(19)
(11) EP 0 404 342 B1

(12) EUROPEAN PATENT SPECIFICATION

(45) Mention of the grant of the patent:
20.01.1993 Bulletin 1993/03

(21) Application number: 90305384.1

(22) Date of filing: 18.05.1990
(51) International Patent Classification (IPC)5F02M 69/50, F02M 51/02, F16K 31/10

(54)

Injector for fuel-injection system

Einspritzventil für Kraftstoffeinspritzsystem

Injecteur pour système d'injection de combustible


(84) Designated Contracting States:
DE FR GB

(30) Priority: 21.06.1989 US 369505

(43) Date of publication of application:
27.12.1990 Bulletin 1990/52

(73) Proprietor: GENERAL MOTORS CORPORATION
Detroit Michigan 48202 (US)

(72) Inventors:
  • Stettner, Ernest Richmond
    Spencerport, New York 14559 (US)
  • Taylor, Roland Stuart
    Fairport, New York 14450 (US)
  • Stoltman, Donald Dibble
    Henrietta, New York 14467 (US)

(74) Representative: Denton, Michael John et al
Delphi Automotive Systems Centre Technique Paris 117 avenue des Nations B.P. 60059
95972 Roissy Charles de Gaulle Cedex
95972 Roissy Charles de Gaulle Cedex (FR)


(56) References cited: : 
US-A- 4 572 436
US-A- 4 787 418
   
       
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description

    Technical field



    [0001] This invention relates to a fuel-injection system for a multi-cylinder internal combustion engine in which a plurality of injection nozzles discharge fuel adjacent the engine inlet ports and a single injector meters the fuel to all of the injection nozzles as specified in the preamble of claim 1, for example as disclosed in US-A-4,572,436.

    [0002] An injector according to the present invention is characterised by the features specified in the characterising portion of claim 1.

    Summary of the drawings



    [0003] Figure 1 is a sectional view of a single injector that meters fuel to six injection nozzles in accordance with this invention.

    [0004] Figure 2 is an enlarged sectional view of the lower portion of the Figure 1 injector, taken along the line 2-2 of Figure 1, showing an injector valve engaging its seat.

    [0005] Figure 3 is a view similar to Figure 2, showing the injector valve lifted from its seat.

    [0006] Figure 4 is an enlarged sectional view of the Figure 1 injector, taken along line 4-4 of Figure 1 and with various portions broken away, showing the relationship of the injector valve and the orifices through which the injector meters the fuel to the injection nozzles.

    Detailed description



    [0007] Referring to the drawings, an injector 10 has a body 12 that receives fuel through a plurality of radial inlet passages 14 surrounded by a filter 16. A distributor 18 threaded into the lower end of body 12 delivers fuel through six outlet passages 20, each of which directs fuel to an associated injection nozzle.

    [0008] A valve 22 controls the delivery of fuel through passages 20. As shown in Figure 2, valve 22 is biased by a spring 24 to engage a planar surface 26 formed by raised valve seat lands 28, each one surrounding a respective one of the passages 20, and thereby to interrupt fuel delivery through passages 20.

    [0009] Injector 10 includes a solenoid having a coil 30, a centre pole 32 surrounding spring 24, a spacer ring 34 surrounding valve 22 and sandwiched with a shim 36 between body 12 and distributor 18, and an armature formed by valve 22. Valve 22 is tapered from its thickest portion on the left as viewed in Figures 2-3 to its thinnest portion on the right. When coil 30 is energized as shown in Figure 3 to actuate valve 22, the thickest portion of valve 22 engages shim 36 and causes the valve to pivot about its left edge, thereby lifting the valve 22 from lands 28 to allow fuel delivery through passages 20.

    [0010] Each land 28 is separated from the other lands by a recessed space 38 between the lands. The recessed space 38 assures that each land 28 is isolated from the other lands to minimize the effect or interaction of fuel delivery through any one passage 20 on fuel delivery through the other passages.

    [0011] Because valve 22 pivots as it lifts from lands 28, the clearance between valve 22 and lands 28a and 28b is less than the clearance between valve 22 and lands 28c and 28d which in turn is less than the clearance between valve 22 and lands 28e and 28f. Unless otherwise compensated, the differences in clearance would create undesirable inequalities in fuel delivery through passages 20.

