Liquid Conveying Pump Back-Suction Control for Freezing Protection
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Solution Overview
Problem
Existing methods for operating devices that deliver liquid additives to exhaust-gas treatment systems in vehicles face issues with freezing at low temperatures, leading to volume expansion damage and inefficient pump operation during evacuation and refilling, with potential leakage and prolonged pump usage.
Innovation Solution
A method involving a reversible pump and a filter layer that allows back-suctioning of liquid against the usual delivery direction, monitoring counterpressure to prevent air ingress and ensure liquid remains in the filter space, thereby reducing the need for extensive pump operation and minimizing energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the device is completely evacuated and refilled during operation stoppage and resumption, then freezing damage is prevented, but pump operating duration increases and energy consumption rises
Solution Approach 1:
The patent applies partial action by evacuating only the pressure line section instead of the entire device. The pump removes liquid only from the pressure line section between itself and the injector, while leaving the suction line section and tank filled. This partial evacuation prevents freezing damage in the critical pressure line while minimizing pump operating duration and energy consumption compared to complete device evacuation.
2Reliability
If the device is evacuated and refilled during operation stoppage and resumption, then freezing damage is prevented, but pump wear increases
Solution Approach 1:
The patent reduces pump wear by limiting evacuation to only the pressure line section. The pump operates for a shorter duration at lower intensity, removing liquid only from the section between the pump and injector. This partial action maintains reliability by preventing freezing in the pressure line while reducing the mechanical stress and wear on the pump compared to complete device evacuation.
3Reliability
If liquid is removed from the device during evacuation, then freezing damage is prevented, but leakage risk increases during refilling
Solution Approach 1:
The patent reduces leakage risk during refilling by evacuating only the pressure line section while keeping the suction line section and tank filled with liquid. Since the suction line remains filled, liquid is already present to flow into the pressure line during refilling, preventing air ingress and potential leakage at the injector. This partial evacuation approach maintains freezing protection while reducing the refilling complexity and leakage risk compared to complete evacuation.
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 effectively prevents damage from freezing liquids and reduces energy consumption by optimizing the evacuation and refilling process, ensuring the device is ready for operation while minimizing wear on components.
Implementation Method 1
back-suctioning a liquid situated in the pressure line section counter to a usual delivery direction by way of the at least one pump
Implementation Method 2
The filter layer has a different permeability for liquid and air
Data Source
AI summary
A method for operating a device configured to deliver a liquid includes: a) back-suctioning a liquid situated in a pressure line section counter to a usual delivery direction by at least one pump; b) monitoring at least one operating parameter of the at least one pump during the back-suctioning, the at least one operating parameter being representative of a counterpressure that the at least one pump operates against during the back-suctioning; and c) detecting an increase in the counterpressure, and stopping the back-suctioning.