Exhaust Gas Catalyst Recessed Layer Design
Solution Overview
Problem
Existing exhaust gas catalysts face challenges in achieving high purification performance, especially at low temperatures and high exhaust gas flow rates, due to insufficient diffusion speed and increased pressure loss, which limits complete purification and requires a smaller base material capacity.
Innovation Solution
The exhaust gas catalyst features a base material with through holes having a catalyst layer sectioned into three regions, where the distance from the central axis to the inner surface varies, creating a recessed portion that disturbs gas flow and enhances diffusivity, allowing for improved purification performance with a smaller base material capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the exhaust gas flow speed is increased due to large air intake amount, then the productivity is improved, but the diffusion speed becomes insufficient and purification performance deteriorates
Solution Approach 1:
The catalyst layer is designed with non-uniform thickness distribution, creating a recessed portion in the central region and thicker regions at the periphery. This local quality variation optimizes the balance between gas flow through the center and diffusion to catalyst surfaces, enabling effective purification even at high exhaust gas flow rates where uniform thickness would fail.
2Stress or pressure
If the catalyst layer thickness is decreased to reduce pressure loss, then the pressure loss is reduced, but the purification function deteriorates
Solution Approach 1:
The catalyst layer thickness is optimized locally rather than uniformly. The recessed central portion reduces flow resistance and pressure loss, while the thicker peripheral regions maintain sufficient catalytic activity for purification, achieving both low pressure loss and high purification function simultaneously.
Solution Approach 2:
Instead of uniformly reducing catalyst layer thickness in one dimension, the invention creates a three-dimensional thickness distribution pattern with a recessed center and raised periphery. This dimensional variation allows the system to maintain purification function through increased peripheral surface area while reducing overall flow resistance.
3Quantity of substance
If the base material capacity is reduced to decrease cost, then the cost is reduced, but the purification performance deteriorates
Solution Approach 1:
The non-uniform catalyst layer distribution concentrates catalytic material where it is most effective for the given flow pattern, with thicker layers at the periphery where diffusion paths are longer and thinner layers in the center where flow velocity is higher. This optimizes material utilization and achieves high purification performance with reduced base material capacity.
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 achieves high purification performance by improving gas diffusivity and reducing pressure loss, enabling effective exhaust gas purification even at high flow rates and low temperatures, while maintaining a smaller base material capacity and cost-effectiveness.
Implementation Method 1
The gas diffusivity indicates that exhaust gas is diffused in the catalyst layer. However, in a case where an air intake amount of the internal combustion engine is large, an exhaust-gas flow speed becomes fast, and therefore, a diffusion speed is insufficient relative to an amount of the exhaust gas.
Implementation Method 2
a catalytic layer is provided on an inner wall surface formed by the through hole
Data Source
AI summary
An object of the present invention is to provide an exhaust gas catalyst that can achieve high purification performance. The exhaust gas catalyst includes: a base material (3) having a plurality of inner wall surfaces (7) formed by a plurality of through holes (5) penetrating therethrough from a first end surface (3a) to a second end surface (3b); and a plurality of catalyst layers (9) formed on the plurality of inner wall surfaces (7), respectively, wherein: each of the through holes (5) has a central axis (5X); each of the catalyst layers (9) is sectioned into a first region (9A) extending from the first end surface (3a) toward the second end surface (3b) by a predetermined distance, a second region (9B) extending from the second end surface (3b) toward the first end surface (3a) by a predetermined distance, and a third region (9C) placed between the first region (9A) and the second region (9B); and the catalyst layer (9) is formed such that a distance (h1) from the central axis (5X) of the through hole (5) to an inner surface (9m) of the catalyst layer (9) in the first region (9A) of the catalyst layer (9) is smaller than a distance (h3) from the central axis (5X) of the through hole (5) to the inner surface (9m) of the catalyst layer (9) in the third region (9C) of the catalyst layer (9), but is larger than a distance (h2) from the central axis (5X) of the through hole (5) to the inner surface (9m) of the catalyst layer (9) in the second region (9B).