Reductant Apportionment for Multi-Doser SCR Systems
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Solution Overview
Problem
In selective catalytic reduction systems for internal combustion engines, equal dosing of reductant across multiple dosers can lead to reductant impingement and deposit formation due to differing designs and positions of decomposition reaction tubes, resulting in localized cooling and increased deposit formation.
Innovation Solution
A controller dynamically apportions reductant dosing amounts based on maximum dosing amounts for each doser, calculated from engine operating conditions such as exhaust temperature and flow rate, to reduce reductant impingement and deposit formation by reallocating excess dosing amounts to dosers with higher capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If equal dosing of reductant is applied across multiple dosers, then the total reductant amount is evenly distributed, but reductant impingement and deposit formation occur due to differing doser designs and positions
Solution Approach 1:
The patent applies local quality by assigning different maximum dosing amounts to different dosers based on their individual characteristics (design, position, decomposition reaction tube configuration). Each doser receives a dosing amount tailored to its specific capacity rather than uniform dosing, preventing impingement in dosers with lower capacity while充分利用 dosers with higher capacity.
Solution Approach 2:
The patent implements dynamics by dynamically adjusting the dosing amount for each doser based on real-time exhaust conditions (temperature, flow rate) and the doser's maximum dosing capacity. The controller continuously monitors and redistributes reductant dosing amounts to optimize performance and prevent deposit formation under varying operating conditions.
2Productivity
If the total reductant dosing amount is increased to maximize NOx reduction, then NOx conversion efficiency improves, but the likelihood of reductant impingement and deposit formation increases
Solution Approach 1:
The patent applies parameter changes by adjusting the dosing amount parameters for each doser based on exhaust temperature and flow rate conditions. The system determines a total reductant dosing amount optimized for NOx reduction, then distributes it across dosers with individually calculated maximum dosing amounts, changing the dosing parameters dynamically to prevent impingement while maximizing conversion efficiency.
3Quantity of substance
If multiple dosers are used to handle large reductant dosing requirements, then the system capacity increases, but the complexity of dosing distribution and control increases
Solution Approach 1:
The patent applies segmentation by dividing the total reductant dosing task into separate dosing operations for multiple dosers. Each doser is assigned a specific dosing amount based on its maximum capacity and current operating conditions, allowing the system to handle large total dosing requirements while simplifying control through independent doser management.
Solution Approach 2:
The patent implements feedback by continuously monitoring exhaust conditions (temperature, flow rate) and using this information to adjust the dosing amount for each doser. The controller receives feedback on system state and dynamically redistributes reductant dosing to maintain optimal performance and prevent deposit formation, simplifying control through automated closed-loop management.
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 effectively reduces reductant deposit formation by optimizing dosing across multiple dosers, maximizing reductant injection while minimizing impingement, thereby enhancing the efficiency of NOx reduction in the selective catalytic reduction process.
Implementation Method 1
an SCR system may dose or otherwise introduce the reductant through a doser that vaporizes or sprays the reductant into an exhaust pipe
Implementation Method 2
a selective catalytic reduction (SCR) process may be implemented to convert the NOx compounds into more neutral compounds, such as diatomic nitrogen, water, or carbon dioxide, with the aid of a catalyst and a reductant
Data Source
AI summary
A system for apportioning reductant dosing amounts in multi-doser architectures includes an engine, an aftertreatment system in fluid communication with the engine, and a controller. The aftertreatment system includes a first doser configured to dose reductant into a first decomposition reaction member and a second doser configured to dose reductant into a second decomposition reaction member. The controller receives engine operating conditions and determines a total reductant amount based on the engine operating conditions. The controller also apportions the total reductant amount into a first apportioned reductant amount based on a first maximum reductant dosing amount for the first doser and a second apportioned reductant amount based on a second maximum reductant dosing amount for the second doser. The controller outputs a first apportioned reductant dosing command to the first doser and a second apportioned reductant dosing command to the second doser.