Recessed Ground Electrode Spark Plug for High Thermal Loads
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Solution Overview
Problem
Spark plugs used in engines subject to high thermal loads, such as hydrogen-powered engines, face challenges due to the high thermal stress caused by the necessary length of the ground electrode, which limits their durability and performance.
Innovation Solution
The spark plug design features a housing with a recess on the end side, where the ground electrode is arranged, creating an ignition gap inside the housing. This configuration allows for shorter electrodes, reduced heat absorption from the combustion chamber, and improved heat dissipation through the housing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the ground electrode is designed with necessary length for traditional spark plugs, then the ignition function is ensured, but the thermal load on the spark plug increases
Solution Approach 1:
The ground electrode is moved from a traditional external position to an internal position within a recess in the housing end side. This spatial reconfiguration allows the ignition gap to be formed inside the housing rather than protruding into the combustion chamber, thereby reducing the electrode length exposed to high temperatures while maintaining ignition functionality
Solution Approach 2:
The ground electrode is extracted from the traditional combustion chamber environment and placed into a protected recess in the housing. This separation removes the electrode from the harsh thermal environment of the combustion chamber while preserving its essential ignition function through the newly formed internal ignition gap
2Reliability
If the ground electrode protrudes into the combustion chamber, then the ignition gap can be formed, but heat absorption from the combustion chamber increases
Solution Approach 1:
The ignition gap formation is relocated from the combustion chamber space to the internal housing space. By forming the ignition gap inside the housing through the recess configuration, the electrodes no longer need to protrude into the combustion chamber, thus eliminating direct exposure to combustion heat while maintaining the ignition function
3Reliability
If the electrodes are made longer to ensure ignition function, then the ignition reliability is improved, but the heat dissipation from electrodes via housing becomes less effective
Solution Approach 1:
Instead of extending electrodes outward to ensure ignition function, the solution inverts the approach by recessing the ground electrode into the housing. This inversion allows the ignition gap to be formed internally while the housing structure itself becomes the primary heat dissipation path, improving thermal management
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 enhances the thermal resilience of the spark plug, improves heat dissipation, and reduces the risk of overheating, making it suitable for high-thermal-load engines like hydrogen-powered engines.
Implementation Method 1
the ground electrode and the central electrode are arranged such that an ignition gap is formed inside the housing
Implementation Method 2
the heat dissipation from the electrodes via the housing into a cylinder head, in which the spark plug according to the present invention is fitted, is more effective
Data Source
AI summary
A spark plug with a longitudinal axis. The spark plug includes a housing with a hole along the spark plug longitudinal axis and a combustion-chamber-side end side, wherein the housing has a recess on the end side thereof; an insulator arranged inside the housing; a central electrode arranged inside the insulator; and a ground electrode arranged in one of the recesses on the housing end side; wherein the ground electrode and the central electrode are arranged such that an ignition gap is formed within the housing.