Selective Plugging in Diesel Particulate Filters

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Solution Overview

Problem

Diesel particulate filters (DPFs) face issues with thermal runaway and structural damage due to thermal gradients and material strength limitations, which affect their durability and filtration efficiency during regeneration.

Innovation Solution

The design incorporates a modified structure with a combination of wall-flow and flow-through channels, including a peripheral ring of closed channels and strategically positioned flow-through channels to reduce back pressure and thermal gradients, while maintaining high filtration efficiency and durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the filter structure is modified to reduce back pressure and thermal gradients, then filtration performance and durability are improved, but structural strength and resistance to thermal stress may be compromised

Engineering Contradiction:

Improvefiltration efficiencyVSAvoidstructural strength

Core Design Contradiction:

ProductivityVSStrength

Solution Approach 1:

The filter structure is divided into multiple channel types (wall-flow channels and flow-through channels) with different functions. The wall-flow channels provide filtration while the flow-through channels reduce back pressure and thermal gradients, allowing the system to achieve both high filtration efficiency and structural durability without compromising overall strength

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the filter are assigned different channel configurations to optimize local performance. Peripheral channels are designed as flow-through channels to reduce thermal gradients at the edges, while central channels maintain wall-flow configuration for efficient soot trapping, creating localized quality variations that improve overall structural resilience

Inventive Principle:

Principle #3Local quality

2Reliability

If wall-flow channels are used to trap soot, then filtration efficiency is improved, but thermal gradients and risk of thermal runaway increase

Engineering Contradiction:

Improvefiltration efficiencyVSAvoidthermal gradient

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

The filter merges wall-flow channels and flow-through channels into a single integrated structure. The wall-flow channels trap soot efficiently while the flow-through channels allow exhaust to bypass certain regions, reducing thermal gradients and the risk of thermal runaway, thereby combining the benefits of both channel types

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

Flow-through channels act as intermediary pathways that allow exhaust gases to flow through the filter structure without being filtered. This intermediary flow path reduces thermal gradients by providing alternative routes for heat dissipation, protecting the wall-flow channels from excessive thermal stress

Inventive Principle:

Principle #24Intermediary (Mediator)

3Stress or pressure

If porosity is increased to reduce back pressure, then exhaust flow is improved, but material strength and structural integrity decrease

Engineering Contradiction:

Improveback pressureVSAvoidmaterial strength

Core Design Contradiction:

Stress or pressureVSStrength

Solution Approach 1:

The filter is segmented into different channel types with different porosity requirements. Flow-through channels have higher porosity to reduce back pressure, while wall-flow channels maintain lower porosity for effective soot trapping. This segmentation allows the system to achieve low back pressure without compromising the structural integrity of the filtration channels

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The filter structure serves multiple functions simultaneously: wall-flow channels perform soot trapping, flow-through channels reduce back pressure and thermal gradients, and the combined structure maintains overall structural strength. This multi-functionality allows the system to achieve low back pressure without sacrificing material strength

Inventive Principle:

Principle #6Universality (Multi-functionality)

4Reliability

If selective plugging is applied to modify channel flow, then thermal robustness is improved, but device complexity increases

Engineering Contradiction:

Improvethermal robustnessVSAvoidfilter structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The filter is segmented into different channel types (wall-flow and flow-through) with distinct plugging patterns. Selective plugging is applied to specific channels to create the desired flow distribution and thermal management, while maintaining a relatively simple overall structure that is manufacturable with standard techniques

Inventive Principle:

Principle #1Segmentation

Data Source

PatentEP2180936B1Tuning particulate filter performance through selective plugging and use of multiple particulate filters to reduce emissions and improve thermal robustness

Publication Date: 2015.07.08 CUMMINS FILTRATION IP INC

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Figure 3A~3B

AI summary

Modified exhaust aftertreatment filters for filtering engine exhaust are provided as are methods of design and manufacturing modified exhaust aftertreatment filters. The modified filters are subject to reduced back pressure and reduced thermal gradients experienced during regeneration as compared to unmodified filters. The modified filters include flow-through channels obtained by unplugging channels which normally are plugged in an unmodified filter.