Multi-leg Aftertreatment System Flow Imbalance Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Modern internal combustion engines face challenges in meeting stringent emission standards for soot and nitrogen oxides due to the complexity of aftertreatment systems, particularly in managing flow imbalances and soot loading during regeneration processes.
Innovation Solution
A multi-leg aftertreatment system with a controller that determines a flow imbalance value by using differential pressure sensors, NOx sensors, and flow control valves to optimize the flow through diesel particulate filters and bypass paths, ensuring efficient reduction of emissions by adjusting reductant injection and exhaust flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If aftertreatment systems are made more complex to reduce total emissions, then emission reduction capability is improved, but system complexity increases
Solution Approach 1:
The aftertreatment system is divided into multiple independent legs (first leg with DPF1, second leg with DPF2) that can operate semi-autonomously. Each leg has its own flow control valve and reductant dosing system, allowing individual optimization while maintaining overall system functionality. This segmentation reduces the complexity burden on any single component while achieving comprehensive emission reduction.
Solution Approach 2:
The system dynamically adjusts exhaust flow distribution between legs using flow control valves (314, 315) and reductant dosing rates based on real-time operating conditions. The controller continuously monitors and modifies leg flow ratios during regeneration cycles, enabling adaptive optimization of emission reduction performance without requiring a completely complex static system design.
2Productivity
If flow control valves and reductant dosing are adjusted to minimize flow imbalances, then regeneration efficiency is improved, but control complexity increases
Solution Approach 1:
The controller receives feedback from differential pressure sensors (316, 317) that monitor soot loading in each DPF leg, and from flow sensors that measure exhaust flow rates. Based on this feedback, the controller automatically adjusts flow control valve positions and reductant dosing rates to maintain balanced flow distribution and optimize regeneration efficiency, reducing the perceived control complexity through automated closed-loop control.
Solution Approach 2:
Each DPF leg is equipped with its own flow control valve and reductant dosing system, allowing each leg to essentially self-regulate its regeneration process. The controller coordinates between legs but the individualized self-service architecture reduces the overall control complexity by distributing control functions rather than requiring centralized management of all parameters.
3Measurement precision
If differential pressure sensors and flow sensors are installed in each leg, then measurement precision is improved, but device complexity increases
Solution Approach 1:
Differential pressure sensors (316, 317) and flow sensors are installed in each DPF leg separately to provide independent, precise measurements of soot loading and exhaust flow for each leg. This segmentation of measurement systems enables accurate monitoring of individual leg conditions, which is essential for balanced flow control and optimized regeneration, while the modular sensor architecture prevents excessive overall complexity.
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
The system effectively reduces emissions by minimizing flow imbalances and soot loading, enhancing the regeneration efficiency of aftertreatment systems and adhering to regulatory standards.
Implementation Method 1
a differential pressure sensor fluidly coupled to the DPF flowpath at a first position upstream of the DPF and at a second position downstream of the DPF
Implementation Method 2
a NOx sensor in the bypass leg downstream of the second reductant catalyst and downstream of a second doser
Implementation Method 3
a first reductant catalyst in the DPF flowpath downstream of the DPF and upstream of a first doser, and a second reductant catalyst in the bypass downstream of the second doser
Implementation Method 4
a flow control valve in fluid communication with the DPF flowpath that controls the admission of exhaust gas through the DPF flowpath
Data Source
AI summary
An apparatus is disclosed, including an exhaust conditions module structured to interpret a diesel particulate filter (DPF) delta pressure value, a flow balance correlation, a NOx input value, and an exhaust flow rate value. A flow determination module is structured to determine a flow imbalance value in response to the DPF delta pressure value, the flow balance correlation, and the exhaust flow rate value. A reductant determination module is structured to determine a first reductant injection command and a second reductant injection command in response to the flow imbalance value and the NOx input value.