Wall Flow Filter Gradient Coating for Exhaust Storage Efficiency
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Catalytically activated particle filters with storage materials have poor storage efficiency under operating conditions with a discontinuous air ratio λ, leading to increased exhaust gas pressure loss and inefficient pollutant removal.
Innovation Solution
A method involving a wall flow filter substrate with a catalytically active coating, where at least 60% of the storage material is present in the walls between inflow and outflow channels, with a gradient concentration, ensuring maximum contact with exhaust gases and reducing unused storage material, thereby enhancing storage efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a catalytically activated particle filter with storage material is used under operating conditions with discontinuous air ratio, then pollutant removal function is provided, but storage efficiency deteriorates and exhaust gas pressure loss increases
Solution Approach 1:
The patent applies local quality by creating a non-uniform distribution of storage material within the filter substrate. Specifically, the storage material concentration varies through the wall thickness and along the flow direction, with higher concentrations positioned where they most effectively interact with exhaust gases under discontinuous air ratio conditions. This localized optimization resolves the contradiction by maintaining pollutant removal effectiveness while improving storage material utilization efficiency.
Solution Approach 2:
The patent implements preliminary action by pre-positioning storage material in strategic locations within the filter substrate before exhaust gas flow occurs. The storage material is distributed in advance during manufacturing with a specific spatial pattern that anticipates the discontinuous air ratio operating conditions, allowing it to be ready to absorb pollutants efficiently when needed without requiring real-time adjustment.
2Quantity of substance
If storage material is added to enhance pollutant storage, then storage capacity improves, but exhaust gas pressure loss increases
Solution Approach 1:
The patent resolves this contradiction by applying local quality through non-uniform storage material distribution. Instead of uniformly adding storage material throughout the filter, the concentration is optimized locally - higher where it provides maximum storage capacity benefit and lower where it would excessively increase pressure loss. This selective placement maintains storage capacity while minimizing pressure drop.
Solution Approach 2:
The patent applies parameter changes by varying the storage material concentration as a spatial parameter throughout the filter substrate. The concentration parameter is changed from uniform to gradient-based distribution, allowing optimization of the balance between storage capacity and pressure loss by adjusting material density in different regions rather than using a single uniform concentration.
3Ease of manufacture
If uniform coating of storage material is applied, then manufacturing simplicity is maintained, but storage material utilization efficiency deteriorates
Solution Approach 1:
The patent implements local quality by transitioning from uniform to non-uniform storage material distribution. The coating process is designed to deposit varying concentrations of storage material at different locations within the filter substrate, creating a functionally optimized structure that improves utilization efficiency while remaining manufacturable through controlled application methods.
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 approach significantly improves storage material utilization, reducing exhaust gas pressure loss and maintaining effective pollutant removal, allowing for fewer purification units and cost-effective operations.
Implementation Method 1
Nitrogen oxide storage materials that store nitrogen oxides from the lean exhaust gas and release them again under reducing exhaust gas conditions
Implementation Method 2
oxygen-storing materials are used in three-way catalytic converters to remove CO, HC and NO x from the exhaust gas
Implementation Method 3
This catalyst promotes the chemical reaction of various exhaust gas components to form harmless products such as carbon dioxide CO 2 and water
Implementation Method 4
catalytically activated particle filters, which are usually ceramic wall flow filter substrates that contain a catalytically active coating
Data Source
Figure 1a~1c
Figure 2
Figure 3~4
AI summary
A method for cleaning the exhaust gases of combustion engines is described, suitable for reducing pollutant gases and particulate emissions. The exhaust gas to be cleaned is passed over a wall-flow filter substrate under operating conditions with a discontinuous air-fuel ratio (λ). This substrate contains a catalytically active coating with a storage material. The storage material is capable of temporarily storing one or more exhaust gas components under specific operating conditions and releasing them selectively when the operating conditions change appropriately. The coating is designed such that the component exhibits a gradient in the storage material concentration and/or the total coating amount, with the highest concentration of the storage material occurring longitudinally on the upstream side of the component. A minimum of 60 wt.-% of the storage material, based on its total quantity, is located in the walls between inflow and outflow channels; at least 50% by weight of the storage material, based on its total quantity, is present in a first, upstream zone in the wall flow filter substrate.