Pre-Chamber Spark Plug Two-Part Housing Deformation
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Solution Overview
Problem
Existing spark plugs, particularly prechamber spark plugs, face issues with inhomogeneous prestress and leakage due to local heat introduction during welding, leading to potential leaks and insulator displacement under high pressure, and one-piece housing designs are not solid enough to resist pressure loads.
Innovation Solution
A two-part housing design with a deformation area that is heated and pressed together to create a constant preload around the circumference, ensuring a stable and gas-tight seal, and optionally using different materials for the housing parts and a ceramic insulator to manage thermal expansion and conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the housing is designed in one piece with a flanged upper edge, then the manufacturing process is simplified, but the housing cannot be made solid enough to resist pressure loads and the insulator may be pushed out under high pressure
Solution Approach 1:
The housing is divided into two separate parts (first housing part and second housing part) that are connected via a weld seam. This segmentation allows each part to be optimized for specific functions: the first housing part can be designed with a solid, non-flanged structure for pressure resistance, while the second housing part can accommodate the insulator. The deformation area on the second housing part provides additional bracing against the insulator under pressure loads, preventing the insulator from being pushed out.
2Ease of manufacture
If local heat is introduced during welding of the two-part housing, then the housing parts are joined together, but this leads to inhomogeneous prestress and leakage at the sealing surfaces
Solution Approach 1:
The deformation area is designed with a reduced cross-sectional area compared to the rest of the housing structure. This local quality change allows the deformation area to be selectively heated and deformed without affecting the overall structural integrity. The reduced cross-section enables the deformation area to undergo controlled thermal deformation that creates a tensioning effect on the insulator, generating homogeneous prestress at the sealing surfaces between the housing parts and the insulator, thereby preventing leakage.
3Ease of manufacture
If the deformation area has a reduced cross-sectional area, then the processing becomes extremely simple, but the structural strength may be compromised
Solution Approach 1:
The deformation area undergoes parameter changes through controlled heating and deformation. By heating the deformation area to a temperature where the material becomes more ductile, it can be pressed together with reduced cross-sectional area without compromising overall structural strength. The subsequent cooling creates a tensioning effect that generates the necessary prestress. This parameter change allows simple processing while maintaining structural integrity through the residual stress state.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides a robust and gas-tight spark plug with reduced risk of insulator displacement and leakage, ensuring a homogeneous pressure distribution and maintaining a permanent seal under high pressure loads.
Implementation Method 1
The deformation area can be heated and the two housing parts can be pressed against one another, so that the deformation of the deformation area and after the cooling of the deformation area results in a tensioning of the insulator in the housing
Implementation Method 2
the deformation of the deformation area and after the cooling of the deformation area results in a tensioning of the insulator in the housing
Data Source
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AI summary
A spark plug, in particular a pre-chamber spark plug, comprising a housing (1), a center electrode (6) and a ground electrode (7), wherein the center electrode (6) can be supplied with electrical voltage via a supply line running at least partially within an insulator (2), and wherein the housing (1) consists of a first housing part (3) and a second housing part (4) and incorporates at least a part of the insulator (2), and wherein the first housing part (3) and/or the second housing part (4) have a deformation area (11) for prestressing the insulator (2) within the first housing part (3) and the second housing part (4). Furthermore, a method for manufacturing a spark plug is described.