    [0012] To minimize the differences in clearance, passages 20 are clustered beneath the right, free end of armature valve 22, and pins 40 hold valve 22 in alignment with passages 20. Pins 40 are imbedded in distributor 18 and constrain the movement of valve 22 to the pivotal motion described above, preventing valve 22 from rotating on distributor 18.

    [0013] To compensate for the remaining differences in clearance, an orifice formed at the entrance to each passage 20 is sized to assure equal fuel delivery through passages 20. Orifices 42a and 42b associated with lands 28a and 28b are larger than orifices 42c and 42d associated with lands 28c and 28d, and orifices 42c and 42d in turn are larger than orifices 42e and 42f associated with lands 28e and 28f. In one embodiment, the clearance between valve 22 and lands 28a and 28b is about 0.0056 and the diameter of orifices 42a and 42b is about 0.041, the clearance between valve 22 and lands 28c and 28d is about 0.0060 and the diameter of orifices 42c and 42d is about 0.0395, and the clearance between valve 22 and lands 28e and 28f is about 0.0065 and the diameter of orifices 42e and 42f is about 0.038.

    [0014] Specific dimensional units are not quoted for the above figures for the various clearances and diameters, since it is only the proportions of these figures, one to the other, which are significant.

    [0015] Stated another way, the dimensional relationships between the respective clearances and the diameters of the orifices in this embodiment are such that the clearance between valve 22 and lands 28a and 28b is 86.15% of the clearance between valve 22 and lands 28e and 28f, and the clearance between valve 22 and lands 28c and 28d is 92.30% of the clearance between valve 22 and lands 28e and 28f; whilst the diameter of the orifices 42a and 42b is 108% of the diameter of orifices 42e and 42f, and the diameter of the orifices 42c and 42d is 104% of the diameter of orifices 42e and 42f.

    [0016] Injector 10 also includes an invention as set forth in European patent application No. 90305385.8 (0 404 343) filed concurrently herewith.


    Claims

    1. An injector (10) comprising a distributor (18) having a plurality of outlet passages (20) and an orifice at the entrance of each of said passages (20) and a valve seat (28a,28b,28c,28d,28e, 28f) surrounding each orifice (42a,42b,42c,42d,42e, 42f), a tapered valve (22) biased to engage said valve seats (28a,28b,28c,28d,28e,28f) to interrupt fuel delivery through said outlet passages, and a valve actuator (30) adapted to pivotally displace said valve (22) from said valve seat (28) to allow fuel delivery through said passages (20), said valve (22) pivoting about one end thereof as it is displaced, and the lift of said valve (22) from the valve seats (28e,28f) furthest from said end of said valve (22) being greater than the lift of said valve (22) from the valve seats (28a,28b) closest to said end of said valve (22), characterised in that said orifices (42a,42b,42c,42d, 42e,42f) are sized to compensate for the differences in lift of the valve (22) from the associated valve seats (28a,28b,28c,28d,28e,28f), the orifices (42a,42b) associated with the valve seats (28a,28b) closest to said end of said valve (22) being larger than the orifices (42e,42f) associated with the valve seats (28e,28f) furthest from said end of said valve (22).
     
    2. An injector (10) according to claim 1, characterised in that, on lift of the valve (22), the clearance between said valve (22) and the valve seats (28a,28b) closest to said end of said valve (22) is 86.15% of the clearance between said valve (22) from the valve seats (28e,28f) furthest from said end of said valve (22); and the diameter of the orifices (42a,42b) associated with the valve seats (28a,28b) closest to said end of said valve (22) is 108% of the diameter of the orifices (42e,42f) associated with the valve seats (28e,28f) furthest from said end of said valve (22).
     


    Revendications

    1. Injecteur (10) comprenant un distributeur (18) pourvu de plusieurs passages de sortie (20) et d'un orifice à l'entrée de chacun des dits passages (20) et d'un siège de clapet (28a, 28b, 28c, 28d, 28e, 28f) entourant chacun des orifices (42a, 42b, 42c, 42d, 42e, 42f), un clapet biaisé (22) destiné à s'engager sur lesdits sièges de clapet (28a, 28b, 28c, 28d, 28e, 28f) de manière à interrompre la distribution de carburant à travers lesdits passages de sortie, et un actionneur (30) de clapet adapté pour déplacer ledit clapet (22) de façon basculante depuis ledit siège (28) de clapet, de manière à permettre la distribution de carburant à travers lesdits passages (20), ledit clapet (22) basculant sur l'une de ses extrémités lorsqu'il est déplacé, et la levée du clapet (22) par rapport aux sièges de clapet (28e, 28f) les plus éloignés de ladite extrémité du dit clapet (22) étant supérieure à la levée du clapet (22) par rapport aux sièges de clapet (28a, 28f) les plus proches de ladite extrémité du dit clapet (22), caractérisé en ce que lesdits orifices (42a, 42b, 42c, 42d, 42e, 42f) sont calculés de façon à compenser les différences de levée du clapet (22) par rapport aux sièges de clapet associés (28a, 28b, 28c, 28d, 28e, 28f), les orifices (42a, 42b) associés aux sièges de clapet (28a, 28b) les plus proches de ladite extrémité du dit clapet (22) étant plus larges que les orifices (42e, 42f) associés aux sièges de clapet (28e, 28f) les plus éloignés de ladite extrémité du dit clapet (22).
     
