Exhaust Housing Spin-Capture Retention for Aftertreatment
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Solution Overview
Problem
Existing exhaust system designs, particularly those using ceramic fiber mats and sheet metal housings, fail to adequately secure aftertreatment elements like catalytic converters or exhaust filters due to temperature and vibration-induced radial deformation of the sheet metal body shell, leading to axial movement of the elements.
Innovation Solution
The design incorporates a thermally expanding ceramic fiber mat with wire mesh or rope stabilizers and a sheet metal housing with spun-reduction diameter portions that radially bias the stabilizers inwardly and axially secure the mat, preventing radial outward deformation and enhancing retention of the aftertreatment element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a ceramic fiber mat is used to contain and compress against the aftertreatment element, then the element is retained axially, but the sheet metal body shell opens up radially due to heat and vibration, allowing axial movement
Solution Approach 1:
The patent changes the physical state and dimensions of the housing by forming spun-reduction diameter portions that create conical sections with reduced radial dimensions. This geometric parameter change prevents radial outward deformation of the sheet metal body shell while maintaining axial retention of the aftertreatment element through the combined action of the ceramic fiber mat and stabilizers.
Solution Approach 2:
The patent introduces curved conical sections (spun-reduction diameter portions) into the housing structure. These curved surfaces radially bias the stabilizers inwardly and prevent radial opening-up of the sheet metal body shell due to heat and vibration, while still allowing axial retention of the aftertreatment element.
2Reliability
If the sheet metal body shell is dubbed radially inwardly to trap the stabilizer and mat, then axial retention is improved, but the dubbed end opens up radially due to heat and vibration
Solution Approach 1:
The patent forms the housing with spun-reduction diameter portions that create conical sections. These curved surfaces radially bias the stabilizers inwardly and prevent radial opening-up of the dubbed end of the sheet metal body shell, while maintaining axial retention of the aftertreatment element through the combined action of the ceramic fiber mat and stabilizers.
Solution Approach 2:
The patent changes the geometric parameters of the housing by creating conical sections with reduced radial dimensions. This parameter change prevents radial deformation of the dubbed end while maintaining axial retention, as the conical surfaces provide continuous radial support to the stabilizers and mat assembly.
3Reliability
If stabilizers are provided around the aftertreatment element, then axial movement is reduced, but the stabilizers move axially when the body shell opens up radially
Solution Approach 1:
The patent applies preliminary anti-action by pre-biasing the stabilizers inwardly through the spun-reduction diameter portions of the housing. This preventive measure counteracts the radial outward forces generated by heat and vibration before they can cause axial movement of the stabilizers and aftertreatment element.
Solution Approach 2:
The conical spun-reduction diameter portions create curved surfaces that continuously contact and radially bias the stabilizers inwardly. This geometric feature prevents the stabilizers from moving axially when radial forces are applied, as the curved surfaces provide continuous radial support.
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
This solution effectively secures the aftertreatment element by preventing axial movement and improving durability, while also providing improved flow distribution and sealing against air flow and contamination.
Implementation Method 1
The temperature in the exhaust system cycles from ambient temperature to elevated temperatures near the exhaust gas temperature. Existing aftertreatment devices typically use a ceramic fiber mat that contains vermiculite, which is known to expand with increasing temperature.
Implementation Method 2
The housing has stabilizing sections around respective stabilizers. The housing has spun-reduction diameter portions that radially bias the stabilizers inwardly and axially, creating triangular cavities and spun-reduction diameter portions to securely retain the aftertreatment element.
Data Source
AI summary
A spin-capture retention system engages and retains a thermally expanding mat, stabilizer and exhaust aftertreatment element in an exhaust system, and provides secure axial and radial location, and provides protective sealing of the mat.