EP3309386B1 - Fuel injector valve member - Google Patents

Description

TECHNICAL AREA

The invention relates to a fuel injector provided with a device for reinforcing the valve member of the injector.

TECHNOLOGICAL BACKGROUND OF THE INVENTION

A fuel injector conventionally comprises a valve member or commonly called a needle controlled in opening and closing according to the pressure prevailing in a control chamber, which pressure is a function of the position of a control solenoid valve. The needle is slidable within a bore of the nozzle body, wherein one end of the needle is sealingly arranged with a nozzle seat provided on an inner surface of the bore of the nozzle body, in order to control the fuel supply through injection holes located through the wall of the nozzle body. The fuel is at high pressure and flows through the injector from the inlet channel to the injection holes as described in the documents

US 6,257,506 B1 , DE102004047183 A1 and US2003/213459 A1 . The pressure exerted on the nozzle seat creates wear which generates variations in the distribution of fuel pressure in the injection holes and, moreover, the opening pressure of the needle in the control chamber varies at a given pressure. The object of the present invention is to provide a solution which solves these drawbacks.

SUMMARY OF THE INVENTION

The present invention proposes to solve these problems by means of a device for reinforcing the valve member of the injector. The valve member of a fuel injector comprises a cylindrical body at a first end of which is formed a valve shutter defining a conical male face adapted to cooperate with a complementary female face of a valve seat integrated in a nozzle body . The cylindrical body and the shutter connect along a line of intersection. The valve member includes at least a first annular groove arranged adjacent to the line of intersection.

In a first embodiment not forming part of the invention, the first annular groove of the valve member is arranged on the cylindrical body of the valve member,
adjacent to the line of intersection. In a second embodiment not forming part of the invention, the first annular groove of the valve member is arranged on the conical male face of the obturator, adjacent to the line of intersection. In a third embodiment, the valve member comprises a second annular groove adjacent to the line of intersection, one of the two grooves is arranged on the cylindrical body on one side of the zone of intersection and the other of the two grooves is arranged on the shutter on the other side of the line of intersection. In addition, the profile of the annular groove can be semi-circular. The profile of the annular groove can also be polygonal. In addition the throat can be obtained by the following characteristics: D/D40 < 0.9 and H < 0.2 mm, in which D is the diameter of the valve member at the level of the throat arranged either above the line of intersection is below the line of intersection, D40 is the diameter of the valve member at the line of intersection and H is the distance between the line of intersection and the bottom of the groove arranged either at above the line of intersection or below the line of intersection . In another embodiment the valve member of a fuel injector comprises a cylindrical body at a first end of which is formed a valve shutter defining a conical male face adapted to cooperate with a complementary female face of a valve seat , the cylindrical body and the shutter being connected along a line of intersection. The cylindrical body comprises at least two different diameters defining between them a shoulder adjacent to the line of intersection. Additionally a nozzle assembly includes a valve member adapted to slide within the bore of the nozzle body, the valve member as defined in previous embodiments of the invention.

Moreover, an injector comprises the nozzle assembly as previously described.

BRIEF DESCRIPTION OF THE DRAWINGS

• La figure 1 est un vue d'ensemble d'un injecteur qui ne fait pas partie de l'invention.
• La figure 2 est une vue en coupe d'un membre de vanne selon un premier mode de réalisation qui ne fait pas partie de l'invention.
• La figure 3 est une vue en coupe longitudinale d'un membre de vanne selon un deuxième mode de réalisation qui ne fait pas partie de l'invention.
• La figure 4 est une vue en coupe d'un membre de vanne selon un troisième mode de réalisation.
• La figure 5 est une vue en coupe d'un membre de vanne selon un quatrième mode de réalisation qui ne fait pas partie de l'invention.
• La figure 6 est une vue en coupe d'un membre de vanne selon un cinquième mode de réalisation qui ne fait pas partie de l'invention.
• La figure 7 est une vue en coupe d'un membre de vanne selon un sixième mode de réalisation.
• La figure 8 est une vue en coupe d'un membre de vanne selon un septième mode de réalisation qui ne fait pas partie de l'invention.

