Zeolite Hydrocarbon Trap Catalyst for Cold Start Emissions
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Solution Overview
Problem
Current catalysts struggle to effectively reduce hydrocarbon cold start emissions due to the need for high temperatures for HC light-off, which is a challenge in meeting stringent emission standards like SULEV30 and SULEV20, especially during the initial engine warm-up phase.
Innovation Solution
A hydrocarbon trap catalyst is developed, incorporating a zeolite layer with copper and nickel/manganese, which enhances HC adsorption and desorption performance, allowing for higher temperature release of hydrocarbons, thereby improving conversion efficiency when the Three-Way Catalyst layer is warmed up.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If traditional catalysts are used, then catalyst structure is simple, but cold start HC emissions cannot be reduced effectively due to high light-off temperature requirement
Solution Approach 1:
The catalyst is divided into multiple functional layers: a hydrocarbon trap layer containing zeolite with copper and nickel/manganese for adsorption, and a three-way catalyst layer for conversion. This segmentation allows each layer to perform its specific function optimally, with the trap layer capturing HC at low temperatures and the TWC layer converting them at higher temperatures.
Solution Approach 2:
The hydrocarbon trap layer performs preliminary adsorption of hydrocarbons during cold start conditions before the three-way catalyst is warm enough to convert them. This preliminary action stores HC on the trap layer, preventing immediate emissions, and then releases them for conversion when the TWC layer reaches operating temperature.
2Object-affected harmful factors
If catalyst light-off temperature is reduced, then cold start HC emissions are reduced, but catalyst conversion efficiency at operating temperature decreases
Solution Approach 1:
The catalyst is divided into multiple functional layers: a hydrocarbon trap layer containing zeolite with copper and nickel/manganese for adsorption, and a three-way catalyst layer for conversion. This segmentation allows each layer to perform its specific function optimally, with the trap layer capturing HC at low temperatures and the TWC layer converting them at higher temperatures.
Solution Approach 2:
The trap layer uses transition metals (copper at 15-75% of ion-exchange capacity and nickel/manganese at 50-100% of ion-exchange capacity) to modify the zeolite's adsorption and desorption characteristics, enabling HC release at temperatures that optimize conversion efficiency while reducing cold start emissions.
3Object-affected harmful factors
If transition metals are added to zeolite, then HC adsorption and desorption performance is enhanced, but manufacturing complexity increases
Solution Approach 1:
The trap layer uses transition metals (copper at 15-75% of ion-exchange capacity and nickel/manganese at 50-100% of ion-exchange capacity) to modify the zeolite's adsorption and desorption characteristics, enabling HC release at temperatures that optimize conversion efficiency while reducing cold start emissions.
Solution Approach 2:
The hydrocarbon trap layer is formed as a composite material combining zeolite with transition metals (copper and nickel/manganese). This composite structure provides synergistic effects where the zeolite provides the framework and adsorption sites, while the transition metals enhance the adsorption capacity and modify desorption behavior.
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 effectively reduces cold start hydrocarbon emissions by adsorbing and releasing hydrocarbons at higher temperatures, enhancing conversion efficiency and meeting stringent emission standards for both E10 and E85 fueled engines.
Implementation Method 1
enhances HC adsorption and desorption performance
Implementation Method 2
releasing the adsorbed HCs at higher temperature
Data Source
AI summary
A hydrocarbon trap catalyst and method of forming the same are disclosed. The method may include introducing copper into a zeolite at 10% to 75% of an ion-exchange level of the zeolite, introducing at least one of nickel and manganese into a zeolite at 50% to 100% total of an ion-exchange level of the zeolite, and applying a three-way catalyst layer. The copper and nickel and/or manganese may be introduced into a single zeolite or the copper may be introduced into a first zeolite layer and the nickel and/or manganese may be introduced into a second zeolite layer. If copper and another metal are introduced into the same zeolite, copper may be introduced first. The disclosed trap catalyst may increase the release temperature of hydrocarbons such as ethanol, propylene and toluene, and thus reduce vehicle cold start tailpipe emissions.