SPARK PLUG AND METHOD FOR PRODUCING A SPARK PLUG

Abstract

A spark plug of an internal combustion engine has a sealing area between a mounting portion (e.g., threads) and an end portion of a housing of the spark plug. The end portion faces a combustion chamber of the internal combustion engine. The spark plug includes a flow control element coupled to the end portion, wherein the flow control element projects beyond an igniter in a direction toward the combustion chamber.

Claims

1. An apparatus, comprising: a spark plug for igniting a combustible fuel in an internal combustion engine, comprising: a mounting portion comprising a thread configured to mount the spark plug in the internal combustion engine, an igniter configured to face the combustion chamber, when the spark plug is mounted in the internal combustion engine, and a sealing area having a conical shape configured to seal the combustion chamber against the environment, wherein a housing of the spark plug comprises the sealing area and the sealing area is located between the mounting portion and an end portion of the housing, which end portion faces the combustion chamber when the spark plug is mounted in the internal combustion engine, wherein the spark plug further comprises a flow control element attached to or integrated in the end portion of the housing, wherein the flow control element projects beyond the igniter in a direction towards the combustion chamber when the spark plug is mounted in the internal combustion engine.

2. The apparatus as set forth in claim 1, wherein the sealing area is located between the mounting portion and the flow control element on an outer surface of the housing, near or at a transition of the housing into the flow control member.

3. The apparatus as set forth in claim 1, wherein the flow control element is formed by at least one separate component part, wherein the at least one separate component part is arranged at the housing, wherein the housing and the at least one separate component part are connected by a welded joint.

4. The apparatus as set forth in claim 3, wherein the housing comprises a ledge, wherein the at least one separate component part is arranged at the ledge of the housing.

5. The apparatus as set forth in claim 1, wherein the sealing area is located at a terminal portion of the housing, wherein the terminal portion faces the combustion chamber, when the spark plug is mounted in the internal combustion engine.

6. The apparatus as set forth in claim 1, wherein the flow control element is attached to the housing with a ground electrode carrier as an intermediary part.

7. The apparatus as set forth in claim 1, wherein the flow control element has a cylindrical shape.

8. The apparatus as set forth in claim 1, wherein the igniter comprises at least one middle electrode and at least one ground electrode, wherein a spark gap is disposed between the at least one middle electrode and the least one ground electrode.

9. The apparatus as set forth in claim 1, wherein an electrical connection for connecting the spark plug with an electrical power supply is arranged at an end of the spark plug facing away from the igniter.

10. The apparatus as set forth in claim 8, wherein the at least one ground electrode carrier is: attached to or integrated in the housing; or attached to or integrated in the flow control element; or arranged between the housing and/or the flow control element.

11. The apparatus as set forth in claim 8, wherein the at least one middle electrode is connected at a centrally arranged middle electrode carrier.

12. The apparatus as set forth in claim 8, wherein the at least one ground electrode comprises a ring electrode, the at least one middle electrode comprises an annular middle electrode, the ring electrode at least partially surrounds the annular middle electrode, and the spark gap comprises an annular spark gap between the ring electrode and the annular middle electrode.

13. The apparatus as set forth in claim 1, wherein an outer diameter of the flow control element is smaller than the diameter of the mounting portion.

14. The apparatus as set forth in claim 1, comprising the internal combustion engine, a cylinder head, and/or a spark plug sleeve having the spark plug.

15. A method, comprising: attaching or integrating a flow control element at or in an end portion of a housing of a spark plug, wherein the spark plug comprises a mounting portion having a thread, an igniter at the end portion, and a sealing area having a conical shape between the mounting portion and the end portion, wherein the flow control element projects beyond the igniter in a direction towards a combustion chamber when the spark plug is mounted in the internal combustion engine.

16. An apparatus, comprising: a spark plug, comprising: a housing; a mounting portion; a sealing portion; and an end portion comprising an igniter having one or more electrodes, and a flow control sleeve disposed about the igniter and extending beyond the igniter away from the mounting portion.

17. The apparatus of claim 16, wherein the flow control sleeve comprises a plurality of radial openings.

18. The apparatus of claim 17, wherein the plurality of radial openings are disposed between the mounting portion and the one or more electrodes.

19. The apparatus of claim 16, wherein the one or more electrodes comprises at least first and second annular electrodes and an annular spark gap.

