SCR Exhaust Aftertreatment Control for NOx Conversion Efficiency
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Solution Overview
Problem
Existing exhaust-gas aftertreatment devices for internal combustion engines face limitations in achieving high total efficiency due to the interdependence of SCR components, which restricts the efficiency of nitrogen oxide conversion, especially under stricter emission regulations.
Innovation Solution
A method for regulating the exhaust-gas aftertreatment device by detecting and adjusting the loading states of SCR components using sensors and an efficiency model, allowing for targeted dosing of reducing agents to optimize the operation of both components, thereby increasing the overall efficiency and preventing slip, even under varying engine conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the first SCR component is regulated to have high ammonia loading for high conversion efficiency, then the efficiency of the first SCR component is improved, but the achievable total efficiency of the exhaust-gas aftertreatment device is limited by the second SCR component's loading state
Solution Approach 1:
The exhaust-gas aftertreatment device is divided into two independent SCR components (first SCR component near engine block, second SCR component further away), each capable of independent ammonia storage and nitrogen oxide conversion. This segmentation allows the first SCR component to operate at high efficiency without being constrained by the second SCR component's loading state, as each component functions semi-independently with its own control strategy.
2Reliability
If the second SCR component's loading state is used to limit the target loading of the first SCR component, then the system operates within detected constraints, but the total efficiency of the exhaust-gas aftertreatment device is reduced
Solution Approach 1:
The control strategy dynamically adjusts the target ammonia loading of the first SCR component based on real-time detection of the second SCR component's loading state. When the second SCR component has low ammonia storage capacity, the system dynamically increases the first SCR component's target loading to compensate, thereby maintaining high total efficiency while adapting to changing system conditions.
Solution Approach 2:
The system continuously detects the loading state (ammonia storage capacity) of the second SCR component and uses this feedback information to adjust the control parameters of the first SCR component. This feedback mechanism enables the first SCR component to operate at optimally high efficiency by compensating for variations in the second component's performance, rather than being passively limited by it.
3Ease of manufacture
If a less expensive, lower-quality second SCR component is used, then cost-effectiveness is improved, but the ability to achieve high total efficiency is compromised
Solution Approach 1:
The control strategy changes the operating parameters (ammonia loading targets) of the first SCR component to compensate for the lower quality of the second SCR component. By adjusting the first component's target loading based on the second component's actual performance characteristics, the system achieves high total efficiency even when the second component is less expensive and lower quality, rather than requiring both components to be high-performance units.
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 approach enhances the efficiency of the first SCR component by allowing it to operate at a higher loading state, while ensuring the second SCR component is protected against slip, resulting in improved total efficiency and cost-effectiveness by allowing the use of a less expensive, lower-quality second SCR component.
Implementation Method 1
The first and the second SCR component are components of the exhaust-gas aftertreatment device and which are able to store the reducing agent and to bring about a selective catalytic reaction (SCR) of the reducing agent with a nitrogen oxide (NOX)
Implementation Method 2
bring about a selective catalytic reaction (SCR) of the reducing agent with a nitrogen oxide (NOX)
Data Source
AI summary
A method for regulating an exhaust-gas aftertreatment device for an internal combustion engine, wherein respectively one loading state of a first SCR component and of a second SCR component arranged downstream of the first SCR component is determined. The loading state of the second SCR component is regulated by way of a dosing system for dosing a reducing agent.