SPARK PLUG AND METHOD FOR PRODUCING A SPARK PLUG

Abstract

Spark plug for igniting a combustible fuel in an internal combustion engine, wherein the spark plug has an igniter arranged at an end of the spark plug facing the combustion chamber, when the spark plug is mounted in the internal combustion engine. The spark plug includes a wall and a sealing area. The wall at least partially surrounds the igniter. The sealing area is used for sealing the combustion chamber against the environment. The wall has the sealing area located at an end of the wall, which end faces the combustion chamber when the spark plug is mounted in the internal combustion engine.

Claims

1. An apparatus, comprising: a spark plug configured to ignite a combustible fuel in an internal combustion engine, wherein the spark plug comprises: an igniter arranged at an end of the spark plug and configured to face the combustion chamber, when the spark plug is mounted in the internal combustion engine, wherein the igniter comprises at least one middle electrode and at least one ground electrode, wherein the igniter comprises a spark gap between the at least one middle electrode and the least one ground electrode, wherein the at least one ground electrode is arranged on a ground electrode carrier, a wall at least partially surrounding the igniter, and a sealing area configured to seal the combustion chamber against the environment, wherein the wall comprises the sealing area located at an end of the wall, which end faces the combustion chamber when the spark plug is mounted in the internal combustion engine, wherein the sealing area comprises a chamfer, and the sealing area comprising the chamfer extends at least partially onto the ground electrode carrier.

2. The apparatus of claim 1, comprising a cylinder head having the spark plug.

3. The apparatus of claim 1, wherein the sealing area is a terminal portion of the wall, wherein the terminal portion is configured to face the combustion chamber when the spark plug is mounted in the internal combustion engine.

4. The apparatus of claim 1, comprising the internal combustion engine having the spark plug.

5. The apparatus of claim 1, wherein an upper end of the spark plug comprises an electrical connection configured to connect the spark plug with an electrical power supply.

6. The apparatus of claim 1, wherein the at least one ground electrode is connected to the ground electrode carrier by a weldseam.

7. The apparatus of claim 1, wherein the sealing area comprising the chamfer extends at least partially onto the at least one ground electrode.

8. The apparatus of claim 1, wherein the sealing area comprising the chamfer is at an angle (α) between 20° and 50° with respect to a perpendicular (y) of a center axis (x) of the spark plug.

9. The apparatus of claim 1, wherein the wall comprises a mounting portion configured to mount the spark plug in the internal combustion engine and/or in a cylinder head and/or in a spark plug sleeve.

10. The apparatus of claim 9, wherein the mounting portion comprises at least a partial external thread.

11. The apparatus of claim 1, wherein at least one middle electrode is connected at a centrally arranged middle electrode carrier via a weldseam.

12. The apparatus of claim 1, wherein an isolator is arranged between the middle electrode carrier and the ground electrode carrier.

13. The apparatus of claim 1, wherein the at least one ground electrode comprises a ring electrode, wherein the at least one middle electrode comprises a circular shaped electrode, wherein an annular spark gap is formed between the at least one ground electrode and the at least one middle electrode.

14. The apparatus of claim 1, comprising a pre-load device configured to pre-load the sealing area against a surface of a cylinder head or a spark plug sleeve.

15. The apparatus of claim 14, wherein the pre-load device comprises a mounting portion of the spark plug having an external thread.

16. The apparatus of claim 1, comprising a spark plug sleeve configured to receive the spark plug, wherein the spark plug sleeve comprises a screw portion having an internal thread and a sealing portion, wherein the sealing portion comprises a further chamfer of the spark plug sleeve, which forms a counterpart to the chamfer of the spark plug.

17. The apparatus of claim 8, wherein the angle (α) is between 27° and 41°.

18. A method for producing a spark plug, wherein providing an igniter at an end of the spark plug configured to face a combustion chamber when the spark plug is mounted in an internal combustion engine, wherein the igniter comprises at least one middle electrode and at least one ground electrode, wherein the igniter comprises a spark gap between the at least one middle electrode and the least one ground electrode, wherein the at least one ground electrode is arranged on a ground electrode carrier, providing a wall of the spark plug at least partially surrounding the igniter, and providing a sealing area of the spark plug configured to seal the combustion chamber against the environment, wherein the sealing area comprises a chamfer at an end of the wall facing the combustion chamber when the spark plug is mounted in the internal combustion engine, wherein the sealing area (4) comprising the chamfer extends at least partially onto the ground electrode carrier.

19. The method of claim 18, comprising a weldseam coupling together the at least one ground electrode and the ground electrode carrier, wherein a groove for the weldseam is manufactured in a depth, such that at least one part of the weldseam acts as a connection between the ground electrode carrier and a spark plug body of the spark plug, after manufacturing of the chamfer.

20. A system, comprising: at least part of an internal combustion engine having a spark plug receptacle; and a spark plug disposed in the spark plug receptacle, wherein the spark plug comprises: an igniter having a spark gap between at least one middle electrode and at least one ground electrode arranged on a ground electrode carrier; a wall at least partially surrounding the igniter; and a sealing area on the wall, wherein the sealing area comprises a chamfer extending at least partially onto the ground electrode carrier.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Further details and advantages of the invention are apparent from the accompanying figures and the following description of the drawings. The figures show:

[0039] FIG. 1a illustrates an first embodiment of a spark plug according to the invention,

[0040] FIG. 1b illustrates an isometric view of an embodiment similar to FIG. 1a,

[0041] FIGS. 2a, 2b illustrate third and fourth embodiments of a spark plug according to the invention,

[0042] FIG. 3 illustrates a spark plug sleeve for receiving a spark plug according to the invention,

[0043] FIG. 4 illustrates a spark plug mounted in the spark plug sleeve and

[0044] FIG. 5 illustrates a further embodiment of a spark plug.