20. The apparatus of claim 16, comprising an internal combustion engine having one or more of the spark plug.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0066] Further details and advantages of the invention are apparent from the accompanying figures and the following description of the drawings. The figures show:

[0067] FIG. 1 illustrates a first embodiment of a spark plug according to certain aspects of the invention,

[0068] FIG. 2 illustrates the detail view characterised in FIG. 1,

[0069] FIG. 3 illustrates the embodiment of FIG. 1 in an unmounted state,

[0070] FIG. 4 illustrates an isometric view of an embodiment similar to FIG. 1,

[0071] FIG. 5 illustrates a second embodiment of a spark plug according to certain aspects of the invention,

[0072] FIG. 6 illustrates a third embodiment of a spark plug according to certain aspects of the invention,

[0073] FIG. 7 illustrates a fourth embodiment of a spark plug according to certain aspects the invention, and

[0074] FIG. 8 illustrates a fifth embodiment of a spark plug according to certain aspects the invention.

DETAILED DESCRIPTION

[0075] FIG. 1 shows a first embodiment of a spark plug 1, according to aspects of the invention, mounted in the spark plug sleeve 15. The spark plug 1 is connected to a spark plug sleeve 15 by a mounting portion 11, which is provided by an external thread 12 of the spark plug 1 in conjunction with the internal thread 17 of the spark plug sleeve 15.

[0076] FIG. 2 shows the detail view indicated by A-A in FIG. 1.

[0077] The sealing area 4 (which is provided by the chamfer 5) of the spark plug 1 can be braced against a surface of the spark plug sleeve 15 by help of the threaded connection.

[0078] The spark plug 1 comprises an ignition means 2 embodied as 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. The ground electrode 7 is arranged on the ground electrode carrier 9.

[0079] In this specific embodiment, the flow control element 20, which surrounds the ignition means 2, is formed by a separate component part (separate from the housing 3).

[0080] The housing 3 comprises the sealing area 4. The second component (which actually carries the ground electrode 7 which is arranged at the ground electrode carrier 9) is provided by the flow control element 20. The flow control element 20 is connected to the spark plug body, e.g., by laser beam welding.

[0081] The housing 3 comprises a ledge 10, wherein the separate flow control element 20 is arranged at the ledge 10 of the housing 3. Of course, the flow control element 20 can be arranged at the front portion (terminal portion) of the housing without such a ledge 10.

[0082] The flow control element 20 carries the ground electrode carrier 9 and the latter carries the ground electrode 7. Therefore, in this specific embodiment, the flow control element 20 can be considered as a part of the ground electrode carrier 9. The ground electrode 7 is connected to the ground electrode carrier 9, e.g., by laser beam welding.

[0083] The flow control element 20 has openings 21, which permit good access for the mixture. The openings 21 can be in the form of bores, slots, polygons, or ellipses, or of a similar shape.

[0084] The flow control element 20 and the ground electrode carriers 9 can be produced in one piece (as shown in the FIGS. 1-3). It is also possible to provide an annulus shaped metal pieces or at least one rectangular metal parallelepipeds to be welded as ground electrode carrier 9 to or into the flow control element 20.

[0085] The ground electrode carrier 9 is provided with a metal plate as the ground electrode 7, wherein the ground electrode 7 is welded to the ground electrode carrier 9, preferably by means of a laser at one side or on both sides. The welding is such that the gap is closed at the electrode sides. In other words, between the ground electrode 7 and the ground electrode carrier 9, there is in this embodiment no open gap (or aperture) through which gas can enter.

[0086] The welding processes can employ pulsed lasers, continuously operating lasers (CW-lasers), electron beam welding processes, or vacuum and high-vacuum brazing processes as well as plasma welding or resistance welding.

[0087] As shown, the middle electrode 6 of the spark plug 1 is welded to a middle electrode carrier 14. The spark position can be established by the middle electrode carrier 14 in relation to the flow control element 20 and the ground electrode carrier 9.

[0088] The middle electrode 6 is also connected to the middle electrode carrier 14, preferably by laser beam welding.

[0089] Between the ceramic insulator and the housing 3, a gasket 13 is arranged.

[0090] The spark plug body (housing 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.

[0091] FIG. 3 shows the embodiment of FIG. 1 and FIG. 2 of a spark plug 1, according to aspects of the invention, in an unmounted state. FIG. 4 shows the same embodiment in a perspective view.

[0092] The sealing area 4 in the form of the chamfer 5 is designed with an angle α with respect to a perpendicular y of a center axis x of the spark plug 1.

[0093] This can be seen in more detail in FIG. 3. FIG. 3 shows an embodiment of a spark plug 1, according to aspects of the invention, with a chamfer 5 at angle α of 41° with respect to the perpendicular y of a center axis x of the spark plug 1.

