Diesel Particulate Filter Dual Coating Back Pressure
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional diesel particle filters with SCR catalytic coatings experience excessive back pressure during soot loading, poor filtration efficiency, and reduced long-term stability due to increased thermal load from frequent active regenerations, leading to inefficient engine power utilization and increased fuel consumption.
Innovation Solution
A diesel particle filter with a ceramic wall-flow substrate featuring two coatings: a high-melting material overcoat that closes pores in the inflow channels to reduce depth filtration and an SCR catalytically active coating between the inflow and outflow channels for selective nitrogen oxide reduction, optimizing filtration efficiency and reducing dynamic pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a reduction catalyst coating is applied to the diesel particle filter, then nitrogen oxide reduction capability is improved, but back pressure increases excessively during soot loading
Solution Approach 1:
The filter is divided into two functionally distinct zones: inflow channels are optimized for particle filtration with appropriate porosity and surface area, while outflow channels are optimized for SCR reactions. This segmentation allows each zone to perform its specific function efficiently without the performance degradation caused by the other function, thereby reducing back pressure while maintaining nitrogen oxide reduction capability.
Solution Approach 2:
Different regions of the filter are assigned different functional properties: the inflow channel walls are designed with porosity and surface characteristics optimized for soot particle capture, while the outflow channel walls are designed with catalyst coating and surface properties optimized for SCR reactions. This local differentiation of quality allows the filter to achieve both functions without the trade-off that previously caused excessive back pressure.
2Reliability
If SCR catalytic coating is applied, then nitrogen oxide reduction is improved, but filtration efficiency decreases
Solution Approach 1:
The filter structure segments the filtration and SCR functions into separate channel systems. The inflow channels with their wall porosity and surface area are dedicated to capturing soot particles, achieving high filtration efficiency. The outflow channels are dedicated to SCR reactions. This segmentation eliminates the compromise that previously forced a trade-off between filtration efficiency and nitrogen oxide reduction.
Solution Approach 2:
The filter applies different surface qualities to different locations: inflow channel walls have surface properties and porosity optimized for particle capture and filtration, while outflow channel walls have catalyst-coated surfaces optimized for SCR reactions. This local quality differentiation allows the system to achieve both high filtration efficiency and effective nitrogen oxide reduction without compromise.
3Reliability
If reduction catalyst coating is applied, then nitrogen oxide reduction capability is improved, but long-term stability decreases due to thermal load
Solution Approach 1:
By segmenting the filter into separate inflow and outflow channel systems with distinct functions, the thermal load from SCR reactions is localized to the outflow channels. The inflow channels, which handle the bulk of exhaust flow and soot loading, are not subjected to the same thermal stresses. This spatial segmentation of thermal loads protects the catalyst coating in the inflow region from degradation, improving long-term stability.
Solution Approach 2:
The filter creates local differences in thermal exposure: the outflow channel walls with catalyst coating are designed to withstand SCR reaction temperatures, while the inflow channel walls experience different thermal conditions during soot loading. This local quality differentiation in thermal management reduces the overall thermal stress on the catalyst system, thereby improving long-term stability and durability.
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 solution significantly reduces dynamic pressure during soot loading, enhances filtration efficiency, and improves passive regeneration behavior, leading to less frequent active regeneration cycles and increased long-term stability of the SCR coating, thus optimizing engine power utilization and reducing fuel consumption.
Implementation Method 1
a high-melting material overcoat which is applied in the inflow channels and is designed in such a way that it closes the pores in the wall connecting the inflow and outflow channels on the inflow side for soot particles
Implementation Method 2
an SCR catalytically active coating in the wall between the inflow channels and the outflow channels which is designed in such a way that it effectively catalyzes the selective reduction of nitrogen oxides with a reducing agent
Implementation Method 3
The exhaust gas introduced into the inflow channels must flow through the porous channel walls of the flow channels into the outflow channels
Data Source
Figure 1~1b
Figure 2~2c
Figure 3~4
AI summary
The invention proposes a diesel particle filter which comprises a ceramic wall-flow filter substrate and two coatings. The first coating, which is applied in the inflow ducts and is composed of material with a high melting point, is provided in such a way that the pores in the wall which connect the inflow ducts and outflow ducts are closed to soot particles at the inflow side by said first coating, without the passage of the gaseous constituents of the exhaust gas thereby being prevented. The second coating is introduced into the wall between the inflow ducts and outflow ducts and is provided in such a way that it can actively catalyze the selective reduction of nitrogen oxides with a reducing agent. The resulting component is a particle filter which is catalytically active in terms of an SCR process and exhibits excellent back-pressure characteristics while having high filtration efficiency and good regeneration characteristics. The component also exhibits good aging stability of the NOx conversion activity.