SCR Pump Flushing via Reverse Rotation and Pressure Feedback
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Solution Overview
Problem
Existing methods for flushing the conveying device in SCR systems are not adaptable to changes in the system, such as pump wear and tear, leading to inconsistent flushing processes.
Innovation Solution
A method that adjusts the flushing process based on device state variables by determining and storing the operating time and rotation speed of the pump during a calibration process, using a pressure sensor to monitor and adjust the negative pressure in the pressure line, and applying correction factors to maintain optimal flushing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the pump operates at fixed parameters during flushing, then the flushing process is simple to control, but the flushing effectiveness deteriorates due to pump wear and system changes
Solution Approach 1:
The patent implements a feedback mechanism where a pressure sensor monitors the negative pressure in the pressure line during flushing, and the control unit adjusts the pump's operating parameters (rotational speed and/or operating time) based on the measured pressure to maintain a predetermined negative pressure level, thereby adapting to pump wear and system changes
Solution Approach 2:
The patent transitions from fixed pump parameters to dynamic parameter adjustment during flushing, where the pump's rotational speed and/or operating time are continuously adapted based on real-time pressure measurements to maintain optimal flushing effectiveness throughout the system's operational life
2Reliability
If the pump operates at higher rotational speed and longer duration, then the flushing effectiveness is improved, but the energy consumption increases
Solution Approach 1:
The control unit uses feedback from the pressure sensor to adjust the pump's rotational speed and/or operating time, increasing these parameters when wear reduces negative pressure generation, and potentially reducing them when the system is new and efficient, thereby optimizing the balance between flushing effectiveness and energy consumption throughout the system's life
Solution Approach 2:
The patent changes the pump's operating parameters (rotational speed, operating time) based on system state and pressure measurements, allowing the system to adapt energy consumption to actual flushing needs rather than operating at constant high parameters
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
Ensures consistent and effective flushing by adjusting the pump's operating parameters to maintain desired negative pressure levels, even as the device ages, thereby maintaining system performance and preventing dry running.
Implementation Method 1
In this first phase a negative pressure p1 is generated in the pressure line that is directly dependent on the operating time t1 and the rotational speed n1
Data Source
AI summary
The invention relates to a method for controlling a conveyor for an aqueous urea solution in a motor vehicle, having a tank, a suction line, a pump, a pressure line and an injector, wherein the aqueous urea solution is conveyable from the tank along the suction line, through the pump, through the pressure line to the injector, the method being designed to carry out a flushing process at least of the pressure line, the pump being operated counter to the usual conveying direction thereof during the flushing process, and the injector being closed in a first phase of the method, the pump being operated for an operating duration t1 and at a rotation speed n1 during the first phase of the method. The invention also relates to an apparatus for carrying out the method.