Multipoint Ignition Device Thermal Expansion Mediator
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing multipoint ignition devices face issues with secure holding due to thermal expansion coefficient differences between insulating and metallic materials, leading to potential dislodging at increased temperatures.
Innovation Solution
Incorporating an intermediate member with a larger thermal expansion coefficient between the main body and insulating member, which expands to maintain contact and secure the insulating member's position, preventing gap formation and ensuring secure holding during temperature increases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the main body portion is formed from metallic material and the insulating member is formed from ceramic material, then the electrical insulation performance is improved, but the thermal expansion coefficient difference causes insecure holding at increased temperatures
Solution Approach 1:
An intermediate member made of metallic material is introduced between the main body portion (metallic) and the insulating member (ceramic). This intermediate member acts as a mediator that accommodates thermal expansion differences through its own expansion, maintaining secure holding of the insulating member even at elevated temperatures while preserving the electrical insulation performance provided by the ceramic material.
2Device complexity
If the insulating member is held directly by the main body portion, then the device structure is simplified, but gaps form between components when temperature increases due to differential thermal expansion
Solution Approach 1:
The intermediate member serves as a mediator component between the main body portion and the insulating member. Although this adds a component to the structure, it prevents gap formation by utilizing its thermal expansion properties to maintain continuous contact between the metallic main body and the ceramic insulating member during temperature increases, thereby ensuring stable component positioning.
3Reliability
If an intermediate member with larger thermal expansion coefficient is added, then the secure holding at high temperature is improved, but the device complexity increases
Solution Approach 1:
The intermediate member is specifically designed with a thermal expansion coefficient larger than that of the insulating member. This deliberate selection of material property allows the intermediate member to expand more during temperature increases, actively compensating for the thermal expansion mismatch between the metallic main body and ceramic insulating member, thereby maintaining secure holding without requiring complex additional mechanisms.
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 solution effectively suppresses the formation of gaps between the main body and insulating member, ensuring the device remains securely attached and functional even at elevated temperatures, enhancing thermal stability and reliability.
Implementation Method 1
the intermediate member undergoes thermal expansion, and as a result, formation of a gap between the main body portion and the insulating member is suppressed
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A multipoint ignition device (100) for igniting an air-fuel mixture in a combustion chamber (4) of an engine (1) includes: an insulating member (12) formed in an annular shape such that an inner periphery thereof faces the combustion chamber (4); a plurality of electrodes (14) held on the insulating member (12) so as to form a plurality of ignition gaps (17) inside the combustion chamber (4); a main body portion (10) provided on an outer periphery of the insulating member (12); and an intermediate member (11) that is provided between the main body portion (10) and the insulating member (12) and has a larger thermal expansion coefficient than the insulating member (12).