Corona Igniter Electrode Thermal Management
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Solution Overview
Problem
Corona igniters in internal combustion engines often reach undesirable high temperatures at the firing end, leading to degraded ignition quality and reduced endurance due to the lack of effective thermal management.
Innovation Solution
The use of a central electrode with a high thermal conductivity core material, such as copper, surrounded by a clad material like nickel, combined with a specific geometry of the insulator and central electrode, reduces the operating temperature at the firing end by minimizing parasitic capacitance and allowing for exceptional heat transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a conventional corona igniter design is used, then the igniter can provide corona discharge ignition, but the temperature at the firing end becomes excessively high (greater than 950°C)
Solution Approach 1:
The central electrode employs a composite structure with a copper core material surrounded by a nickel or nickel alloy clad material. The copper core provides high thermal conductivity to manage heat, while the nickel clad offers corrosion resistance and appropriate electrical properties, creating a composite material solution that resolves the temperature-quality contradiction
Solution Approach 2:
The igniter design implements local quality by concentrating the high thermal conductivity core material specifically at the firing end where heat management is critical, while the clad material provides localized protection at the surface. This spatial differentiation of material properties enables effective temperature control where needed most
2Temperature
If the central electrode uses high thermal conductivity core material with specific geometry, then heat transfer improves and temperature reduces, but the device structure becomes more complex
Solution Approach 1:
The two-layer composite electrode structure (copper core with nickel clad) achieves superior temperature management through the synergistic combination of materials with different properties, resolving the contradiction between thermal performance and structural simplicity by integrating multiple functions into a single composite component
3Power
If the corona igniter operates at high temperature, then the electrical field can be maintained, but the endurance and combustion performance degrade
Solution Approach 1:
The design converts the potentially harmful effect of heat generation into a beneficial thermal management system. The high thermal conductivity core material actively dissipates heat that would otherwise degrade performance, transforming the harmful thermal buildup into a controlled thermal regime that extends endurance while maintaining power
Solution Approach 2:
The invention changes the thermal parameters of the central electrode by introducing high thermal conductivity materials, fundamentally altering the temperature profile and enabling sustained operation at lower temperatures, thereby extending the duration of effective 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
The solution achieves a temperature reduction of approximately 100°C or more at the electrode firing end and insulator nose end compared to prior art, enhancing ignition performance and endurance by maintaining lower operating temperatures.
Implementation Method 1
The central electrode of the corona igniter, which includes a core material having a high thermal conductivity
Implementation Method 2
A corona igniter of a corona discharge ignition system receives a voltage from a power source and emits an electrical field that forms a corona to ionize a mixture of fuel and air
Implementation Method 3
An insulator is disposed along the central electrode
Data Source
Figure 1
Figure 1A
Figure 2
AI summary
A corona igniter 20 with improved temperature control at the firing end is provided. The corona igniter 20 comprises a central electrode 24 include a core material 30, such as copper, surrounded by a clad material 32, such as nickel. The core material 30 extends longitudinally between an electrode terminal end 34 and an electrode firing end 36. The core material 30 is disposed at the electrode terminal end 34 and has a core length lc equal to at least 90% of an electrode length le of the central electrode 24. At least 97% of the core length lc is surrounded by an insulator 26. The electrode diameter is increased, such that a clad thickness tcl of the central electrode 24 is equal to at least 5% of an insulator thickness ti, and a core diameter Dc is equal to at least 30% of the insulator thickness ti.