Pre-combustion Chamber Tip Orifice Segmentation for Thermal Stress Reduction
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Solution Overview
Problem
The high temperatures in pre-combustion chambers of internal combustion engines, particularly in gaseous fuel engines, pose a challenge for the longevity of spark plugs and pre-combustion chamber tips, and existing designs face difficulties in maintaining performance and power output while ensuring stable fuel transition and reducing mechanical and thermal stress.
Innovation Solution
A pre-combustion chamber tip with a dome-like shaped wall structure featuring a plurality of orifices, where the outlets are distributed azimuthically and arranged in two groups at different angles, providing a tapered cross-section to enhance the effective cross-sectional area and reduce thermal stress, while maintaining efficient fuel flow and power output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the pre-combustion chamber is downsized to meet future emission regulations, then emission performance is improved, but the effective cross-section of the orifices must be maintained to ensure stable fuel transition
Solution Approach 1:
The orifice system is segmented into multiple smaller orifices arranged in a specific pattern on the outlet band. This segmentation allows the total effective cross-section to be maintained while fitting within a downsized pre-combustion chamber volume, thus resolving the contradiction between chamber size reduction and orifice area maintenance for stable fuel transition.
2Power
If the pre-combustion chamber operates at high temperatures to maintain power output, then power output is improved, but the lifespan of spark plug and pre-combustion chamber tip deteriorates
Solution Approach 1:
The pre-combustion chamber tip is designed with a specific geometric configuration including a outlet band with distributed orifices that creates favorable flow patterns. This local structural quality optimization ensures stable fuel transition and reduces thermal stress concentration at critical locations, thereby extending component lifespan while maintaining the high temperatures necessary for power output.
3Productivity
If the velocity of burning fuel is increased to improve combustion efficiency, then combustion efficiency is improved, but mechanical and thermal stress on the pre-combustion chamber tip increases
Solution Approach 1:
The orifices are arranged on a circumferential outlet band at a specific axial position, creating a three-dimensional flow distribution pattern. This spatial arrangement in multiple dimensions allows the burning fuel to expand and mix more effectively, maintaining high combustion efficiency while reducing velocity concentration and associated mechanical and thermal stress on the chamber tip.
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 effectively reduces thermal and mechanical stress on the pre-combustion chamber tip, enhances the effective cross-sectional area for fuel flow, and maintains engine performance and power output by distributing the outlets at specific angles and positions, thus extending the lifespan of the components.
Implementation Method 1
Central regions of the outlets of the plurality of orifices are distributed azimuthically with respect to the center axis
Implementation Method 2
providing a tapered cross-section to enhance the effective cross-sectional area and reduce thermal stress
Implementation Method 3
a dome-like shaped wall structure forming at least a portion of a pre-combustion chamber and having a center axis
Data Source
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AI summary
A pre-combustion chamber tip (76) of an internal combustion engine (10) exposed to high thermal and mechanical stress may be limited in space for arranging orifices (190, 290) fluidly communicating with a main combustion chamber (26) of the internal combustion engine. It is disclosed to efficiently use the limited space by providing a first group of orifices (190) extending at a first angle (α) with respect to a center axis (112) and a second group of orifices (290) extending at a second angle with respect to the center axis (112), wherein the outlets of the orifices are arranged at a first axial position (P1).