Catalyst Support Structure Brazing Alignment
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Solution Overview
Problem
Conventional catalyst support structures for exhaust systems in small watercrafts are complex and costly due to high parts count and multiple brazing steps, leading to potential breakage under impact and increased assembly time.
Innovation Solution
A catalyst support structure comprising an exhaust pipe, a support flange, and a catalyst with a carrier formed by layered flat and corrugated plates, where the catalyst is fixed to the support flange with a brazing foil aligned axially with the upstream end, reducing the number of brazing steps and providing balanced support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If an intermediate pipe is used to connect the honeycomb structure and outer pipe, then the catalyst can be assembled, but the parts count increases and multiple brazing steps are required
Solution Approach 1:
The patent removes the intermediate pipe from the catalyst assembly structure. The outer pipe is directly connected to the honeycomb structure through brazing at two locations (upper and lower ends), eliminating the need for the intermediate pipe component and reducing the overall parts count while maintaining assembly feasibility.
Solution Approach 2:
The patent merges the connection function previously distributed across the intermediate pipe and outer pipe into a direct connection between the outer pipe and honeycomb structure. This consolidation reduces the number of separate components and simplifies the overall structure while achieving the same catalytic function.
2Ease of manufacture
If an intermediate pipe is used to connect the honeycomb structure and outer pipe, then the catalyst can be assembled, but multiple brazing steps are required increasing assembly time
Solution Approach 1:
By removing the intermediate pipe, the patent reduces the number of brazing operations from three (honeycomb to intermediate pipe, intermediate pipe to outer pipe, and additional sealing brazes) to two direct brazing locations between the outer pipe and honeycomb structure, significantly reducing assembly time.
3Ease of operation
If the honeycomb structure is supported in a cantilevered fashion, then the catalyst can be installed, but breakage may occur under impact
Solution Approach 1:
The patent employs bilateral support where the outer pipe contacts and supports the honeycomb structure at both the upper end and lower end. This balanced support configuration counteracts the cantilevered load, distributing mechanical stresses evenly and preventing breakage under impact or thermal expansion 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
This configuration reduces assembly costs, minimizes thermal fatigue, and enhances the reliability of the catalyst fixation, preventing breakage and extending the service life of the catalyst support structure.
Implementation Method 1
a brazing foil joining the first part of the outer peripheral surface of the carrier and a first part of an inner peripheral surface of the outer pipe
Data Source
AI summary
A catalyst for purifying an exhaust gas can include a carrier having a honeycomb structure, an outer pipe for covering a part of the carrier, and a brazing foil for joining the outer peripheral surface of the carrier and the inner peripheral surface of the outer pipe on the downstream side of the catalyst. The catalyst can be fixed to a support flange such that an axial direction of the catalyst coincides with the direction in which an exhaust gas flows through an exhaust pipe. An upstream end of the brazing foil can be aligned with the upstream end of a catalyst fixing part of the support flange. An upstream end of the catalyst fixing part can be positioned upstream of the axial middle of the carrier. The brazing foil can be provided in a portion from the upstream end of the catalyst fixing part to the downstream side of the carrier. The catalyst can be supported at its generally middle part by the support flange. An upstream end of the outer pipe can be aligned with the upstream end of the catalyst fixing part.