Inorganic Fiber Mat with Patterned Needle Marks for Exhaust Gas Cleaning
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Solution Overview
Problem
Inorganic fiber-formed articles used in exhaust gas cleaning devices face a trade-off between delamination strength and surface pressure, where increasing needle mark density enhances delamination strength but decreases surface pressure, and vice versa.
Innovation Solution
The article features a mat-shaped inorganic fiber assembly with needle marks of varying diameters and densities, including dense and non-dense portions, where needle marks A are arranged densely in specific patterns and needle marks B are introduced in non-dense areas to enhance delamination strength without compromising surface pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If needle mark density is increased to enhance delamination strength, then delamination strength is improved, but surface pressure decreases
Solution Approach 1:
The patent applies local quality by creating non-uniform needle mark distribution with dense portions (high needle mark density) and non-dense portions (low needle mark density) in different regions of the inorganic fiber-formed article. The dense portions provide high delamination strength where layer separation resistance is critical, while the non-dense portions maintain high surface pressure and resilience. This spatial variation in needle mark density allows simultaneous optimization of both delamination strength and surface pressure, resolving the technical contradiction between these two properties.
2Stress or pressure
If needle mark density is decreased to maintain surface pressure, then surface pressure is improved, but delamination strength decreases
Solution Approach 1:
The patent resolves this contradiction by strategically locating non-dense portions (low needle mark density) in specific regions where surface pressure and resilience are prioritized, while maintaining dense portions (high needle mark density) in regions where delamination strength is critical. This localized differentiation allows the article to exhibit high surface pressure overall while maintaining sufficient delamination strength through the dense portions, thus overcoming the trade-off between these two properties.
3Ease of manufacture
If uniform needle mark distribution is used to simplify manufacturing, then manufacturing complexity is reduced, but both delamination strength and surface pressure cannot be optimized simultaneously
Solution Approach 1:
The patent implements local quality through a needling process that creates regions of different needle mark densities. While this requires more complex process control than uniform needling, the patent provides specific guidance on creating dense and non-dense portions through controlled needling parameters, needle arrangement patterns, and multi-stage needling processes. This approach achieves simultaneous optimization of delamination strength (through dense portions) and surface pressure (through non-dense portions), making the performance benefit outweigh the moderate increase in manufacturing complexity.
Solution Approach 2:
The patent applies segmentation by dividing the inorganic fiber-formed article into functional zones: dense portions for delamination resistance and non-dense portions for surface pressure maintenance. This segmentation is achieved through controlled needling processes that create distinct regions with different needle mark densities. The segmented structure allows each region to perform its specific function optimally, resolving the contradiction between manufacturing simplicity and performance optimization by providing a systematic approach to patterned needling.
Data Source
Figure 1a~1b
Figure 2~3
Figure 4a~6
AI summary
Provided are: an inorganic fiber-formed article having a high delamination strength between layers as well a high surface pressure; a mat for an exhaust gas cleaning apparatus; and an exhaust gas cleaning apparatus, the mat and the apparatus using the inorganic fiber-formed article. The inorganic fiber-formed article 1 is composed of a mat-shaped inorganic fiber assembly and has needle marks A, B which extend in a direction including the thickness direction of the mat-shaped assembly. Dense portions 2, in which a plurality of needle marks A lie densely, are arranged apart in a spread out manner. In both a first direction which any direction extending through the dense portions 2 on the surface of the mat, and a second direction orthogonal to the first direction, non-dense portions 4 are present between the dense portions 2. The needle marks B have a diameter smaller than that of the needle marks A.