Particulate Filter with Dual Pore Zones for Ash Management
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Solution Overview
Problem
The existing exhaust purification systems for internal combustion engines face challenges in managing ash accumulation in particulate filters, which leads to increased pressure loss and reduced engine output, as ash is not effectively removed and can re-deposit on the filter due to reverse flow during pulsation control.
Innovation Solution
The system employs a particulate filter with alternately arranged exhaust gas inflow and outflow passages separated by porous partition walls, featuring micropore zones for trapping particulate matter and ash, and macropore zones allowing ash to pass through, along with a control unit that increases gas flow to remove ash when the particulate matter is below a certain threshold, ensuring ash is directed out of the filter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If control for removing PM is performed to remove particulate matter from the particulate filter, then the pressure loss due to particulate matter is suppressed, but ash accumulates on the filter and pressure loss increases over time
Solution Approach 1:
The partition walls are designed with dual pore size characteristics: small pores (10-25 μm) for trapping particulate matter and large pores (25-100 μm) for allowing ash passage. This porous structure enables selective filtration based on particle size, resolving the contradiction by trapping PM while permitting ash removal through the larger pores.
Solution Approach 2:
The partition walls are segmented into functionally distinct regions: micropore zones for PM trapping and macropore zones for ash removal. This segmentation allows each zone to perform its specific function independently, enabling simultaneous PM retention and ash elimination without interference between the two processes.
2Quantity of substance
If exhaust gas pulsation is used to separate ash from the particulate filter, then ash is removed, but the separated ash is returned to the exhaust passage upstream and re-trapped on the filter
Solution Approach 1:
The partition walls exhibit locally different properties: the micropore zones have small pore sizes to trap PM and prevent ash from moving upstream, while the macropore zones have large pore sizes to facilitate ash removal. This local quality differentiation ensures that ash is removed downstream without being returned upstream to re-trap on the filter.
Solution Approach 2:
The macropore zones act as intermediary pathways that enable ash to pass through the partition walls and be removed from the system. These large pores serve as conduits that bypass the micropore zones where PM is trapped, providing a dedicated route for ash elimination that prevents re-deposition upstream.
3Manufacturing precision
If the pore size of partition walls is reduced to trap more particulate matter, then PM trapping efficiency increases, but ash cannot pass through and pressure loss increases
Solution Approach 1:
The partition walls utilize a dual-pore porous material structure with small pores (10-25 μm) for PM trapping and large pores (25-100 μm) for ash passage. This hierarchical porous structure simultaneously achieves high PM trapping efficiency while maintaining ash permeability, resolving the contradiction between filtration precision and ash removal capability.
Solution Approach 2:
The partition walls are constructed as composite structures combining micropore and macropore regions within the same wall. This composite design integrates two different pore size regimes, enabling the wall to perform both PM trapping and ash removal functions concurrently without compromising either efficiency.
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 solution effectively suppresses the increase in pressure loss due to ash accumulation by ensuring ash is removed from the particulate filter, maintaining engine efficiency and output by preventing re-deposition of ash on the filter.
Implementation Method 1
porous partition walls which separate these exhaust gas inflow passages and exhaust gas outflow passages from each other, micropore zones are defined at upstream sides of the partition walls... a pore size of the partition walls in the micropore zones is set so that particulate matter and ash can be trapped by the partition walls
Implementation Method 2
a pore size of the partition walls in the micropore zones is set so that particulate matter and ash can be trapped by the partition walls at the micropore zones, a pore size of the partition walls in the macropore zones is set so that ash can pass through the partition walls at the macropore zones
Implementation Method 3
the control unit is configured to increase gas which temporarily increases the flow rate of gas which flows into the particulate filter in order to remove the ash from the particulate filter
Data Source
Figure 1
Figure 2A~2B
Figure 3~4
AI summary
Micropore zones ZMI are defined at upstream sides of partition walls 72 of a particulate filter and macropore zones ZMA are defined at downstream sides of partition walls. The pore size of the partition walls at the micropore zones is set so that the particulate matter and the ash can be trapped by the partition walls at the micropore zones, while the pore size of the partition walls at the macropore zones is set so that the ash can pass through the partition walls at the macropore zones. When a quantity of trapped particulate matter is smaller than a limit quantity, control for increasing gas which temporarily increases the flow rate of the gas which flows into the particulate filter in order to remove the ash from the particulate filter, is performed.