Holding Sealing Material Interface Design for Exhaust Gas Purifying Apparatus
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Solution Overview
Problem
Existing holding sealing materials for exhaust gas purifying apparatuses face challenges in maintaining high shear strength and preventing peeling and fracture under high temperature and shear stress conditions, which can lead to exhaust gas leakage.
Innovation Solution
A holding sealing material comprising a needle mat with entangled inorganic fibers and a sheet-processed mat, where staple fibers with a shorter average length than the second inorganic fibers are localized in the interface area, and the binder content is higher in the interface area than in the needle mat, enhancing the bonding and anchoring effect between the mats.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a holding sealing material includes two inorganic fiber layers (alumina fibers and ceramic fibers) to provide heat resistance, then the material can withstand high temperature, but the material lacks sufficient shear strength and winding ability under high temperature conditions
Solution Approach 1:
The patent combines organic binder with inorganic fibers to create a composite holding sealing material. The organic binder (polyvinyl alcohol, carboxymethyl cellulose, or starch) provides cohesive bonding that enhances shear strength, while the inorganic fiber matrix maintains heat resistance. This composite structure allows the material to withstand both high temperatures and shear stresses that would cause conventional inorganic fiber materials to fail.
Solution Approach 2:
The patent modifies the chemical composition parameters by introducing specific organic binders with controlled content (5-30% by weight). These parameter changes transform the material properties, enabling the holding sealing material to maintain structural integrity and shear strength at high temperatures where conventional inorganic fiber materials would lose strength.
2Reliability
If the holding sealing material is wound around the exhaust gas treating body and press-fitted into the casing, then the material can seal and hold the treating body, but great shear stress is loaded on the material causing crack and fracture formation
Solution Approach 1:
The organic binder-inorganic fiber composite structure provides the necessary toughness and shear strength to withstand the great shear stress during press-fitting. The binder creates a flexible matrix that absorbs shear stress without cracking, while the inorganic fibers provide structural support and sealing capability.
Solution Approach 2:
The patent creates local quality differences by distributing the organic binder throughout the inorganic fiber matrix, concentrating bonding strength at critical interfaces where shear stress is highest during assembly, while maintaining heat resistance in the bulk material.
3Strength
If the holding sealing material is made with high binder content to improve bonding between layers, then the shear strength increases, but the material may lose heat resistance and structural integrity
Solution Approach 1:
The patent optimizes the binder content parameter to a specific range (5-30% by weight) to achieve the right balance. This parameter optimization ensures sufficient bonding strength while maintaining heat resistance, as excessive binder would compromise the inorganic fiber matrix structure and thermal stability.
Solution Approach 2:
The binder is distributed locally within the composite structure, providing bonding strength at fiber interfaces and layer boundaries where needed, while the bulk material retains its inorganic fiber-dominated composition for heat resistance.
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 significantly improves the shear strength and winding ability of the holding sealing material, reducing the likelihood of peeling and fracture, thus preventing exhaust gas leakage and ensuring smooth assembly of the exhaust gas purifying apparatus.
Implementation Method 1
a binder, and second inorganic fibers processed into a sheet
Implementation Method 2
Staple fibers having an average fiber length shorter than an average fiber length of the second inorganic fibers are localized in an interface area extending inside the needle mat from an interface between the needle mat and the sheet-processed mat
Data Source
AI summary
A holding sealing material includes a needle mat, a sheet-processed mat, and a sheet-processed mat. The needle mat includes entangled first inorganic fibers and a binder. The sheet-processed mat includes a binder and second inorganic fibers processed into a sheet. The needle mat and the sheet-processed mat are laminated together. Staple fibers having an average fiber length shorter than an average fiber length of the second inorganic fibers are localized in an interface area extending inside the needle mat from an interface between the needle mat and the sheet-processed mat. A binder content of the interface area is higher than a binder content of the needle mat in terms of weight ratio.