Metallic Honeycomb Microstructures for High-Coating Low-Pressure Exhaust Flow
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional metallic honeycomb bodies face challenges in maximizing ceramic coating adherence and oxygen storage capacity without increasing pressure loss, particularly in eliminating nitrogen oxides from diesel exhaust gases, due to limitations in surface area and coating thickness.
Innovation Solution
The honeycomb body features sheet metal layers with two distinct structures: a larger structure height determining channel size and a smaller structure height with zig-zack corrugations, allowing the ceramic coating to adhere more significantly to the valleys, thereby increasing the amount of coating material and oxygen storage capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the number of channels per unit area is increased to increase coating surface area, then coating adherence is improved, but hydraulic cross-section decreases and pressure drop increases
Solution Approach 1:
The patent transitions from a two-dimensional smooth surface to a three-dimensional structured surface by adding corrugations with valleys and peaks to the channel walls. This dimensional change creates additional surface area within the same channel cross-section, allowing more coating material to adhere without reducing the hydraulic cross-section or increasing pressure drop.
Solution Approach 2:
The corrugated structure creates a porous-like surface topology with valleys and peaks that can trap and retain coating material. The valleys act as reservoirs that hold coating material, effectively increasing the quantity of coating material that can be applied and retained on the channel walls without blocking the flow path.
2Quantity of substance
If coating thickness is increased to increase oxygen storage capacity, then removal efficiency is improved, but pressure loss increases
Solution Approach 1:
Instead of increasing coating thickness in the radial direction (which would block flow and increase pressure loss), the patent utilizes the longitudinal dimension by creating corrugations along the channel length. This allows coating material to be distributed over a longer path length within the valleys, increasing oxygen storage capacity without significantly increasing pressure loss.
3Ease of manufacture
If smooth sheet layers are used to reduce manufacturing complexity, then manufacturing is easier, but coating adherence is insufficient
Solution Approach 1:
The patent applies corrugations only to specific regions of the sheet layers (the channel-forming layers) while keeping other areas smooth. This localized structuring provides the necessary coating adherence in the channel walls without complicating the overall manufacturing process or requiring all sheet layers to be structured.
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 design enhances the adherence and retention of ceramic coating material, increasing the effective surface area and oxygen storage, allowing for efficient removal of nitrogen oxides and hydrocarbons from gas streams with reduced pressure loss.
Implementation Method 1
their ability to adhere particularly well at acute angles between sheet metal walls due to surface and adhesive forces
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The present invention relates to a metallic honeycomb body (1) with channels (4) through which a gas can flow, made up of layers of at least partially structured sheet metal (2), wherein the layers of sheet metal (2) have at least in subregions at least two different structures (3, 5), of which the first structure (3), with a greater structure height (H), determines the size of the channels (4) and the second structure (5) has a much smaller structure height (h) between troughs (6) and peaks (7) and wherein the form and/or the structure height (H) of the second structure (5) is chosen such that a ceramic coating (8) applied later can fill the troughs (6) of the second structure (5) on average to at least 10%, in particular at least 50%, of their structure height (h). With the honeycomb body according to the invention, more coating material per unit volume can be sustainably provided in a metallic honeycomb body without excessively increasing pressure loss. This is of advantage particularly for applications for reducing nitrogen oxides (NOx) in diesel exhausts.