Exhaust Mounting Mat Edge Coating for Fiber Shedding and Erosion
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Solution Overview
Problem
Existing mounting mats for exhaust gas treatment devices face challenges with fiber shedding and erosion, particularly during handling and use, as existing edge protectants either stiffen and crack or fail to provide adequate protection against hot gases.
Innovation Solution
A mounting mat with a protection coating comprising inorganic particles of average diameter at least 1 μm applied to edge surfaces, which prevents fiber shedding and erosion by fixing fibers and sealing the surface, allowing the mat to remain flexible and withstand thermal stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing edge protectants are applied to mounting mats, then erosion resistance is improved, but the mat edge area stiffens and cracks after drying
Solution Approach 1:
The patent changes the particle size parameter of the inorganic erosion resisting agent to between 0.5 μm and 5 μm, which is smaller than conventional particles. This parameter change allows the protectant to penetrate and embed within the fiber structure rather than forming a rigid surface layer, maintaining flexibility while providing erosion resistance. The smaller particles can be incorporated into the mat structure without creating stiffness that leads to cracking.
Solution Approach 2:
The protection coating is applied selectively to the edge surfaces of the mounting mat rather than the entire surface. This local application ensures that the edge areas receive erosion protection while the central areas maintain their original flexibility and bonding properties. The coating thickness and particle distribution are optimized for edge protection without affecting the overall mat performance.
2Productivity
If mounting mats are handled during manufacturing, then production progress is made, but fiber shedding occurs from the mat edges
Solution Approach 1:
The erosion resisting agent is applied to the mounting mat edges before the mat is wound around the pollution control element during assembly. This preliminary protection prevents fiber shedding that would occur during subsequent handling, winding, and installation operations. The protectant is in place before any mechanical stress or fiber exposure risks arise during manufacturing and installation processes.
3Reliability
If larger inorganic particles are used in the protection coating, then erosion resistance is improved, but the coating becomes rigid and cracks
Solution Approach 1:
The patent optimizes the particle size parameter to a specific range (0.5 μm to 5 μm) that balances erosion resistance with flexibility. Particles in this size range are small enough to embed within the fiber matrix and move with the mat during thermal expansion and contraction, preventing crack formation. Larger particles would create rigid inclusions that cause stress concentration and cracking under thermal cycling conditions.
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 prevents fiber shedding during handling and protects against erosion during use, maintaining the mat's flexibility and integrity, even after drying, thus enhancing the mat's performance and durability.
Implementation Method 1
The inorganic particles have an average diameter of at least 1 μm and are applied to edge surfaces to fix fibers and provide erosion protection
Data Source
AI summary
A mounting mat (4) for an exhaust gas treatment device (10), the mounting mat (4) comprises two opposing main surfaces (5, 6) and at least one edge surface (7) extending between the main surfaces; at least one portion of the at least one edge surface comprises a protection coating comprising inorganic particles (15), and the inorganic particles have an average diameter of at least 1 μm.