EP0353657A2 - Kraftstoffeinspritzventil - Google Patents

Kraftstoffeinspritzventil Download PDF

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Publication number
EP0353657A2
EP0353657A2 EP89113992A EP89113992A EP0353657A2 EP 0353657 A2 EP0353657 A2 EP 0353657A2 EP 89113992 A EP89113992 A EP 89113992A EP 89113992 A EP89113992 A EP 89113992A EP 0353657 A2 EP0353657 A2 EP 0353657A2
Authority
EP
European Patent Office
Prior art keywords
needle valve
sleeve
end portion
nozzle body
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.)
Granted
Application number
EP89113992A
Other languages
English (en)
French (fr)
Other versions
EP0353657B1 (de
EP0353657A3 (en
Inventor
Ken Ota
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.)
Nissan Motor Co Ltd
Original Assignee
Nissan Motor Co Ltd
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 Nissan Motor Co Ltd filed Critical Nissan Motor Co Ltd
Publication of EP0353657A2 publication Critical patent/EP0353657A2/de
Publication of EP0353657A3 publication Critical patent/EP0353657A3/en
Application granted granted Critical
Publication of EP0353657B1 publication Critical patent/EP0353657B1/de
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
    • F02M45/00—Fuel-injection apparatus characterised by having a cyclic delivery of specific time/pressure or time/quantity relationship
    • F02M45/02—Fuel-injection apparatus characterised by having a cyclic delivery of specific time/pressure or time/quantity relationship with each cyclic delivery being separated into two or more parts
    • F02M45/04—Fuel-injection apparatus characterised by having a cyclic delivery of specific time/pressure or time/quantity relationship with each cyclic delivery being separated into two or more parts with a small initial part, e.g. initial part for partial load and initial and main part for full load
    • F02M45/08—Injectors peculiar 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
    • F02M61/20—Closing valves mechanically, e.g. arrangements of springs or weights or permanent magnets; Damping of valve lift

