Zoned Catalytic Layer for Particulate Filter Emission Control
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Solution Overview
Problem
Current catalyzed particulate filters struggle to meet the stringent emission standards, particularly in converting pollutants like NOx, HC, and CO efficiently under the World Harmonized Light-duty Vehicle Test Cycle (WLTC) conditions.
Innovation Solution
A catalyzed particulate filter design featuring a zoned catalytic layer with varying platinum group metal (PGM) content across different zones of the filter, optimized for improved conversion efficiency of NOx, HC, and CO.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a uniform catalytic layer is used across the entire filter, then the manufacturing process is simple, but the conversion efficiency of pollutants (NOx, HC, CO) is insufficient under WLTC conditions
Solution Approach 1:
The patent applies local quality by creating different catalytic layer compositions in different zones of the filter. The inlet zone contains higher PGM loading for oxidizing CO and HC, while the outlet zone contains lower PGM loading with higher NOx conversion capability. This spatial variation in catalyst properties optimizes pollutant conversion efficiency under WLTC conditions while maintaining manageable manufacturing complexity through a zoned approach rather than completely different catalyst systems.
2Productivity
If platinum group metal content is increased throughout the filter, then pollutant conversion efficiency improves, but manufacturing cost increases
Solution Approach 1:
The patent optimizes PGM content by concentrating higher metal loading in the inlet zone where CO and HC oxidation is most critical, while using lower PGM content in the outlet zone where NOx conversion is the primary function. This localized optimization achieves high pollutant conversion efficiency without uniformly increasing PGM content throughout the entire filter, thereby controlling manufacturing costs.
Solution Approach 2:
The catalytic layer is segmented into distinct inlet and outlet zones with different PGM compositions. This segmentation allows each zone to be optimized for its specific function - the inlet zone handles oxidizable pollutants with higher PGM content, while the outlet zone handles NOx reduction with lower PGM content - achieving cost efficiency through functional differentiation.
3Productivity
If the filter is designed for high power output under WLTC, then acceleration performance improves, but emission conversion efficiency decreases due to open-loop conditions
Solution Approach 1:
The patent addresses WLTC adaptability by creating a zoned catalytic structure where the inlet zone is optimized for oxidizable pollutants (CO, HC) that are prevalent during acceleration, while the outlet zone is optimized for NOx conversion. This local optimization ensures that even during high-power WLTC operation, the catalyst maintains high conversion efficiency across all pollutant types by having specialized zones for each function.
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 zoned catalytic layer design enhances the conversion efficiency of NOx, HC, and CO by up to 25%, 20%, and 20% respectively, compared to traditional designs, while maintaining operational stability under WLTC conditions.
Implementation Method 1
Catalysts containing platinum group metals (PGMs) are accordingly located in the exhaust gas line of internal combustion engines. Such catalysts promote the oxidation by oxygen in the exhaust gas stream of unburned hydrocarbons and carbon monoxide as well as the reduction of nitrogen oxides to nitrogen.
Implementation Method 2
Such catalysts promote the oxidation by oxygen in the exhaust gas stream of unburned hydrocarbons and carbon monoxide
Implementation Method 3
Such catalysts promote the oxidation by oxygen in the exhaust gas stream of unburned hydrocarbons and carbon monoxide as well as the reduction of nitrogen oxides to nitrogen.
Data Source
AI summary
Disclosed herein is a particulate filter, in particular a catalyzed particulate filter, for use in an emission treatment system of an internal combustion engine. Provided are catalyzed particulate filters, emission treatment systems with catalyzed particulate filters, methods for manufacturing catalyzed particulate filters, and methods for controlling emissions in exhaust gas from internal combustion engines with catalyzed particulate filters.