Catalytic Converter Partial Bonding Thermal Stress
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Solution Overview
Problem
Existing catalytic converters for exhaust gas aftertreatment face challenges with inflexible connections between the metallic matrix and jacket, leading to potential failure under thermal stress, and unintended soldering of non-bonded areas.
Innovation Solution
A catalytic converter design featuring a wound stack of metal foils with a jacket that is only partially connected through radially inward formations like dents or beads, creating a structured contact with sufficient flexibility to absorb thermal expansions, and a method using a glue roller to apply adhesive selectively for controlled soldering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the matrix is bonded to the jacket over its entire surface, then the connection strength is improved, but the flexibility to absorb thermal expansion is reduced
Solution Approach 1:
The continuous bonding surface is segmented into discrete contact points through radially inwardly directed projections. These projections create isolated bonding zones rather than a continuous bond, allowing the matrix to expand and contract thermally while maintaining secure connection at specific locations. The projections are distributed across the matrix surface, providing multiple anchor points that collectively ensure connection strength while preserving overall flexibility.
Solution Approach 2:
The bonding characteristics are made non-uniform by concentrating the bond in specific localized areas where the radially inwardly directed projections contact the matrix. The majority of the matrix surface remains unbonded, creating a structure with locally strong connections at projection contact points and locally flexible regions in between. This local quality approach allows simultaneous achievement of connection strength where needed and thermal flexibility where needed.
2Area of stationary object
If the matrix is inserted into the jacket with alternating smooth and corrugated layers, then the contact area is improved, but the unintended soldering of non-bonded areas occurs
Solution Approach 1:
The bonding is concentrated in specific localized areas defined by the radially inwardly directed projections, rather than being distributed across the entire matrix surface. The projections create distinct contact zones where solder is applied and bonding occurs, while the areas between projections remain unbonded. This local quality approach prevents unintended soldering by restricting the bonding process to precisely defined locations.
Solution Approach 2:
The continuous bonding area is segmented into discrete contact points through the use of radially inwardly directed projections. Each projection creates an isolated bonding zone, separating the bonding process into distinct segments rather than a continuous operation. This segmentation prevents solder from spreading to non-intended areas, as each projection acts as an independent bonding station.
3Strength
If the layers are wound to form the matrix, then the structural integrity is improved, but the contact area with the jacket becomes excessively large
Solution Approach 1:
The large contact area created by the wound stack structure is segmented into discrete contact points through the radially inwardly directed projections. The wound stack maintains its structural integrity from the layering process, but the projections selectively engage only specific portions of the wound stack with the jacket, reducing the effective contact area from the entire outer surface to isolated points at the projection locations.
Solution Approach 2:
The excessive contact area is extracted by removing the bonding function from the majority of the matrix surface. The radially inwardly directed projections extract and concentrate the bonding action into specific locations, leaving the rest of the matrix surface unbonded. This extraction reduces the contact area from the entire outer surface of the wound stack to only the points where projections contact the matrix.
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 design achieves a durable yet flexible connection between the matrix and jacket, preventing unintended soldering and enhancing the converter's ability to handle thermal stresses without compromising strength.
Implementation Method 1
the matrix is inserted into the jacket and is only partially bonded to it, wherein the radially inwardly directed surfaces of the projections form the contact points between the matrix and the jacket
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The invention relates to a catalytic converter for exhaust-gas aftertreatment, comprising a matrix (2, 6, 25, 26) and an envelope (1, 4, 7, 10, 11, 14, 19, 21, 22), the matrix (2, 6, 25, 26) being formed from a coiled layered stack of metal films and inserted into the envelope (1, 4, 7, 10, 11, 14, 19, 21, 22) and bonded therewith only in sections. The invention further relates to a method for producing a catalytic converter.