Other characteristics, objects and advantages of the invention will appear on reading the detailed description which follows, and with reference to the appended drawings given by way of non-limiting example and in which:

• The figure 1 is an overview of an injector which does not form part of the invention.
• The picture 2 is a sectional view of a valve member according to a first embodiment which does not form part of the invention.
• The picture 3 is a longitudinal sectional view of a valve member according to a second embodiment which does not form part of the invention.
• The figure 4 is a sectional view of a valve member according to a third embodiment.
• The figure 5 is a sectional view of a valve member according to a fourth embodiment which does not form part of the invention.
• The figure 6 is a sectional view of a valve member according to a fifth embodiment which does not form part of the invention.
• The figure 7 is a sectional view of a valve member according to a sixth embodiment.
• The figure 8 is a sectional view of a valve member according to a seventh embodiment which does not form part of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

To facilitate and clarify the following description, the orientation from top to bottom is arbitrarily chosen and, words and expressions such as "above, below, above, below, top, bottom ..." may be used without any intention to limit the invention.

According to figure 1 not forming part of the invention, an embodiment of the invention relating to a fuel injector 10 is described, here a diesel injector although the invention is fully transposable to a gasoline injector or any other fuel. The description will detail the elements of the invention and will remain more succinct and general as to the surrounding elements.

According to figure 1 , the injector 10 extends along a longitudinal axis X and comprises from bottom to top, according to the conventional and non-limiting sense of the figures, a nozzle assembly 12 comprising a valve member 14 or also called needle 14 arranged in a body nozzle 16, a control valve assembly 18 arranged in a valve body 20, an actuator 22 arranged in an actuator body 24. The valve member 14 is axially slidably arranged in a longitudinal cylindrical bore 26 of the nozzle body . Nozzle assembly 12, control valve assembly 18 and actuator 22 are held together by a nut 25.

As described in figure 1 and 2 not forming part of the invention, the valve member 14 comprises a cylindrical body 28 having at a first end 30 a valve shutter 32 defining a conical male face 34 adapted to cooperate with a complementary conical female face 36 of a seat valve 38. The cylindrical body 28 and the obturator 32 are connected along a line of intersection 40. The nozzle body 16 comprises a barrel 42, the valve seat 38 and a bag 44 provided with injection holes 46. The nozzle body 16 extends along a longitudinal axis X. The nozzle body 16 defines the longitudinal cylindrical bore 26 along the longitudinal axis X open at a first end 48 and comprising a second end 49 which is in contact with the conical seat 38. The bag 44 is arranged at the top of the conical seat 38. The conical seat 38 comprises the female conical face 36.

In a first embodiment of the invention and according to the figure 2 , the valve member 14 comprises a first annular groove 50 which is adjacent to the line of intersection 40. The groove 50 is adjacent means here according to the definition of the Larousse and Académie française dictionaries that the groove is contiguous, adjoining, neighboring, close to the line of intersection 40. According to the figure 2 , the first annular groove 50 is located on the cylindrical body 28 of the valve member 14 and close to the line of intersection 40. The groove 50 includes a groove bottom 53.

In a second embodiment and as described in the picture 3 not forming part of the invention, a second annular groove 51 of the valve member 14 is arranged on the conical male face 34 of the valve member. The second groove 51 is adjacent to the line of intersection 40. According to the picture 3 , the annular groove 51 comprises a bottom of the groove 55.

In a third embodiment and as described in the figure 4 , the valve member 14 comprises the first ring-shaped groove 50 and the second groove 51. The two grooves 50,51 are ring-shaped. The first groove 50 is arranged on the cylindrical body 28 on one side of the line of intersection 40 and the second groove 51 is arranged on the shutter 32 on the other side of the line of intersection 40. The profile P of the groove 50, 51 is of semi-circular shape as described in the figure 4 .

• $$-\mathrm{Ratio}=\mathrm{D}/\mathrm{D40}<\mathrm{0}\mathrm{,9}$$
  
  et,
• $$\mathrm{H<0}\mathrm{,2}\mathrm{mm}.$$
  

dans lesquels pour la première gorge 50, D est le diamètre D50 de la première gorge 50 et H est la distance H50 mesurée entre la ligne d'intersection 40 et le fond de gorge 53 de la première gorge. De même pour la deuxième gorge 51, D est le diamètre D51 de la gorge 51 et H est la distance H51 mesurée entre la ligne d'intersection 40 et le fond de gorge 55 de la deuxième gorge.The groove 50,51 can have different P profiles. As described in the figure 4 , the profile P of the annular groove 50,51 of the valve member is semi-circular but the profile P can be of any other shape. Valve member 14 defines a throat diameter D which is measured at the bottom of throat 53, 55 of throat 50,51. As described in figure 2 , 3 and 4 , the cylindrical body 28 of the valve member further defines a diameter D40 measured at the level of the line of intersection 40. In addition is defined on the valve member 14 a distance H measured between the line of intersection 40 and the bottom groove 53, 55. The distance H is parallel to the axis X. The groove 50, 51, has the following characteristics:

• $$-\mathrm{Ratio}=\mathrm{D}/\mathrm{D40}<\mathrm{0}\mathrm{,9}$$
  
  and,
• $$\mathrm{H<0}\mathrm{,2}\mathrm{mm}.$$
  

in which for the first groove 50, D is the diameter D50 of the first groove 50 and H is the distance H50 measured between the line of intersection 40 and the bottom of the groove 53 of the first groove. Likewise for the second groove 51, D is the diameter D51 of the groove 51 and H is the distance H51 measured between the line of intersection 40 and the bottom of the groove 55 of the second groove.

