RING ADAPTER FOR INJECTOR AND ASSOCIATED MANUFACTURING METHOD

Abstract

Annular adapter (20) for positioning an injector in the cylinder head of an engine cylinder, the adapter (20) having a body (21) comprising an inner wall (25) and an outer wall (24), the inner wall (25) having a plurality of projections (32) for contacting the injector, the adapter (20) being obtained by cold forming. Figure 3

Description

Title of the invention: RING ADAPTER FOR INJECTOR AND ASSOCIATED MANUFACTURING METHOD technical field

[0001] This disclosure relates to an annular adapter for disposing of an injector in a cylinder head of an engine, and an associated manufacturing method. Previous technique

[0002] An engine, in particular a gasoline direct-injection or GDI engine, comprises a plurality of hollow cylinders delimiting a combustion chamber in which combustion of a fuel-air mixture occurs.

[0003] Fuel arrives in the cylinder from a fuel pump. In particular, the fuel pump is connected to an injection rail which receives the fuel and distributes it to a plurality of injectors, each injector being located in the cylinder head of a respective cylinder. A portion of one end of the injector penetrates the combustion chamber, thus introducing fuel into each cylinder.

[0004] The injector is housed in an intake manifold within the cylinder head. A gap exists between a side wall of the injector and a wall of the intake manifold, creating play between the injector and the cylinder head. This play, which is particularly large when the fuel rail is fixed to the injector, can damage the injector and / or the cylinder head, or even displace the injector from its position in the intake manifold.

[0005] In order to limit the play between the injector and the cylinder head, it is known to have a adapter around the side wall of the injector. The adapter can be, for example, a ring allowing a degree of freedom of the injector when installed in the cylinder head, while keeping the portion of the injector tip in the combustion chamber.

[0006] In order to hold the adapter in position on the injector, the adapter may include a plurality of wings that fit into a notch in the injector. However, such wings may exhibit low resistance to the mechanical stresses induced when the injector is operational, that is, when fuel flows through the injector while the engine is running.

[0007] Alternatively, the adapter can be held in position on the injector by means of a surface projecting around the entire circumference of an inner face of the ring and fitting into the notch of the injector. In a variant, the adapter may include an adapter piece and a piece to hold the adapter piece in position. However, in these configurations, the manufacturing cost of the adapter increases.

[0008] One object of the present invention is to provide an adapter for mounting the injector in the cylinder head, the adapter having sufficient resistance to the mechanical stresses to which the adapter is subjected. Such stresses may, for example, be between 700 N and 1100 N when the injector is not operational, that is, when fuel is not passing through the injector.

[0009] When the injector is operational, the mechanical stresses to which the adapter is subjected can, for example, be between 1200 N and 3500 N due to the pressure exerted by the fuel passing through the injector.

[0010] Another object of the present invention is to provide such an adapter having a low manufacturing cost. Summary

[0011] For this purpose, an annular adapter is proposed for disposing of an injector in a cylinder head of an engine cylinder, the adapter having a body comprising an inner wall and an outer wall, the inner wall having a plurality of projections intended to come into contact with the injector, the adapter being obtained by cold forming.

[0012] Cold forming provides the adapter with sufficient strength to withstand the mechanical stresses to which it is subjected when the injector is located in the cylinder head. In particular, the adapter's strength is sufficient to withstand the mechanical stresses to which it is subjected when fuel passes through the injector.

[0013] Moreover, cold forming makes it possible to limit material losses and increase production volumes, which reduces the manufacturing cost of the adapter.

[0014] According to another aspect, the adapter is obtained by cold forging.

[0015] According to another aspect, the plurality of projections extends substantially perpendicularly to the inner wall.

[0016] According to another aspect, the inner wall comprises between four and six projections.

[0017] According to another aspect, the inner wall comprises five projections.

[0018] According to another aspect, the plurality of projections is made in one piece with the wall internal.

[0019] According to another aspect, the adapter is made of metallic material, preferably stainless steel.

[0020] According to another aspect, the diameter of the external wall is between 10 mm and 20 mm, preferably between 13 mm and 16 mm.

[0021] According to another aspect, the body has an annular shape.

[0022] According to another aspect, a method for manufacturing an adapter for placing an injector in a cylinder head of an engine cylinder is proposed, the method comprising: - to form a body of the adapter by cold forming, the body comprising an inner wall and an outer wall; - to form a plurality of protrusions by cold forming on the internal wall of the body, the protrusions being intended to come into contact with the injector.

