SCR Catalytic Converter Ammonia Control via Dual Model Interpolation
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Solution Overview
Problem
SCR catalytic converters face challenges in maintaining optimal ammonia levels for efficient nitrogen oxide conversion, leading to ammonia slip and potential emission limit exceedances due to temperature fluctuations and limited control strategies, which increases system costs and complexity.
Innovation Solution
The method involves creating two ammonia level models to robustly determine and adjust ammonia levels, allowing for maximum nitrogen oxide conversion efficiency and minimizing ammonia slip, eliminating the need for a control reserve by using interpolation factors to adjust setpoint efficiencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a control reserve is maintained to ensure robust operation, then system reliability is improved, but system costs increase
Solution Approach 1:
The patent changes the parameter of ammonia level estimation by introducing a second model that accounts for controller components, and dynamically adjusts the interpolation factor between models based on operating conditions. This allows robust control without requiring excessive control reserves, thereby reducing system costs while maintaining reliability.
2Productivity
If the ammonia level is increased to achieve high nitrogen oxide conversion, then conversion efficiency is improved, but ammonia slip increases
Solution Approach 1:
The patent implements feedback by continuously monitoring the ammonia level through two different models and adjusting the interpolation factor based on the comparison between actual and modelled efficiency. This feedback mechanism enables precise control of ammonia levels, maintaining high nitrogen oxide conversion while minimizing ammonia slip by avoiding excessive ammonia addition.
3Device complexity
If a single dosing valve is used to reduce system complexity, then device complexity is reduced, but control precision deteriorates
Solution Approach 1:
The patent introduces an intermediary computational approach by creating two different models of the ammonia level and using an interpolation factor to combine their outputs. This software-based intermediary mechanism compensates for the limitations of a single dosing valve, achieving precise ammonia level control without requiring additional hardware, thus maintaining low device complexity while improving control precision.
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 enables precise control of ammonia levels, reducing ammonia slip, and potentially downsizing the SCR catalytic converter while maintaining high efficiency, thereby reducing system costs and enhancing operational robustness.
Implementation Method 1
the level of ammonia absorbed on the surface thereof
Implementation Method 2
selective catalytic reduction (SCR) by means of ammonia or ammonia-reducing reagents
Data Source
AI summary
The invention concerns a method for controlling an SCR catalytic converter. A first modelled level of ammonia (NH3_mod1) and a second modelled level of ammonia (NH3_mod2) of the SCR catalytic converter are determined from two different models. The second modelled level of ammonia (NH3_mod2) is assessed by comparing it with the first modelled level of ammonia (NH3_mod1).