In a fourth embodiment not forming part of the invention and according to the figure 5 , valve member 14 includes a first annular groove 50 which is adjacent line of intersection 40. Groove 50 is polygonal in shape. As described in the figure 5 , the first annular groove 50 is located on the cylindrical body 28 of the valve member 14 and close to the line of intersection 40.

In a fifth embodiment not forming part of the invention and as described in the figure 6 , the second annular groove 51 of the valve member 14 is arranged on the conical male face 34 of the valve member. The second groove 51 is polygonal in shape. The second throat 51 is adjacent to the line of intersection 40. The valve member 14 defines a throat diameter D51 measured at the bottom of the throat 55.

• $$-\mathrm{Ratio}=\mathrm{D}/\mathrm{D40}<\mathrm{0}\mathrm{,9}$$
  
  et,
• $$\mathrm{H<0}\mathrm{,2}\mathrm{mm}.$$
  

dans lesquels pour la première gorge 50, D est le diamètre D50 de la première gorge 50 et H est la distance H50 mesurée entre la ligne d'intersection 40 et le fond de gorge 53 de la première gorge. De même pour les caractéristiques de la deuxième gorge 51, D est le diamètre D51 de la gorge 51 et H est la distance H51 mesurée entre la ligne d'intersection 40 et le fond de gorge 55 de la deuxième gorge.In a sixth embodiment and as described in the figure 7 , the valve member 14 comprises the first annular groove 50 arranged on the cylindrical body 28 and the second annular groove 51 arranged on the conical male face 34 of the valve member. The two grooves 50, 51 are polygonal in shape. The two grooves 50.51 are adjacent to the line of intersection 40. Valve member 14 defines a throat diameter D50 located at throat 50 and a diameter D51 located at throat 51. Both diameters D50, D51 are measured from throat bottoms 53.55. The value of diameter D51 is less than the value of diameter D50. The profile P of the groove 50, 51 as described in the figure 5 , 6 and 7 has the same characteristics as the profile P of the semi-circular groove 50, 51 of the first three embodiments as described in the figure 2 , 3 and 4 . The characteristics of the 50.51 polygonal groove are as follows:

• $$-\mathrm{Ratio}=\mathrm{D}/\mathrm{D40}<\mathrm{0}\mathrm{,9}$$
  
  and,
• $$\mathrm{H<0}\mathrm{,2}\mathrm{mm}.$$
  

in which for the first groove 50, D is the diameter D50 of the first groove 50 and H is the distance H50 measured between the line of intersection 40 and the bottom of the groove 53 of the first groove. Likewise for the characteristics of the second groove 51, D is the diameter D51 of the groove 51 and H is the distance H51 measured between the line of intersection 40 and the bottom of the groove 55 of the second groove.

In an alternative to all the previous modes, the profile P of the groove 50.51 can have any other shape such as an oval shape.

• $$-\mathrm{D14}/\mathrm{D40}<\mathrm{0,9}$$
  
• $$\mathrm{H70<0}\mathrm{,2}\mathrm{mm}.$$
  

dans lequel : D14 est un diamètre au niveau du corps cylindrique 28 au-dessus de l'épaulement 70, D40 est le diamètre au niveau de la ligne d'intersection 40 qui est identique au diamètre de l'épaulement 70 et H70 est la distance entre la ligne d'intersection 40 et la face d'épaulement 72. La distance H70 est en millimètre et elle est mesurée entre la ligne d'intersection 40 et une ligne transversale 74 comme décrit dans la figure 8. La ligne 74 est la ligne qui se situe au niveau du bord de la face d'épaulement 72. Dans une alternative à ce mode de réalisation, la face d'épaulement 72 peut être transversale à l'axe longitudinal X.In a seventh embodiment not forming part of the invention as described in the figure 8 , valve member 14 includes a shoulder 70 defined on cylindrical body 28 of the valve member. This embodiment solves the same problems as the previous embodiments, that is to say, among other things, the reduction of the damage to the seat 34 during repeated contacts between the valve member 14 and the seat 38. According to the figure 8 The shoulder 70 is arranged adjacent the line of intersection 40. The shoulder 70 further includes a shoulder face 72 facing the side of the cylindrical body 28 of the valve member. The shoulder 70 has the following characteristics:

