Conical Spark Plug Jacket Contact Surface for Bolt Force Retention
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Solution Overview
Problem
The existing spark plug jackets in combustion engines suffer from reduced pressure or bolt force due to deformation during mounting, leading to potential leakage of combustion gases into the coolant cavity, especially after spark plug replacement.
Innovation Solution
A spark plug jacket with a biasing element that modifies the contact surface to create a flexible, conical shape with angular offsets, allowing for improved pressure distribution and sealing by adapting to the cylinder head's support surface during mounting, preventing leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a spark plug jacket is provided to seal the coolant cavity and remain in place during spark plug replacement, then coolant discharge is avoided and replacement is facilitated, but the pressure or bolt force between the spark plug jacket and cylinder head is reduced due to mounting sequence
Solution Approach 1:
The contact surface of the spark plug jacket is pre-modified to have a conical shape with angular offsets before mounting. This preliminary modification ensures that when the jacket is installed and the spark plug is subsequently mounted, the pre-formed conical contact surface adapts to the cylinder head support surface, maintaining optimal pressure distribution and bolt force despite the delayed spark plug installation
Solution Approach 2:
The contact surface geometry is changed from a standard cylindrical shape to a conical shape with specific angular offsets. This parameter change in the contact surface geometry allows the spark plug jacket to better adapt to the cylinder head support surface, improving pressure distribution and maintaining bolt force while preserving sealing reliability
2Ease of operation
If the spark plug is mounted after the spark plug jacket, then spark plug replacement is facilitated, but the pressure or bolt force between the spark plug jacket and cylinder head is reduced leading to potential leakage
Solution Approach 1:
The contact surface is pre-modified to a conical shape with angular offsets before the spark plug jacket is installed. This preliminary action ensures that when the spark plug is later mounted, the pre-formed contact surface geometry maintains proper pressure distribution and prevents leakage, even though the spark plug installation is delayed
Solution Approach 2:
The conical contact surface with angular offsets provides a dynamic adaptation mechanism that allows the spark plug jacket to self-adjust to the cylinder head support surface during mounting. This dynamic geometry maintains optimal contact pressure and sealing reliability regardless of the delayed spark plug installation
3Reliability
If the contact surface is modified to create a conical shape with angular offsets, then pressure distribution and sealing are improved, but manufacturing complexity increases
Solution Approach 1:
The contact surface geometry parameters are changed to create a conical shape with specific angular offsets. While this improves sealing reliability and pressure distribution, it does require additional manufacturing steps or specialized tooling to achieve the precise conical geometry and angular offsets on the contact surface
Data Source
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AI summary
The present invention pertains to a spark plug jacket, e.g. for a large or high performance combustion engine, and a corresponding method of manufacturing a spark plug jacket, in particular to provide an improved sealing towards a coolant cavity. Accordingly, a spark plug jacket (10) is suggested, comprising a contact surface (12) for contacting a support surface of a cylinder head of a combustion engine, wherein in a first state, when a spark plug is not mounted in the spark plug jacket (10), at least a portion of the contact surface (12) of the spark plug jacket (10) defines a first angular offset to a contact surface direction defined by the support surface of the cylinder head and, in a second state, when the spark plug is mounted to the spark plug jacket (10), said portion defines a second angular offset, wherein the first angular offset is larger than the second angular offset.