Exhaust Gas Purification Filter with Segmented Partition Zones
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Solution Overview
Problem
The existing particulate filters in compression-ignition internal combustion engines face increased pressure loss due to accumulated ash, which is not effectively removed by the PM removing process, leading to decreased engine output over time.
Innovation Solution
An exhaust gas purification filter with alternately arranged inflow and outflow passages and porous partitions, where the partitions are divided into coated and non-coated zones, allowing ash to pass through the non-coated zone while maintaining a lower passage resistance in the coated zone to collect particulate matter effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If through-holes are formed in downstream-side plugs to allow ash to flow out, then ash discharge is improved, but particulate matter flows out during operation and through-holes take considerable time to close
Solution Approach 1:
The partition is divided into a coated zone with smaller average pore diameter for particulate matter collection and a non-coated zone with larger average pore diameter for ash passage. This segmentation allows different functions to be performed in different zones simultaneously, resolving the contradiction between ash discharge and particulate matter collection.
Solution Approach 2:
Different zones of the partition are given different properties: the coated zone has smaller pores for collecting particulate matter, while the non-coated zone has larger pores for allowing ash to pass through. This local differentiation enables the partition to simultaneously perform both functions without compromising either.
2Loss of substance
If through-hole diameter is set to 0.2 mm or more to facilitate ash discharge, then ash flow is improved, but a considerable amount of time is required for through-holes to close by particulate matter
Solution Approach 1:
The partition is segmented into coated and non-coated zones with different pore sizes. The non-coated zone has larger pores that facilitate ash discharge, while the coated zone with smaller pores ensures rapid closure by particulate matter. This eliminates the need for large through-holes that take considerable time to close.
Solution Approach 2:
The non-coated zone is designed with larger average pore diameter specifically for ash passage, while the coated zone has smaller pores for particulate matter collection. This local quality differentiation allows ash to flow through the non-coated zone without requiring large through-holes that would take time to close.
3Reliability
If ash is collected on the particulate filter along with particulate matter, then particulate matter collection is improved, but pressure loss increases gradually over time
Solution Approach 1:
The partition is divided into coated and non-coated zones that separately handle particulate matter and ash. The non-coated zone with larger pores allows ash to pass through without accumulating on the filter, while the coated zone collects particulate matter. This segmentation prevents pressure loss increase over time.
Solution Approach 2:
The harmful effect of ash accumulation is extracted and separated from the particulate matter collection function. By providing a dedicated non-coated zone with larger pores for ash passage, the patent removes ash from the filtration path, preventing it from accumulating and causing pressure loss.
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 suppresses the increase in pressure loss caused by ash while reliably collecting particulate matter, thereby maintaining engine output by facilitating the passage of ash and oxidizing particulate matter in the non-coated zone.
Implementation Method 1
a coated zone in which a surface of a partition base is coated with a coating layer having a smaller average pore diameter than an average pore diameter of the partition base
Implementation Method 2
a non-coated zone that is located on a downstream side of the coated zone in which a surface of the partition base is not coated with the coating layer, wherein a pore diameter of the partitions is set such that ash contained in the exhaust gas is able to pass through the partitions in the non-coated zone
Implementation Method 3
a PM removing process, in which the temperature of the particulate filter is increased while the particulate filter is maintained in an oxidizing atmosphere, is performed to burn the particulate matter
Data Source
AI summary
An exhaust gas purification filter that is suitable for arrangement in an exhaust passage of an internal combustion engine and for collecting particulate matter contained in exhaust gas, comprises: exhaust gas inflow passages and exhaust gas outflow passages that are arranged alternately; and porous partitions that separate the exhaust gas inflow passages and the exhaust gas outflow passages from each other. Each of the partitions is divided into a coated zone in which a surface of a partition base is coated with a coating layer having a smaller average pore diameter than an average pore diameter of the partition base and a non-coated zone that is located on a downstream side of the coated zone and in which a surface of the partition base is not coated with the coating layer.