Honeycomb Filter Peripheral Plugging Green State
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Solution Overview
Problem
Conventional honeycomb structures used for filtering exhaust gas from internal combustion engines face challenges in yield and manufacturing cost due to difficulties in aligning peripheral plugging and the need for multiple firing steps, which can lead to clogging and thermal stress issues.
Innovation Solution
A honeycomb structure with a cell structure partitioned by porous walls, featuring first and second plugging portions where the second plugging portions are unfired and formed using a ceramic material, allowing for peripheral plugging after determining the peripheral portion's dimensions, reducing manufacturing costs and improving yield by eliminating the need for additional firing steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the peripheral portion of the honeycomb structure is plugged with a plugging material to prevent uneven deposition of particulates, then the reliability of the filter is improved, but the manufacturing complexity increases due to multiple firing steps and alignment difficulties
Solution Approach 1:
The peripheral portion of the honeycomb structure is plugged with plugging material before the firing step. This preliminary action allows the plugging to be performed on the green state honeycomb structure where alignment is easier, avoiding the need for complex post-firing alignment and multiple firing steps, thus reducing manufacturing complexity while maintaining filter reliability
2Strength
If multiple firing steps are performed to ensure proper plugging and structural integrity, then the strength of the honeycomb structure is improved, but the manufacturing time increases
Solution Approach 1:
The plugging of the peripheral portion and the firing of the honeycomb structure are merged into a single firing step. The plugging material is applied to the green state structure, and then both the plugging material and the honeycomb structure are fired together in one cycle, eliminating the need for separate firing steps and reducing manufacturing time while maintaining structural strength
3Productivity
If the peripheral portion is plugged after determining the peripheral dimensions, then the manufacturing yield is improved, but additional processing steps are required
Solution Approach 1:
The peripheral portion is plugged with plugging material in the green state before firing and dimensional determination. This preliminary plugging action ensures that the peripheral structure is properly formed early in the manufacturing process, improving yield by preventing defects that would require rework or scrapping, while the plugging is integrated into the existing process flow without adding significant complexity
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 enhances yield and reduces manufacturing costs by allowing peripheral plugging without firing, preventing erosion and clogging, and improving thermal resistance and separation resistance of the honeycomb structure.
Implementation Method 1
drying the coating material to obtain a honeycomb structure (50)... the second plugging portions being unfired even after plugging
Data Source
AI summary
A honeycomb structure 20 includes a cell structure 10 having a plurality of cells 9 communicating between two open ends being partitioned and defined by porous partition walls 7, an outer wall 30 disposed at the periphery of the cell structure 10, and first plugging portions 25 disposed in a checkered flag pattern at one end and the other end of the cell structure 10 by plugging alternately either of the two open ends of the cells, a fluid to be flown from one of the open ends of each of the cells 9 being capable of penetrating the porous partition walls 7 and flowing out from the other open end 5 of each of the cells 9 as a filtered fluid. The honeycomb structure 20 includes the first plugging portions 25 having been fired after plugging, and second plugging portions 26 having been unfired even after plugging.