Partial Wall-Flow Filter for Diesel Exhaust Backpressure Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional diesel exhaust systems with wall-flow filters face challenges of high backpressure and increased fuel economy penalties due to frequent regeneration events, as they require all channels to be plugged at alternate ends, leading to inefficient soot removal and pressure drop management.
Innovation Solution
A partial wall-flow filter design featuring some plugged and some unplugged channels, with specific porosity and cell density characteristics, allowing for reduced regeneration events and lower backpressure by optimizing channel plugging patterns and porosity distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If all channels are plugged at alternate ends in conventional wall-flow filters, then filtration efficiency is improved, but backpressure increases and regeneration frequency increases
Solution Approach 1:
The filter channels are segmented into two distinct types: plugged channels that provide filtration through porous walls, and unplugged flow-through channels that provide direct flow paths. This segmentation allows the system to achieve both filtration efficiency and reduced backpressure by utilizing both channel types simultaneously, resolving the contradiction between filtering performance and pressure drop.
Solution Approach 2:
Different regions of the filter substrate are assigned different functional qualities: some channels are designed with plugs to maximize filtration, while others remain unplugged to minimize resistance. This local differentiation of channel properties allows the filter to optimize both filtration efficiency and backpressure characteristics according to the specific needs of different flow paths.
2Reliability
If all channels are plugged at alternate ends, then soot capture is improved, but regeneration events increase causing fuel economy penalty
Solution Approach 1:
The channel system is divided into plugged and unplugged channels, creating a dual-pathway approach to soot management. The plugged channels capture soot through wall-flow filtration, while the unplugged channels provide bypass paths that reduce the rate of soot accumulation. This segmentation extends the time between regeneration events, reducing the frequency of fuel-consuming regeneration cycles.
Solution Approach 2:
Instead of plugging all channels to maximize soot capture, the invention applies partial plugging where only some channels are plugged. This partial action approach maintains sufficient soot capture capability while preventing excessive soot accumulation that would trigger frequent regenerative events and associated fuel economy penalties.
3Reliability
If conventional wall-flow filter design is used, then filtration performance is achieved, but pressure drop management becomes difficult
Solution Approach 1:
The filter is segmented into channels with different flow characteristics: plugged channels that provide filtration and unplugged channels that provide low-resistance flow paths. This segmentation creates a more manageable pressure drop profile by distributing flow through multiple pathways with varying resistances, making pressure drop management more predictable and controllable compared to uniform plug configurations.
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 partial wall-flow filter achieves higher filtration efficiency and lower backpressure, promoting passive regeneration and reducing the likelihood of soot overload, while maintaining effective soot capture and minimizing pressure drop across the filter.
Implementation Method 1
the porous walls retain a portion of the particles that were entrained in the exhaust
Implementation Method 2
the location of the filter is such that the temperature of the filter is relatively low and additional energy input may be required to raise the temperature of the exhaust (and the filter) to a level that would cause combustion of the soot trapped in the filter
Data Source
AI summary
A partial wall-flow filter having some unplugged flow-through channels and some plugged channels. Desirable combinations of filtration efficiency and back pressure may be provided by combinations of t wall≦305 urn, MPD≦20 μm, % P≧50%, and CD≧250 cpsi wherein t wall is the transverse thickness of the porous walls, MPD is a mean pore diameter of the porous walls, % P is the total porosity of the porous walls, and CD is the cell density of the channels. In one embodiment, some of the plugged channels are located adjacent to the inlet end and some are located adjacent to the outlet end. Systems and method including the partial wall-flow filter are also described.