Shrink Fit Ceramic Center Electrode Igniter Design
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Solution Overview
Problem
Conventional igniters for fuel-air mixtures suffer from energy losses due to air gaps between components, leading to inefficient electrical discharges and increased manufacturing costs.
Innovation Solution
A hermetically sealed igniter design featuring a conductive core and outer insulator, eliminating the need for separate components and air gaps, achieved through a sintering process that creates a shrink-fit ceramic center electrode capable of emitting a larger diameter electrical field.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional igniters use separate insulator and center electrode components with air gaps between them, then manufacturing is simpler, but energy losses increase due to electrical fields forming in the air gaps
Solution Approach 1:
The patent merges the insulator and center electrode into a single integrated ceramic component with conductive pathways embedded within the ceramic body. This eliminates the separate components and air gaps between them, thereby eliminating the harmful electrical fields that cause energy losses while maintaining manufacturing feasibility through a unified sintering process.
Solution Approach 2:
The patent uses composite ceramic material that combines insulating ceramic matrix with conductive pathways (such as metal particles or conductive glass phases) embedded within it. This composite structure allows the single component to simultaneously provide electrical insulation where needed and electrical conduction where required, eliminating the need for separate components and their interfaces.
2Productivity
If conventional igniters use separate components requiring assembly, then manufacturing precision requirements are lower, but manufacturing time and costs increase
Solution Approach 1:
By combining multiple components into a single integrated ceramic piece, the patent eliminates the assembly step entirely. The conductive pathways are formed within the ceramic body during the sintering process itself, removing the need for precise alignment and assembly of separate components, thereby reducing both manufacturing time and potential alignment errors.
Solution Approach 2:
The conductive pathways are formed within the ceramic green body before the final sintering process. This preliminary formation of conductive structures allows the entire component to be manufactured in a single sintering cycle, eliminating subsequent assembly operations and reducing overall manufacturing time while maintaining precision through the inherent stability of the sintering process.
3Loss of energy
If conventional igniters use air gaps between components, then assembly is easier, but electrical field losses occur during operation
Solution Approach 1:
The patent merges the insulator and center electrode into a single integrated component, eliminating the air gaps that cause harmful electrical fields and energy losses. The unified structure ensures continuous ceramic material between all conductive elements, preventing the formation of parasitic electrical fields while the entire component is manufactured in a single sintering operation, maintaining ease of manufacture.
Solution Approach 2:
The composite ceramic material provides continuous insulating matrix throughout the structure, eliminating air gaps and the associated electrical field losses. The conductive pathways are seamlessly integrated within the ceramic body, ensuring no discontinuities or air interfaces that would cause energy losses, while the single-component nature maintains manufacturing simplicity.
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 reduces energy losses and manufacturing costs by eliminating air gaps and unnecessary components, while enhancing energy efficiency through a larger discharge diameter and eliminating the need for additional parts like firing tips.
Implementation Method 1
sintering the conductive core and the green outer insulator after disposing the conductive core in the insulator bore. The sintering step includes hermetically sealing the insulator inner surface to the conductive core
Implementation Method 2
The conductive core is hermetically sealed to the insulator inner surface
Implementation Method 3
The center electrode of the corona igniter is charged to a high radio frequency voltage potential creating a strong radio frequency electric field in the combustion chamber. The electric field causes a portion of a mixture of fuel and air in the combustion chamber to ionize and begin dielectric breakdown, facilitating combustion of the fuel-air mixture
Data Source
AI summary
An igniter (20) includes an outer insulator (24) formed of an outer ceramic material hermetically sealed to a conductive core (26). The conductive core (26) is formed of a core ceramic material and a conductive component, such as an electrically conductive coating applied to the core ceramic material or metal particles or wires embedded in the core ceramic material. The conductive core (26) is typically sintered and disposed in the green outer insulator (24). The components are then sintered together such that the outer insulator (24) shrinks onto the conductive core (26) and the hermetic seal forms therebetween. The conductive core (26) fills the outer insulator (24), so that the conductive core (26) is disposed at an insulator nose end (34) of the outer insulator (24) and the electrical discharge (22) can be emitted from the conductive core (26), eliminating the need for a separate firing tip.