[0023] According to another aspect, cold forming includes cold striking.

[0024] According to another aspect, the process further comprises applying an anneal to the adapter after body formation and plurality of projections. Brief description of the drawings

[0025] Other features, details and advantages will become apparent from reading the detailed description below and from analyzing the accompanying drawings, in which: Fig. 1

[0026] [Fig.1] shows a front view of an example of an assembly formed by an injector inserted into a cylinder head of an engine cylinder and connected to an injection rail. Fig. 2

[0027] [Fig.2] shows a front view of the assembly example of [Fig.1] in which the injector is surrounded by an adapter according to an embodiment of the present invention for arranging the injector in the cylinder head according to the present invention. Fig. 3

[0028] [Fig.3] shows a schematic perspective view from below of the adapter of [Fig.2], Fig. 4

[0029] [Fig.4] shows a schematic top perspective view of the adapter of [Fig.3]. Fig. 5

[0030] [Fig.5] shows a schematic longitudinal sectional view of the adapter of [Fig.3]. Description of the implementation methods

[0031] Figures 1 and 2 show an injector 10 installed in a cylinder head 11 of a cylinder 12 of an engine (not shown), such as, for example, a gasoline direct-injection or GDI (gasoline direct-injection) engine. In particular, a first end 13 of the injector 10 is disposed in an intake manifold 14 included in the cylinder head 11.

[0032] An injection rail 15 is connected to the injector 10. The rail 15 is for example fixed on a second end 16 of the injector 10 opposite the first end 13.

[0033] The rail 15 supplies fuel to the injector 10, which is then ejected by the injector 10 into the cylinder 12.

[0034] The inlet pipe 14 includes a housing 17 delimited by a wall 18. As can be seen in Figures 1 and 2, the housing 17 has a shape substantially complementary to a shape of the first end 13 of the injector 10, so as to be able to install the first end 13 of the injector 10 in the intake manifold 14. Advantageously, a portion 34 of the first end 13 protrudes inside the cylinder 12.

[0035] A space 19 exists between the injector 10 and the wall 18 of the intake manifold 14, which creates a gap between the injector 10 and the cylinder head 11.

[0036] As seen in [Fig.2], in order to limit the play between the injector 10 and the cylinder head 11, an adapter 20 is installed around the injector 10.

[0037] Adapter 20 will now be described with reference to Figures 3 to 5.

[0038] The adapter 20 is, for example, annular. The adapter 20 comprises a body 21 comprising an upper wall 22, a lower wall 23, an outer wall 24 and an inner wall 25. As can be seen particularly from figures 3 and 4, the body 21 has a substantially annular cross-section, but any other cross-section is possible.

[0039] A passage 26 delimited by the inner wall 25 passes through the body 21 between the upper wall 22 and the lower wall 23 in a longitudinal direction LL. The passage 26 is shaped to receive the injector 10. The passage 26 has, for example, a substantially cylindrical shape, without this being limiting.

[0040] As can be seen in figures 4 and 5, the upper wall 22 includes a rim 27 and a bearing surface 28.

[0041] The bearing surface 28 extends substantially transversely to the longitudinal direction L1 between the rim 27 and the inner wall 25 of the adapter 20. A bend 29, visible on [Fig.5], is formed between the inner wall 25 and the bearing surface 28.

[0042] As clearly shown in [Fig. 5], the bearing surface 28 is substantially inclined. In particular, the bearing surface 28 gradually sinks in along the longitudinal direction L1 from the elbow 29 to the rim 27.

[0043] The rim 27 extends along the direction L1 from the outer wall 24 and protrudes from the bearing surface 28 in the longitudinal direction LL. The bearing surface 28 thus forms a recessed surface.

[0044] Advantageously, the injector 10 rests on the upper wall 22, in particular on the bearing surface 28, when it is received in the passage 26. The elbow 29 has a function of ball joint allowing angular movement of the injector 10 relative to the adapter 20 when installed in the passage 26.

[0045] The lower wall 23, visible in [Fig.3], comprises a main surface 30 and a recessed area 31 which are substantially perpendicular to the longitudinal direction Ll.

[0046] The main surface 30 extends between the outer wall 24 and the recessed zone 31. The recessed zone 31 extends between the main surface 30 and the inner wall 25.

