Real-Time Reductant Deposit Modeling for SCR Aftertreatment
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Solution Overview
Problem
In aftertreatment systems, reductant mass deposits on surfaces can lead to poor NOx conversion and potential engine failure due to inadequate regeneration, especially under high reductant dosing rates and low exhaust gas temperatures.
Innovation Solution
A method and system for real-time calculation and control of reductant mass deposits using a control module that estimates accumulation and decomposition rates based on temperature, flow rate, and reductant dosage, enabling two-tier regeneration strategies to manage deposit growth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If reductant dosing rate is increased to improve NOx conversion, then NOx conversion efficiency is improved, but reductant mass deposits form on surfaces
Solution Approach 1:
The system performs preliminary action by calculating and predicting reductant deposit growth rates before significant deposits form. The control module continuously monitors operating conditions and computes deposit accumulation rates, enabling proactive adjustment of dosing rates or initiation of regeneration before deposits reach harmful levels, thus preventing the contradiction from fully manifesting.
Solution Approach 2:
The system implements feedback by continuously monitoring exhaust gas temperature, flow rate, and dosing rate, then using these inputs to calculate real-time deposit growth rates. This feedback loop allows the control module to dynamically adjust the reductant dosing rate or trigger regeneration events based on predicted deposit accumulation, resolving the contradiction between maintaining high conversion efficiency and preventing deposit formation.
2Object-generated harmful factors
If periodic regeneration is performed to remove deposits, then deposit accumulation is reduced, but system complexity and operation time increase
Solution Approach 1:
The system applies self-service by using the existing SCR catalyst and exhaust gas flow to perform regeneration without requiring separate dedicated components or external intervention. The control module leverages normal system operation parameters (exhaust temperature, flow rate) to create conditions for self-regeneration, eliminating the need for complex external regeneration equipment while still effectively removing deposits.
Solution Approach 2:
The system resolves the contradiction by changing operational parameters dynamically. The control module adjusts dosing rates, exhaust gas temperature, and flow rate parameters based on real-time calculations of deposit growth rates. By modifying these parameters, the system can prevent deposit accumulation during normal operation or create optimal conditions for regeneration, reducing the need for complex regeneration control mechanisms.
3Measurement precision
If real-time deposit calculation is implemented, then deposit management precision is improved, but computational requirements and processing time increase
Solution Approach 1:
The system applies partial action by calculating only the essential deposit growth rate parameters needed for control decisions, rather than performing exhaustive simulations. The control module focuses on computing the net deposit growth rate based on key operating parameters (temperature, flow rate, dosing rate), providing sufficient precision for real-time control without the computational overhead of more complex models, thus balancing measurement precision with processing time requirements.
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 allows for dynamic and efficient management of reductant deposits, improving NOx conversion efficiency and preventing system failure by performing targeted regeneration, thus maintaining optimal aftertreatment system performance.
Implementation Method 1
estimating, by the control module, a reductant deposit accumulation rate value based on the set of values received by the control module
Implementation Method 2
estimating, by the control module, a reductant deposit decomposition rate value based on the set of values received by the control module
Implementation Method 3
a selective catalytic reduction (SCR) module that reduces a concentration of NOx in the exhaust gas flow
Data Source
AI summary
A method and system for modeling growth of reductant deposits for an aftertreatment system on a real time basis using input including exhaust gas temperature, exhaust gas flow rate, and reductant dosing rate. The growth of the reductant deposits are affected by a rate at which reductant accumulates and decomposes from a surface of the aftertreatment system. Thus, the method and system disclosed determines a net reductant deposit growth rate value based on a reductant deposit accumulation rate value and a reductant deposit decomposition rate value. Further, the method and system disclosed determines a reductant mass deposit value based on the net reductant deposit growth rate value. The reductant mass deposit value determined by the method and system may then be used to control a regeneration strategy of the aftertreatment system to eliminate the reductant deposits from the aftertreatment system.