Particulate Filter Loading Control via SCR Kinetic Modeling
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Solution Overview
Problem
Existing methods for regulating the loading of particulate filters in heavy vehicles are inaccurate and costly, requiring additional sensors and failing to maintain optimal filtration efficiency and low flow resistance.
Innovation Solution
A method using a kinetic model to determine the loading of particulate filters in an exhaust gas aftertreatment system with multiple SCR systems, adjusting the amount of reducing agent to optimize nitrogen oxide reduction, thereby regulating the particulate filter's loading and filtration efficiency without additional sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the loading of the particulate filter is determined via differential pressure, then the loading can be detected, but additional pressure sensors are required and the accuracy is insufficient in heavy vehicles
Solution Approach 1:
The system uses the existing NOx sensors and SCR system components to determine particulate filter loading through a kinetic model, rather than requiring separate pressure sensors. The SCR system's own operational parameters and sensor data are leveraged to infer loading conditions.
Solution Approach 2:
The mechanical/differential pressure measurement method is replaced with a chemical/kinetic modeling approach. The kinetic model calculates loading based on chemical reactions, temperature, and NOx reduction data from existing sensors, eliminating the need for pressure sensors.
2Reliability
If the amount of reducing agent is increased to improve nitrogen oxide reduction, then NOx reduction efficiency increases, but the cost of operating material consumption increases
Solution Approach 1:
The control device continuously monitors NOx levels and loading conditions, adjusting the reducing agent injection amount dynamically. The system provides feedback based on actual NOx reduction performance and loading state to optimize reducing agent consumption.
Solution Approach 2:
The system adjusts multiple parameters including reducing agent amount, SCR system operating conditions, and injection timing to optimize the balance between NOx reduction efficiency and operating material consumption. Temperature and residence time parameters are also optimized.
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 method allows for accurate and cost-effective adjustment of particulate filter loading, maintaining high filtration efficiency while minimizing flow resistance, using conventional exhaust gas aftertreatment system sensors and reducing the need for additional sensors.
Implementation Method 1
the state of loading, in particular the soot loading, of the particulate filter is determined using a model, in particular using a kinetic model
Implementation Method 2
for nitrogen oxide reduction of the nitrogen oxides contained in the exhaust gas which is to be cleaned, a first operating material amount is or can be introduced in a metered manner before the SCR catalyst of the first SCR system
Data Source
AI summary
The invention relates in particular to a method for adjusting the loading (19) of a particulate filter (9) and to an assembly designed to carry out the method, wherein the exhaust gas aftertreatment unit (8) comprises at least two SCR systems (11, 12) and a particulate filter (9), a first operating material amount being introduced in a metered manner before the first SCR system (11), and a second operating material amount being introduced in a metered manner before the second SCR system (12), the operating material being convertible into a reducing agent. The state of loading of the particulate filter (9) is determined using a model, and, if the determined state of loading is below a previously defined loading range (16), the first operating material amount is adjusted in such a way that the amount of reducing agent is greater than or equal to the amount of reducing agent necessary for nitrogen oxide reduction in accordance with the reaction stoichiometry in the first SCR system (11), and/or, if the determined state of loading is above a previously defined loading range (16), the first operating material amount is adjusted in such a way that the amount of reducing agent is less than the amount of reducing agent necessary for nitrogen oxide reduction in accordance with the reaction stoichiometry in the first SCR system (11).