Pre-Chamber Spark Plug Cap Recess for Gas Exchange Control
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Solution Overview
Problem
Existing pre-chamber spark plugs experience unfavorable flow situations due to angular position and proximity to engine components, leading to impaired gas exchange and potential thermal issues, which affect ignition reliability.
Innovation Solution
The cap of the pre-chamber spark plug features a recess on its outer side with strategically positioned through-openings, allowing for optimized gas flow guidance and control of flare jets, adaptable to specific combustion chamber conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a uniform dome-like cap shape is used, then manufacturing is simple and cost-effective, but gas flow guidance is poor and exchange of fresh gas and residual gas is impaired
Solution Approach 1:
The cap features a recess on its outer side that creates locally optimized flow conditions. This recess modifies the gas flow pattern specifically in the combustion chamber area, enabling better fresh gas exchange and flare jet direction without changing the entire cap geometry, thus maintaining manufacturing simplicity while improving ignition reliability.
2Ease of operation
If the pre-chamber spark plug is positioned at certain angular positions or near other components, then assembly is straightforward, but unfavorable flow situations arise and thermal overheating occurs
Solution Approach 1:
The recess on the cap's outer side creates localized flow optimization that compensates for unfavorable positioning conditions. By modifying the flow pattern in specific areas through the recess geometry, the system protects against thermal overheating and flow obstruction caused by angular positioning or proximity to other components, without requiring complex assembly adjustments.
3Productivity
If through-openings are provided in the cap, then torch jets can pass into the combustion chamber, but gas flow control is insufficient under certain operating conditions
Solution Approach 1:
The recess on the cap's outer side works in conjunction with the through-openings to provide localized flow control. This recess modifies the gas flow pattern emerging from the through-openings, enabling better direction of flare jets and improved gas exchange under various operating conditions, thus enhancing both ignition effectiveness and flow adaptability.
Solution Approach 2:
The recess creates an asymmetric flow pattern that adapts to different operating conditions. By breaking the symmetry of the uniform dome-like cap, the recess enables differentiated flow control in different directions, allowing the system to adapt to varying angular positions and operating environments while maintaining effective torch jet passage through the through-openings.
Data Source
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AI summary
The present invention relates to a pre-chamber spark plug, comprising a housing (6), and a cap (3) which is provided on a combustion-chamber-side end (10) of the pre-chamber spark plug, wherein the cap (3) has a recess (8) on a combustion-chamber-side outer side (34).