WO2018054744A1

WO2018054744A1 - Shaping method and injector valve

Info

Publication number: WO2018054744A1
Application number: PCT/EP2017/073068
Authority: WO
Inventors: Jean-Luc BEDUNEAU; David Bonneau; Matthieu LACOTTE; Frédéric JAULT
Original assignee: Delphi Technologies Ip Limited
Priority date: 2016-09-20
Filing date: 2017-09-13
Publication date: 2018-03-29
Also published as: FR3056259B1; FR3056259A1

Abstract

Method (100) for shaping an injector valve (31), the valve (31) comprising a seat (34) and a shut-off member (35) designed to slide in a bore (26). The seat (34) defines a conical female face (50) and the shut-off member (35) defines a male conical face (28). The shaping method (100) comprises the following steps: a/providing (110) the nozzle body (16) in which the female face (50) of the seat (34) is roughed out, b/providing (120) the needle (14) in which the male face (28) of the needle is roughed out, d/inserting (140) the needle (14) in the bore (32) of the nozzle body, characterized in that the shaping method (100) additionally comprises a step: e/shaping (150) and finishing the conical faces (28, 50) of the seat and of the needle by simultaneously shaping them by application of an axial force (F) to the needle (14).

Description

SHAPING METHOD AND INJECTOR VALVE

TECHNICAL AREA

The invention relates to a fuel injector provided with a device for reinforcing the seat of the needle of the injector.

BACKGROUND OF THE INVENTION

A fuel injector conventionally comprises a needle controlled opening and closing depending on the pressure 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 provided with a nozzle seat provided on an inner surface of the bore of the nozzle body, in order to control the supply of fuel through injection holes located through the wall of the nozzle body. The fuel is at high pressure and flows into the injector from the inlet channel to the injection holes. The pressure exerted on the nozzle seat creates deformations that generate variations in fuel pressure distribution in the injection holes and furthermore 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 that overcomes these disadvantages.

SUMMARY OF THE INVENTION

The present invention proposes to solve these problems by a method of shaping a valve of an injector. The valve comprises a seat formed in a nozzle body of the injector which extends along an axis and a shutter formed at one end of a needle extending axially adapted to slide in a bore of the body of nozzle. The seat defines a conical female face and the shutter defining a complementary male conical face. The conformation process comprises the following steps:

a / provide the nozzle body in which the female face of the seat is roughed,

b / provide the needle in which the needle face is rough, d / insert the needle into the bore of the nozzle body so that the conical face maie is in contact with the conical female face, characterized in that the conformation process further comprises a step:

e / shaping and finishing the conical faces of the seat and the needle by conforming them simultaneously by applying an axial force on the needle.

In addition, the conformation method in which the applied force of the shaping step is between 600 N and 1000 N, preferably of the order of 800 N. Moreover, the shaping step applies. directly on the injector valve and the shaping step precedes the final assembly of the injector. Thus the force can be applied by a machine directly on the needle. In another embodiment, the shaping step is applied directly to the complete injector at the end of assembly so that the seat on which the needle is based is shaped by the hydraulic force produced by a fluid in a control room. In addition, the shaping step is carried out by the hydraulic force of a value of between 700 and 900 bars, preferably of the order of 800 bars.

In an alternative to the two embodiments, the shaping method further comprises a heating step of the seat area performed simultaneously with the shaping step. Heating the nozzle body mainly applying around the seat of the nozzle body. In addition, the temperature of the heating is of the order of 300 ° C. In addition, the heating can be performed by induction. In addition the conformation achieved by the shaping step applies to 99% on the seat. An injector valve comprises a seat and a shutter shaped as previously described. In addition the seat comprises two faces forming between them an angle less than 180 degrees. In addition, a nozzle assembly includes the injector valve described above. In addition, an injector includes the nozzle assembly described above.