[0047] The lower wall 23 is intended to come into contact with a support area 35 (visible in [Fig.1]) of the housing 17 when the adapter 20 and the injector are arranged in the cylinder head 11. The contact between the lower wall 23 and the support area 35 helps to keep the portion 34 of the injector 10 inside the cylinder 12.

[0048] The outer wall 24 is intended to face the wall 18 of the housing 17. Advantageously, the outer wall 24 and the wall 18 are substantially spaced apart, which allows a degree of freedom of the injector 10 when it is installed in the cylinder head 11.

[0049] In Figures 3 and 4, the outer wall 24 has a substantially cylindrical shape, although this is not a limiting factor. A diameter DI of the outer wall 24 is, for example, between 10 mm and 20 mm, preferably between 13 mm and 16 mm.

[0050] The inner wall 25 has a plurality of projections 32. The plurality of projections 32 comprises, for example, between four and six projections 32, preferably five projections 32. Of course, any other number of projections 32 is possible. The projections 32 are, for example, regularly distributed on the inner wall 25, but any other distribution is possible.

[0051] Each projection 32 extends substantially perpendicularly to the inner wall 25 so as to penetrate the passage 26. Thus, each projection 32 is intended to come into contact with the injector 10 when it is installed in the passage 26.

[0052] In figures 3 and 5, each projection 32 is at the same height along the longitudinal direction L1 as the recessed zone 31, but any other position of the projection 32 on the internal wall 25 is conceivable.

[0053] A hollow portion 33 extends along the longitudinal direction Ll between each projection 32 and the upper wall 22. Each hollow portion 33 has, for example, a width substantially equal to a width of the respective projection 32.

[0054] Advantageously, the plurality of projections 32 is made in one piece with the internal wall 25 as will be explained below.

[0055] Advantageously, the adapter 20 is made of metallic material, preferably stainless steel.

[0056] The plurality of projections 32 allows the adapter 20 to be kept in position relative to the injector 10. Thus, the injector 10 fitted with the adapter 20 can be transported while limiting the risks of detachment of the adapter 20.

[0057] Each projection 32 can be subjected to a stress of between 50 N and 500 N during the installation of the injector 10 in the passage 26, and once it is disposed in said passage 26.

[0058] It should be noted that since each projection 32 is substantially perpendicular to the inner wall 25, deformations of the projections 32 during the installation of the injector 10 in the passage 26, and once it is positioned in said passage 26, are limited. The risk of breakage of the projections 32 is thus reduced.

[0059] It should be noted that the adapter 20 is obtained by cold forming, which improves its mechanical properties. In particular, the adapter 20 is capable of withstanding stresses greater than or equal to 3500 N without undergoing deformation, thus preventing damage to the adapter 20 when the engine is running and, consequently, the injector 10 is operational. Indeed, as indicated above, when the injector is operational, the stress to which the adapter 20 is subjected can be between 1200 N and 3500 N.

[0060] Cold forming also makes it easy to adapt the dimensional characteristics of the adapter 20 to each injector 10 and each cylinder head 11. Cold forming makes it possible, for example, to manufacture adapters 20 having a smaller diameter DI than the known adapters of the prior art, so that the lower wall 23 can come into contact with the bearing area 35.

[0061] Since cold forming allows the adapter 20 to be obtained by material displacement, it is also possible to reduce material losses compared to processes that obtain the adapter by material removal. Consequently, the manufacturing cost of the adapter 20 is reduced.

[0062] Now a manufacturing process for adapter 20 will be described.

[0063] The method comprises forming the body 21 of the adapter 20 by forming at cold. The body 21 is in particular formed by applying cold forming to a wire (not shown) made of the same material as the adapter 20.

[0064] The wire extends along a longitudinal direction and has, for example, a substantially circular cross-section having a diameter smaller than the diameter of the outer wall 24 of the body 21 as defined above. The cross-section of the wire has, for example, a diameter between 7 mm and 10 mm.

[0065] Cold forming includes, for example, cold forging. Cold forging allows the wire to be deformed by displacing material from one or more forces applied to the wire. The upper wall 22, lower wall 23, outer wall 24 and inner wall 25 as described above are thus formed.

[0066] As previously indicated, the section of the body 21 formed is, for example, substantially annular.

