Honeycomb Catalyst Body with Segmented Pore Density
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Honeycomb catalyst bodies face challenges in enhancing exhaust gas purification efficiency while minimizing pressure loss and maintaining mountability in limited spaces, particularly due to increased cell density leading to higher pressure loss and insufficient diffusion rates of target components at low temperatures.
Innovation Solution
A honeycomb catalyst body with porous partition walls and catalyst layers containing noble metals, where the mass ratio of noble metals in the catalyst layers is optimized, and the structure is designed to maximize porosity and surface area, allowing for efficient gas transmission and reduced pressure loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If cell density is increased to enhance purification efficiency, then transmissibility of target components rises, but pressure loss increases
Solution Approach 1:
The partition walls are divided into multiple layers with different pore densities. The first region (near exhaust inlet) has lower pore density to reduce pressure loss, while the second region (near exhaust outlet) has higher pore density to enhance purification efficiency. This segmentation allows each region to optimize for its specific functional requirements.
Solution Approach 2:
Different regions of the partition walls are assigned different local properties: the first region has larger pore diameter and lower pore density suited for high-flow areas, while the second region has smaller pore diameter and higher pore density suited for low-flow areas. This local quality optimization resolves the contradiction between pressure loss and purification efficiency.
2Productivity
If cell density is increased to increase catalyst layer surface area, then purification efficiency improves, but pressure loss increases
Solution Approach 1:
The partition walls are segmented into two regions with different pore densities. The first region provides sufficient surface area for catalyst deposition while maintaining larger pores to minimize pressure loss. The second region provides additional surface area where lower flow rates allow for enhanced purification without significant pressure penalty.
Solution Approach 2:
The pore diameter and pore density parameters are changed across different regions of the partition walls. By varying these parameters spatially, the system achieves optimal balance between surface area for purification and pressure loss characteristics in different flow conditions.
3Loss of energy
If inlet diameter is increased to raise exhaust gas flow rate and reduce pressure loss, then pressure loss decreases, but mounting space requirements increase
Solution Approach 1:
Instead of changing the inlet diameter, the invention changes the pore diameter and pore density parameters within the existing honeycomb structure. This allows optimization of pressure loss characteristics without increasing the overall device volume, maintaining mountability in limited spaces.
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 achieves excellent purification efficiency with low pressure loss and enables mounting in limited spaces by optimizing the distribution and amount of noble metals in the catalyst layers and structure design, enhancing the transmission of target components and reducing pressure loss.
Implementation Method 1
when the target components diffuse in the catalyst layer at an insufficient rate, purification efficiency of the honeycomb catalyst body tends to be lowered
Implementation Method 2
porous partition walls having a large number of pores where gas can pass
Data Source
AI summary
A honeycomb catalyst body includes: porous partition walls having a large number of pores and disposed to form a plurality of cells communicating between two end faces, plugged portions disposed to plug each of the cells on one of the end faces, and catalyst layers loaded in layers on an inner surface of the cells and an inner surface of the pores and containing a noble metal. Mass (Mc) of the noble metal contained in the catalyst layer loaded on the inner surface of the cells and mass (Mp) of the noble metal contained in the catalyst layer loaded on the inner surface of the pores satisfy the relation of (Mp)/(Mc)≧4. The honeycomb catalyst body is excellent in purification efficiency, has low pressure loss, and is mountable even in a limited space.