Plasma Ignition Device with Tiered Prongs
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Solution Overview
Problem
Existing ignition systems in internal combustion engines face challenges with arcing and limited plasma discharge volume, which affect fuel efficiency and emission control.
Innovation Solution
A low-temperature plasma ignition device with a central electrode featuring tiered firing prongs and a dielectric casing, generating multiple plasma discharge streamers that self-limit and prevent arcing, thereby igniting a larger volume of the air-fuel mixture efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a non-thermal corona discharge is generated by high voltage application to an electrode, then plasma discharge is created to ignite the air-fuel mixture, but the plasma discharge is restricted to a small area and exhibits arcing tendency
Solution Approach 1:
The electrode is segmented into multiple sharp corners or projecting points distributed across its surface. Each segment acts as an independent plasma generation site, collectively creating a larger plasma discharge volume while distributing the electrical stress to reduce arcing tendency.
Solution Approach 2:
The plasma discharge is extended from a point-source or line-source configuration to a multi-dimensional distributed array of sharp corners and projecting points. This spatial distribution across multiple dimensions increases the effective plasma volume while maintaining controlled discharge characteristics.
2Object-affected harmful factors
If voltage and duration are closely controlled to minimize arcing in corona discharge, then arcing is reduced, but the plasma discharge remains restricted to a small area
Solution Approach 1:
The electrode structure is divided into multiple segments with sharp corners and projecting points, allowing the plasma discharge to be distributed across many locations simultaneously. This segmentation enables larger plasma volume without requiring proportional increases in voltage or duration that would cause arcing.
Solution Approach 2:
Multiple small plasma discharge regions at different sharp corners and projecting points are merged into a unified plasma field that collectively covers a larger volume. The individual discharges combine to create an extended ignition zone while each local discharge remains controlled and arc-free.
3Object-affected harmful factors
If a dielectric barrier is used in barrier discharge igniters to prevent arcing, then arcing is prevented, but the ignition is confined to a small volume defined by the gap between electrodes
Solution Approach 1:
The dielectric barrier surface is segmented by the distribution of sharp corners and projecting points, creating multiple localized discharge sites. Each site generates its own plasma region, and the collective effect of all sites produces a larger overall ignition volume while the dielectric barrier continues to prevent arcing at each location.
Solution Approach 2:
The ignition volume is expanded by distributing discharge sites across the surface area of the dielectric barrier rather than confining discharge to a single gap. This creates a two-dimensional or three-dimensional array of plasma regions, significantly increasing the effective ignition volume while maintaining arc prevention through the dielectric barrier.
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 enhances fuel economy, combustion stability, and reduces emissions by providing a larger discharge volume and self-extinguishing plasma streamers, improving fuel reactivity and burn efficiency.
Implementation Method 1
a high frequency/high voltage pulse is applied to the central electrode such that an electric field forms at each firing prong and is concentrated at the firing tip of the respective firing prong. The electric field ionizes the combustible mixture and provides a plasma discharge igniting the combustible mixture.
Implementation Method 2
a high frequency/high voltage pulse is applied to the central electrode such that an electric field forms at each firing prong and is concentrated at the firing tip of the respective firing prong
Implementation Method 3
The casing is configured such that the dielectric barrier is of variable thickness, and is thinnest at the prong tip of each firing prong. In this configuration, a plasma discharge streamer originates from the dielectric casing surface that is closest to the tip of each prong. The discharge streamers formed in this manner are self-limiting and prevent the streamer from turning into an arc due to charge-trapping behavior of the dielectric surface
Data Source
AI summary
An igniter includes a central electrode terminating in a firing portion including a plurality of prong tiers distributed axially on the firing portion. Each prong tier including at least one firing prong extending radially outward from the firing portion. The igniter body includes a port end to be received into an engine igniter port, and a shank. The firing portion of the central electrode extends from the shank opposing the port end. A dielectric casing can fully encapsulate the firing portion of the central electrode to define a dielectric barrier adjacent the firing prong. The igniter may include a generally cylindrical ground electrode defining a discharge cavity surrounding the central electrode. The ground electrode includes a plurality of ground prongs defined by the ground electrode and extending radially toward the firing portion. A plurality of apertures defined by the ground electrode are in fluid communication with the discharge cavity.