Honeycomb Filter Trapping Layer Thickness Design
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Solution Overview
Problem
Honeycomb filters experience thermal expansion differences between segments and bonding members during regeneration treatment due to uneven temperature distribution, leading to potential bonding strength degradation and separation.
Innovation Solution
A honeycomb filter design with a trapping layer thickness on outermost partitions being 60% or less of the inner region's thickness, facilitating heat conduction and reducing thermal expansion differences between segments and bonding layers, while maintaining efficient PM trapping and low pressure loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a uniform thickness trapping layer is formed on all partition portions, then the structure is simple and manufacturing is easy, but thermal expansion difference occurs between honeycomb segments and bonding members during regeneration treatment
Solution Approach 1:
The trapping layer thickness is made non-uniform, with outermost partitions having thinner layers (60% or less of inner region thickness) and inner partitions having thicker layers. This local variation in thickness creates corresponding variations in heat generation during regeneration, which balances the thermal expansion between honeycomb segments and bonding members, preventing bonding strength degradation.
2Reliability
If trapping layer thickness on outermost partitions is reduced to 60% or less of inner region, then thermal expansion difference decreases and bonding strength is maintained, but flow path resistance may increase
Solution Approach 1:
The trapping layer thickness is optimized locally: outermost partitions have thinner layers (60% or less of inner region) to reduce thermal expansion difference and maintain bonding strength, while inner partitions have thicker layers to ensure adequate PM trapping capacity. This local optimization balances flow path resistance with bonding reliability.
3Reliability
If trapping layer thickness on outermost partitions is reduced, then thermal expansion difference decreases, but PM trapping capacity may be reduced
Solution Approach 1:
The trapping layer thickness is optimized locally: outermost partitions have thinner layers (60% or less of inner region) to reduce thermal expansion difference and maintain bonding strength, while inner partitions have thicker layers to ensure adequate PM trapping capacity. The overall PM trapping capacity is maintained through the thicker inner layers compensating for the thinner outer layers.
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 effectively decreases thermal expansion differences and prevents bonding strength degradation, ensuring the filter's integrity during regeneration treatment and abnormal heat generation scenarios.
Implementation Method 1
a trapping layer for trapping and removing solid components contained in the fluid
Implementation Method 2
the outermost partitions having high temperatures can increase the temperature of the bonding layers through heat conduction and decrease the temperature difference between the honeycomb segment and the bonding layer
Implementation Method 3
combustion of deposited solid components increases the temperature of the outermost partitions
Data Source
Figure 1
Figure 2
Figure 3(a)~3(b)
AI summary
A honeycomb filter 20 includes a plurality of porous partition portions 22 each forming a cell 23, the cell 23 being open at one end and closed at the other end and serving as a flow path of an exhaust gas, and a trapping layer 24 for trapping and removing solid components contained in the exhaust gas, the trapping layer 24 being formed on each of the partition portions 22. In a honeycomb segment 21, the trapping layers 24 are formed such that the ratio A/B of the thickness A (µm) of the trapping layer 24 formed on each of outermost partition portions 22a to the thickness B (µm) of the trapping layer 24 formed on each of partition portions 22b in an inner region is 60% or less.