Automotive Tail-Pipe Catalyst for CO Reduction
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Solution Overview
Problem
Current automotive catalyst systems face challenges in effectively reducing carbon monoxide emissions due to deactivation issues and poisoning of platinum group metals, especially under severe aging conditions, and there is a need for a system that can selectively target CO emissions while maintaining high PGM dispersion and thermal stability.
Innovation Solution
An automotive catalyst system comprising a close-coupled three-way conversion catalytic article, an underfloor catalytic article, and a tail-pipe catalytic article, with the tail-pipe catalytic article positioned downstream and using a platinum group metal or non-platinum group metal supported on ceria-zirconia or alumina-based substrates, to minimize aging effects and enhance CO conversion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If nickel or copper is used in the three-way catalyst to reduce CO, then CO conversion is improved, but catalyst deactivation occurs due to aluminate formation during severe aging
Solution Approach 1:
The patent extracts the CO reduction function from the close-coupled three-way catalyst and relocates it to a separate tail-pipe catalyst. This allows the tail-pipe catalyst to be optimized specifically for CO conversion using base metals (nickel or copper) without the deactivation constraints of the close-coupled catalyst, while the close-coupled catalyst maintains its three-way conversion function.
Solution Approach 2:
The catalyst system is segmented into two distinct functional units: a close-coupled three-way conversion catalyst for handling hydrocarbons and NOx, and a separate tail-pipe catalyst dedicated to CO reduction. This segmentation allows each catalyst to be optimized for its specific function, with the tail-pipe catalyst using base metals that would be problematic in a unified three-way catalyst.
2Productivity
If base metals are used in the catalyst to reduce CO, then CO conversion is improved, but platinum group metal poisoning occurs
Solution Approach 1:
The patent extracts the CO reduction function from the close-coupled three-way catalyst and relocates it to a separate tail-pipe catalyst. This allows the tail-pipe catalyst to be optimized specifically for CO conversion using base metals (nickel or copper) without the deactivation constraints of the close-coupled catalyst, while the close-coupled catalyst maintains its three-way conversion function.
3Productivity
If nickel is used in the catalyst to reduce CO, then CO conversion is improved, but thermal stability decreases
Solution Approach 1:
The patent extracts the CO reduction function from the close-coupled three-way catalyst and relocates it to a separate tail-pipe catalyst. This allows the tail-pipe catalyst to be optimized specifically for CO conversion using base metals (nickel or copper) without the deactivation constraints of the close-coupled catalyst, while the close-coupled catalyst maintains its three-way conversion function.
4Productivity
If nickel is used in the catalyst to reduce CO, then CO conversion is improved, but toxic nickel tetracarbonyl formation occurs
Solution Approach 1:
The patent extracts the CO reduction function from the close-coupled three-way catalyst and relocates it to a separate tail-pipe catalyst. This allows the tail-pipe catalyst to be optimized specifically for CO conversion using base metals (nickel or copper) without the deactivation constraints of the close-coupled catalyst, while the close-coupled catalyst maintains its three-way conversion 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 system effectively reduces CO emissions during vehicle acceleration by positioning the tail-pipe catalytic article to optimize water-gas shift reaction conditions, maintaining high PGM dispersion, and avoiding deactivation, thus achieving significant CO conversion without impacting THC and NOx emissions.
Implementation Method 1
positioning the tail-pipe catalytic article to optimize water-gas shift reaction conditions
Implementation Method 2
The three-way conversion catalyst is typically known to oxidize unburnt hydrocarbon and carbon monoxide and reduce nitrogen oxides
Data Source
AI summary
The presently claimed invention relates an automotive catalyst system which can be used to selectively reduce carbon monoxide. The system comprises a first close coupled three-way conversion catalytic article in fluid communication with an engine exhaust outlet, a catalytic article located downstream of and in fluid communication with the first close coupled three-way conversion catalytic article, a tail-pipe catalytic article arranged downstream in fluid communication and 1.0 to 10 feet away from the catalytic article at a position selected from before or behind a resonator, before or after a muffler, between the resonator and the muffler, inside the muffler, inside the resonator, and at a tail pipe end.