Pre-chamber spark plug with conical contact surface between housing and cap
By designing the tapered contact surface between the housing and the cover in the pre-combustion chamber spark plug, the problem of the cover slipping during placement and tightening is solved, and a firmer mechanical connection and better thermal and electrical contact effect is achieved.
Patent Information
- Application Number
- CN202411890078.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2023-12-21
- Filing Date
- 2024-12-20
- Publication Date
- 2025-06-24
AI Technical Summary
In existing pre-combustion chamber spark plugs, the cover easily slips off during placement and fastening at the housing, especially in designs with butt contact surfaces.
A pre-combustion chamber spark plug with a tapered contact surface between the housing and the cover is designed, and the end face angles of the cover and the housing are adjusted to form a self-centered tapered contact surface, thereby reducing the risk of sliding off the cover.
Through the tapered contact surface design, the cover no longer slides down during placement and fastening, and the contact surface is added, thereby improving the firmness of the mechanical connection and the effect of thermal and electrical contact.
Smart Images
Figure CN120200098A_ABST
Abstract
Description
Field of the Invention
[0001] The present invention relates to a pre-chamber spark plug having a conical contact surface between a housing and a cover, thereby simplifying the placement of the cover at the housing. Background Art
[0002] Pre-chamber spark plugs are known from the prior art in different designs. A pre-chamber spark plug typically has a cover that defines a pre-chamber, wherein the cover has a so-called cover hole that establishes a connection between the pre-chamber of an internal combustion engine and the combustion chamber. Here, the cover is arranged at the end side of the housing on the combustion chamber side. Different designs exist for the common contact surface between the housing and the cover, for example a stepped contact surface that enables the advantage of a large contact surface or a so-called butting contact surface, in which case the cover and the housing have flat end faces perpendicular to the longitudinal axis of the pre-chamber spark plug. The butting contact surface has the advantage that it can be easily manufactured. However, the challenge in placing and fastening the cover at the housing is that the cover may slip slightly during the process steps. This challenge does not exist in pre-chamber spark plugs having a stepped contact surface between the housing and the cover. Summary of the Invention
[0003] The object of the present invention is to provide a pre-chamber spark plug having a butting contact surface (Stoβ-auf-Stoβ- ) in which the risk of slipping of the cover is minimized.
[0004] The pre-chamber spark plug according to the invention having a longitudinal axis X has: a housing having an inner side (Innenseite) and an outer side (Auβenseite); and a cover having an inner side and an outer side. The cover has at least one cover hole that establishes a connection between the pre-chamber within the cover and the region outside the cover. In addition, the cover and the housing each have a flat end face facing each other. The end face of the cover has an angle A° not equal to 90° with respect to the inner side of the cover. In addition, the end face of the housing also has an angle B° not equal to 90° with respect to the inner side of the cover, where these two end faces have an angle either greater than 90° or less than 90° with respect to the inner side of the cover.
[0005] It follows therefrom that the end faces of the cover and the housing form a conical flat contact surface with respect to each other, which has a self-centering effect when the cover is placed on the housing, such that the cover no longer slips after placement and during fastening. In addition, the contact surface is increased compared to the contact surface generated when the end face is constructed perpendicular to the longitudinal axis.
[0006] The dependent claims indicate preferred refinements of the invention.
[0007] In one embodiment of the present invention, the angle A° is equal to or less than the angle B°.
[0008] In an improved embodiment, it is provided that the end faces of the cover and the housing abut against each other at the inner surfaces of the cover and the housing, and the end faces of the cover and the housing are spaced apart at the outer surfaces of the cover and the housing, thereby forming a gap. This allows for greater manufacturing tolerances in terms of angles.
[0009] Furthermore, it is possible that the gap between the cover and the housing is at least partially filled by a weld seam. This achieves a firm mechanical connection between the cover and the housing as well as good thermal and electrical contact. This is especially the case when the weld seam is configured circumferentially and additionally completely fills the gap.
[0010] In a further embodiment and further improvement of the pre-chamber spark plug according to the present invention, it is provided that the inner surfaces of the cover and the housing are aligned parallel to the longitudinal axis of the pre-chamber spark plug in the region of the end face, and / or the outer surfaces of the cover and the housing are aligned parallel to the longitudinal axis in the region of the end face. As a result, there are no flow-impeding edges in the pre-chamber.
[0011] In a design of the pre-chamber spark plug according to the present invention, the radially inner section of the end face of the housing is arranged axially closer to the combustion chamber compared to the radially outer section of the end face of the housing and in particular compared to the radially outer section of the end face of the cover. When viewed in the direction of the combustion chamber along the longitudinal axis of the pre-chamber spark plug, a conically narrowing end face is formed at the housing. The end face of the housing is radially surrounded by the end face of the cover.
[0012] In an alternative design of the pre-chamber spark plug according to the present invention, the radially outer section of the end face of the housing is arranged axially closer to the combustion chamber compared to the radially inner section of the end face of the housing and in particular compared to the radially inner section of the end face of the cover. When viewed in the direction of the combustion chamber along the longitudinal axis of the pre-chamber spark plug, a conically widening end face is formed at the housing. The end face of the cover is radially surrounded by the end face of the housing.
[0013] In both of these designs, the effect is that the cover self-centers when it is placed on the housing and slipping is prevented. Description of the Drawings
[0014] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. In the drawings:
[0015] Figure 1 A schematic diagram of a pre-chamber spark plug according to the present invention is shown.
[0016] Figure 2 FIG. 1 shows a schematic partial cross-sectional view of a cover of a pre-chamber spark plug according to a first embodiment.
