Plugged Honeycomb Segment With Asymmetric Cell Regions
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Solution Overview
Problem
Conventional plugged honeycomb structures with segmented structures face challenges in continuous regeneration performance and particulate matter segregation, especially when used in gasoline engines with high exhaust gas temperatures, leading to excessive PM accumulation and potential honeycomb segment breakage.
Innovation Solution
The design of honeycomb segments with a larger open frontal area in the circumferential region compared to the center region, featuring a prismatic-columnar shape with specific cell arrangements and plugging configurations, enhances continuous regeneration performance and prevents particulate matter segregation by allowing easier gas flow and efficient PM burning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a plugged honeycomb structure with segmented structure is used in gasoline engines with high exhaust gas temperatures, then the filter can trap particulate matter, but excessive PM accumulation occurs at the circumferential part leading to potential honeycomb segment breakage
Solution Approach 1:
The patent applies local quality by creating different cell configurations in different regions of the honeycomb segment. Specifically, the circumferential region has a larger open frontal area compared to the center region, allowing differentiated PM trapping and gas flow characteristics. This local variation prevents excessive PM accumulation at the circumferential part while maintaining effective filtration, thereby resolving the contradiction between reliable continuous regeneration and preventing harmful PM accumulation.
Solution Approach 2:
The patent employs asymmetry by designing the honeycomb segment with non-uniform cell distribution. The circumferential region contains more cells with larger open frontal areas, while the center region has fewer cells with smaller open frontal areas. This asymmetric configuration creates intentional flow distribution that prevents the harmful effect of excessive PM accumulation at the circumferential region, while maintaining reliable continuous regeneration performance throughout the filter.
2Reliability
If the circumferential region has the same open frontal area as the center region, then the structure is simpler, but PM segregation occurs and continuous regeneration performance deteriorates
Solution Approach 1:
The patent implements local quality by specifying that the circumferential region has a larger open frontal area than the center region. This local differentiation improves continuous regeneration performance by preventing PM segregation, while the complexity is managed through a systematic rather than random configuration. The local quality approach allows the filter to handle high-temperature gasoline engine exhaust effectively without excessive structural complexity.
3Productivity
If less exhaust gas flows through the circumferential part, then the initial pressure loss is reduced, but PM accumulation increases and regeneration performance worsens
Solution Approach 1:
The patent applies asymmetry by creating a non-uniform cell distribution where the circumferential region has larger open frontal areas compared to the center region. This asymmetric design intentionally redirects more exhaust gas flow to the circumferential part, preventing excessive PM accumulation and enabling continuous regeneration. The asymmetry resolves the contradiction between productivity (regeneration efficiency) and quantity of substance (PM accumulation) by creating favorable flow distribution.
Solution Approach 2:
The patent employs parameter changes by varying the open frontal area parameter across different regions of the honeycomb segment. The circumferential region is designed with a larger open frontal area parameter, which changes the flow characteristics and prevents excessive PM accumulation. This parameter variation enables the filter to maintain high regeneration efficiency while controlling PM distribution, resolving the contradiction between productivity and quantity of substance.
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 configuration improves the continuous regeneration performance and prevents particulate matter segregation, ensuring effective PM trapping and burning, even at high temperatures, thereby reducing the risk of honeycomb segment damage.
Implementation Method 1
the porous partition wall making up the cells functions as a filter. As an exhaust gas containing a particulate matter flows into the plugged honeycomb structure from the inflow end face (first end face) of the plugged honeycomb structure, the particulate matter in the exhaust gas is filtered when the exhaust gas passes through the partition wall
Implementation Method 2
cracks during burning of the PM to be suppressed and a lot of ash at the partition wall to be accumulated
Data Source
AI summary
A plugged honeycomb structure includes: a plurality of honeycomb segments, a bonding layer, and plugging portions to plug open ends of cells of the honeycomb segments. The honeycomb segment is configured so that the cells having at least two kinds of different shapes are disposed in a cross section orthogonal to an extension direction of the cells, the honeycomb segment has a center region configured by repeating units to maintain a repeated pattern including cell arrangement in which inflow cells surround an inflow cell, and a circumferential region located at the circumference of the center region, the circumferential region has open frontal area that is larger than open frontal area of the center region at the inflow end face of the honeycomb segment, the segment circumferential wall and the bonding layer have a special range of a thickness.