Wall-Flow Catalyst Layer Structure for PM Capture With Low Pressure Loss
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing exhaust gas purification catalysts face a challenge in achieving both improved PM collection performance and reduced pressure loss, as smaller pores enhance PM collection but increase pressure loss, while larger pores suppress pressure loss but decrease PM collection.
Innovation Solution
The catalyst design includes a substrate with a first catalyst layer on the inflow-side cell and a second catalyst layer on the outflow-side cell, each with specific pore size distributions and formation methods using inorganic oxide particles and pore forming agents to balance PM collection and pressure loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If smaller pores are used in the catalyst layer and partition wall, then PM collection performance is improved, but pressure loss increases
Solution Approach 1:
The patent applies local quality by creating different pore size distributions in different regions of the catalyst layer. The first catalyst layer (inflow-side) has a different pore size distribution compared to the second catalyst layer (outflow-side), with each region optimized for its specific function. This allows the inflow-side to focus on PM collection while the outflow-side manages pressure loss characteristics.
Solution Approach 2:
The catalyst layer is segmented into a first catalyst layer and a second catalyst layer along the exhaust gas flow direction. Each layer has distinct pore size distribution characteristics, allowing independent optimization of PM collection and pressure loss properties for each segment of the catalyst structure.
2Loss of energy
If larger pores are used in the catalyst layer and partition wall, then pressure loss is suppressed, but PM collection performance decreases
Solution Approach 1:
The patent implements local quality by establishing different pore size distributions in the first and second catalyst layers. The outflow-side catalyst layer is designed with pore size characteristics that suppress pressure loss, while the inflow-side catalyst layer has pore size characteristics optimized for PM collection, allowing each region to serve its specific function optimally.
Solution Approach 2:
By dividing the catalyst layer into two distinct segments with different pore size distributions, the patent allows each segment to be optimized independently. The second catalyst layer (outflow-side) specifically targets pressure loss suppression through its pore size characteristics, while the first catalyst layer (inflow-side) targets PM collection.
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 catalyst achieves enhanced PM collection performance while minimizing pressure loss by optimizing the pore size distribution and formation of catalyst layers on a wall-flow type substrate.
Implementation Method 1
PM in the exhaust gas is trapped in pores of the catalyst and partition wall
Data Source
AI summary
An object of the present invention is to provide an exhaust gas purification catalyst that can realize improvement of PM collection performance and suppression of an increase in pressure loss, and the present invention provides an exhaust gas purification catalyst (1A) including: a wall-flow type substrate (10); a first catalyst layer (20); and a second catalyst layer (30),wherein,assuming that:Conditions 1 and 2 are defined as the conditions that, in a logarithmic differential pore volume distribution curve of the first catalyst layer (20), a peak value A present in a pore size range of 1 μm or more and 3 μm or less is 0.20 mL/g or more, and a peak value B present in a pore size range of more than 3 μm and 10 μm or less is 0.20 mL/g or more, respectively,Conditions 3 and 4 are defined as the conditions that, in a logarithmic differential pore volume distribution curve of the second catalyst layer (30), a peak value C present in a pore size range of 1 μm or more and 3 μm or less is 0.20 mL/g or more, and a peak value D present in a pore size range of more than 3 μm and 10 μm or less is 0.20 mL/g or more, respectively,the first catalyst layer (20) and the second catalyst layer (30) satisfy a predetermined combination of the conditions.