Exhaust Mounting Mat Microspheres Thermal Conductance
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Solution Overview
Problem
Existing exhaust gas treatment devices face challenges in providing effective thermal insulation and mechanical support to fragile structures like catalytic converters and diesel particulate traps across a wide temperature range without increasing housing size or mass, and current mounting mats do not adequately reduce thermal conductance while maintaining holding pressure.
Innovation Solution
A mounting mat comprising high temperature resistant inorganic fibers, organic binder, and high temperature resistant inorganic microspheres, with the microspheres present proximate to the surface, reduces thermal conductance and maintains holding pressure performance across a broad temperature range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional inorganic fiber based mounting mat material is used, then the fragile structure is held in position and thermal insulation is provided, but the thermal conductance is not sufficiently reduced and housing temperature remains high
Solution Approach 1:
The mounting mat uses a composite material system combining inorganic fibers (alumina, silica, magnesia) with intumescent materials (expandable graphite, vermiculite, hydrobiotite) and binder materials. This composite structure provides both mechanical support and enhanced thermal insulation, reducing thermal conductance while maintaining holding pressure across wide temperature ranges.
Solution Approach 2:
The mounting mat material undergoes parameter changes through intumescence - the intumescent materials expand when exposed to heat, changing the physical structure and increasing insulation properties. This parameter change allows the material to adapt to thermal conditions and reduce thermal conductance dynamically.
2Weight of stationary object
If the mounting mat thickness is reduced to decrease housing mass, then the overall device mass is reduced, but the holding pressure performance may be compromised
Solution Approach 1:
The composite mounting mat material provides enhanced mechanical properties and thermal insulation in a thinner profile, allowing mass reduction while maintaining holding pressure performance through the synergistic combination of fiber, binder, and intumescent materials.
Solution Approach 2:
The mounting mat material has varying local properties - the inorganic fibers provide structural strength and holding pressure, while the intumescent materials provide thermal insulation. This local differentiation of material functions allows optimized performance in a thinner configuration.
3Reliability
If the mounting mat provides robust holding pressure across wide temperature range, then the fragile structure is securely held, but the thermal insulation performance may be compromised
Solution Approach 1:
The composite mounting mat combines inorganic fibers for structural integrity and holding pressure with intumescent materials for thermal insulation. This composite structure maintains both mechanical support and thermal insulation performance across the operating temperature range of 20°C to 1200°C.
Solution Approach 2:
The mounting mat material serves multiple functions simultaneously: mechanical support to hold the fragile structure, thermal insulation to reduce housing temperature, and thermal stability to maintain properties across wide temperature ranges. The composite formulation enables this multi-functionality.
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 reduces thermal conductance and maintains holding pressure, lowering the housing temperature and protecting fragile structures from mechanical shock, while allowing for thinner mats without compromising performance.
Implementation Method 1
the inorganic microspheres may be present substantially proximate to at least one surface of the mounting mat... provide a superior reduction in thermal conductance
Implementation Method 2
the mat resists propagation of heat from the substrate to the housing and thereby lowers the steady state operating temperature of the housing
Implementation Method 3
the mounting mat also compensates for the fact that the metal housing expands more or less than the substrate itself
Implementation Method 4
a mounting mat is positioned within the gap between the fragile structure and the housing to resiliently hold the fragile catalyst support structure
Data Source
AI summary
A mounting mat for an exhaust gas treatment device including inorganic fibers, organic binder, high temperature resistant inorganic microspheres, and optionally intumescent material. The exhaust gas treatment device includes a housing, a fragile catalyst support structure resiliently mounted within the housing, and the mounting mat disposed in a gap between the housing and the fragile catalyst support structure.