Four-Way Catalyst In-Wall On-Wall Coating Back-Pressure
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current four-way conversion catalysts for gasoline engines face challenges in achieving high particle filtration efficiency while minimizing back-pressure increase, which is essential for compliance with stringent emission regulations and maintaining vehicle performance and fuel economy.
Innovation Solution
A four-way conversion catalyst with a porous wall flow filter substrate featuring a three-way conversion catalytic coating comprising an oxygen storage compound and a platinum group metal supported on a refractory metal oxide, applied as both an in-wall and on-wall coating, optimized to maintain low back-pressure and enhance filtration efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If higher catalyst loading is applied to achieve higher filtration efficiency, then particle filtration efficiency is improved, but back-pressure increases
Solution Approach 1:
The catalytic coating is segmented into two distinct configurations: in-wall coating (within the substrate pores) and on-wall coating (on the substrate surface). This segmentation allows the catalyst to be distributed in two different locations, each contributing differently to filtration efficiency while having different impacts on back-pressure, thus resolving the contradiction between achieving high filtration efficiency and maintaining low back-pressure
Solution Approach 2:
Different regions of the substrate are assigned different coating configurations. The in-wall coating provides catalytic activity deep within the substrate structure, while the on-wall coating provides surface-level catalytic function. This local differentiation optimizes the balance between filtration efficiency and back-pressure by placing catalyst in locations that maximize performance while minimizing flow resistance
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 catalyst achieves improved particle filtration efficiency with a moderate increase in back-pressure, ensuring compliance with emission regulations and maintaining vehicle performance and fuel economy.
Implementation Method 1
the catalyst comprises a three-way conversion catalytic coating comprising an oxygen storage compound and a platinum group metal supported on a refractory metal oxide
Implementation Method 2
three-way conversion catalytic coating comprising an oxygen storage compound and a platinum group metal
Implementation Method 3
three-way conversion catalytic coating comprising an oxygen storage compound and a platinum group metal
Implementation Method 4
a porous wall flow filter substrate comprising an inlet end, an outlet end, a substrate axial length extending between the inlet end and the outlet end, and a plurality of passages defined by porous internal walls
Implementation Method 5
in the pores of the porous internal walls and on the surface of the porous internal walls, which surface defines the interface between the porous internal walls and the passages
Implementation Method 6
the three-way conversion catalytic coating is present as in-wall-coating and on the surface of the porous internal walls
Data Source
AI summary
A four-way conversion catalyst for the treatment of an exhaust gas stream of a gasoline engine, the catalyst comprising a porous wall flow filter substrate comprising an inlet end, an outlet end, a substrate axial length extending between the inlet end and the outlet end, and a plurality of passages defined by porous internal walls of the porous wall flow filter substrate, wherein the plurality of passages comprise inlet passages having an open inlet end and a closed outlet end, and outlet passages having a closed inlet end and an open outlet end; wherein in the pores of the porous internal walls and on the surface of the porous internal walls, which surface defines the interface between the porous internal walls and the passages, the catalyst comprises a three-way conversion catalytic coating comprising an oxygen storage compound and a platinum group metal supported on a refractory metal oxide; wherein in the pores of the porous internal walls, the three-way conversion catalytic coating is present as in-wall-coating and on the surface of the porous internal walls, the three-way conversion catalytic coating is present as on-wall-coating; wherein in addition to said three-way conversion catalytic coating, the catalyst comprises no further coating in the pores of the porous internal walls and no further coating on the surface of the porous internal walls.