Catalyst-Loaded Honeycomb Coating for Low-Backpressure Conversion
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Solution Overview
Problem
Existing catalyst-loaded substrates in exhaust aftertreatment systems increase backpressure, compromising engine performance while aiming for higher conversion efficiency.
Innovation Solution
A two-step catalyst deposition process is employed, where catalyst material is deposited both within the walls (in-wall) and on the surfaces (on-wall) of a ceramic honeycomb article, controlling pore occupancy to maintain unoccupied spaces and ensure effective diffusion of reactive species, using different deposition parameters for each step.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If catalyst material is deposited within the channels of a honeycomb substrate to enable catalytic conversion, then conversion efficiency is improved, but backpressure increases
Solution Approach 1:
The patent applies local quality by differentiating catalyst deposition locations into two distinct zones: in-wall deposition within the porous structure of honeycomb walls and on-wall deposition on the outer surfaces. This spatial differentiation allows optimized catalyst distribution to maximize conversion efficiency while minimizing flow resistance and backpressure.
Solution Approach 2:
The patent transitions from traditional two-dimensional on-wall coating to a three-dimensional deposition strategy by incorporating in-wall catalyst placement within the porous wall structure. This dimensional expansion into the wall interior provides additional catalyst volume and surface area for reactions without proportionally increasing backpressure.
2Productivity
If in-wall catalyst deposition is increased to improve conversion efficiency, then catalytic performance is improved, but pore occupancy exceeds target levels reducing diffusion
Solution Approach 1:
The patent implements feedback control through a two-step deposition process where the first step deposits catalyst to an intermediate pore occupancy level, and the second step adds supplemental catalyst only to achieve a target final pore occupancy. This controlled feedback mechanism ensures sufficient catalyst loading for high catalytic performance while maintaining adequate pore space for reactive species diffusion.
Solution Approach 2:
The patent applies partial action by depositing catalyst material in controlled portions across two separate deposition steps rather than applying the full catalyst loading in one step. This allows precise control over pore occupancy levels, ensuring enough catalyst is present for effective catalysis while leaving sufficient pore volume open for diffusion.
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 approach maintains catalytic performance with reduced backpressure by ensuring sufficient diffusion of reactive species to in-wall catalyst sites, achieving comparable conversion efficiency with lower overall backpressure compared to traditional on-wall coating methods.
Implementation Method 1
ensuring sufficient diffusion of reactive species to in-wall catalyst sites
Implementation Method 2
catalyst material deposited as an in-wall portion and an on-wall portion
Data Source
AI summary
A catalyst-loaded porous ceramic honeycomb article and method of manufacture. The ceramic honeycomb article comprises an array of intersecting walls defining channels extending axially through the ceramic honeycomb article. The method comprises depositing catalyst material within a pore structure of a porous ceramic material of the walls in a first deposition process comprising a first set of deposition parameters to form an in-wall portion of a catalyst deposition. Catalyst material is deposited onto outer surfaces of the walls in a second deposition process comprising a second set of deposition parameters that differ from the first set of deposition parameters to form an on-wall portion of the catalyst deposition. The second deposition process does not increase the in-wall portion of the catalyst deposition to above a target final pore occupancy of the pore structure.