Spark Plug Electrode Tip Assembly With Additive-Made Precious Metal Interface
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Solution Overview
Problem
Conventional spark plug electrode tips made from precious metals face challenges such as erosion, corrosion, and thermal stresses due to material differences with nickel-based electrode bodies, leading to increased costs and manufacturing difficulties, especially in harsh engine environments.
Innovation Solution
An electrode tip assembly is created using additive manufacturing, where a nickel-based electrode base is built with a precious metal-based electrode tip using laser deposition layers, eliminating the need for a welded joint between dissimilar materials and reducing thermal stresses through an interfused boundary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If precious metals are used for electrode tips to reduce erosion and corrosion, then electrode durability is improved, but material cost increases
Solution Approach 1:
The patent applies local quality by using precious metals only at the electrode tip where the spark occurs, rather than throughout the entire electrode. The electrode base uses nickel-based material while the tip uses precious metal, concentrating the expensive material only where it is most needed for erosion and corrosion resistance during sparking.
Solution Approach 2:
The patent uses composite materials by combining nickel-based electrode base material with precious metal electrode tip material. This creates a hybrid structure that leverages the cost-effectiveness of nickel for the bulk structure while utilizing the superior durability of precious metals at the critical sparking interface.
2Ease of manufacture
If precious metal electrode tips are joined to nickel-based electrode bodies using conventional welding techniques, then electrode assembly is achieved, but thermal stresses cause cracking and damage
Solution Approach 1:
The patent changes the manufacturing parameter from conventional welding to additive manufacturing. This process transformation allows for controlled material deposition and creates a gradient transition zone between dissimilar materials, reducing thermal stress concentration and preventing cracking while maintaining joint integrity.
Solution Approach 2:
The additive manufacturing process creates a composite structure with intermediate layers that gradually transition between nickel-based and precious metal compositions. This gradient composite structure reduces thermal stress by avoiding abrupt material property changes at the interface.
3Reliability
If precious metals are used throughout the entire electrode body, then electrode durability is maximized, but manufacturing cost increases substantially
Solution Approach 1:
The patent implements local quality by applying precious metals only to the electrode tip region where sparking occurs, rather than throughout the entire electrode body. This localized application maintains durability at the critical interface while minimizing precious metal consumption and cost.
Solution Approach 2:
The electrode is segmented into two distinct regions: a nickel-based base providing structural support and electrical conductivity, and a precious metal tip providing erosion and corrosion resistance. This segmentation allows each material to perform its optimal function while reducing overall precious metal usage.
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
This solution reduces material costs by minimizing precious metal usage and enhances durability by distributing thermal stresses, improving the longevity and performance of spark plug electrodes in harsh engine conditions.
Implementation Method 1
an electrode tip that is formed on the electrode base, wherein the electrode tip includes a plurality of laser deposition layers
Data Source
AI summary
An electrode tip assembly for a spark plug includes an electrode tip that is formed on an electrode base using an additive manufacturing process, such as a powder bed fusion technique, after which the electrode base is welded to an electrode body. The electrode base includes a welding side and an additive manufacturing side, and the electrode tip includes a plurality of laser deposition layers built on the additive manufacturing side of the electrode base.