Wall-Flow Honeycomb Catalyst Zoning for Noble Metal Utilization
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Solution Overview
Problem
Existing exhaust gas purification catalyst apparatuses using wall-flow substrates face inefficiencies in the utilization of catalyst noble metals, leading to suboptimal exhaust gas purification efficiency.
Innovation Solution
The catalyst noble metals are strategically supported in specific regions of the honeycomb substrate, with the inlet side support region covering 60-100% of the substrate length near the upstream end and the outlet side support region covering 5-50% of the substrate length near the downstream end, utilizing ceria-zirconia composite oxide particles as the partition wall material without a catalyst coating layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If catalyst noble metal is uniformly distributed throughout the partition wall, then the catalyst coating is simple to manufacture, but the catalyst noble metal utilization efficiency is low
Solution Approach 1:
The patent applies local quality by creating distinct inlet side and outlet side support regions with different catalyst noble metal distribution characteristics. The inlet side support region has catalyst primarily near the inlet side surface, while the outlet side support region has catalyst primarily near the outlet side surface. This localized differentiation optimizes exhaust gas contact efficiency in each region without requiring complex manufacturing processes.
Solution Approach 2:
The patent segments the partition wall into functionally distinct inlet side and outlet side support regions. Each region has specific structural characteristics: the inlet side support region extends from the inlet side surface to a first depth position, while the outlet side support region extends from the outlet side surface to a second depth position. This segmentation allows optimized catalyst distribution for different flow conditions.
2Manufacturing precision
If catalyst noble metal is supported only near the inlet side surface, then exhaust gas contact is improved at the inlet, but outlet side purification efficiency decreases
Solution Approach 1:
The patent creates different catalyst support structures for inlet and outlet sides. The inlet side support region has catalyst concentrated near the inlet side surface to maximize contact with incoming exhaust gas. The outlet side support region has catalyst concentrated near the outlet side surface to efficiently treat gas before discharge. This local quality differentiation ensures optimal purification at both ends.
Solution Approach 2:
The patent divides the catalyst support structure into separate inlet side and outlet side support regions with different depth extensions. The inlet side support region extends to a first depth position from the inlet side surface, while the outlet side support region extends to a second depth position from the outlet side surface. This segmentation ensures both inlet and outlet sides have optimized catalyst distribution for their respective functions.
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 ensures high catalyst noble metal utilization efficiency, enabling efficient exhaust gas purification by ensuring optimal contact between the gas and the catalyst metals, thereby enhancing purification effectiveness.
Implementation Method 1
The porous partition wall contains ceria-zirconia composite oxide particles as a constituent material
Implementation Method 2
one or more catalyst noble metals supported by the honeycomb substrate... the catalyst noble metal is supported in an inlet side support region and an outlet side support region of the porous partition wall
Data Source
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AI summary
An exhaust gas purification catalyst apparatus 100 has a honeycomb base material and a catalyst noble metal supported by the honeycomb base material, wherein: the honeycomb base material contains ceria-zirconia composite oxide particles as one of the constituent materials, is of a wall flow type, and includes inlet-side cells 21 and outlet-side cells 22 demarcated by porous partition walls 10; the catalyst noble metal is supported in inlet-side support regions 30 and outlet-side support regions 40; each of the inlet-side support regions 30 is formed with a specific length 31 from the exhaust gas flow upstream end; the catalyst noble metal 70% support depth is not greater than 50% of the thickness of the porous partition walls 10; each of the outlet-side support regions 40 is formed with a specific length 41 from the exhaust gas flow downstream end; and the catalyst noble metal 70% support depth is greater than 50% of the thickness of the porous partition walls 10.