Definitions

  • the present invention relates to a fuel injector for an internal combustion engine as for example a diesel engine.
  • a fuel injector is opened automatically by means of fuel pressure supplied thereto from a fuel injection pump.
  • fuel pressure exceeds a predetermined valve opening pressure
  • a needle valve is raised to its maximumly lifted position momentarily, whereby to effect a relatively sudden or abrupt fuel injection.
  • the fuel injection rate (the amount of injected fuel per a unit time or a unit crank angle) at the initial stage of fuel injection becomes excessively high to causes an increased engine noise.
  • a fuel injector which is adapted to effect stepwise variations of lift in response to two different valve opening pressures.
  • Fig. 5 shows this kind of fuel injector.
  • a needle valve 32 which is urged in a valve closing direction by a first spring 34 and by way of a first push rod 33.
  • the rear end of the first push rod 33 is arranged in opposition to the front end of a second push rod 35.
  • the second push rod 35 is urged toward the first push rod 33 by a second spring 36.
  • a clearance corresponding to a predetermined pre-lift “l” is provided between the rear end of the first push rod 33 and the front end of the second push rod 35.
  • a distance piece is provided for determining a maximum lift "L" of the needle valve 32.
  • the needle valve 32 starts lifting when fuel pressure exceeds the valve opening pressure determined by the first spring 34.
  • the needle valve 32 stops lifting once when the first push rod 33 abuts upon the second push rod 35.
  • the needle valve 32 starts lifting again and is moved into its maximumly lifted position.
  • the needle valve 32 effects two step variations of lift, i.e., a pre-lift "l” and a maximum lift "L". This makes it possible to prevent rapid combustion under a low speed and low to medium load condition of an engine.
  • the prior art fuel injector encounters a problem that it requires a number of constitutent parts since it is adapted to employ two springs 34, 36.
  • valve opening pressures determined by the respective springs 34, 36 need to be adjusted independently, thus resulting in a poor working efficiency.
  • a further problem is that a valve lift characteristic provided by two kinds of springs 34, 36 is liable to become unstable.
  • a fuel injector which comprises a nozzle body having a plurality of injection orifices at an end portion and an inner circumferential surface at the other end portion, a generally cylindrical sleeve installed in the nozzle body for sliding movement on the inner circumferential surface, and a needle valve movably installed in the sleeve for controlling supply of pressurized fuel to the injection orifices.
  • the needle valve has a pressure receiving surface which is subjected to fuel pressure for urging the needle valve in one direction.
  • the sleeve has a pressure receiving surface which is subjected to fuel pressure for urging the sleeve in the above described one direction.
  • the fuel injector further comprises spring means for urging the needle valve in the opposite direction, first abutment means for limiting movement of the sleeve relative to the nozzle body to a first movable range, second abutment means for limiting movement of the needle valve relative to the nozzle body to a second movable range which is larger than the first movable range, and engagement means for engaging the needle valve and the sleeve with each other and thereby allowing same to move all together at the time of movement of the sleeve within the first movable range.
  • a fuel injector includes a nozzle body 1 having at an end portion a plurality of injection orifices 2.
  • a nozzle holder 3 is arranged in line with the nozzle body 1 and has a pressurized fuel passage 4 and a return passage 5.
  • a distance piece 6 is interposed between the nozzle body 1 and the nozzle holder 3.
  • the nozzle body 1 and the distance piece 6 is fastened to the nozzle holder 3 by means of a holder nut 7.
  • the nozzle body 1 is hollow and has an inner circumferential surface 1a at the other end portion opposite to the end portion formed with the injection orifices 2.
  • An auxiliary sleeve 8 which is generally cylindrical is installed in the nozzle body 1 for sliding movement on the inner circumferential surface 1a of the nozzle body 1.
  • a needle valve 9 is concentrically installed in the nozzle body 1 and partly received by the auxiliary sleeve 8 for sliding movement on an inner circumferential surface 8b of the auxiliary sleeve 8.
  • a nozzle spring 10 is provided for urging the needle valve 9 toward the nozzle body end portion formed with the injection orifices 2, i.e., in the valve closing direction by way of a push rod 11.
  • the auxiliary sleeve 8 is reduced in outer diameter at an end portion nearer to the injection orifices 2 to provide a radially inwardly extending shoulder 8c while the inner circumferential surface 1a is reduced in diameter at an end portion to provide a radially inwardly extending stopper 12 upon which the shoulder 8c of the auxiliary sleeve 8 is capable of abutting and thereby preventing further movement of the auxiliary sleeve 8 toward the injection orifices 2, i.e., in the direction corresponding to that in which the needle valve 9 is moved to contact a conical or tapered seat 1b of the injector body 1 to close the fuel injector.
  • a clearance "l” is provided between the other end of the auxiliary sleeve 8 and the distance piece 6 when the shoulder 8c is in contact with the stopper 12.
  • the auxiliary sleeve 8 is capable of abutting upon the distance piece 6 through movement over the distance "l” and thus limited in movement toward the distance piece 6, i.e., in movement in the direction corresponding to that in which the needle valve 9 moves to open the fuel injector.
  • the reciprocative stroke of the auxiliary sleeve 8 is set so as to coincide with a predetermined pre-lift "l” .
  • the auxiliary sleeve 8 has at an end nearer to the injection orifices 2 a conical or tapered pressure receiving surface 8a constituting part of a wall defining a pressure chamber 13.
  • the pressue chamber 13 is annular in shape and formed in the nozzle body 1 in such a way as to concentrically encircle the neele valve 9.
  • the pressure chamber 13 is communicated with the pressurized fuel passage 4 of the nozzle holder 3 through a pressurized fuel passage 14 formed in the nozzle body 1 and adapted to be supplied with pressurized fuel from a fuel injection pump (not shown).
  • the needle valve 9 has a conical end 9a capable of contacting the conical seat 1b of the nozzle body 11 to obstruct communication between the pressure chamber 13 and the injection ports 2.
  • the needle valve 9 has at an axially intermediate portion a conical or tapered pressure receiving surface 9b and at a portion next to the conical end 9a a conical or tapered pressure receiving surface 9c.
  • the pressure receiving surface 9b is continuous with the pressure receiving surface 8a of the auxiliary sleeve 8 when the shoulder 8b is in contact with the stopper 12 and adapted to define part of the pressure chamber 13.
  • the needle valve 9 has, at an end opposite to the conical end portion 9a, a disk-like flange portion 15 which is arranged outside of the auxiliary sleeve 8 and formed so as to have an outer diameter than is larger than the inner diameter of the auxiliary sleeve 8 and thus capable of abutting upon the corresponding end of the auxiliary sleeve 8 at the time of lifting of the auxiliary sleeve 8.
  • the distance piece 6 is formed with a concentric circular recess 16 into which the flage portion 15 is insertable while sliding on the inner circumferential surface of same.
  • a shim 17 for adjusting the valve opening pressure.
  • the auxiliary sleeve 8 When the needle valve 9 and the auxiliary sleeve 8 performs the pre-lift "l' , the auxiliary sleeve 8 abuts upon the distance piece 6. In this instance, the flange portion 15 of the needle valve 9 is out of contact with the bottom surface 16a of the recess 16 so that the needle valve 9 is solely liftable further. From this stage onward, only the pressure receiving surfaces 9b, 9c of the needle valve 9 are thus effective for driving the needle valve 9. Since a relatively smaller pressure receiving surface is obtained for driving the needle valve 9 as compared with that during the pre-lifting, the needle valve 9 stops lifting once when it is raised the pre-lift "l” as shown in Fig. 2 and remains in the standstill condition when the fuel pressure ranges from P1 to P2.
  • the needle valve 9 When the fuel pressure increases further to cause the force acting on the pressure receiving surfaces 9a-9c of the needle valve 9 to exceed beyond the valve opening pressure given by the nozzle spring 10, the needle valve 9 solely starts lifting further and keeps on same until it raised the maximum lift "L" whereupon the flange portion 15 abuts upon the bottom surface 16a of the recess 16.
  • the fuel injector of the present invention can reduce the number of constitutent parts and therefore the cost.
  • valve opening pressure can be attained by an easy adjusting work of the single nozzle spring 10, thus making it possible to increase the working efficiency.
  • pre-lift “l” and the maximum lift “L” are determined by the clearance between the needle valve 9 and the distance piece 6 and the clearance between the auxiliary valve 8 and the distance piece 6, respectively, thus making it possible to control their accuracies with ease and attain their repairments before they are installed in place, and therefore making it possible to attain an improved working efficiency.
  • Fig. 4 shows another embodiment which is adapted to vary the fuel injecting directions, etc. by using the above described stepwisely varing lift.
  • the nozzle body 1 has a relatively large domed end portion 21 including a cylindrical inner circumferential surface 22.
  • the domed end portion 21 has adjacent the terminal end a single or a plurality of first injection orifices 24.
  • the nozzle body 1 has next to the inner circumferential surface 22 a conical or tapered seat 23 on which the needle valve 9 rests.
  • a plurality of second injection orifices 25 are formed in a conical or tapered wall portion of the nozzle body 1 defining the seat 23 and adjacent the smaller diameter end of same.
  • the needle valve 9 has at a terminal end a throttle pin 26 which slides on the the inner circumerential surface 22.
  • the thottle pin 26 is of such a length that corresponds to the above described pre-lift "l" when the conical end portion 9a rests on the seat 23.
  • the throttle pin 26 keeps obstructing communicating between the inside of the domed end portion 21 and the pressure chamber 13, thus allowing fuel to be injected only through the second injection orifices 25.
  • the throttle pin 26 allows to communicate the inside of the domed end portion 21 and the pressure chabmer 13, thus allowing fuel to be injected through both the first injection orifices 24 and the second injection orifices 25.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Fuel-Injection Apparatus (AREA)
EP19890113992 1988-07-30 1989-07-28 Kraftstoffeinspritzventil Expired - Lifetime EP0353657B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP190783/88 1988-07-30
JP19078388A JPH0240078A (ja) 1988-07-30 1988-07-30 内燃機関の燃料噴射弁

