Spark Plug Pre-Chamber Injection Hole Diameter Optimization
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Solution Overview
Problem
Pre-chamber spark plugs lack the ability to adapt injection strength to varying ignitability across different portions of the main combustion chamber, leading to suboptimal combustion efficiency due to uniform injection hole strength.
Innovation Solution
A spark plug design with a displaced middle point of the shortest line connecting the center electrode and the facing portion of the ground electrode, allowing for varying injection strengths through the use of multiple injection holes in different parts of the pre-chamber, and a ground electrode configuration that adjusts obstruction based on the layout of the combustion chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If uniform injection strength is provided through all injection holes, then manufacturing simplicity is maintained, but ignitability in different portions of the combustion chamber cannot be optimized
Solution Approach 1:
The patent applies local quality by providing different injection strengths at different locations. Specifically, injection holes are provided with different diameters (first diameter for first injection holes, second diameter for second injection holes) to create different injection strengths corresponding to different ignitability requirements in various portions of the combustion chamber. This allows the pre-chamber to adapt to the combustion chamber layout while maintaining a relatively simple overall structure.
Solution Approach 2:
The patent segments the injection holes into different groups based on their injection strength requirements. The injection holes are divided into first injection holes with a first diameter and second injection holes with a second diameter, allowing independent optimization of each group's injection characteristics to match different regions of the combustion chamber.
2Adaptability or versatility
If the middle point of the shortest line connecting center electrode and ground electrode facing portion is positioned on the axial line, then symmetric structure is maintained, but ignitability cannot be optimized for different combustion chamber layouts
Solution Approach 1:
The patent employs asymmetry by positioning the middle point of the shortest line connecting the center electrode front end portion and the ground electrode facing portion to be displaced from the axial line of the center electrode. This asymmetric configuration allows the spark plug to be adapted to different combustion chamber layouts and flow conditions, optimizing ignitability for specific applications while maintaining a relatively simple electrode structure.
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
Enhances ignitability by adjusting injection strengths according to the combustion chamber layout, improving combustion efficiency and wear resistance of the facing portion.
Implementation Method 1
a ground electrode that includes a facing portion facing a front end portion of the center electrode and forms a discharge gap between the facing portion and the front end portion of the center electrode
Implementation Method 2
after ignition of a spark between electrodes, combustion first occurs in a pre-chamber. Then, flame of the combustion in the pre-chamber is injected out via through holes (injection holes) that are in communication with the outside
Data Source
AI summary
A spark plug having excellent ignitability including a rod-shaped center electrode; a ground electrode that includes a facing portion facing a front end portion of the center electrode and forms a discharge gap between the facing portion and the front end portion of the center electrode; an insulator; a metal shell; and a cover portion that covers, from a front end side of the spark plug, the front end portion of the center electrode and the facing portion of the ground electrode to form a pre-chamber and includes injection holes that are through holes.