Flexible Mounting Mat for Pollution Control Device Vibration
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Solution Overview
Problem
Ceramic monoliths used in pollution control devices are fragile and susceptible to vibration and thermal expansion differences with metal housings, leading to potential damage and exhaust gas bypassing.
Innovation Solution
A non-woven mat with inorganic fibers and a three-dimensional polymeric layer, optionally with an intumescent layer, is used to securely mount and insulate pollution control elements, providing flexibility and reducing fiber shedding, while preventing cracking and ensuring proper attachment around curved surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rigid mounting structure is used to securely hold the ceramic monolith, then the monolith is protected from vibration and shock damage, but the structure cannot accommodate thermal expansion differences between the metal housing and ceramic monolith
Solution Approach 1:
The patent uses a flexible mat comprising a non-woven fabric layer and a flexible membrane layer to mount the ceramic monolith. The mat can deform elastically to accommodate thermal expansion differences between the metal housing and ceramic monolith while maintaining secure holding force to protect against vibration and shock damage.
Solution Approach 2:
The mounting mat's physical parameters (flexibility, thermal conductivity) are specifically selected to balance mechanical support and thermal accommodation. The mat's elastic properties allow it to adapt its shape and density under thermal cycling conditions while maintaining sufficient holding pressure.
2Reliability
If pressure is increased to hold the monolith securely in place, then vibration and shock damage is reduced, but the ceramic monolith may be damaged by excessive pressure
Solution Approach 1:
The flexible mat distributes mounting pressure uniformly across the monolith surface through its elastic deformation capability, preventing localized stress concentrations that could damage the ceramic while maintaining sufficient overall holding force to secure the monolith against vibration and shock.
Solution Approach 2:
The mat's elastic properties provide inherent cushioning that absorbs shock and vibration energy before it can damage the monolith, while the uniform pressure distribution prevents excessive point loads that could compromise ceramic integrity during normal operation.
3Loss of time
If insulation material is added to reduce heat loss and decrease light-off time, then thermal performance is improved, but the device complexity and space requirements increase
Solution Approach 1:
The mounting mat serves multiple functions simultaneously: it provides mechanical support to hold the monolith, acts as a thermal insulator to reduce heat loss and decrease light-off time, and accommodates thermal expansion differences. This multi-functionality reduces overall device complexity compared to separate components for each function.
Solution Approach 2:
The patent combines the mounting function and insulation function into a single integrated mat structure. The non-woven fabric layer provides mechanical support while the flexible membrane layer provides thermal insulation, eliminating the need for separate mounting brackets and insulation materials.
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 mat effectively supports and seals pollution control elements, minimizing damage from vibrations and thermal expansion, while maintaining flexibility and reducing fiber shedding, thus enhancing the performance and durability of pollution control devices.
Implementation Method 1
a first polymeric layer vacuum-formed onto the non-woven layer
Implementation Method 2
insulation is typically provided between the pollution control device and the housing of the converter, and it is generally also preferred to insulate exhaust system components between the engine and the pollution control device so as to minimize heat loss
Implementation Method 3
They have a coefficient of thermal expansion generally an order of magnitude less than the metal housing that contains them. This means that as the pollution control device is heated the gap between the inside periphery wall of the housing and the outer wall of the monolith increases.
Data Source
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AI summary
Mats comprising a non-woven layer and a first polymeric layer on a major surface thereof. The mats are useful, for example, a mounting mats for pollution control devices, as well as thermal and acoustic insulation for pollution control devices and exhaust systems.