Feed Device Venting Air to Prevent Metering Errors in Freezing Liquids
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Solution Overview
Problem
Existing feed devices for liquids at risk of freezing in motor vehicle systems face issues with incorrect metering due to air entrainment in lines when the vehicle is restarted, leading to inefficient re-injection of the liquid into the system.
Innovation Solution
A ventilation device with an air-permeable membrane covering a ventilation opening near the dispensing member, which is impermeable to the freezing liquid, is used to displace air in the line with the liquid, and a non-return valve ensures that air is vented without allowing the liquid to escape, utilizing a mushroom valve or similar mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the dispensing device is opened to dispense liquid, then the liquid can be injected into the fluid line, but air already present in the line is introduced into the fluid line causing incorrect metering
Solution Approach 1:
The patent extracts and removes air from the fluid line before liquid dispensing by providing a dedicated vent opening that allows air to escape. The vent opening is positioned to enable air removal while preventing liquid loss, separating the air venting function from the liquid dispensing function to ensure accurate metering.
2Reliability
If a vent opening is provided to discharge air, then air can be removed from the line, but the freezing-prone liquid may escape through the same opening
Solution Approach 1:
The patent applies local quality by providing different characteristics at different locations: the vent opening has an air-permeable membrane that is permeable to air but impermeable to liquid, creating location-specific permeability properties that allow air discharge while preventing liquid loss.
Solution Approach 2:
The patent uses porous or selectively permeable materials in the form of an air-permeable membrane at the vent opening. This membrane allows air molecules to pass through while blocking larger liquid molecules, enabling differential transport based on material porosity and surface properties.
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 solution allows for accurate re-injection of the liquid by ensuring the line is filled with the liquid upon restart, preventing air from entering and ensuring precise metering by maintaining the liquid within the system during operation.
Implementation Method 1
an air-permeable membrane which is impermeable to the freezing-prone liquid at least up to the maximum pressure values prevailing in the line
Implementation Method 2
a mushroom valve at the vent opening that covers it and acts as a blocking check valve when the freezing-prone liquid is pumped back
Data Source
Figure 1~2
AI summary
The invention relates to a feed device for feeding a liquid at risk of freezing into a fluid line of a motor vehicle, having a line which leads from a reservoir to a discharge element which opens in a controlled manner, through which line the liquid that is still situated in and upstream of the discharge element after a shutdown of the motor vehicle can be conveyed back into the reservoir. Here, at the discharge element or in said line in the immediate vicinity of the discharge element, a ventilation opening is provided which is independent of the controlled opening of the discharge element, through which ventilation opening air situated in the line upon or after a restart of the motor vehicle can be dissipated. The ventilation opening is preferably covered by an air-permeable diaphragm which, at least up to the maximum pressure values prevailing in said line, is impermeable to the liquid at risk of freezing. Furthermore, at the ventilation opening, there is provided a mushroom valve which covers said ventilation opening and which acts as a blocking check valve as the liquid at risk of freezing is being conveyed back.