Three-Way Catalyst with Zoned Oxygen Storage for Exhaust Purification
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Solution Overview
Problem
The existing exhaust gas purification systems face inefficiencies in fuel consumption during NOx purge processes due to the high oxygen storage capacity of three-way catalysts, which increases the amount of fuel required for NOx purification, thereby reducing fuel efficiency.
Innovation Solution
The exhaust gas purification apparatus incorporates a three-way catalyst with a first region and a second region of varying oxygen storage capacity, where the first region is located on the center axis of the gas flow, allowing exhaust gas to primarily pass through the high OSC region in normal conditions and the lower OSC region during NOx purge, reducing the reaction with oxygen and thus minimizing fuel consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a three-way catalyst with high oxygen storage capacity is used, then the NOx purification effectiveness is improved, but the fuel consumption during NOx purge increases
Solution Approach 1:
The three-way catalyst is designed with non-uniform oxygen storage capacity distribution, where the central region has high OSC for effective NOx purification, while the peripheral region has low OSC to minimize fuel consumption during purge operations. This spatial differentiation of catalyst properties resolves the contradiction between purification effectiveness and fuel efficiency.
Solution Approach 2:
The catalyst is segmented into distinct regions with different oxygen storage capacities - a central high-OSC region and peripheral low-OSC regions. This segmentation allows the system to achieve both high NOx purification (through the central region) and reduced fuel consumption during purge (through the peripheral regions), thereby resolving the technical contradiction.
2Quantity of substance
If the oxygen storage capacity of the three-way catalyst is increased, then the NOx occlusion capacity is improved, but the amount of fuel required for NOx purge increases
Solution Approach 1:
By creating localized zones of high and low oxygen storage capacity within the catalyst, the system maintains high overall NOx occlusion capacity through the high-OSC central region while minimizing fuel consumption during purge through the low-OSC peripheral regions, thus resolving the contradiction between NOx capacity and fuel loss.
Solution Approach 2:
The oxygen storage capacity parameter is varied spatially within the catalyst structure, creating a gradient or zoned distribution rather than uniform properties. This parameter variation allows optimization of both NOx occlusion capacity and purge fuel requirements simultaneously.
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
This configuration reduces the increase in fuel usage during NOx purge, enhancing fuel efficiency by optimizing the oxygen storage capacity distribution within the three-way catalyst.
Implementation Method 1
The three-way catalyst comprises a first region and a second region. The second region has a lower oxygen storage capacity than the first region.
Implementation Method 2
a nitrogen oxide occlusion catalyst, which is capable of occluding nitrogen oxide (hereinafter also abbreviated to NOx) contained in the exhaust gas
Implementation Method 3
In the process of NOx purge, the NOx occluded in the nitrogen oxide occlusion catalyst is purified by reduction.
Data Source
AI summary
An exhaust gas purification apparatus includes a first exhaust pipe, a first housing, a second exhaust pipe, and a second housing. The first exhaust pipe is coupled to an engine. The first housing is coupled to a downstream end of the first exhaust pipe and houses a three-way catalyst. The second exhaust pipe is coupled to a downstream end of the first housing. The second housing is coupled to a downstream end of the second exhaust pipe and houses a nitrogen oxide occlusion catalyst. The three-way catalyst comprises a first region and a second region. The second region has a lower oxygen storage capacity than the first region. The first region is located on a center axis of a flow of gas that is to be sent from the first exhaust pipe into the first housing.