[0094] The spark plug 1 can be substantially symmetric with respect to the center axis x.

[0095] It can be seen in FIG. 4 that the ground electrode 7 is designed as a ring electrode, wherein the ring electrode surrounds the middle electrode 6, wherein an annular spark gap 8 is formed between the ground electrode 7 and the middle electrode 6. The middle electrode 6 is in this case also shaped as a ring electrode welded to the middle electrode carrier 14.

[0096] FIG. 5 shows a similar embodiment in detail view analogous to FIG. 2 with the difference that the flow control element 20 of FIG. 6 is designed by three separate component parts 22, 23, 24.

[0097] The first separate component part 22 of the flow control element 20 is attached to the housing 3, to be precise, attached at the ledge 10 of the housing 3. The first separate component part 22 is used as spacer.

[0098] The second separate component part 23 of the flow control element 20 is attached to the first separate component part 22 and immediately surrounds the ignition means 2. The ground electrode 7 is attached to the second separate component part 23 of the flow control element 20, such that the second separate component part 23 can be seen as the ground electrode carrier 9. The ground electrode carrier 9 and the second separate component part 23 are joined together by welding, preferably laser beam welding or brazing.

[0099] The third separate component part 24 of the flow control element 20 is attached to the second separate component part 23 and improves the effect of the first separate component part 22 and the second separate component part 23 as flow control element 20.

[0100] The separate component parts 22, 23, 24 are joined together by welding, preferably laser beam welding or brazing. The combination of the separate component parts 22, 23, 24 may be seen as ground electrode carrier 9 and flow control element 20.

[0101] FIG. 6 discloses a similar (third) embodiment in detail view analogous to FIG. 5 with the difference that the flow control element 20 of FIG. 6 is designed as one single component part, wherein the ground electrode carrier 9 is arranged at the inner surface of the flow control element 20.

[0102] The ground electrode carrier 9 is arranged at the inner diameter of the flow control element 20, wherein the ground electrode carrier 9 is fixed by welding or brazing at the flow control element 20.

[0103] FIG. 7 shows a fourth embodiment of a spark plug 1 according to aspects of the invention. Compared to the previous embodiments, the embodiment of FIG. 7 comprises a ground electrode carrier 9, which acts as intermediary part through which the flow control element 20 is attached to the housing 3.

[0104] The ground electrode carrier 9 is attached to the housing 3, to be precise, attached at the ledge 10 of the housing 3.

[0105] The ignition means 2 is embodied as 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. The ground electrode 7 is fixed on the ground electrode carrier 9 by welding, preferably laser beam welding or brazing.

[0106] The flow control element 20 is connected to the ground electrode carrier 9, e.g., by welding, preferably laser beam welding or brazing.

[0107] FIG. 8 shows a fifth embodiment of a spark plug 1 according to aspects of the invention. Compared to FIG. 7, in FIG. 8 the ground electrode carrier 9 is designed in such a way that the middle electrode 6 and the ground electrode 7 are distanced in a direction along the center axis X of the spark plug 1, wherein the spark gap 8 is arranged between the ground electrode 7 and the middle electrode 6. Therefore, the sparks extend parallel to the center axis X of the spark plug 1.

[0108] For all embodiments, it can be provided that at least the sealing portion is coated, preferably having a higher degree of hardness than the material forming the sealing portion. More preferred is an anti-corrosive coating with before-mentioned features.

[0109] Advantageously, such a coating not only prevents corrosive wear in the said area, but also prevents tribological wear of the sealing area.

[0110] As an example, the coating can be a CrWC (Chrome-Wolfram carbide) coating, but of course other coatings exhibiting the before-mentioned features are conceivable.

[0111] The coating is preferably generated by a PVD-coating process (Physical Vapor Deposition).

REFERENCE SIGNS

[0112] 1. spark plug [0113] 2. ignition means [0114] 3. housing [0115] 4. sealing area [0116] 5. chamfer [0117] 6. middle electrode [0118] 7. ground electrode [0119] 8. spark gap [0120] 9. ground electrode carrier [0121] 10. ledge [0122] 11. mounting portion [0123] 12. external thread [0124] 13. gasket [0125] 14. middle electrode carrier [0126] 15. spark plug sleeve [0127] 16. screw portion (spark plug hole) [0128] 17. internal thread [0129] 18. sealing portion [0130] 19. further chamfer [0131] 20. flow control element [0132] 21. opening [0133] 22. first separate component part of the flow control element [0134] 23. second separate component part of the flow control element [0135] 24. third separate component part of the flow control element [0136] α angle [0137] x center axis [0138] y perpendicular of center axis