Dynamic NOx Purge Interval Control for Catalyst Deterioration
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Solution Overview
Problem
The existing NOx purge systems in exhaust gas purification systems are ineffective in starting NOx purges based on the degree of catalyst deterioration, leading to worsening exhaust emissions due to fixed target intervals that do not account for catalyst degradation over time or heat.
Innovation Solution
An exhaust gas purification system and NOx purification capacity restoration method that dynamically adjust the NOx purge target intervals and thresholds based on the degree of catalyst deterioration, using sensors and control units to monitor and correct the NOx storage capacity and purification factors, ensuring timely and effective NOx purges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed target interval is used for NOx purges, then the system operation is simple, but the NOx purge cannot be started effectively according to the degree of catalyst deterioration, causing worsening exhaust emissions
Solution Approach 1:
The patent applies dynamics by transitioning from a fixed target interval to a dynamic target interval that automatically adjusts based on catalyst deterioration degree. The control unit calculates the deterioration degree using the purification factor and NOx storage capacity, then sets the target interval accordingly, making the system adaptive to changing catalyst conditions without requiring complex manual intervention
Solution Approach 2:
The patent implements feedback by continuously monitoring the purification factor and NOx storage capacity of the catalyst, calculating the deterioration degree, and using this information to adjust the target interval for NOx purges. This closed-loop feedback mechanism ensures the system responds appropriately to catalyst aging and maintains effective emissions control
2Reliability
If the NOx storage capacity of the catalyst is reduced due to deterioration, then the catalyst lifespan increases, but the NOx purge cannot be started effectively, causing worsening exhaust emissions
Solution Approach 1:
The patent applies preliminary action by proactively monitoring the purification factor and calculating the deterioration degree before significant performance loss occurs. The system determines the appropriate target interval in advance based on the calculated deterioration degree, ensuring NOx purges are initiated at optimal times rather than waiting for performance degradation to become apparent
Solution Approach 2:
The patent replaces traditional time-based or fixed-schedule purge mechanisms with a performance-based control system that uses real-time measurements of purification factor and NOx storage capacity to determine purge timing, substituting mechanical timing systems with intelligent control algorithms
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
Prevents worsening exhaust emissions by ensuring NOx purges are initiated according to the catalyst's deterioration state, maintaining the NOx storage capacity and reducing the risk of hydrocarbon slip and fuel inefficiency.
Implementation Method 1
This NOx storage-reduction catalyst stores NOx contained in exhaust gas when the exhaust gas is in a lean atmosphere
Implementation Method 2
reduces and purifies the NOx that is stored therein with hydrocarbons contained in the exhaust gas when the exhaust gas is in a rich atmosphere
Data Source
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AI summary
There is provided an exhaust gas purification system including: a NOx storage-reduction catalyst 32 that is provided in an exhaust system of an internal combustion engine 10 to reduce and purify NOx in exhaust gas; a deterioration degree estimation module 120 for estimating a degree of deterioration of the NOx storage-reduction catalyst 32; a regeneration control unit 100 for executing a regeneration process in which exhaust gas is enriched so as to restore a NOx storage capacity of the NOx storage-reduction catalyst 32; an interval setting module 118 for setting a target interval from an end of the regeneration process to a start of the subsequent regeneration process by the regeneration control unit 100; and an interval target value correction module 119 for correcting the target interval based on the degree of deterioration that is estimated by the deterioration degree estimation module 120.