Urea Dosing Pressure Control for Accurate Exhaust Fluid Delivery
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Solution Overview
Problem
Current systems for transferring urea into combustion engine exhaust systems lack precision and efficiency, often resulting in urea overdosing and increased storage needs due to inaccurate metering, which is undesirable in mobile applications.
Innovation Solution
A fluid transfer system comprising a dosing pump, a controllable shut-off valve, and a controlling unit that ensures the pressure of fluid fed to a nozzle is above a pre-selected pressure limit and the delivered amount corresponds to demand, using a combination of a dosing pump, measuring unit, or measuring pump to achieve accurate and efficient urea delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a simple fluid transfer system is used, then the device complexity is reduced, but the manufacturing precision of fluid delivery is insufficient leading to overdosing
Solution Approach 1:
The system is divided into distinct functional modules: a dosing pump for precise metering, a buffer reservoir for pressure stabilization, and a nozzle for delivery. This segmentation allows each component to be optimized for its specific function, achieving high delivery precision without requiring the entire system to be overly complex.
Solution Approach 2:
The buffer reservoir is positioned between the dosing pump and the nozzle to pre-stabilize the fluid pressure before delivery. This preliminary action ensures that pressure fluctuations are minimized before the fluid reaches the nozzle, improving delivery precision without adding complex real-time control mechanisms.
2Reliability
If urea is overdosed to ensure sufficient catalytic conversion, then the reliability of NOx conversion is improved, but the loss of substance increases due to waste
Solution Approach 1:
The system incorporates sensors and control mechanisms that monitor the actual urea delivery and provide feedback to the dosing pump. This allows the system to adjust the dosing rate in real-time to match the actual catalytic needs, ensuring reliable NOx conversion while minimizing urea waste through precise control.
Solution Approach 2:
The system replaces simple mechanical dosing with an electronically controlled dosing pump that can precisely meter urea delivery based on feedback signals. This substitution enables accurate control of the dosing rate, preventing both overdosing and underdosing, thereby maintaining catalytic reliability while reducing substance loss.
3Reliability
If urea is overdosed due to inaccurate metering, then the reliability of catalytic performance is maintained, but the volume of storage required increases
Solution Approach 1:
The electronically controlled dosing pump replaces inaccurate mechanical metering systems, enabling precise delivery of urea. This allows the system to use smaller storage capacities because the precise metering ensures that urea is delivered accurately according to actual needs, eliminating the requirement for oversized storage to compensate for metering inaccuracies.
4Manufacturing precision
If a dosing pump and buffer system is used, then the manufacturing precision of fluid delivery is improved, but the device complexity increases
Solution Approach 1:
The system divides the fluid delivery function into two separate components: a dosing pump for precise metering and a buffer reservoir for pressure stabilization. This segmentation allows each component to be relatively simple in design while collectively achieving high delivery accuracy, as each component focuses on a single function rather than attempting to perform multiple functions in one complex device.
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 provides precise and efficient delivery of urea, minimizing dynamic and accumulative errors, ensuring accurate atomization and reducing storage needs by accurately meeting demand, thus enhancing the efficiency of NOx conversion in catalytic systems.
Implementation Method 1
a dosing pump... wherein the controlling unit is adapted to control the state of the shut-off valve so that the pressure of fluid being fed to the receiving device is above a first pre-selected pressure limit (Pmin)
Implementation Method 2
a controllable shut-off valve arranged upstream of the receiving device... so that the delivered amount corresponds to a demand
Data Source
AI summary
A fluid transfer system for transferring fluid from a reservoir to a receiving device having a through flow device adapted to receive fluid from the reservoir and transfer fluid through the system or measure the amount of fluid being transferred from the reservoir to the receiving device, a controllable shut-off valve arranged upstream of the receiving device, and a controlling unit that controls at least the state of the shut-off valve. The present invention relates in particular to a fluid transfer system and methods of transferring fluid from a reservoir to a receiving device and controlling the state of the state of the shut-off valve so that the pressure of fluid being fed to the receiving device is above a first pre-selected pressure limit (Pmin) so that the delivered amount corresponds to a demand.