished in relation to the wearing of the prior art injector in which even a very slight misalignment between the end section and the atomizer may result in seizing and rapid wearing of the atomizer.
• the foremost section of the slide valve may be manuafctured independently of the rearmost section.
• this is utilized in facilitating the manufacturing of the slide valve in that the cylindric- al external side of the foremost end section of the slide valve is finally ground to size independently of the grinding of the slide section to be journalled in the valve guide.
• the lifetime of the slide valve has further been enhanced by a preferred embodiment in which at least the foremost part of the cylindrical external surface of the end section consists of an erosion-resistant material, such as Stellite 6.
• the erosion-resistant material reduces the wearing of the front end of the end section that may occur when the end section by the opening of the injector valve exposes the nozzle holes, and the fuel starts flowing at very high velocities through the nozzle holes.
• the high flow velocities occurring at the opening of the valve immediately next to the extreme end of the end section apply heavy pressure loads thereon.
• the erosion-resistant material is capable of receiving said loads, thereby prolonging the lifetime of the slide valve.
• Pig. 1 is an axial section through an embodiment of the injector valve, the slide valve being shown in the opening position.
• Fig. 2 is an axial section on a larger scale through the foremost part of the injector valve illus ⁇ trated in Fig. 1, the slide valve being shown in the closing position,
• Fig. 3 is a sectional view of a side elevation of the foremost section of the slide valve,
• Fig. 4 is a cross-section through the slide valve along the line IV-IV in Fig. 3,
• Fig. 5 is an axial view through the foremost part of a second embodiment of the injector valve
• Fig. 6 is a cross-section along the line Vl-vi in Fig. 5 through the foremost section of the slide valve.
• the fuel injector valve illustrated in Figs l, 2 and 5 has an elongated external housing 1 which at its rearmost end has a head 2 by which the injector valve in a known manner may be mounted in the cylinder cover of an internal combustion engine and be connected with a fuel pump, not shown.
• the head 2 includes a fuel oil inlet 3 which is in flow connection with a duct 4 extending through a central thrust piece 5 and a valve member 6 journalled in a valve housing 7, the rearmost end of which abuts on a forwards facing shoulder on the thrust piece 5 and whose fore- most end has a conical surface kept in tight abutment on a corresponding conical surface on a valve guide 8 which at its rearmost end fits tightly into housing 1 and carries at its foremost end an atomizer 9 pro ⁇ jecting through housing 1 and into the combustion chamber of the engine cylinder, not shown, when the injector valve is mounted on the cylinder cover.
• a slide valve generally designated 10 is axially displaceable internally of the valve guide 8 and includes a rearmost section 11 whose cylindrical external surface is ground to size and journalled with tight fit in a central guide bore in valve guide 8.
• the slide section 11 carries a foremost slide section 12 that is substantially thinner than the rearmost section 11 and projects into a central bore 13 in the atomizer.
• a central tube 14 extending into the rearmost section of the slide valve is integral with the valve guide 8 and has a forwards facing shoulder restrain ⁇ ing the rearwards movement of slide valve 10.
• a closure spring 16 rearwardly abutting on the valve guide 8 and forwardly on a rearwards facing shoulder 17 at the rear end of the slide valve sec ⁇ tion 11 is received in a hollow space 15 in the valve guide so that the closure spring loads the slide valve in the forwards direction towards the closing position shown in Fig. 2.
• the inlet duct 4 is through transverse bores and a following valve seat 18 in communication with a flow passage 19 extending through pipe 14 and dis ⁇ charging in front into a distributor chamber 20 pro- vided in the slide valve and which chamber through transverse bores 21 is in flow connection with an annular chamber 22 defined between the external side of the slide valve and the surrounding parts of the valve guide.
• a conical seating 23 is formed in valve guide 8 at the foremost end of the chamber 22, and the slide valve is at the front end of section 11 provided with a corresponding conical seating 24 which in the closing position of the injector valve is urged sealingly in abutment on seating 23 by closure spring 16.
• the foremost section 12 of the slide valve is at its backwards end provided with a threaded portion 25 screwed into a central bore at the foremost end of the slide valve section 11 so that a rearwards directed shoulder 26 on section 12 abuts on the front end of section 11.
• a safety pin 27 inserted through unitary bores in slide valve sections 11 and 12 prevents the foremost section from unintentionally rotating clear of the rearmost section 11. This safety against releasing may also be effected in other ways, e.g. by glue, such as Loctite (reg. Trademark).
