Wall-flow filter with thermolabile powder coating for exhaust back pressure management
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Solution Overview
Problem
Current particulate filters for internal combustion engines face challenges in achieving high fresh filtration efficiency while minimizing exhaust gas back pressure, which can lead to reduced engine performance and increased fuel consumption, especially under real driving emissions testing.
Innovation Solution
A wall-flow filter is designed with a thermolabile powder coating that increases filtration efficiency in the fresh state, which decreases in surface area and volume due to thermal loading, thereby minimizing exhaust gas back pressure and maintaining filtration performance over time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a particulate filter is designed with high filtration efficiency in the fresh state, then fresh filtration performance is improved, but exhaust gas back pressure increases significantly
Solution Approach 1:
The patent applies parameter changes by using a thermolabile powder coating that changes its physical properties (surface area and volume) in response to temperature changes. In the fresh cold state, the powder maintains high surface area for excellent filtration efficiency. During operation, thermal loading causes the powder to decrease in surface area and volume, reducing exhaust gas back pressure while maintaining adequate filtration performance.
Solution Approach 2:
The patent implements dynamics by making the filter media properties dynamic rather than static. The thermolabile powder coating dynamically adjusts its structure based on operating conditions - maintaining expanded high-surface-area structure during cold operation for maximum filtration, and transitioning to a contracted lower-surface-area structure during hot operation to minimize back pressure.
2Reliability
If the filter operates with high filtration efficiency over time, then particulate removal performance is maintained, but exhaust gas back pressure continues to increase
Solution Approach 1:
The thermolabile powder coating undergoes parameter changes during operation - specifically, it decreases in surface area and volume due to thermal loading. This natural parameter change counteracts the back pressure increase that would normally occur from particulate accumulation, thereby maintaining more stable back pressure levels over time while preserving filtration performance.
3Manufacturing precision
If thermolabile powder is applied to increase fresh filtration, then initial filtration efficiency is improved, but the powder decreases in surface area due to thermal loading
Solution Approach 1:
The patent applies local quality by creating different functional zones within the filter media. The thermolabile powder coating provides high surface area and filtration capability in the fresh cold state, while allowing localized structural changes in response to thermal loading during operation. This localized adaptation maintains filtration performance while adjusting back pressure characteristics.
Solution Approach 2:
The filter experiences periodic thermal cycles during operation - cold start conditions followed by hot operating conditions. The thermolabile powder responds to these periodic thermal actions by expanding during cold phases for maximum filtration and contracting during hot phases to reduce back pressure, creating a dynamic adaptation cycle.
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 filter achieves high initial filtration efficiency with minimal increase in exhaust gas back pressure, maintaining performance through the accumulation of oil ash and controlled sintering of the thermolabile powder, thus addressing the need for efficient particulate filtration without significant back pressure increase.
Implementation Method 1
decreases in surface area and volume due to thermal loading
Data Source
AI summary
The present invention is directed to a wall-flow filter. Said wall-flow filter contains a powder coating which increases the filtration efficiency only in the fresh state. An exhaust gas system comprising such a wall-flow filter is also claimed.