Enhanced Spark Plug Design for Improved Durability
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Summary
Problems
Conventional spark plugs with noble metal tips embedded through resistance welding suffer from insufficient joint strength between the noble metal tip and the ground electrode base member, leading to potential separation due to oxide scale formation under high engine temperatures, which compromises durability.
Innovation solutions
A spark plug design where the noble metal tip is embedded in the ground electrode base member through resistance welding, with specific orientation and weld formation characteristics, including a tip inclination angle of 2° to 25°, weld extension to boundary regions, and specific width and thickness ratios, enhancing the fusion and joint strength between the noble metal tip and the ground electrode base member.
TRIZ Analysis
Specific contradictions:
General conflict description:
Principle concept:
If resistance welding is used to join the noble metal tip to the ground electrode base member, then the noble metal tip can be firmly attached, but excessive oxide scale forms at the joint portion leading to separation
Why choose this principle:
The patent applies parameter changes by optimizing the inclination angle of the noble metal tip (2° ≤ θ ≤ 25°) relative to the ground electrode base member. This angular parameter modification accelerates fusion during resistance welding, enhances joint strength, and simultaneously prevents excessive oxide scale formation that would cause separation, thereby resolving the contradiction between strong attachment and long-term durability
Principle concept:
If resistance welding is used to join the noble metal tip to the ground electrode base member, then the noble metal tip can be firmly attached, but excessive oxide scale forms at the joint portion leading to separation
Why choose this principle:
The patent implements local quality by creating a weld that extends to boundary regions on the side surface of the ground electrode base member. This localized weld configuration concentrates the bonding strength at critical areas while controlling oxide scale formation at the joint portion, achieving both strong attachment and prevention of separation
Application Domain
Data Source
AI summary:
A spark plug design where the noble metal tip is embedded in the ground electrode base member through resistance welding, with specific orientation and weld formation characteristics, including a tip inclination angle of 2° to 25°, weld extension to boundary regions, and specific width and thickness ratios, enhancing the fusion and joint strength between the noble metal tip and the ground electrode base member.
Abstract
[Objective] An object of the present invention is to provide a technique for improving durability of a spark plug. [Means for Solution] A ground electrode 40 of a spark plug 100 is composed of a ground electrode base member 41 and a noble metal tip 42. The center axis CA3 of the noble metal tip 42 slants in relation to the center axis CA2 of the ground electrode base member 41 at angle θ which satisfies a relation 2° ≤ θ ≤ 25°.