BRIEF DESCRIPTION OF THE DRAWINGS

Other features, 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:

FIG. 1 is a general perspective view of an injector

FIG. 2 is a sectional view of a nozzle assembly FIG. 3 represents in logic diagram form the steps of the method which is the subject of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

To facilitate and clarify the description that follows, the top-down orientation is chosen arbitrarily and, words and phrases such as "above, below, above, below, up, down ..." can be used without any intention to limit the invention.

According to Figure 1, there is described an embodiment of the invention relating to a fuel injector 10, here a diesel injector although the invention is fully transferable to a gas 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 FIG. 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 comprising a needle valve element 14 or

commonly called needle 14 arranged in a nozzle body 16, a control valve assembly 18 arranged in a valve body 20, an actuator 22 arranged in an actuator body 24 and a nut 25. The needle 14 is arranged axially sliding in a longitudinally cylindrical bore 26 of the nozzle body.

According to Figure 2 is shown the nozzle assembly 12 further comprising an injector valve 31. The valve 31 comprises a seat 34 formed in a nozzle body 16 of the injector which extends along the axis X and a shutter 35 formed at a first end 30 of the axially extending needle adapted to slide in the bore 26 of the nozzle body. The seat 34 defines a conical female face 50 and the shutter 35 defines a complementary male conical face 28, the needle 14 comprises a longitudinal cylindrical portion 27 and the conical male face 28. The conical face 28 is arranged at a first end 30. The nozzle body 16 comprises a barrel 32, the nozzle seat 34 and a bag 36 provided with injection holes 38. The nozzle body 16 is provided with a longitudinal cylindrical inner wall 40 and an outer wall 42 cylindrical longitudinally extending along the axis X. The bore 26 is cylindrical and extends along the longitudinal axis X open at the first end 44 and having a second end 46 which is in contact with the conical seat 34. The bag 36 is arranged at the top of the conical seat 34. The seat 34 conical comprises a conical face 50 female.

The nozzle seat 34 is rough machined, for example by

rectifying the conical female face 50. The conical female face 50 has a slope 70 between the bore 26 and the bag 36. In order to improve the resistance of the seat 34 to the deformation caused by the repeated contacts of the needle 14, the nozzle seat 34 is made by a shaping process 100 which will be described in the following. The conformation process 100, also called the shaping process 100, is part of the manufacturing process of the injector 10. The steps of the shaping method 100 comprise the following steps:

- a / provide 110 the nozzle body 16 in which the female face 50 of the seat 34 is rough rough and machining the seat 34 of the nozzle body,

b) supplying the needle 14 and machining the rough machined face 28 of the needle 14,

and coupling the needle 14 with the bore 26 of the nozzle body and adjusting the stroke of the needle 14,

inserting the needle 14 into the bore 26 of the nozzle body,

and to shape the conical faces 28, 50 of the seat and the needle.

- f / assemble 160 the injector 10.

The shaping step 150 consists in simultaneously conforming the conical female face 50 of the seat and the conical male face 28 of the needle, the two faces 28,50 being in contact and touching each other. The shaping step 150 is performed by simultaneously shaping the faces 28,50 by applying an axial force F to the needle 14 being in contact with the seat 34 of the nozzle. The complete assembly step 160 of the injector 10 consists in assembling together the actuator 22, the valve assembly 18 and the injector valve 31 by means of the nut 25. As described in FIG. 1, the nut 25 is screwed on the actuator body 24.

The step of shaping the seat 34 as described in FIGS. 2 and 3 is carried out by shaping, that is to say, by giving a shape to the female face 50 of the seat. The shape given to the female face 50 is a shape complementary to the conical face 28 and the male face 28 then has a clipped profile of its roughness peaks. The male face 28 of the needle is shaped by the application of an axial force F directed downwards on the needle 14, the needle 14 being in contact with the female face 50 of the seat. The needle 14 is made of a material harder than the nozzle body 16, which explains why the shape given to the female face 50 by the conformation is given by the shape of the male face 28. The material of the male face 28 the needle may be for example high speed steel while the female face 58 of the nozzle body seat may be 18CrNi8-8 type steel.

