Prechamber Spark Plug Lateral-Bore Electrode Gap Adjustment
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Solution Overview
Problem
Existing pre-chamber spark plugs for stationary gas engines are not suitable for mass production and are costly due to their design, which makes them unsuitable for use in mobile internal combustion engines, particularly in vehicles, where precise electrode gap maintenance across varying loads is required.
Innovation Solution
A pre-chamber spark plug design with a ground electrode arranged in a lateral bore of the housing, allowing for precise adjustment of the electrode gap through a clearance fit and a fixing area, enabling mass production by eliminating the need for separate welding and allowing for a single-piece cap and housing construction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the electrode gap is set during the firing life of the spark plug, then the gap can be adjusted to maintain optimal performance, but the manufacturing precision and reliability are compromised due to gap variation over time
Solution Approach 1:
The spark plug incorporates a movable ground electrode that can be positioned at different gaps relative to the center electrode. This dynamic structure allows the electrode gap to be adjusted during the firing life of the spark plug, enabling maintenance of optimal performance without requiring replacement. The movable electrode is driven by a piezoelectric element that responds to changes in combustion chamber conditions, automatically adjusting the gap to maintain peak efficiency.
2Adaptability or versatility
If a movable ground electrode is used to adjust the electrode gap, then the spark plug can adapt to changing conditions, but the device complexity increases
Solution Approach 1:
The spark plug utilizes piezoelectric elements that change their physical state in response to combustion chamber conditions. These piezoelectric elements expand or contract based on temperature and pressure changes, which in turn moves the ground electrode to adjust the electrode gap. This parameter-based control mechanism provides automatic adaptation to changing combustion conditions without requiring complex control systems or multiple moving parts.
3Adaptability or versatility
If the electrode gap varies during firing life, then adaptability is improved, but the reliability decreases due to unpredictable gap changes
Solution Approach 1:
The spark plug incorporates a feedback mechanism where piezoelectric elements continuously monitor combustion chamber conditions and automatically adjust the electrode gap in response. This closed-loop system ensures that the gap is adjusted in a controlled and predictable manner based on actual combustion conditions, maintaining reliability while providing adaptability. The feedback control prevents random or unpredictable gap variations by using measurable physical parameters to drive the adjustment.
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 design enables precise and cost-effective mass production of pre-chamber spark plugs suitable for mobile internal combustion engines, ensuring consistent ignition across varying loads with reduced manufacturing costs and thermal distortion.
Implementation Method 1
the piezoelectric element expanding or contracting in response to combustion chamber conditions, thereby moving the ground electrode
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The present invention relates to a prechamber spark plug comprising a central electrode (2) and a ground electrode (3) which are arranged in a prechamber (7), and a housing (4) having a lateral hole (40), the ground electrode (3) being arranged in the lateral hole (40) in such a way that there is a gap portion (8) and a fastening portion (8) between the ground electrode (3) and the housing (4).