Multi-Zone Catalyzed Particulate Filter for Diesel Emissions
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current diesel engine exhaust treatment systems require multiple substrates to effectively manage CO, HC, NOx, and particulate matter, leading to increased size, cost, and complexity, while existing catalysts face challenges in maintaining effectiveness over time and across varying temperatures.
Innovation Solution
A multi-zone catalyzed particulate filter with porous walls coated with multiple catalyst zones, including SCR and platinum group metal coatings, designed to treat CO, HC, NOx, soot, NH3, and H2S in a single article, optimizing catalyst distribution to minimize backpressure and maintain activity across temperature ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple separate substrates are used to treat different exhaust components (CO, HC, NOx, PM), then effective emission treatment is achieved, but system size, cost, and complexity increase
Solution Approach 1:
The patent combines multiple catalytic functions (oxidation catalyst for CO/HC, SCR catalyst for NOx, and particulate filter for PM) into a single integrated substrate structure. The substrate contains multiple zones with different catalyst distributions, allowing simultaneous treatment of all exhaust components in one device rather than requiring separate substrates for each function.
Solution Approach 2:
The single substrate is designed to perform multiple functions: it acts as a particulate filter to capture PM, an oxidation catalyst to convert CO and HC, and an SCR catalyst support to reduce NOx. This multi-functional design eliminates the need for multiple separate emission treatment devices.
2Reliability
If multiple separate substrates are used to treat different exhaust components, then effective emission treatment is achieved, but system size and cost increase
Solution Approach 1:
The patent merges multiple emission treatment functions into one compact substrate, reducing the overall volume required compared to using multiple separate substrates. The integrated design allows all catalytic activities to occur within a single component occupying less space.
3Reliability
If multiple separate substrates are used to treat different exhaust components, then effective emission treatment is achieved, but manufacturing cost increases
Solution Approach 1:
The patent combines multiple catalytic functions into a single substrate that can be manufactured as one integrated component rather than assembling multiple separate substrates. This reduces manufacturing complexity and associated costs while maintaining effective emission treatment.
4Ease of manufacture
If catalyst is distributed uniformly throughout the substrate, then simple manufacturing is achieved, but catalytic activity varies across different temperature zones
Solution Approach 1:
The patent implements non-uniform catalyst distribution with different zones having different catalyst types and concentrations. The first zone has higher oxidation catalyst content for cooler temperatures, while the second zone has higher SCR catalyst content for hotter temperatures. This local differentiation optimizes catalytic activity for the specific temperature conditions in each zone.
Solution Approach 2:
The substrate is divided into multiple zones along the exhaust flow direction, with each zone containing catalysts optimized for the local temperature conditions. This segmentation allows the system to handle the temperature gradient effectively, with cooler inlet zones optimized for oxidation and hotter outlet zones optimized for SCR reactions.
5Reliability
If exhaust temperature is increased to burn soot particles, then particulate matter removal is improved, but temperatures exceed typical diesel exhaust conditions
Solution Approach 1:
The patent uses oxidation catalysts containing platinum group metals to accelerate the oxidation of soot particles at lower temperatures than would be required without catalysis. The catalyst promotes the reaction between soot and oxygen, enabling effective PM removal at typical diesel exhaust temperatures rather than requiring excessive temperature increases.
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 multi-zone catalyzed particulate filter achieves efficient reduction of diesel engine emissions by balancing competing reactions, reducing system size and cost, and maintaining catalytic activity over a wide temperature range, ensuring effective treatment of multiple pollutants in a single component.
Implementation Method 1
a first zone extends axially from the inlet end of the porous walls a distance less than the full length of the porous wall and consists essentially of the first SCR catalyst coating
Implementation Method 2
a second zone extends axially from the first zone a distance less than the distance to the outlet end of the porous wall and comprises the platinum group metal coating and the first SCR catalyst coating
Implementation Method 3
These filters are capable of removing over 90% of the solid carbonaceous particulate material from diesel exhaust
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
Provided are multi-zone catalyst articles, methods of manufacturing multi-zone catalyst articles, and methods for controlling emissions in diesel engine exhaust streams with multi-zone catalyst articles, where the emission treatment system of various embodiments effectively treats diesel engine exhaust with a single multi-zone catalyst article.