The conformation of the two faces 28, 50 that is to say the obtaining of the two complementary faces 28,50 allows to have better contact and better sealing of the needle 14 on the seat 34 because the profiles of both faces 28.50 are stackable. The force F is greater than 1000 N.

In an alternative to this embodiment, the shaping step 150 is carried out simultaneously by applying the axial force F directed downwards on the needle 14 in contact with the female face 50 and a step of applying a heating 170 by induction of a temperature of the order of 300 ° C. The induction heating may for example be located around the seat 34 for a time between 10 seconds and 60 seconds. The axial mechanical force F is between 600 N and 1000 N, preferably 800 Newtons. The axial force F thus conforms to the female face 50 by the direct contact of the male face 28 on the female face 50.

In another embodiment, the conformation process 100 is done on the assembled injector 10, that is to say at the end of the assembly of the injector 10 complete, that is to say with the valve of the injector 31 as described

previously, the actuator 22 and the valve assembly 18 fixed together by the nut 25. The axial force F is achieved by the application of a hydraulic pressure produced by a fluid in a control chamber 56 between 700 and 900 bar, preferably of the order of 800 bar on the needle 14, the fluid flowing between an inlet of the injector (not shown) and the injection holes 38.

In an alternative to the embodiment applied to the assembled injector 10, the shaping step 150 is carried out simultaneously. applying the axial force F directed downwards on the needle 14 in contact with the female face 50 and a step of applying a heating 170 by induction of a temperature of the order of 300 ° C. The axial force F is achieved by the application of a hydraulic pressure produced by a fluid in the control chamber 56 of between 700 and 900 bar, preferably of the order of 800 bar on the needle 14, the circulating fluid between an inlet of the injector (not shown) and the injection holes 38. The induction heating may for example be located around the seat 34 for a time between 10 seconds and 60 seconds. The axial mechanical force F is between 600 N and 1000 N, preferably 800 Newtons. The axial force F thus conforms to the female face 50 by the direct contact of the male face 28 on the female face 50.

In both embodiments, the profiles of the two male and female faces 28, 50 complementary and shaped by the conformation process 100 eliminate the early drift of the flow injected by the injector into the combustion chamber of an engine as a function of the pressure of the fluid and the length of the control valve of the injection. The conformation process 100 makes it possible to blunt the roughness peaks and to obtain complementary surfaces for both the female 28 and female 50 faces. The straightness of the seat 34 obtained with the conformation process 100 is less than the straightness of the front seat. the shaping step 150 which is of the order of 0.5. Moreover, after the step of shaping the female face 50 comprises two faces 66, 68 inclined differently with respect to the slope 70. The two faces 66, 68 define between them an angle B, less than 180 degrees as described. in Figure 2, for example 179 degrees. As described in FIG. 2, the change of slope between the faces 66, 68 is made at a point A created during the shaping step. According to FIG. 2, the point A is a radial zone of contact between the female face 50 and the point A '. The point A 'is a radial zone located at the intersection of a lower end of the cylindrical portion 27 and the conical male face 28. The point A' is inscribed in a circle of diameter D14 of the needle 14. The first face 66 is arranged proximal to the bore 26 while the second face 68 is arranged proximal to the bag 36.

The angle B is also called double angle.

In another alternative (not shown) to both embodiments, the needle 14 may have at least two faces with two different slopes on the maie face 28 before the shaping step 150 which creates after the shaping step 150 two points of contact on the female face 50.

In this chapter we will describe the operation of the injector 10. As described in Figure 1, when the actuator 22 is electrically powered, 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 enclosed 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 lower end of the needle 14 moves away from the seat 34 of the body nozzle. As a result, a second upper end 58 of the needle contacts a lower face 60 of the valve body.