    2. Injecteur (10) selon la revendication 1, caractérisé en ce que, lorsque ledit clapet (22) est soulevé, le jeu entre ledit clapet (22) et les sièges de clapet (28a, 28b) les plus proches de ladite extrémité du dit clapet (22) représente 86,15 % du jeu existant entre ledit clapet (22) et lesdits sièges de clapet (28e, 28f) les plus éloignés de ladite extrémité du dit clapet (22); et en ce que le diamètre des orifices (42a, 42b) associés aux sièges de clapet (28a, 28b) les plus proches de ladite extrémité du dit clapet (22) représente 108 % du diamètre des orifices (42e, 42f) associés aux sièges de clapet (28e, 28f) les plus éloignés de ladite extrémité du dit clapet (22).
     


    Ansprüche

    1. Einspritzventil (10) das umfaßt einen Verteiler (18) mit einer Vielzahl von Auslaßkanälen (20) und einer Düse am Eingang eines jeden der Kanäle (20) und einem Ventilsitz (28a, 28b, 28c, 28d, 28e, 28f), der jede Düse (42a, 42b, 42c, 42d, 42e, 42f) umrandet, ein sich verjüngendes Ventil (22), das geführt ist, um in die Ventilsitze (28a, 28b, 28c, 28d, 28e, 28f) einzugreifen, um die Kraftstoffabgabe durch die Auslaßkanäle zu unterbrechen, und ein Ventilantrieb (30), der ausgebildet ist, schwenkbar das Ventil (22) von dem Ventilsitz (28) zu verstellen um Kraftstoffabgabe durch die Kanäle (20) zu ermöglichen, wobei das Ventil (22) sich bei seiner Versetzung um eines seiner Enden verschwenkt, und die Hubhöhe des Ventils (22) von den Ventilsitzen (28e, 28f), die am weitesten von dem Ende des Ventils (22) entfernt sind, größer ist als die Hubhöhe des Ventils (22) von den Ventilsitzen (28a, 28b), die am nächsten zu dem Ende des Ventils (22) liegen,
    dadurch gekennzeichnet,
    daß die Düsen (42a, 42b, 42c, 42d, 42e, 42f) eine Größe aufweisen, um die Hubhöhenunterschiede der Ventile (22) von den zugehörigen Ventilsitzen (28a, 28b, 28c, 28d, 28e, 28f) zu kompensieren, wobei die Düsen (42a, 42b), die den Ventilsitzen (28a, 28b) zugeordnet sind, welche dem Ende des Ventils (22) am nächsten liegen, größer sind als die Düsen (42e, 42f), die den Ventilsitzen (28e, 28f) zugeordnet sind, welche am weitesten von dem Ende des Ventils (22) entfernt liegen.
     
    2. Einspritzventil (10) nach Anspruch 1,
    dadurch gekennzeichnet,
    daß beim Heben des Ventils (22) der Spielraum zwischen dem Ventil (22) und den dem Ende des Ventils (22) nächstliegendsten Ventilsitzen (28a, 28b) 86,15 % des Spielraums zwischen dem Ventil (22) und den Ventilsitzen (28e, 28f) beträgt, welche von dem Ende des Ventils (22) am weitesten entfernt sind; und daß der Durchmesser der Düsen (42a, 42b), die den dem Ende des Ventils (22) nächstliegendsten Ventilsitzen (28a, 28b) zugeordnet sind, 108 % des Durchmessers der Düsen (42e, 42f) beträgt, welche den Ventilsitzen (28e, 28f) zugeordnet sind, die am weitesten von dem Ende des Ventils (22) entfernt liegen.
     




    Drawing