Gasoline Particulate Filter with Localized Pt-Rh and Pt-Pd Washcoats
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Solution Overview
Problem
Existing gasoline particulate filters (GPFs) with three-way catalyst (TWC) coatings face challenges such as increased back pressure, difficulty in maintaining stoichiometric exhaust gas composition, and high costs, while also requiring a balance between performance and cost.
Innovation Solution
A method for manufacturing a GPF with improved catalytic activity and reduced back pressure, involving the formation of a washcoat slurry containing a platinum group metal (PGM) component of Pt and Rh, an oxygen storage capacity (OSC) material, and a carboxylate ion, which is then coated onto a wall-flow filter substrate and calcined.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a three-way catalyst (TWC) coating is applied to a GPF, then catalytic activity for CO, NOx and HC conversion is improved, but back pressure increases
Solution Approach 1:
The patent applies different catalyst compositions to different regions of the filter substrate. The first region contains Pt and Rh for NOx reduction, while the second region contains Pt and Pd for CO and HC oxidation. This local differentiation allows each region to be optimized for its specific function, reducing overall back pressure while maintaining catalytic effectiveness.
Solution Approach 2:
The patent uses composite washcoat materials with specific compositions in different regions. The first washcoat comprises Pt and Rh on a support, while the second washcoat comprises Pt and Pd on a support. These composite materials provide tailored catalytic properties for different emission components, achieving effective catalysis with reduced material quantity and lower back pressure.
2Reliability
If Pd and Rh are used in the catalyst, then catalytic performance is improved, but cost increases
Solution Approach 1:
The patent strategically places different metal combinations in different regions based on emission characteristics. Rh is used only in the first region for NOx reduction where it is most effective, while Pt and Pd are used in the second region for CO and HC oxidation. This localized approach reduces overall metal content and cost while maintaining performance.
Solution Approach 2:
The patent optimizes the composition and distribution parameters of the catalyst materials. By adjusting the types and amounts of metals (Pt, Rh, Pd) in different spatial parameters (first and second regions), the patent achieves cost reduction without sacrificing catalytic performance for the specific emission components targeted in each region.
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 method results in a GPF with enhanced catalytic performance, reduced back pressure, and improved oxygen storage capacity, potentially offering better performance than GPFs containing Pd and Rh, while also addressing cost considerations.
Implementation Method 1
calcining the washcoated substrate to form a GPF
Implementation Method 2
oxidation of carbon monoxide to carbon dioxide
Implementation Method 3
oxidation of carbon monoxide to carbon dioxide
Implementation Method 4
oxidation of unburned hydrocarbons to carbon dioxide and water
Implementation Method 5
oxidation of unburned hydrocarbons to carbon dioxide and water
Implementation Method 6
reduction of nitrogen oxides to nitrogen and oxygen
Implementation Method 7
reduction of nitrogen oxides to nitrogen and oxygen
Implementation Method 8
an oxygen storage capacity (OSC) material
Data Source
AI summary
A method for the manufacture of a Gasoline Particulate Filter is disclosed. The method comprises forming a washcoat slurry, coating a wall-flow filter substrate with the washcoat slurry to form a washcoated substrate, and calcining the washcoated substrate to form a Gasoline Particulate Filter. The washcoat slurry comprises a platinum group metal component consisting of Pt and Rh, an oxygen storage capacity material, and a carboxylate ion.