When the actuator 22 is not powered, the magnetic armature assembly 52 and control rod 54 is pushed by a valve spring 62 to a position that prevents the fuel from flowing to the channel

exhaust 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 pushed down by a needle spring 64 and the first lower end of the needle is in contact with the nozzle seat 34 and the second end. 58 upper of the needle is remote from the lower face 60 of the valve body.

LIST OF REFERENCES USED

10 injector

12 nozzle assembly

14 needle

16 nozzle body

18 valve assembly

20 valve bodies

22 actuator

24 actuator body

25 nut

26 bore nozzle body

27 cylindrical part of the needle 8 face maie of needle

0 first end of needle 1 injector valve

2 barrels

4 nozzle seat

5 shutter

6 bag

8 injection holes

0 Nozzle body inner wall 2 Nozzle body outer wall 4 Nozzle body end 6 Nozzle body end 0 Conical female seat side 2 Armature

4 valve stem

6 control room

8 second end of the needle 0 underside of the valve body 2 valve spring

4 needle spring

6 first face of the seat

8 second face of the seat

0 seat slope before conformation 0 conformation process

10 provide the nozzle body

0 fill the needle

0 Match the needle and the bore 0 Insert the needle into the bore 0 Shape the faces

0 assemble the injector

X longitudinal axis

F Axial force

At point of change of slope

Α 'point of the needle

14 diameter of the needle

Claims

A method of forming (100) an injector valve (31), the valve (31) comprising:

a seat (34) formed in a nozzle body (16) of the injector which extends along an axis (X) and,

a shutter (35) formed at one end of an axially extending needle (14) adapted to slide in a bore (26) of the nozzle body, the seat (34) defining a conical female face (50) and shutter (35) defining a complementary conical male face (28),

the conformation process (100) comprising the following steps:

a / providing (110) the nozzle body (16) in which the female face (50) of the seat (34) is roughed,

b / providing (120) the needle (14) in which the male face (28) of the needle is roughed,

d) inserting (140) the needle (14) into the bore (32) of the nozzle body so that the conical male face (28) is in contact with the conical female face (50),

characterized in that the conformation process (100) further comprises a step:

e / shaping (150) and finishing the conical faces (28,50) by conforming them simultaneously by applying an axial force (F) to the needle (14).

2. conformation process (100) according to claim 1, wherein the applied force (F) of the shaping step (e) is between 600 N and 1000 N, preferably of the order of 800 N .

3. conformation process (100) according to any one of claims 1 or 2, wherein the shaping step (e) applies directly to the injector valve (31), the step (e) ) preceding the final assembly of the injector (10), the force (F) being applied by a machine directly to the needle (14).

4. conformation process (100) according to any one of claims 1 to 2, wherein the shaping step (e) is applied directly to the injector (10) complete assembly end, the seat (34) on which the needle (14) is supported is shaped by the hydraulic force (F) produced by a fluid in a control chamber (56).

5. Shaping process (100) according to claim 4, wherein the shaping step (e) is carried out by the hydraulic force (F) of a value of between 700 and 900 bar, preferably of order of 800 bars.

6. conformation process (100) according to any one of the preceding claims, further comprises a step (g) of heating (170) of the seat area (34) performed simultaneously with step (e) of implementation form, the heating applying mainly around the seat (34) of the nozzle body.

The shaping method (100) of claim 6, wherein the temperature of the heating is of the order of 300 ° C.

8. The method of conformation (100) according to any one of claims 6 to 7, wherein the heating is performed by induction.

The method of conformation (100) according to claim 8, wherein the conformation achieved by the shaping step (e) (150) is 99% applied to the seat (34).

An injector valve (31) comprising a seat (34) and a shutter (35) shaped according to any one of the preceding claims.

Injector valve (31) according to claim 10, wherein the seat comprises two faces (66,68) forming between them an angle less than 180 degrees.

A nozzle assembly (12) comprising the injector valve (31) according to claim 10. Injector (10) comprising the nozzle assembly (12) according to the claim