• $$-\mathrm{D14}/\mathrm{D40}<0.9$$
  
• $$\mathrm{H70<0}\mathrm{,2}\mathrm{mm}.$$
  

where: D14 is a diameter at the cylindrical body 28 above the shoulder 70, D40 is the diameter at the line of intersection 40 which is the same as the diameter of the shoulder 70, and H70 is the distance between the line of intersection 40 and the shoulder face 72. The distance H70 is in millimeters and it is measured between the line of intersection 40 and a transverse line 74 as described in the figure 8 . Line 74 is the line that is at the edge of the shoulder face 72. In an alternative to this embodiment, the shoulder face 72 may be transverse to the longitudinal axis X.

In this chapter we will describe the operation of the injector 10. As described in the figure 1 , when the actuator 22 is electrically energized, it attracts the magnetic armature 52 and the valve stem 54 which are fixed together, which opens the evacuation channel (not shown) and allows the fuel trapped in the control chamber 56 to evacuate to a low pressure circuit (not shown). Then the pressure decreases in the control chamber 56 and the needle 14 moves in the bore 26 of the nozzle body to an open position in which the first end 30 of the valve member 14 moves away from the seat 38 of the nozzle body. nozzle. Consequently a second end 58 of the valve member 14 comes into contact with an underside 60 of the valve body.

When the actuator 22 is not energized, the magnetic armature 52 and control rod 54 assembly is pushed back by a valve spring 62 towards a position which prevents fuel from flowing towards the evacuation channel which is closed. , which retains the high-pressure fuel that gets there. Then the pressure in the control chamber 56 rises and the needle 14 is forced downward by a needle spring 64 and the first lower end 30 of the needle is in contact with the seat 38 and the second upper end 58 of the needle is away from the underside 60 of the valve body.

LIST OF REFERENCES USED

10

injector

12

nozzle assembly

14

valve member or needle

16

nozzle body

18

control valve assembly

20

valve body

22

actuator

24

actuator body actuator body bore

26

nozzle

28

cylindrical body of the needle

30

first needle end

32

shutter

34

male face

36

female side

38

valve seat

40

intersection line

42

was

44

bag

46

injection holes

48

first nozzle body end

49

second nozzle body end

50

first throat

51

second throat

52

armature

54

valve stem

56

Control Chamber

58

second needle end

60

underside of valve body

62

valve spring

64

needle spring

70

shoulder

72

shoulder face

X

longitudinal axis

D40

diameter at the line of intersection

D50

diameter at throat 50

D51

diameter at throat 51

D14

diameter at the cylindrical body

H50

axial distance of the first groove

H51

axial distance of the second groove

H70

axial distance from shoulder face

Claims (6)

1. A valve member (14) of a fuel injector (10), comprising:

   - a cylindrical body (28) at a first end (30) of which is formed a valve plug (32) defining a conical male face (34) adapted to cooperate with a female complementary face (36) of a valve seat (38) integrated in a nozzle body (16), the cylindrical body (28) and the plug (32) connecting to each other along an intersection line (40),

   characterized in that the valve member (14) comprises at least one first annular groove (50) arranged adjacent to the intersection line (40), and a second annular groove (51) adjacent to the intersection line (40), one of the two grooves (50, 51) is arranged on the cylindrical body on one side of the intersection zone and the other of the two grooves (50, 51) is arranged on the plug (32) on the other side of the intersection line (40).
2. The valve member (14) according to the preceding claim, characterized in that a profile (P) of the annular groove (50, 51) is semicircular.
3. The valve member (14) according to any one of claims 1 to 2, characterized in that the profile (P) of the annular groove (50, 51) is polygonal.
4. The valve member (14) according to any one of claims 1 to 3, wherein the groove (50, 51) is obtained by the following characteristics: $$\mathrm{D}/\mathrm{D}40<0.9$$

   

   and, $$\mathrm{H}<0.2\mathrm{mm},$$

   

   wherein:

   - D is the diameter (D50, D51) of the valve member (14) at the groove bottom (53, 55),

   - D40 is the diameter of the valve member (14) at the intersection line (40) and,

   - H is the distance (H50, H51) between the intersection line (40) and the groove (50, 51).
5. A nozzle assembly (12) comprising a valve member (14) adapted to slide in the bore (26) of the nozzle body (16), the valve member (14) according to any one of the preceding claims.
6. An injector (10) comprising the nozzle assembly (12) according to claim 5.

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