Publications (3)

Publication Number Publication Date
EP0353657A2 true EP0353657A2 (de) 1990-02-07
EP0353657A3 EP0353657A3 (en) 1990-09-19
EP0353657B1 EP0353657B1 (de) 1993-01-20

Family

ID=16263663

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19890113992 Expired - Lifetime EP0353657B1 (de) 1988-07-30 1989-07-28 Kraftstoffeinspritzventil

Country Status (3)

Country Link
EP (1) EP0353657B1 (de)
JP (1) JPH0240078A (de)
DE (1) DE68904496T2 (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5533482A (en) * 1994-05-23 1996-07-09 Nissan Motor Co., Ltd. Fuel injection nozzle

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE581476C (de) * 1931-11-15 1933-07-28 Robert Bosch Akt Ges Fluessigkeitsgesteuerte Einspritzduese
FR2050592A5 (de) * 1969-06-18 1971-04-02 Ffsa
FR2333973A1 (fr) * 1975-12-06 1977-07-01 Bosch Gmbh Robert Soupape d'injection de carburant pour pre-injection et injection principale
EP0280401A1 (de) * 1987-02-24 1988-08-31 LUCAS INDUSTRIES public limited company Kraftstoffeinspritzdüse
GB2215397A (en) * 1988-02-26 1989-09-20 Lucas Ind Plc I.C. engine fuel injection nozzle

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE581476C (de) * 1931-11-15 1933-07-28 Robert Bosch Akt Ges Fluessigkeitsgesteuerte Einspritzduese
FR2050592A5 (de) * 1969-06-18 1971-04-02 Ffsa
FR2333973A1 (fr) * 1975-12-06 1977-07-01 Bosch Gmbh Robert Soupape d'injection de carburant pour pre-injection et injection principale
EP0280401A1 (de) * 1987-02-24 1988-08-31 LUCAS INDUSTRIES public limited company Kraftstoffeinspritzdüse
GB2215397A (en) * 1988-02-26 1989-09-20 Lucas Ind Plc I.C. engine fuel injection nozzle

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5533482A (en) * 1994-05-23 1996-07-09 Nissan Motor Co., Ltd. Fuel injection nozzle

Also Published As

Publication number Publication date
EP0353657B1 (de) 1993-01-20
DE68904496D1 (de) 1993-03-04
EP0353657A3 (en) 1990-09-19
DE68904496T2 (de) 1993-08-12
JPH0240078A (ja) 1990-02-08

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