Vehicle Exhaust Heating Grid Thermal Expansion Relief
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Solution Overview
Problem
Existing heating members in vehicle exhaust gas purification devices face issues with radial thermal expansion leading to short circuits and hot spots due to increased temperature, causing brittleness and potential breakage.
Innovation Solution
A heating member design featuring a perforated grid with elongate heating elements, outer and inner connection legs, and a relief structure to absorb radial thermal expansion, preventing node contact and enhancing mechanical strength and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the heating grid temperature is increased to heat the purification member, then the heating performance is improved, but radial thermal expansion causes the wires to be compressed resulting in short circuits and hot spots
Solution Approach 1:
The heating grid is segmented into multiple independent heating strands connected by nodes, allowing each strand to expand independently rather than as a rigid grid, thereby preventing compression-induced short circuits while maintaining heating effectiveness
Solution Approach 2:
The material properties of the heating strands are selected to have low thermal expansion coefficients, and the geometric configuration of the grid is designed with appropriate strand spacing and node flexibility to accommodate thermal expansion without causing wire compression or short circuits
2Duration of action of moving object
If the heating grid operates at high temperature for extended periods, then the heating function is maintained, but hot spots develop causing significant brittleness and potential breakage
Solution Approach 1:
The heating grid employs nodes with locally optimized geometry and material properties that distribute thermal stress uniformly across connection points, preventing hot spot formation and maintaining structural integrity during prolonged high-temperature operation
Solution Approach 2:
The design accepts thermal expansion as an inevitable phenomenon but converts it into a beneficial effect by incorporating expansion accommodation features that prevent wire compression, thereby transforming the potential harm of thermal expansion into a design advantage that enhances durability
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 design significantly increases the durability and performance of heating members by effectively managing thermal expansion, preventing hot spots and breakage, while maintaining efficient heating performance.
Implementation Method 1
a heating member for a vehicle exhaust gas purification device
Implementation Method 2
the increased temperature of the heating grid causes radial thermal expansion
Implementation Method 3
the heating grid is deformed, preferably by stamping, so as to form a relief having an annular shape
Data Source
AI summary
A heating member for a vehicle exhaust gas purification device includes an electrically conductive outer peripheral frame that has a geometric center and is symmetrical about an axis. An electrically conductive central support is centered on the geometric center, and a perforated heating grid is centered on the geometric center. The heating grid extends between the electrically conductive central support and the electrically conductive outer peripheral frame. The heating grid is formed of a plurality of strands connected by nodes, with the plurality of strands delimiting openings therebetween.