Spark Plug Conductive Layer Eliminates Air Gap Energy Loss
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Solution Overview
Problem
The existing spark plugs using non-equilibrium plasma suffer from energy loss due to an air layer between the center electrode and the metal shell, which reduces the apparent dielectric constant and the amount of electric charge generated, affecting ignitability.
Innovation Solution
A spark plug design featuring a conductive layer covering the inner peripheral surface of the insulator, eliminating the air layer and enhancing the dielectric constant, with the terminal electrically connected to the conductive layer and insulated from the metal shell, allowing for improved energy efficiency and plasma generation closer to the combustion chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a clearance is provided between the inner peripheral surface of the insulator and the center electrode, then the ease of manufacture is improved, but the apparent dielectric constant decreases and energy loss increases
Solution Approach 1:
The patent removes the harmful air layer between the insulator and center electrode by filling the clearance with conductive material. This extracts the problematic element (air) that causes dielectric constant reduction and replaces it with a beneficial substance (conductive material) that enhances plasma generation while maintaining manufacturing ease.
Solution Approach 2:
The patent changes the physical parameter of the clearance by filling it with conductive material, thereby transforming the dielectric properties of the spark plug. This parameter change increases the apparent dielectric constant and reduces energy loss while preserving the ease of center electrode insertion during manufacturing.
2Ease of manufacture
If a clearance is provided between the insulator and center electrode, then the ease of manufacture is improved, but the ignitability deteriorates
Solution Approach 1:
The patent extracts the air layer from the clearance between insulator and center electrode, removing the element that deteriorates ignitability. By replacing air with conductive material, the plasma generation capability is enhanced, thereby improving reliability of ignition while maintaining manufacturing simplicity.
Solution Approach 2:
The patent modifies the dielectric parameter by filling the clearance with conductive material, which changes the electrical characteristics of the spark plug. This parameter change enhances plasma generation and improves ignitability reliability without complicating the manufacturing process.
3Loss of energy
If the conductive layer covers the inner peripheral surface of the insulator, then the energy efficiency is improved, but the device complexity increases
Solution Approach 1:
The conductive layer serves multiple functions simultaneously: it fills the clearance to eliminate air layer losses, enhances plasma generation by increasing apparent dielectric constant, and provides a pathway for charge accumulation. This multi-functionality achieves energy efficiency improvement without proportionally increasing device complexity.
Solution Approach 2:
The patent employs a composite structure combining the insulator material with a conductive layer. This composite material approach allows the spark plug to exhibit both insulating properties (from the insulator) and conductive properties (from the conductive layer), achieving energy efficiency enhancement while maintaining manageable structural complexity.
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 spark plug achieves improved ignitability by reducing energy loss and increasing the amount of gas ionized, with enhanced heat dissipation and efficient plasma generation at the center of the combustion chamber.
Implementation Method 1
electric charge generated based on a dielectric constant of the spark plug moves to the surface of the insulator and a gas around the insulator is ionized (a non-equilibrium plasma is generated around the insulator)
Implementation Method 2
The inner peripheral surface of the insulator at that part is covered with the conductive layer and no air layer is arranged between the conductive layer and the insulator. Therefore, influence of the air layer on the ignitability can be suppressed.
Data Source
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AI summary
A spark plug including a bottomed tubular insulator (20), a tubular metal shell (30), a conductive layer (40), and a terminal. The insulator (20) extends along an axial line (O) from a front end side to a rear end side and is closed at a front end. The metal shell (30) has a ledge portion (37) that projects radially inward and locks the insulator (20) from the front end side. The metal shell (30) holds the insulator (20) from an outer peripheral side. The conductive layer (40) covers at least a part of an inner peripheral surface (25) of a portion of the insulator (20) which is located on the front end side with respect to a locking portion (24) locked by the ledge portion (37). The terminal is electrically connected to the conductive layer (40) and is insulated from the metal shell (30).