Ceramic Insulator with Conductive Matrix for Arc Suppression
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Solution Overview
Problem
Existing corona discharge ignition systems for internal combustion engines often experience arcing issues due to high voltage thresholds, leading to a single stream of ions instead of multiple streams, which reduces ignition quality and can result in thermal plasma formation.
Innovation Solution
Incorporating a matrix of electrically insulating material with embedded electrically conducting elements around the electrode, which reduces arcing and maintains multiple streams of ions, ensuring a controlled non-thermal plasma is formed for efficient ignition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high voltage above threshold is applied to the igniter, then the density of ions increases, but arc discharge is formed instead of corona discharge
Solution Approach 1:
The insulator with embedded conducting elements acts as an intermediary structure between the electrode and the fuel-air mixture. It modifies the electric field distribution to prevent direct arcing while maintaining high ion density through controlled corona discharge, thus mediating between the need for high voltage and the need to avoid arc formation
Solution Approach 2:
The invention changes the physical parameters of the ignition system by introducing an insulator with specific electrical properties and geometric configuration. This modifies the electric field strength distribution and voltage thresholds, allowing operation at high voltages without transitioning to arc discharge, thereby maintaining reliable corona discharge across varying operating conditions
2Quantity of substance
If arc discharge occurs, then a single stream of ions is formed, but the ignition quality is reduced
Solution Approach 1:
The insulator structure serves as a field-shaping intermediary that distributes the electric field to create multiple corona discharge streams rather than a single arc. This intermediary structure ensures multiple ion streams are formed, maintaining high ignition quality even at high voltages where arc discharge would normally occur
3Temperature
If the electric field is increased to create non-thermal plasma, then ignition is achieved, but thermal plasma and electric arc may form
Solution Approach 1:
The insulator with embedded conducting elements acts as a field-distributing intermediary that maintains electric field strength sufficient for non-thermal plasma generation while preventing field concentration that would lead to arc discharge. This allows high electric fields to be maintained without the harmful effects of thermal plasma formation
Solution Approach 2:
The invention changes the electrical parameters of the system by introducing the insulator structure, which modifies the breakdown voltage and electric field distribution. This allows the system to operate in the non-thermal plasma regime at higher voltages without transitioning to thermal plasma or arc discharge, effectively separating the useful effect from the harmful effect
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 effectively reduces arcing and maintains a controlled non-thermal plasma, leading to improved fuel economy and reduced CO2 emissions by ensuring rapid and robust ignition in internal combustion engines.
Implementation Method 1
an electrode of an igniter is charged to a high radio frequency ('RF') voltage potential, creating a strong RF electric field in the combustion chamber. The electric field causes a portion of the fuel-air mixture in the combustion chamber to ionize and begin dielectric breakdown, facilitating combustion of the fuel-air mixture. The electric field is controlled so that the fuel-air mixture maintains dielectric properties and corona discharge occurs, also referred to as a non-thermal plasma.
Implementation Method 2
The electric field is controlled so that the fuel-air mixture does not lose of all dielectric properties, which would create a thermal plasma and an electric arc between the electrode and grounded cylinder walls or piston. The insulator includes a matrix of electrically insulating material around the electrode firing end, and a plurality of electrically conducting elements disposed in the matrix of electrically insulating material.
Data Source
AI summary
An igniter (20) of a corona ignition system emits a non-thermal plasma in the form of a corona (30) to ionize and ignite a fuel mixture. The igniter (20) includes an electrode (32) and a ceramic insulator (22) surrounding the electrode (32). The insulator (22) surrounds a firing end (38) of the electrode (32) and blocks the electrode (32) from exposure to the combustion chamber (28). The insulator (22) presents a firing surface (56) exposed to the combustion chamber (28) and emitting the non-thermal plasma. A plurality of electrically conducting elements (24) are disposed in a matrix (26) of the ceramic material and along the firing surface (56) of the insulator (22), such as metal particles embedded in the ceramic material or holes in the ceramic material. The electrically conducting elements (24) reduce arc discharge during operation of the igniter (20) and thus improve the quality of ignition.