Gasoline Exhaust Catalyst Layout for NH3 Adsorption and TWC Performance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Automotive exhaust gas regulations have tightened to include NH3 as a target, necessitating an exhaust gas purification catalytic device for gasoline engines that maintains high three-way catalytic performance while reducing NH3 discharge.
Innovation Solution
An exhaust gas purification catalytic device for gasoline engines featuring a substrate with a proton-type zeolite NH3 adsorption layer and a PGM layer, where the NH3 adsorption layer is positioned upstream and shorter than the substrate, and the PGM layer is longer and positioned downstream, with specific zeolite and noble metal configurations to enhance adsorption and purification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If an upstream side three-way catalytic device is used to purify exhaust gas, then HC, CO, and NOx are purified, but NH3 is generated and discharged which violates new emission standards
Solution Approach 1:
The invention extracts and removes the harmful NH3 generated in the upstream catalytic device by introducing a separate NH3 adsorption layer in the downstream device. This layer specifically captures NH3 through adsorption, separating the NH3 removal function from the main three-way catalytic function, thereby eliminating NH3 discharge while preserving three-way catalytic performance.
Solution Approach 2:
The NH3 adsorption layer acts as an intermediary between the upstream three-way catalytic device and the atmosphere. It intercepts NH3 that would otherwise be discharged, providing a intermediate step that captures the harmful substance before it reaches the environment, thus solving the NH3 discharge problem without affecting upstream catalytic performance.
2Object-generated harmful factors
If a downstream side catalytic device with NH3 storage capacity is added to reduce NH3 discharge, then NH3 purification is improved, but device complexity increases
Solution Approach 1:
The invention merges the NH3 adsorption function with the downstream three-way catalytic device by integrating an NH3 adsorption layer into its structure. This combines multiple functions (NH3 adsorption and three-way catalysis) into a single device, reducing system complexity compared to adding a completely separate NH3 storage device while still achieving NH3 purification.
Solution Approach 2:
The downstream catalytic device is designed with multi-functionality, serving both as a three-way catalytic converter and an NH3 adsorption device. The NH3 adsorption layer is incorporated into the downstream device structure, allowing it to perform multiple functions simultaneously and avoid the need for additional separate components.
3Quantity of substance
If Cu-zeolite is used in the second purification unit for NH3 storage, then NH3 adsorption capacity is improved, but heat resistance deteriorates
Solution Approach 1:
The invention changes the material parameter of the zeolite from Cu-zeolite to proton-type zeolite. This parameter change maintains the NH3 adsorption capacity while significantly improving heat resistance, as proton-type zeolite is more thermally stable than Cu-zeolite, thus resolving the contradiction between adsorption capacity and heat 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 device achieves high heat resistance and effective NH3 adsorption, reducing NH3 discharge while maintaining high three-way catalytic performance.
Implementation Method 1
a NH3 adsorption layer containing a proton-type zeolite
Implementation Method 2
a PGM layer containing a catalytic noble metal selected from Pd, Pt, and Rh
Data Source
AI summary
Provided is an exhaust gas purification catalyst device for a gasoline engine, the exhaust gas purification catalyst device comprising: a base material; an NH3 adsorption layer containing proton-type zeolite; and a PGM layer containing a catalyst noble metal selected from Pd, Pt, and Rh. The proton-type zeolite included in the NH3 adsorption layer has an average pore size of 0.60 nm or less. The NH3 adsorption layer is arranged on the base material side relative to the PGM layer, and is arranged with a length shorter than the total length of the base material from the exhaust gas flow upstream end of the base material. The PGM layer is arranged with a length longer than the NH3 adsorption layer from the exhaust gas flow upstream end of the base material.