DETAILED DESCRIPTION

[0045] FIG. 1a shows a first embodiment of a spark plug 1 according to the invention, wherein an end of the spark plug 1 facing the combustion chamber, when the spark plug 1 is mounted in the internal combustion engine, is shown in more detail.

[0046] The spark plug 1 comprises an igniter or ignition means 2 having a middle electrode 6 and a ground electrode 7, wherein there is a spark gap 8 between the middle electrode 6 and the ground electrode 7.

[0047] The ground electrode 7 is arranged on the ground electrode carrier 9. In this specific embodiment the wall 3, which surrounds the ignition means 4, is formed as part of the spark plug body.

[0048] The spark plug body (e.g., wall 3) surrounds the ground electrode carrier 9, and the at least one ground electrode 7 is connected to the ground electrode carrier 9, e.g., by laser beam welding.

[0049] A weldseam 10 may be part of a chamfer 5. In such embodiments, the weldseam 10 may be deep enough, so that the ground electrode carrier 9 is appropriately fixed by the weldseam 10.

[0050] The manufacturing process can comprise a step, in which a groove for a weldseam 10 is manufactured, in a depth, such that at least one part of the weldseam 10 acts as a connection between the ground electrode carrier 9 and the spark plug body (e.g., wall 3), even after the manufacturing of the chamfer 5.

[0051] The middle electrode 6 is also connected to the middle electrode carrier 13 by laser beam welding.

[0052] Between the middle electrode carrier 13 and the ground electrode carrier 9, an isolator 14 is arranged.

[0053] For sealing the combustion chamber against the environment, the spark plug 1 comprises a sealing area 4, which is designed as the chamfer 5. This chamfer 5 is placed at the wall 3 (which is formed by the spark plug body in this embodiment). How the chamfer 5 acts as a sealing in area is described in connection with FIG. 3 below.

[0054] The spark plug body (e.g., wall 3) further comprises a mounting portion 11, for mounting the spark plug 1 in an internal combustion engine and/or in a cylinder head and/or in a spark plug sleeve. The mounting portion 11 is provided in this embodiment as (external) thread 12.

[0055] FIG. 1b shows an isometric view of a second embodiment similar to the embodiment of FIG. 1a. The only difference is that the weldseam 10 is not present in FIG. 1b.

[0056] It can be seen in FIG. 1a that the ground electrode 7 is designed as a ring electrode, wherein the ring electrode surrounds a circular formed middle electrode 6, wherein an annular spark gap 8 is formed between the ground electrode 7 and the middle electrode 6.

[0057] Further, in this embodiment of FIG. 1a, the chamfer 5 extents to the ground electrode carrier 9, with the advantage of an enhanced heat transfer between the spark plug body 3 and the spark plug sleeve as well as between the ground electrode carrier 9 and the spark plug sleeve.

[0058] The sealing area 4 in the form of the chamfer 5 is designed with an angle a with respect to a perpendicular y of a center axis x of the spark plug 1. This can be seen in more detail in FIGS. 2a and 2b. FIG. 2a shows an embodiment of a spark plug 1 according to the invention with a chamfer 5 at angle α of 41° and FIG. 2b an embodiment with a chamfer 5 at angle α of 27° with respect to the perpendicular y of a center axis x of the spark plug 1.

[0059] The spark plug 1 can be substantially symmetric with respect to the center axis x.

[0060] FIG. 3 shows a spark plug sleeve 15 for receiving a spark plug 1 according to the invention (and shown in FIG. 1a). Therefore, the spark plug sleeve 15 comprises a screw portion 16, having an internal thread 17 and a sealing portion 18. The sealing portion 18 is accordingly designed as a further chamfer 19 of the spark plug sleeve 15, which forms the counterpart to the chamfer 5 of the spark plug 1.

[0061] FIG. 4 shows the spark plug 1 (from FIG. 1a) mounted in the spark plug sleeve 15 (from FIG. 3). It can be seen that a pre-load device (which is provided by the external thread 12 in conjunction with the internal thread 17) is configured to pre-load the chamfer 5 of the spark plug 1 against a surface of the spark plug sleeve 15 (in particular against the further chamfer 19 of the spark plug sleeve 15).

[0062] FIG. 5 shows the further embodiment of a spark plug 1 according to the invention mounted in the spark plug sleeve 15 (from FIG. 3). It can be seen that a pre-load device (which is provided by the external thread 12 in conjunction with the internal thread 17) is configured to pre-load the sealing area of the spark plug 1 against a surface of the spark plug sleeve 15. This embodiment of a spark plug 1 comprises a sealing area, which extends rectangular from the center axis x. This sealing area interacts with a corresponding inner surface of the spark plug sleeve 15.

[0063] Embodiments with interchanged external/male and internal/female threads are conceivable.

[0064] Reference Signs:

[0065] 1. spark plug

[0066] 2. ignition means

[0067] 3. wall

[0068] 4. sealing area

[0069] 5. chamfer

[0070] 6. middle electrode

[0071] 7. ground electrode

[0072] 8. spark gap

[0073] 9. ground electrode carrier

[0074] 10. weldseam

[0075] 11. mounting portion

[0076] 12. external thread

[0077] 13. middle electrode carrier

[0078] 14. isolator

[0079] 15. spark plug sleeve

[0080] 16. screw portion (spark plug hole)

[0081] 17. internal thread

[0082] 18. sealing portion

[0083] 19. further chamfer

[0084] α angle

[0085] x center axis

[0086] y perpendicular of center axis