External Vent Valve for Liquid Tanks
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Solution Overview
Problem
Vent valves for liquid tanks in motor vehicles are prone to damage from moving liquids, such as ice floes in aqueous urea solutions, due to their protruding design, which disrupts their functionality during vehicle movement.
Innovation Solution
A vent valve design with a float mechanism and line connection that allows the valve to be positioned outside the tank, featuring a cup-shaped float body, seal carrier, and elastic membrane to prevent damage and maintain functionality, including a guide insert to prevent jamming and a protective cap to prevent dirt entry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the vent valve protrudes into the liquid tank to vent displaced air during refueling, then the venting function is achieved, but the vent valve is damaged by moving liquids and objects such as ice floes during vehicle movement
Solution Approach 1:
The vent valve is extracted from the liquid tank environment and relocated to the vehicle's underfloor. The liquid connection is established through a line connection that allows the vent valve to remain outside the tank, eliminating exposure to damaging moving liquids and objects while maintaining the venting function through the line connection to the tank
2Object-affected harmful factors
If the vent valve is positioned outside the liquid tank, then damage from moving liquids is prevented, but the venting function may be disturbed by liquid movements in the tank
Solution Approach 1:
A line connection acts as an intermediary between the liquid tank and the vent valve. This flexible connection transmits the venting function from the tank to the externally positioned vent valve while isolating the valve from liquid movements and vibrations inside the tank, ensuring reliable operation
3Extent of automation
If a float mechanism is used to close the vent opening, then automatic venting control is achieved, but the float may become jammed or tilted causing sealing issues
Solution Approach 1:
The float mechanism operates through periodic vertical movements in response to liquid level changes. The cup-shaped float body rises and falls regularly, activating the vent opening closure only when liquid enters the float chamber, providing reliable automatic control without tilting or jamming
Solution Approach 2:
A float seal with a flexible membrane is used to ensure reliable sealing of the vent opening. The flexible seal adapts to the float's movements and maintains contact with the vent opening surface, preventing leakage even during dynamic operation
4Productivity
If the vent opening is exposed to the environment, then air exchange occurs facilitating venting, but drying and crystallization of urea may occur
Solution Approach 1:
The vent opening is selectively opened or closed based on local conditions (liquid presence). When liquid is present, the vent opening is closed to prevent drying. When liquid is absent or during normal operation, the vent opening is open to allow air exchange. This localized control maintains both productivity and reliability
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
Prevents damage from moving liquids while ensuring the vent valve's functionality by positioning it outside the tank, improving sealing efficiency, and reducing air exchange to prevent drying and crystallization, thus maintaining the valve's performance under various conditions.
Implementation Method 1
The float chamber ( 107) forms a pressure equalization chamber for equalizing a pressure difference between the liquid tank ( 1) and the ambient environment
Implementation Method 2
The elastic membrane ( 121) is arranged in such a way that when there is an overpressure in the vent valve, it creates an air gap from which the air can escape from the vent valve
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The vent valve (100) has a vent (103) for venting a liquid tank in a motor vehicle. A float (101) is positioned in a float chamber (107) for sealing the vent. A line connection (109) is provided for supplying liquid from liquid tank to float chamber. A seal carrier (113) is mounted with a freedom of movement on the float.