Pre-chamber Spark Plug Fuel Valve Thermal Management
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Solution Overview
Problem
In gaseous fuel internal combustion engines, the close proximity of the fuel valve to the pre-chamber leads to increased wear and potential failure due to heat generated during ignition and combustion, as the fuel valve is sensitive to high temperatures.
Innovation Solution
The fuel valve is positioned at a safe distance from the pre-chamber, with a fuel supply channel and capillary tube arrangement that reduces temperature impact, including a capillary tube with a reduced diameter to prevent flame propagation and dampen pressure influences, and a fuel valve reception design that ensures the fuel valve is not ejected unintentionally.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the fuel valve is positioned close to the pre-chamber for compact design, then device complexity is reduced, but the fuel valve experiences increased temperature and wear leading to reduced reliability
Solution Approach 1:
The fuel valve is extracted from the immediate vicinity of the pre-chamber and positioned in the rear housing portion, separating it from the high-temperature combustion zone. This extraction reduces thermal exposure and wear on the fuel valve while maintaining functional integration through the fuel supply channel system
Solution Approach 2:
The first fuel supply channel acts as an intermediary element connecting the fuel valve (in the rear housing) to the pre-chamber (in the tip housing). This intermediary allows functional connection while maintaining spatial separation, enabling the fuel valve to be positioned away from heat sources
2Temperature
If the fuel valve is positioned far from the pre-chamber to reduce heat exposure, then temperature impact on the fuel valve is reduced, but the overall length of the spark plug increases
Solution Approach 1:
The spark plug structure utilizes multiple spatial dimensions and sections (tip housing portion, intermediate housing portion, rear housing portion) arranged along the longitudinal axis. The fuel valve is positioned in the rear housing portion while the pre-chamber is in the tip housing portion, distributing components along the length to achieve thermal separation without excessive overall elongation
3Reliability
If a capillary tube with reduced diameter is used to prevent flame propagation, then flame arrest capability is improved, but fuel flow resistance increases
Solution Approach 1:
The capillary tube has a specifically optimized reduced diameter that balances flame arrest capability with acceptable fuel flow characteristics. The diameter is sufficiently small to prevent flame propagation through the fuel supply channel while remaining large enough to maintain adequate fuel delivery to the pre-chamber
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 configuration significantly reduces the temperature impact on the fuel valve, increasing its lifespan by maintaining it in a cooler region and preventing accidental ejection, thereby enhancing the reliability and durability of the pre-chamber spark plug system.
Implementation Method 1
a capillary tube with a reduced diameter to prevent flame propagation
Implementation Method 2
a fuel valve reception design that ensures the fuel valve is not ejected unintentionally
Data Source
Figure 1
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AI summary
The present disclosure relates to a pre-chamber spark plug (10) for a gaseous fuel internal combustion engine. The pre-chamber spark plug (10) comprises a pre-chamber (26) having a maximum pre-chamber height (h) measured along the first longitudinal axis (A). The pre-chamber spark plug (10) further comprises a fuel valve (48) arranged in a distance (s) to the pre-chamber (26). The distance (s) is at least three times greater than the maximum pre-chamber height (h) to considerably reduce the temperature impact from the pre-chamber (26) onto the fuel valve (48).