Honeycomb Filter Plugs with Bimodal Filler for Depth Consistency
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Solution Overview
Problem
Ceramic wall flow filters face challenges in achieving consistent plug depth and mechanical strength due to variability in plug depth, which affects the filtration efficiency and fuel economy, as plugs in channels with higher resistance tend to be shorter and those with lower resistance tend to be longer, leading to inadequate mechanical strength in some cases.
Innovation Solution
A composition for honeycomb bodies comprising a refractory filler with a specific particle size distribution, an organic binder, and a gelled inorganic binder, such as polydisperse colloidal silica, is applied to achieve plugs with a consistent average depth and reduced depth range, ensuring adequate mechanical strength and minimizing variability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the plugging composition is applied to achieve shorter plugs, then filter volume increases and fuel economy improves, but plug depth variability increases causing insufficient mechanical strength in some channels
Solution Approach 1:
The patent applies parameter changes by modifying the particle size distribution of refractory filler (using a bimodal distribution with particles ranging from 10-40 micrometers) and adjusting binder composition (combining organic binder at 1-5 wt% with inorganic binder at 5-20 wt%) to achieve consistent plug depth across channels with varying resistance, ensuring adequate mechanical strength while maintaining optimal plug length for fuel economy
Solution Approach 2:
The patent uses composite materials by combining organic binder and inorganic binder in specific proportions, along with refractory filler having controlled particle size distribution, to create a plugging composition that maintains structural integrity and consistent depth across channels with different flow resistance conditions
2Productivity
If plug depth is reduced to provide less back pressure, then filtration efficiency improves, but mechanical strength of plugs decreases
Solution Approach 1:
The patent optimizes the particle size distribution parameter of refractory filler (10-40 micrometers bimodal distribution) and binder composition parameters to achieve the shortest possible plug depth that still provides adequate mechanical strength, balancing filtration efficiency with structural integrity
Solution Approach 2:
The patent applies local quality by ensuring that plugs in channels with higher resistance (which naturally form shorter) receive the same composition formulation that provides sufficient mechanical strength, rather than uniformly increasing plug depth across all channels
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 solution results in plugs with a depth range less than 30% of the average plug depth, providing consistent mechanical strength and improved filtration efficiency while reducing the frequency of regenerations and lowering manufacturing costs.
Implementation Method 1
differences in the flow rate of a plugging composition in different filter channels
Implementation Method 2
when the composition is applied to plug a plurality of channels of the honeycomb body, a plurality of plugs formed therefrom
Data Source
AI summary
A composition for applying to a honeycomb body includes a refractory filler, an organic binder, an inorganic binder, and a liquid vehicle, wherein the refractory filler, the particle size distribution of the refractory filler, the organic binder, and the inorganic binder are selected such that, when the composition is applied to plug a plurality of channels of the honeycomb body, the plug depth variability is reduced.