Zoned Catalyst Composite Flat Profile Washcoat
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Solution Overview
Problem
Current catalytic converters face challenges in achieving uniform catalytic activity and component trapping/adsorbing properties across the length of zoned catalysts, leading to inefficiencies in exhaust gas treatment, particularly in diesel and gasoline engines.
Innovation Solution
The development of zoned catalyst composites with a flat profile on a monolithic carrier, utilizing a shear thinning washcoat with a pseudoplastic index of 5-7, containing platinum group metals, base metals, and molecular sieves, to create highly controlled zones for efficient light-off and soot burning, with uniform thickness and component concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If zoned catalysts are used to achieve specific chemistries at specific locations, then catalytic activity and component trapping are improved, but uniformity of catalytic material distribution and zone thickness control deteriorate
Solution Approach 1:
The patent applies local quality by creating zoned catalysts with different catalytic materials at specific locations along the carrier length. The washcoat formulation is modified locally in the zone region to provide specific chemistries (e.g., light-off promotion, soot burning) at targeted positions while maintaining uniform application thickness through controlled rheology properties.
Solution Approach 2:
The patent changes the rheological parameters of the washcoat (viscosity, yield point, pseudoplastic index) to enable precise control of zone formation. By adjusting these parameters, the washcoat can be made to deposit uniformly at controlled thicknesses in specific zones during the coating process, resolving the contradiction between localized functionality and uniformity control.
2Productivity
If short zones are provided to achieve specific functionalities efficiently, then productivity and component trapping efficiency are improved, but manufacturing control precision deteriorates
Solution Approach 1:
The patent utilizes rheological parameter changes, specifically the pseudoplastic index (5-7) and yield point (1.5-10.0), to control washcoat deposition behavior. These parameter adjustments enable the formation of short, well-defined zones (up to 1 inch length) with consistent dimensions during manufacturing, achieving both high productivity and precise control.
3Reliability
If zoned catalysts with varying component concentrations are used, then specific chemistries are enhanced, but homogeneity of catalytic material distribution deteriorates
Solution Approach 1:
The patent implements local quality by formulating the washcoat with specific catalytic materials and component concentrations tailored for specific zones. The washcoat composition is optimized locally to provide enhanced chemistries (e.g., PGM distribution, base metals, molecular sieves) at targeted locations while maintaining overall compositional stability through controlled application processes.
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 enables improved catalytic activity and component trapping, maintaining low pressure drop and preventing fouling, while ensuring efficient treatment of exhaust gases, including hydrocarbons, carbon monoxide, and nitrogen oxides, with minimal variation in zone thickness and component concentration.
Implementation Method 1
The zone may be formed from a washcoat that is shear thinning having a pseudoplastic index in the range of 5-7
Implementation Method 2
a zone comprising a catalytic material that is effective to convert and/or trap one or more components in the exhaust stream
Implementation Method 3
Components used in catalytic converters include, but are not limited to platinum group metals (PGM), base metals (BM), oxygen storage components (OSC), and/or molecular sieves
Data Source
AI summary
Provided herein are zoned catalysts that utilize components efficiently in that relatively short zones are provided to achieve specific functionalities to convert and/or trap one or more components in the exhaust stream. Highly controlled zoned are formed from one end of a monolithic carrier. The zones have a flat profile such that the zoned catalytic material within each passage of the substrate is at a substantially uniform distance from one end of the carrier. Methods of making and using the same are also provided.