[0067] According to a non-limiting embodiment of the method for manufacturing the adapter 20, the cold-forging of the body 21 comprises applying a force along the longitudinal direction of the wire to a portion of the wire's cross-section. This force causes a displacement of material along the longitudinal direction of the wire, so as to create a cavity running longitudinally through the wire. The cold-forging of the body may then comprise applying a force to the cavity in a direction substantially transverse to the longitudinal direction of the wire, so as to enlarge the cavity and form the passage 26. The cold-forging of the body 21 may also comprise crushing the wire along its longitudinal direction in order to flatten it.

[0068] The method further comprises the formation of the plurality of the projections 32 by cold forming on the inner wall 25. In particular, each projection 32 is formed by cold stamping applied to the inner wall 25, so that each projection 32 is formed in one piece with the inner wall 25.

[0069] Each projection 32 is for example formed by applying a force causing a displacement of material from the inner wall 25. The hollow portion 33 associated with each projection 32 is thus formed.

[0070] As previously stated, the projections 32 formed extend substantially perpendicularly to the internal wall 25 and are, for example, four to six in number, preferably five.

[0071] Once the body 21 and the plurality of projections 32 have been formed, the process may further include applying annealing to the adapter 20. Annealing allows for a relaxation of the internal stresses generated by cold forging.

[0072] In addition to the advantages of cold forming indicated above, cold forming makes it possible to increase the manufacturing volumes of adapters 20, which contributes to reducing the manufacturing cost of each adapter 20.

[0073] The embodiments described above are a simple illustration of the present invention. Various modifications may be made to them without departing from the scope of the invention as set forth in the appended claims.

Claims

Demands

1. Annular adapter (20) for disposing of an injector (10) in a cylinder head (11) of an engine cylinder (12), the adapter (20) having a body (21) comprising an upper wall (22), a lower wall (23), an inner wall (25) and an outer wall (24), the inner wall (25) having a plurality of projections (32) intended to come into contact with the injector (10), the adapter (20) being obtained by deforming a wire by cold forging, so that the plurality of projections (32) extend substantially perpendicularly to the inner wall (25).

2. Adapter (20) according to claim 1, wherein the inner wall (25) comprises between four and six projections (32).

3. Adapter (20) according to any one of the preceding claims, wherein the plurality of projections (32) is made in one piece with the inner wall (25), a hollow portion (33) extends, along the longitudinal direction (L1) of the passage defined by the inner wall, between each projection (32) and the upper wall (22), each hollow portion (33) having a width substantially equal to a width of the respective projection (32).

4. Adapter (20) according to any one of the preceding claims, the adapter (20) being made of metallic material, preferably stainless steel.

5. Adapter (20) according to any one of the preceding claims, wherein a diameter (Dl) of the outer wall (24) is between 10 mm and 20 mm, preferably between 13 mm and 16 mm.

6. Adapter (20) according to any one of the preceding claims, wherein the upper wall (22) comprises a rim (27) and a bearing surface (28), the bearing surface (28) extending substantially transversely in a longitudinal direction (L1) of the passage defined by the inner wall, between the rim (27) and the inner wall (25), a bend (29) being formed between the inner wall (25) and the bearing surface (28).

7. A method for manufacturing an adapter (20) for disposing of an injector (10) in a cylinder head (11) of an engine cylinder (12), the method comprising: - forming a body (21) of the adapter (20) by cold forming from a wire, the cold forming comprising cold forging, the body (21) comprising an upper wall (22), a lower wall (23), an inner wall (25) and an outer wall (24); - forming a plurality of projections (32) by cold forming on the inner wall (25) of the body (21), so that the plurality of projections (32) extend substantially perpendicularly to the inner wall, the projections (32) being intended to come into contact with the injector (10).

8. A manufacturing method according to claim 7, wherein the cold forging process comprises: applying a force along the longitudinal direction (L1) of the wire on a portion of the cross-section of the wire, so as to form an annular body with a passage cavity; forming a plurality of protrusions on the inner wall, so that each protrusion (32) is formed as a single unit with the inner wall (25), the displacement of material forming hollow portions (33).

9. A manufacturing method according to claim 8, wherein the cold forging forming further comprises applying a force to the cavity in a direction substantially transverse to the longitudinal direction of the wire (Ll), so as to enlarge the cavity.

10. A manufacturing method according to claim 8 or 9, wherein the cold forging further comprises crushing the wire along its longitudinal direction in order to flatten it.

11. A manufacturing method according to claim 7, 8, 9 or 10, further comprising applying an anneal to the adapter (20) after forming the body (21) and the plurality of projections (32).

12. Injector (10) comprising an adapter (20) according to any one of claims 1 to 6, installed around the injector.

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