Perforated Metallic Honeycomb Catalyst with Filled Holes
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Solution Overview
Problem
Existing metallic honeycomb catalyst supports for internal combustion engines face challenges in achieving a balance between reducing heat capacity for quick warm-up and maintaining sufficient catalyst mass for effective pollutant conversion, while also ensuring mechanical stability and resistance to corrosive exhaust atmospheres.
Innovation Solution
The honeycomb body is designed with perforated metal sheets where the holes and/or slots are filled with catalyst material during the coating process, allowing for a reduced heat capacity without decreasing the catalyst mass, and using expanded metals to enhance exhaust gas contact with the catalyst.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the honeycomb body is designed with perforated metal sheets to reduce heat capacity, then the warm-up speed is improved, but the catalyst mass is reduced leading to poorer pollutant conversion after warm-up
Solution Approach 1:
The patent applies porous materials by using perforated metal sheets where the holes are filled with catalyst material during the coating process. This creates a porous structure that reduces heat capacity while maintaining sufficient catalyst mass through the filled holes, resolving the contradiction between warm-up speed and pollutant conversion capability
Solution Approach 2:
The patent uses composite materials by combining perforated metal sheets with catalyst material filling. The composite structure integrates the heat-dissipating advantage of perforations with the catalytic functionality of the filled material, achieving both rapid warm-up and sustained pollutant conversion
2Temperature
If the slot area of sheet metal layers is increased to reduce heat capacity, then the light-off temperature is reached quicker, but the available catalyst mass decreases
Solution Approach 1:
The patent applies parameter changes by optimizing the hole area percentage within the range of 5-80% and controlling the coating thickness to 1-10 μm. This parameter optimization allows sufficient heat capacity reduction for quick light-off while maintaining enough catalyst mass for effective pollutant conversion
3Loss of time
If holes are made in sheet metal layers to reduce heat capacity, then the dynamic pressure increases due to turbulence, but the catalyst mass is reduced
Solution Approach 1:
The patent uses porous materials with controlled hole sizes and patterns that reduce heat capacity while minimizing turbulence-induced pressure increases. The perforated structure with optimized hole distribution allows heat dissipation without excessive dynamic pressure buildup
4Quantity of substance
If the thickness of catalyst layer is increased to maintain catalyst mass, then the flow resistance increases
Solution Approach 1:
The patent applies parameter changes by optimizing the catalyst layer thickness within the range of 1-10 μm. This thin-layer approach maintains sufficient catalyst mass through the perforated structure while minimizing flow resistance, avoiding the need for thicker coatings that would increase backpressure
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 enables the catalyst to reach light-off temperature quickly, maintain full catalytic activity, and improve aging stability, while minimizing flow resistance and dynamic pressure increases.
Implementation Method 1
a catalyst for cleaning the exhaust gases from internal combustion engines, which contains a honeycomb body made of smooth and corrugated metal sheets with an inlet face and an exit face for the exhaust gases
Implementation Method 2
the applied catalyst coating reaches its light-off temperature more quickly and thus also improves the conversion of carbon monoxide and hydrocarbons
Data Source
Figure 1~4
Figure 5
Figure 6a~6b
AI summary
In known automobile exhaust gas catalytic converters comprising a metallic honeycomb body consisting of corrugated and smooth sheet metal layers, the thermal capacity and thermal conductivity of said body is reduced by perforations in the sheet metal layers. This permits a more rapid heating of the honeycomb body and the catalytic coating that is applied to the honeycomb body reaches its operating temperature more quickly. One disadvantage of this is the reduction of the support surface as a result of the perforations in the sheet metal layers. According to the invention, the perforations can be permanently filled with the catalytic substance by the appropriate adaptation of the characteristics of the coating suspension used for the catalytic coating to the dimensions of the perforations. The resultant catalytic converter has a significantly reduced thermal capacity and thermal conductivity, whilst retaining the same coating concentration as a catalytic converter with unperforated sheet metal layers.