[0017] Figure 3 FIG. 2 shows a schematic partial cross-sectional view of a cover of a pre-chamber spark plug according to a second embodiment. DETAILED DESCRIPTION
[0018] As Figure 1 shown, the pre-chamber spark plug 10 has a metallic housing 2 and an insulator 4. Typically, the pre-chamber spark plug has a center electrode located on the central axis X-X of the pre-chamber spark plug, and at least one laterally arranged ground electrode, which is not shown here.
[0019] An external thread is formed on the housing 2, which is provided for screwing the pre-chamber spark plug 10 into the cylinder head of an internal combustion engine.
[0020] The pre-chamber spark plug 10 further includes a cover 1, which together with a part of the housing 2 defines a pre-chamber 16. Here, the center electrode and the ground electrode are arranged in the pre-chamber 16.
[0021] The cover 1 has a plurality of cover holes 15, which enable a fluid connection between the pre-chamber 16 of the internal combustion engine and the combustion chamber.
[0022] In Figure 2 FIG. 3, a first embodiment of the contact surface according to the invention between the cover 1 and the housing 2 is shown.
[0023] The housing 2 has an inner surface 22, an outer surface 23, and a flat end face 21 on the combustion chamber side, wherein the end face 21 on the combustion chamber side faces the cover 1 and has an angle B° with respect to the inner surface 13 of the cover 1. Here, the angle B° is not equal to 90°. In this embodiment, it is less than 90°, so that the end face 21 has a conical shape that widens in the direction of the combustion chamber. This results in that the radially outer section 21b of the end face 21 is axially closer to the combustion chamber side end of the pre-chamber spark plug 10 than the radially inner section 21a of the end face 21.
[0024] In this example, the cover 1 has an inner surface 13, an outer surface 14, and a flat end face 12 on the combustion chamber side, wherein the end face 12 faces the housing 2 and has an angle A° with respect to the inner surface 13 of the cover 1. The angle A° is not equal to 90°. In this embodiment, the angle A° is less than 90°, so that the end face 12 has a conical shape that widens in the direction of the combustion chamber. This results in that the end face 12 of the cover 1 is radially surrounded by the end face 21 of the housing 2.
[0025] Figure 3Shows a second example of the contact surface according to the invention between the cover 1 and the housing 2. The second embodiment differs from the first embodiment in that the angles A° and B° are greater than 90°, and thus the contact surface between the cover 1 and the housing 2 tapers conically in the direction of the end of the combustion chamber side of the pre-chamber spark plug 10. The cover 1 is arranged radially externally around the end face 21 of the housing 2 with its end face 12. Compared with the radially outer end 21b of the end face 21 of the housing 2 and also compared with the radially outer end 12b of the end face 12 of the cover 1, the radially inner end 21a of the end face 21 of the housing 2 is axially closer to the end of the combustion chamber side of the pre-chamber spark plug 10.
[0026] In Figure 2 and Figure 3 drawings show an extension E of the inner face 13 of the cover 1 in the region of the transition from the cover 1 to the housing 2. In this example, the extension E is parallel to the longitudinal axis X of the pre-chamber spark plug 10. It can be seen in both figures that the inner face 13 of the cover 1 and the inner face 22 of the housing 2 are aligned. This also applies to the outer faces 23, 14.
Claims
1. A pre-chamber spark plug (10) having a longitudinal axis X, the pre-chamber spark plug comprising: - a housing (2) having an inner face (22) and an outer face (23); and - a cover (1) having an inner face (13) and an outer face (14), -in, The cover (1) has at least one cover hole (15) which establishes a connection between a pre-combustion chamber (16) inside the cover (1) and an area outside the cover (1), and -Wherein, the cover (1) and the shell (2) respectively have flat end faces (12, 21) facing each other, characterized in that the end face (12) of the cover (1) has an angle A° not equal to 90° relative to the inner face (13) of the cover (1) and the end face (21) of the shell (2) has an angle B° not equal to 90° relative to the inner face (13) of the cover (1), wherein the two end faces (12, 21) have an angle with respect to the inner face (13) of the cover (1) that is either greater than 90° or less than 90°.
2. The pre-chamber spark plug (10) according to claim 1, characterized in that: The angle A° is equal to or smaller than the angle B°.
3. A pre-chamber spark plug (10) according to any one of the preceding claims, characterized in that The end faces (12, 21) of the cover (1) and the shell (2) abut against each other at the inner face (13) of the cover and the inner face (22) of the shell, and the end faces (12, 21) of the cover (1) and the shell (2) are spaced apart at the outer face (14) of the cover (1) and the outer face (23) of the shell (2), thereby forming a gap (3).
4. The pre-chamber spark plug (10) according to claim 3, characterized in that: A gap (3) between the cover (1) and the housing (2) is at least partially filled by a weld seam.
5. A pre-chamber spark plug (10) according to any one of the preceding claims, characterised in that The inner surface (13) of the cover (1) and the inner surface (22) of the housing (2) are aligned in parallel to the longitudinal axis X of the pre-combustion chamber spark plug (10) in the region of the end surfaces (12, 21), and / or the outer surface (14) of the cover and the outer surface (23) of the housing (2) are aligned in parallel to the longitudinal axis X in the region of the end surfaces (12, 21).
6. A pre-chamber spark plug (10) according to any one of the preceding claims, characterised in that Compared to a radially outer section (21b) of the end face (21) of the housing (2) and in particular compared to a radially outer section (12b) of the end face (12) of the cover (1), a radially inner section (21a) of the end face (21) of the housing (2) is arranged axially closer to the combustion chamber.
7. A pre-chamber spark plug (10) according to any one of the preceding claims 1 to 6, characterized in that Compared to a radially inner section (21a) of the end face (21) of the housing (2) and in particular compared to a radially inner section (12a) of the end face (12) of the cover (1), a radially outer section (21b) of the end face (21) of the housing (2) is arranged axially closer to the combustion chamber.