CeO2 Trapping Layer Honeycomb Filter for Low-Temperature Soot Oxidation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Honeycomb filters face challenges in effectively trapping particulate matter (PM) while minimizing pressure loss, and in oxidizing and burning soot at lower temperatures, especially in cold environments where regeneration operations are frequent and difficult.
Innovation Solution
A honeycomb filter design featuring a porous partition wall with a trapping layer composed of a sintered body of CeO2 particles with an average particle diameter of 1.1 μm or less, which acts as an oxidation catalyst, allowing for efficient trapping and burning of PM at lower temperatures without additional catalysts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thickness of the partition walls is increased or the size of the pores is decreased to improve trap performance, then the filtration efficiency for trapping PM is improved, but the pores are easily clogged by PM causing the pressure loss to increase
Solution Approach 1:
The patent applies porous materials by forming a trapping layer with controlled porosity on the partition walls. The trapping layer has a pore size distribution that allows it to trap PM effectively while maintaining sufficient porosity to prevent clogging and excessive pressure loss. The porous structure enables the layer to capture particles through diffusion and interception mechanisms without completely blocking the flow paths.
Solution Approach 2:
The patent creates a composite structure by combining the base partition wall material with a trapping layer material. The trapping layer is formed as a composite coating on the partition walls, integrating two different material properties: the structural integrity of the partition wall and the trapping functionality of the trapping layer material. This composite approach allows optimization of both filtration efficiency and pressure loss characteristics.
2Reliability
If trapping layers are provided on the surfaces of the partition walls to improve PM trapping while suppressing pressure loss increase, then the filtration efficiency is improved and pressure loss is suppressed, but much soot accumulates on the trapping layers requiring frequent regeneration operations
Solution Approach 1:
The patent changes the chemical composition parameters of the trapping layer by incorporating oxidation catalyst components. This parameter change enables the trapping layer to not only physically trap soot particles but also chemically oxidize them at lower temperatures. The oxidation catalyst reduces the activation energy required for soot combustion, allowing regeneration to occur more frequently and at lower temperatures, thus reducing the time loss associated with regeneration operations.
3Reliability
If the trapping layers are loaded with an oxidation catalyst to burn soot by catalytic reaction, then the soot can be removed more effectively, but the oxidation and burning start temperature must be significantly decreased to achieve the desired effect
Solution Approach 1:
The patent employs strong oxidants by incorporating oxidation catalysts that accelerate the oxidation of soot. The catalyst promotes the reaction between soot and oxygen, significantly enhancing the oxidation rate. This accelerated oxidation allows soot to be burned at lower temperatures than would be required without the catalyst, thereby improving soot removal efficiency while reducing the temperature threshold for oxidation to begin.
Solution Approach 2:
The patent creates a composite trapping layer that combines the base trapping layer material with oxidation catalyst materials. This composite structure provides both the physical trapping function and the chemical oxidation function. The catalyst particles are dispersed within or on the trapping layer matrix, creating a multi-functional composite material that simultaneously traps and oxidizes soot, achieving effective soot removal at reduced temperatures.
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 filter effectively traps and oxidizes PM at lower temperatures, reducing the need for frequent regeneration operations and maintaining low pressure loss, even in cold environments.
Implementation Method 1
the trapping layer includes a portion composed of a sintered body of CeO2 particles on at least a surface layer of the trapping layer... oxidizing and burning the trapped particulate matter at a lower temperature
Data Source
AI summary
A honeycomb filter including: a honeycomb structure having a porous partition wall provided surrounding a plurality of cells; and a plugging portion disposed to seal either one end portion on the inflow or the outflow end face side of the cells, wherein the cell in which the plugging portion is provided at the outflow end face side and the inflow end face side is open is defined as an inflow cell, the cell the plugging portion is provided at the inflow end face side and the outflow end face side is open is defined as an outflow cell, the honeycomb structure further has a trapping layer for the particulate matter on an inner surface side of the partition wall, the trapping layer includes a portion composed of a sintered body of CeO2 particles on at least a surface layer, and the average particle diameter is 1.1 μm or less.