Honeycomb Catalyst Partition Wall Thickness Variation
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Solution Overview
Problem
Honeycomb catalyst articles face challenges in simultaneously achieving quick temperature-rising ability and high thermal capacity, which affects the effective purification of exhaust gas from diesel engines, particularly during low load conditions and engine start-stop cycles.
Innovation Solution
A honeycomb catalyst article with ceramic partition walls of varying thickness, where the outer peripheral portion has thicker walls for high thermal capacity and the inner peripheral portion has thinner walls for rapid temperature rise, optimizing the catalyst loading distribution to maintain activation temperature during engine operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the partition wall thickness is decreased to improve temperature rise characteristic, then the temperature rise ability is improved, but the thermal capacity decreases causing rapid temperature fall
Solution Approach 1:
The patent applies local quality by creating different partition wall thicknesses in different regions of the honeycomb structure. Specifically, the partition walls have a first thickness in certain regions and a second thickness (smaller than the first) in other regions. This allows the thicker walls to provide thermal capacity for heat retention while thinner walls enable rapid temperature rise in catalyst activation zones, resolving the contradiction between temperature rise speed and thermal capacity.
2Quantity of substance
If the partition wall thickness is increased to improve thermal capacity, then the temperature capacity is improved, but the temperature rise performance is deteriorated
Solution Approach 1:
The patent applies local quality by creating different partition wall thicknesses in different regions of the honeycomb structure. Specifically, the partition walls have a first thickness in certain regions and a second thickness (smaller than the first) in other regions. This allows the thicker walls to provide thermal capacity for heat retention while thinner walls enable rapid temperature rise in catalyst activation zones, resolving the contradiction between temperature rise speed and thermal capacity.
3Speed
If the porosity is increased to improve temperature rise characteristic, then the temperature rise ability is improved, but the structural strength decreases
Solution Approach 1:
The patent applies local quality by creating different partition wall thicknesses in different regions of the honeycomb structure. Specifically, the partition walls have a first thickness in certain regions and a second thickness (smaller than the first) in other regions. This allows the thicker walls to provide thermal capacity for heat retention while thinner walls enable rapid temperature rise in catalyst activation zones, resolving the contradiction between temperature rise speed and thermal 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 design ensures the catalyst is activated quickly and maintains effective purification performance even during frequent engine stop-start cycles by balancing temperature rise and heat retention, improving exhaust gas purification efficiency.
Implementation Method 1
a honeycomb catalyst article satisfying both quick temperature-rising ability and high thermal capacity at the same time
Implementation Method 2
a catalyst for oxidizing PM is coated on a DPF, and a honeycomb structure having a catalyst coated thereon is mounted in a front portion of the DPF
Implementation Method 3
by changing NO contained in exhaust gas to NO2, PM deposited in the DPF is combusted
Data Source
Figure 1~2
Figure 3~5
Figure 6
AI summary
There is provided a honeycomb catalyst article. The cells 2 are formed by the partition walls 1 including first partition walls 1a having a first thickness and second partition walls 1b having a second thickness smaller than the first thickness. An inner peripheral portion of the honeycomb catalyst article 10 is constituted of the second partition walls 1b, and an outer peripheral portion surrounding the inner peripheral portion of the honeycomb catalyst article 10 is constituted of the first partition walls 1a. A ratio of a first partition wall region area constituted of the first partition walls 1a to a second partition wall region area constituted of the second partition walls 1b (first partition wall region area / second partition wall area) in a cross section perpendicular to a cell extension direction is 1 to 30. A higher amount of catalyst is loaded on the first partition walls 1a than on the second partition walls 1b.