• the shoulder 26 merges forwardly into a comparatively thin and elongated shank 28 the foremost end of which carries an end section 29 with a cylindrical external surface 30 journalled tightly fitting into the bore 13 of the atomizer.
• a number of transversely extending nozzle holes 31 so positioned that the end section 29 bars the nozzle holes when the injector valve is in the closing posi- tion illustrated in Fig. 2, whereas the end section 29 in the opening position of the injector valve (Fig. 1) has been moved so much backwards that the nozzle holes are completely exposed.
• valve member 6 When the valve member 6 abuts on the valve seat 18, preheated oil may over a transverse bore in thrust piece 5 flow through the injector valve and keep it heated.
• the valve member 6 When the pressure of the fuel oil in inlet 3 rises sharply immediately prior to initi ⁇ ating the injection, the valve member 6 is displaced to the rear into the position shown in Fig. 1 and bars the passage for circulating oil, following which the fuel oil flows past the valve seat 18 down through the passage 19 and out into chamber 22 in which the pressure in the oil builds up until it overcomes the force exerted by the closure spring 17 and the slide valve is moved rearwards from the closing position shown in Fig. 2.
• the fuel oil flows for ⁇ wards into the space surrounding the shank 28 and passes through recesses 32 therein on to the part of the bore 13 positioned in front of the end section 29. Due to the fact that the end section 29 in the closed position of the injector extends a distance for ⁇ wards past the nozzle holes 31, a pressure build-up is effected in the fuel oil in front of the end section 29 prior to exposing the nozzle holes, meaning that the fuel oil substantially from the beginning of the injec ⁇ tion is injected at full pressure, thereby ensuring a good combustion.
• the foremost section 12 and the rearmost sec- tion 11 of the slide valve are ready-made as two separate units which are assembled only immediately before mounting the slide valve 10 in the injector valve.
• the comparatively thick slide valve section 11 may due to its large rigidity against transverse bending be processed at a high cutting force.
• the foremost section 12 is in the embodiment illustrated in Figs 2, 3 and 4 composed of two ele ⁇ ments, viz. the shank 28 and a ring 33 consisting of an erosion-resistant material, such as Stellite 6.
• the shank 32 At its foremost end the shank 32 has a larger diame ⁇ ter and is there provided with three longitudinal recesses 32 distributed along the circumference and allowing, as mentioned, the fuel oil to pass internally past the ring 33.
• the recesses 32 leave in the fore- most end of the shank three radially protruding lobes 34 to which the ring 33 is secured, for instance by means of hard soldering. Alloy 50 may be used as the solder.
• the foremost section 12 of the slide valve shall only be produced on a smaller scale, it may appropriately be implemented as shown in Figs 5 and 6.
• the foremost section is there manufactured from a single steel blank on the foremost end section and a distance up along the side, corresponding to the intended face for journalling in the bore 13 of the
• the portion 36 of the shank positioned behind the end section 29 and having a smaller diameter than .the end section 29 but a larger diameter than the part of the shank 28 positioned behind, is sub ⁇ sequently provided with an appropriate number, e.g.
• the flow passage allowing the combustible to flow past the slide valve includes the recesses 32 of the embodiment illustrated in Fig. 2 whereas they include the grooves 37 and the bore 35 in the embo ⁇ diment illustrated in Fig. 5.
• the sections may of course be assembled in another way, for instance by means of press fit or by a similar joining method.
• the shank may further be designed in another way, e.g. as a

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

Priority Applications (5)

Applications Claiming Priority (2)

Publications (1)

Family

ID=8107302

Family Applications (1)

Country Status (9)

Cited By (11)

Families Citing this family (3)

Citations (4)

• 1991
  • 1991-10-04 DK DK169891A patent/DK167502B1/da not_active IP Right Cessation
• 1992
  • 1992-09-24 JP JP5506552A patent/JP3027191B2/ja not_active Expired - Lifetime
  • 1992-09-24 WO PCT/DK1992/000282 patent/WO1993007386A1/en active IP Right Grant
  • 1992-09-24 PL PL92303043A patent/PL169883B1/pl unknown
  • 1992-09-24 DE DE69204075T patent/DE69204075T2/de not_active Expired - Lifetime
  • 1992-09-24 EP EP92921416A patent/EP0606371B1/en not_active Expired - Lifetime
  • 1992-09-24 KR KR1019940701085A patent/KR100253673B1/ko not_active IP Right Cessation
  • 1992-09-30 HR HR1698/91A patent/HRP920658B1/xx not_active IP Right Cessation
  • 1992-10-02 TW TW081107844A patent/TW250529B/zh active

Patent Citations (4)

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