Honeycomb Body with Variable Hydraulic Diameter Channels
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Solution Overview
Problem
Honeycomb bodies with high channel density suffer from face-plugging due to soot buildup in automotive exhaust systems, leading to reduced catalytic efficiency and increased backpressure, which affects fuel economy and engine performance.
Innovation Solution
A honeycomb body design featuring a combination of large and small channels, where the large channels act as bypass channels to reduce face-plugging and maintain catalytic efficiency, with a geometric surface area greater than 2.9 mm^-1 and a channel density greater than 62 channels/cm^2, ensuring that the honeycomb body remains resistant to face-plugging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high channel density is used to increase catalytic efficiency, then catalytic efficiency per unit volume is improved, but face-plugging resistance deteriorates
Solution Approach 1:
The honeycomb body is segmented into two distinct channel populations: first channels with hydraulic diameter ≥1.1 mm for bypass functionality and second channels with hydraulic diameter <1.1 mm for catalytic conversion. This segmentation allows each channel type to perform its specialized function, resolving the contradiction between high catalytic efficiency and face-plugging resistance.
Solution Approach 2:
Different regions of the honeycomb body have different channel sizes optimized for different functions. The first channels (larger) are positioned to handle bypass flow and prevent face-plugging, while second channels (smaller) provide high surface area for catalysis. This local differentiation of channel quality resolves the contradiction.
2Productivity
If small channels are used to increase channel density, then catalytic efficiency is improved, but pressure drop increases
Solution Approach 1:
The channel system is segmented into large bypass channels and small catalytic channels. The large channels maintain low pressure drop for bypass flow, while the small channels provide high catalytic efficiency. The parallel arrangement allows exhaust to分流 through both pathways, reducing overall pressure drop while maintaining catalytic performance.
3Ease of manufacture
If uniform channel size is used to simplify manufacturing, then ease of manufacture is improved, but face-plugging resistance deteriorates
Solution Approach 1:
The manufacturing process is segmented into forming the honeycomb green body with varied channel sizes through extrusion die design, followed by selective coating of catalysts on different channel types. This segmentation allows complex multi-functional performance to be achieved through systematic process steps rather than requiring complex post-processing.
Solution Approach 2:
The hydraulic diameter parameter is varied systematically across different channel populations (≥1.1 mm vs. <1.1 mm) to create distinct functional zones. This parameter differentiation is built into the manufacturing process through extrusion die design, achieving face-plugging resistance without requiring complex post-manufacturing modifications.
Data Source
AI summary
A ceramic honeycomb body, suitable for use in exhaust gas processing, includes a honeycomb structure having a plurality of through-channels, a first portion of the plurality of through-channels have a first hydraulic diameter dh1, a second portion of the plurality of through-channels have a second hydraulic diameter that is smaller than the first hydraulic diameter dh1, the first hydraulic diameter dh1 is equal to or greater than 1.1 mm, and the first and second portions of through-channels, taken together, have a geometric surface area GSA greater than 2.9 mm−1. Diesel oxidation catalysts and methods of soot removal are also provided, as are other aspects.