Exhaust Purification Catalyst with Spinel Support

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Solution Overview

Problem

Existing exhaust gas purification systems face challenges in efficiently removing NOx, CO, and HC from internal combustion engine emissions, particularly when the exhaust gas composition fluctuates between excess reducing agents and excess oxidants, as these components are not simultaneously present in the second purification device to effectively react.

Innovation Solution

An exhaust gas purification system comprising a first device with a three-way catalyst and a second device with spinel-type MgAlxFe2.00−xO4.00 supporting particles on which Rh is supported, where 0.00<×≤1.50, allowing for efficient removal of NOx, CO, and HC by alternately switching between compositions of excess reducing agents and oxidants.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a second exhaust gas purification device is added to further purify exhaust gas, then the purification performance is improved, but the device complexity increases

Engineering Contradiction:

Improvepurification performanceVSAvoiddevice complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The exhaust gas purification system is divided into two separate devices: a first exhaust gas purification device and a second exhaust gas purification device. Each device contains a catalyst with specific properties optimized for different purification functions, allowing the system to handle fluctuating exhaust gas compositions more effectively while maintaining manageable device complexity through modular design

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent uses composite catalyst materials with different compositions in the first and second purification devices. The first device uses a catalyst optimized for reducing agents excess conditions, while the second device uses a catalyst optimized for oxidants excess conditions. This composite material approach enables each device to specialize in specific purification tasks, improving overall system performance

Inventive Principle:

Principle #40Composite materials

2Adaptability or versatility

If the exhaust gas composition fluctuates between excess reducing agents and excess oxidants, then the adaptability to engine operation conditions is improved, but the purification efficiency deteriorates because NOx and reducing agents are not simultaneously present

Engineering Contradiction:

Improveadaptability to exhaust gas compositionVSAvoidpurification efficiency

Core Design Contradiction:

Adaptability or versatilityVSProductivity

Solution Approach 1:

The purification system dynamically adapts to changing exhaust gas compositions by using two different catalysts in sequence. The first catalyst handles periods when reducing agents are in excess, while the second catalyst handles periods when oxidants are in excess. This dynamic approach allows the system to maintain high purification efficiency despite fluctuating engine operation conditions

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The oxygen absorbing and releasing material acts as an intermediary between the first and second purification devices. It stores oxygen during periods when reducing agents are in excess and releases it during periods when oxidants are in excess, facilitating continuous effective purification and enabling the second device to function effectively even when exhaust gas composition fluctuates

Inventive Principle:

Principle #24Intermediary (Mediator)

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 removes NOx, CO, and HC by utilizing the spinel-type MgAlxFe2.00−xO4.00 particles to oxidize CO/HC and reduce NOx, achieving high exhaust gas purification performance even with fluctuating compositions.

Implementation Method 1

spinel-type MgAlxFe2.00−xO4.00 supporting particles on which Rh is supported

Methodology Applied

Scientific EffectCatalysis: Catalysis

Implementation Method 2

oxidize CO/HC

Methodology Applied

Scientific EffectOxidation: Oxidation

Implementation Method 3

spinel-type MgAlxFe2.00−xO4.00 supporting particles on which Rh is supported

Methodology Applied

Scientific EffectCatalysis: Catalysis

Implementation Method 4

reduce NOx

Methodology Applied

Scientific EffectReduction: Reduction

Implementation Method 5

oxygen absorbing and releasing material such as ceria that stores oxygen

Methodology Applied

Scientific EffectAbsorption: Absorption (physical)

Data Source

PatentUS11480091B2Exhaust gas purification system

Publication Date: 2022.10.25 TOYOTA JIDOSHA KK

AI summary

An exhaust gas purification system of the present disclosure includes a first exhaust gas purification device that purifies exhaust gas discharged from an internal combustion engine and a second exhaust gas purification device that additionally purifies the exhaust gas purified by the first exhaust gas purification device, wherein the exhaust gas is exhaust gas with a gaseous composition in which an amount of reducing agents is in excess compared to a stoichiometric gaseous composition and a gaseous composition in which an amount of oxidants is in excess compared to the stoichiometric gaseous composition are alternately switched between, the first exhaust gas purification device includes a three-way catalyst, and the second exhaust gas purification device includes an exhaust gas purification catalyst containing spinel-type MgAlxFe2.00−xO4.00 supporting particles on which Rh is supported, where 0.00<×≤1.50.