Wall-Flow Filter Sintered Coating for Exhaust Gas Filtration
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Solution Overview
Problem
Existing particulate filters face challenges in maintaining filtration functionality after exposure to liquid water, which can impair their efficiency and robustness under varying operating conditions.
Innovation Solution
A wall-flow filter with a sintered coating composed of oxides, oxide-hydroxides, or other materials applied via a dry-coating process, ensuring the coating is stable and not affected by liquid water, thereby maintaining filtration efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a particulate filter is used to remove particles from exhaust gas, then filtration efficiency is improved, but exhaust-gas back pressure increases
Solution Approach 1:
The filter substrate employs a porous ceramic structure with controlled pore size and distribution. The porous walls allow exhaust gas to pass through while trapping particles, achieving filtration efficiency without excessive pressure buildup. The porosity is optimized to balance particle capture with gas flow resistance.
Solution Approach 2:
The filter features non-uniform pore distribution and varying wall thickness along its length. The inlet region has larger pores to handle high particle loads, while the outlet region has smaller pores for finer filtration. This local variation in structure allows efficient particle removal across different flow conditions while minimizing overall back pressure.
2Reliability
If catalytically active coating is applied as a layer on the wall of a porous wall-flow filter, then catalytic effectiveness is improved, but exhaust-gas back pressure increases
Solution Approach 1:
The catalytically active material is pre-dispersed within the porous wall structure during manufacturing, rather than applied as a surface coating. This preliminary incorporation ensures uniform distribution of catalyst throughout the filter walls, maximizing catalytic surface area while avoiding the formation of thick surface layers that would increase flow resistance.
Solution Approach 2:
The catalytic material is integrated into the porous matrix of the filter walls, utilizing the existing pore structure to distribute the catalyst throughout the wall thickness. This approach provides extensive catalytic activity without adding significant material that would block gas flow, thereby maintaining low back pressure while achieving high catalytic effectiveness.
3Reliability
If a filtration layer is created on the walls of the flow channels by deposition of ceramic particles, then filtration efficiency is improved, but the filter becomes affected by liquid water
Solution Approach 1:
The filter substrate is made from a composite ceramic material combining multiple oxides (e.g., cordierite with alumina and silica) that provide both filtration capability and inherent hydrophobicity. This composite structure creates a surface energy that repels liquid water while maintaining porous structure for particle filtration, preventing water from blocking the filtration pores.
Solution Approach 2:
The porous ceramic structure is designed with specific pore size, shape, and surface chemistry that inherently resist liquid water penetration. The pore structure allows gas molecules to pass through while the surface properties prevent liquid water from adhering and blocking the pores, maintaining filtration efficiency in wet conditions without requiring additional hydrophobic coatings.
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 proposed solution achieves enhanced filtration efficiency with minimal increase in exhaust-gas back pressure and maintains filtration properties even after exposure to liquid water, ensuring robust performance across a wide range of operating conditions.
Implementation Method 1
a dry-coating process is used to apply a coating F on the surfaces OE
Implementation Method 2
coating F comprises a sintered material S, wherein material S comprises an oxide, oxide-hydroxide, carbonate, sulphate, silicate, phosphate, mixed oxide, composite oxide, molecular sieve or a mixture comprising two or more of these materials
Data Source
AI summary
The present invention relates to a wall-flow filter for removing particles from the exhaust gas of an internal combustion engine, which comprises a coating F, which comprises a sintered material S, wherein material S comprises an oxide, oxide-hydroxide, carbonate, sulphate, silicate, phosphate, mixed oxide, composite oxide, molecular sieve or a mixture comprising two or more of these materials.