Dosing Module Branch Segmentation for Reductant Flow Control
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Solution Overview
Problem
Current aftertreatment systems for internal combustion engines face challenges in achieving precise control over the flow rate of reductants, such as ammonia or urea, due to inconsistent flow rates and lack of control over pressure fluctuations, leading to inefficient NOx emission reduction and excessive reductant deposition.
Innovation Solution
A reductant delivery system with a dosing module featuring multiple branches, each with independently controllable valves and flow restrictors, allowing for customized flow rates and continuous flow without the need for accumulators or pressure regulators, and utilizing a closed-loop process for precise control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single valve or pump is used to meter liquid reductant, then the system structure is simple, but the flow rate control precision and turndown ratio are insufficient
Solution Approach 1:
The dosing module is divided into multiple independent flow paths (first branch, second branch, etc.), each with its own valve and orifice. This segmentation allows independent control of each path, enabling precise flow rate adjustment and high turndown ratio by selectively opening/closing paths and adjusting individual valve positions.
Solution Approach 2:
The patent transitions from single-dimension control (one valve) to multi-dimensional control (multiple valves in parallel paths). Each branch represents an additional control dimension, allowing the system to achieve precise flow rate control through combinatorial control of multiple valves rather than relying on a single valve's full range adjustment.
2Ease of operation
If fixed displacement pump with variable strokes is used, then valve control is eliminated, but the ability to achieve customized flow rates through additive/subtractive control is lost
Solution Approach 1:
The system uses dynamically controllable valves in each branch that can be independently opened, closed, or positioned at intermediate states. This dynamic control allows flexible adjustment of total flow rate by combining different branch contributions, providing customized flow rates that adapt to varying operational requirements.
Solution Approach 2:
Multiple flow paths with predetermined orifices are prepared in advance, each designed for specific flow characteristics. The control system selects and activates appropriate pre-configured paths based on required flow rate, enabling rapid adjustment without complex real-time calculations or modifications.
3Adaptability or versatility
If single flow path is used, then the system is simple, but the turndown ratio control through addition and subtraction of flow paths is not achieved
Solution Approach 1:
The dosing module segments the total flow requirement into multiple discrete branches, each capable of independent on/off control. By combining different segments (branches) in various configurations, the system achieves a wide turndown ratio through additive and subtractive control of individual path flows.
Solution Approach 2:
Each flow path is designed to be multi-functional, serving both as a complete flow path when opened and as a controllable resistance element when partially opened. The parallel architecture provides universal applicability for achieving different flow rates, making the system adaptable to various operating conditions without requiring complete redesign.
Data Source
AI summary
A controller for a dosing module including a pump, an inlet manifold coupled to the pump, a nozzle, an outlet manifold coupled to the nozzle, a first branch coupled to the inlet manifold and the outlet manifold and having a first flow restrictor and a first valve, a second branch coupled to the inlet manifold and the outlet manifold and having a second flow restrictor and a second valve, and a sensor coupled to the inlet manifold and the outlet manifold, includes an input/output interface and a processing circuit. The input/output interface is configured to electronically communicate with the first valve and the second valve. The processing circuit configured to selectively cause the first valve to be in a first valve first position, in which the first valve facilitates fluid communication from the inlet manifold to the outlet manifold through the first branch, and a first valve second position.