Honeycomb Filter Pore Size Control for Pressure Loss
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Solution Overview
Problem
Honeycomb filters used in diesel particulate filters face increased pressure loss and difficulty in accurately detecting deposited particulate matter (PM) due to non-uniform pore size distribution, leading to inefficiencies in PM combustion and potential fuel consumption issues.
Innovation Solution
A honeycomb filter with partition walls made from a porous base material having a porosity of 45-70% and a pore size differential rate of 35% or less, measured by mercury porosimetry and bubble point methods, which reduces initial pressure loss and allows for more accurate PM detection by linearizing pressure loss increase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional porous partition walls are used in honeycomb filter, then PM can be deposited on partition walls for filtration, but pressure loss increases rapidly in initial stage of PM deposition
Solution Approach 1:
The patent applies parameter changes by precisely controlling the pore size distribution of the porous partition walls. Specifically, it adjusts the average pore size measured by mercury porosimetry (A) and bubble point method (B) to achieve a differential rate of 35% or less, and limits maximum pore size to 150 μm or less. This parameter optimization prevents rapid pressure loss increase during initial PM deposition while maintaining effective filtration.
Solution Approach 2:
The patent implements local quality by creating a specific pore size distribution pattern within the partition walls. The pore structure is designed with controlled characteristics: average pore size differential rate ≤35% between measurement methods and maximum pore size ≤150 μm. This localized structural quality ensures uniform PM deposition behavior and prevents the rapid pressure loss increase observed in conventional filters with non-uniform pore distributions.
2Object-affected harmful factors
If conventional porous partition walls with non-uniform pore size distribution are used, then filtration can occur, but accurate detection of deposited PM amount becomes difficult
Solution Approach 1:
The patent uses parameter changes to achieve linear pressure loss characteristics. By controlling the pore size distribution parameters (average pore size differential rate ≤35%, maximum pore size ≤150 μm), the pressure loss increases linearly with PM deposition amount. This linear relationship enables accurate detection of PM accumulation, facilitating timely regeneration control.
3Loss of energy
If rapid PM combustion is pursued to remove deposited substances, then pressure loss can be reduced, but fuel consumption increases and filter damage may occur
Solution Approach 1:
The patent applies preliminary action by preventing rapid pressure loss increase through optimized pore size distribution from the design stage. The partition walls are manufactured with controlled pore characteristics (average pore size differential rate ≤35%, maximum pore size ≤150 μm), which prevents excessive PM accumulation and associated pressure loss. This proactive approach reduces or eliminates the need for aggressive regeneration operations, thereby reducing fuel consumption and preventing filter damage.
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 reduces initial pressure loss and enables precise detection of PM deposited on the partition walls, enhancing fuel efficiency and preventing filter regeneration errors.
Implementation Method 1
a fluid flows into the cells 3 through inflow openings (e.g. cell openings at the end 42), passes through the partition walls 2, and is discharged from the adjacent cells 3. In this case, the partition walls 2 serve as a filter so that PM is deposited on the partition walls 2.
Implementation Method 2
a catalyst is supported on the partition walls in order to assist burning and removal of PM deposited on the partition walls
Implementation Method 3
a catalyst is supported on the partition walls in order to assist burning and removal of PM deposited on the partition walls
Data Source
AI summary
A honeycomb filter includes partition walls forming a plurality of cells extending in one direction, and plugging sections alternately plugging the cells at the ends of the honeycomb filter, the partition walls being formed of a porous base material having a porosity of 45 to 70%. When the average pore size of the base material measured by mercury porosimetry is (A) μm and the average pore size of the base material measured by a bubble point method is (B) μm, the average pore size differential rate expressed by “{(A−B)/B}*100” is 35% or less, and the maximum pore size of the base material measured by the bubble point method is 150 μm or less.