Honeycomb Structure Resin Impregnation for GPF Crack Prevention
Solution Overview
Problem
Conventional gasoline particulate filters (GPFs) face challenges in preventing catalyst slurry from leaching out during wash coating, leading to contamination, waste of noble metals, and uneven catalyst distribution, while also risking cracking due to thermal expansion differences and high porosity, which affects air permeability and pressure loss.
Innovation Solution
A honeycomb structure with a porous outer portion impregnated with a resin composition to a depth equal to its thickness, ensuring the catalyst slurry does not leach out and maintaining air permeability, using materials like polyvinyl alcohol or acrylic resins to reinforce the structure and prevent cracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the outer portion is made porous to ensure air permeability, then exhaust gas flow is improved, but catalyst slurry leaks out during wash coating
Solution Approach 1:
The outer portion is impregnated with a resin composition before the wash coating process. This preliminary impregnation creates a barrier that prevents catalyst slurry from leaking out during subsequent wash coating operations, while maintaining the porous structure needed for air permeability.
Solution Approach 2:
A resin composition acts as an intermediary substance impregnated into the porous outer portion. This resin layer serves as a mediator that blocks catalyst slurry penetration while allowing the underlying porous structure to maintain its air permeability function.
2Quantity of substance
If the porosity is increased to reduce pressure loss, then air permeability is improved, but the structure becomes weaker and cracking occurs
Solution Approach 1:
The outer portion is formed as a composite structure combining the porous ceramic substrate with an impregnated resin composition. This composite approach maintains the high porosity needed for low pressure loss while the resin reinforcement prevents cracking and improves structural strength.
Solution Approach 2:
The resin composition is selectively impregnated into the outer portion rather than the entire honeycomb structure. This local treatment reinforces only the area where mechanical strength is needed (the outer portion) while maintaining high porosity throughout the structure for optimal air permeability.
3Strength
If the outer portion is made dense to increase strength, then cracking is prevented, but air permeability is reduced
Solution Approach 1:
The resin composition is applied locally to the outer portion surface and pores, providing crack resistance only where needed for mechanical strength, while the bulk of the outer portion maintains its porous structure for air permeability. This localized reinforcement avoids the need to densify the entire outer portion.
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 effectively prevents catalyst slurry from leaching out, manages thermal expansion, and maintains air permeability, ensuring stable and efficient exhaust gas purification performance without increasing pressure loss or causing cracking, facilitating mass production and reducing noble metal waste.
Implementation Method 1
the outer portion impregnated with a resin composition
Data Source
AI summary
A honeycomb structure prevents catalyst slurry from leaching out when applying a wash coat for making a catalyst supported, ensuring air permeability of the outer portion and in which there is no occurrence of cracking when used as a gasoline particulate filter. The honeycomb structure having: a honeycomb substrate composed of porous partition walls forming a plurality of cells and a porous outer portion; and a resin composition on the outer portion of the honeycomb substrate, wherein the outer portion and the partition walls of the honeycomb substrate are formed of the same material; a porosity of the honeycomb structure is 50% or more; and the resin composition is impregnated into pores of the whole outer portion; and the impregnation depth is equal to the outer portion thickness or a part of the resin composition is impregnated deeper than the outer portion and reaches the cell partition walls.