Corona Enhancing Tip for Igniter Erosion Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional corona discharge igniters in internal combustion engines experience electrical erosion and chemical corrosion, leading to a decrease in electrical field strength and ignition performance over time, resulting in arcing and irregular ignition positions.
Innovation Solution
The igniter features a corona enhancing tip with a base member made of a material with a higher erosion and corrosion rate, paired with an emitting member made of a volume-stable material with lower erosion and corrosion rates, maintaining a sharp point for consistent electrical field emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the corona enhancing tip is made of a single material with high electrical conductivity, then the electrical field emission is strong initially, but the tip experiences rapid electrical erosion and corrosion leading to performance degradation
Solution Approach 1:
The corona enhancing tip is constructed as a composite structure with a nickel base material providing mechanical strength and electrical conductivity, and an iridium emitting member providing erosion and corrosion resistance. This composite design allows the tip to maintain strong electrical field emission while resisting degradation from electrical erosion and chemical corrosion in the combustion chamber environment.
Solution Approach 2:
The emitting member is positioned specifically at the distal ends of the branches where the electrical field is most concentrated and erosion is most severe. This localized placement of the erosion-resistant iridium material provides protection exactly where it is needed most, while the nickel base material provides structural support throughout the entire tip structure.
2Productivity
If the spherical radius at the distal ends is minimized to concentrate the electrical field, then ignition efficiency is improved, but the tip becomes more susceptible to electrical erosion and spherical radius increase over time
Solution Approach 1:
The combination of nickel and iridium creates a structure where the iridium emitting member maintains a small spherical radius resistant to erosion, while the nickel base provides structural integrity. This allows the tip to maintain the sharp geometry needed for efficient ignition while being protected against the erosion that would otherwise rapidly blunt such a sharp feature.
3Power
If the corona enhancing tip operates at high voltage to maintain strong electrical field, then ignition performance is improved, but electrical erosion and corrosion rates increase
Solution Approach 1:
The iridium emitting member provides exceptional resistance to electrical erosion and chemical corrosion, allowing the tip to operate at high voltages needed for strong electrical field emission without suffering rapid material loss. The nickel base material provides additional erosion resistance and structural support, enabling sustained high-voltage operation.
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 design maintains a strong and consistent electrical field over time, improving ignition quality and efficiency, and providing energy cost savings by emitting a stronger field at lower voltages compared to conventional igniters.
Implementation Method 1
emitting an electrical field that forms a corona to ionize and ignite a mixture of fuel and air
Implementation Method 2
ionize and ignite a mixture of fuel and air
Data Source
AI summary
An igniter (20) emitting an electrical field including a plurality of streamers forming a corona includes a corona enhancing tip (52) at an electrode firing end (28). The corona enhancing tip (52) includes an emitting member (58) such as a wire, layer, or sintered mass, formed of a precious metal and disposed on a base member (54). The base member (54) is formed of a nickel alloy. The emitting member (58) has a lower electrical erosion rate and chemical corrosion rate than the base member (54). The emitting member (58) presents the smallest spherical radius of the corona enhancing tip (52) at the outermost radial point (56) to concentrate the electrical field emissions and provide a consistently strong electrical field strength over time.