Fuel Tank Vent Valve Membrane Flow Control Against Liquid Escape
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Solution Overview
Problem
Fuel tank valve assemblies face challenges in preventing liquid escape due to sloshing and roll-over conditions while maintaining vapor venting and balanced pressure as fuel levels change, and existing solutions are inadequate in controlling vapor flow effectively.
Innovation Solution
A valve assembly with a housing that includes a vapor passage and a membrane allowing vapor passage while preventing liquid passage, along with a flow control feature such as a deflector or head valve to manage vapor flow and prevent liquid from reaching the membrane, ensuring controlled vapor exit and minimizing liquid escape.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a membrane is used to allow vapor passage while preventing liquid passage, then vapor venting ability is improved, but liquid escape prevention under sloshing conditions deteriorates
Solution Approach 1:
A flow control member is introduced as an intermediary component between the liquid and the membrane. This member selectively blocks liquid flow paths while allowing vapor to pass through to the membrane, preventing liquid from reaching the membrane during sloshing conditions while maintaining vapor venting capability
Solution Approach 2:
The valve assembly is segmented into distinct functional zones: a vapor passage for vapor flow, a liquid blockage feature for liquid containment, and a flow control member positioned strategically to regulate liquid-vapor interaction. This segmentation allows independent optimization of vapor venting and liquid prevention functions
2Object-affected harmful factors
If protection from liquid escape during roll over conditions is provided, then liquid escape prevention is improved, but vapor venting effectiveness deteriorates
Solution Approach 1:
The flow control member is designed to be movable rather than fixed, allowing it to dynamically adjust its position based on flow conditions. During normal operation it permits vapor flow, but during roll-over or sloshing conditions it moves to block liquid while maintaining vapor passage capability
Solution Approach 2:
Different regions of the flow control member have different properties: one surface is configured to interact with liquid flow for blocking, while another region maintains openness for vapor passage. This local differentiation allows simultaneous liquid prevention and vapor venting under various conditions
3Ease of operation
If a flow control mechanism is added to regulate vapor flow, then vapor flow control is improved, but device complexity increases
Solution Approach 1:
The flow control member is designed to automatically respond to flow conditions without external control mechanisms. It self-regulates vapor and liquid flow based on pressure differentials and flow dynamics, eliminating the need for complex control systems, sensors, or actuation mechanisms
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 solution effectively prevents liquid escape during normal conditions and roll-over scenarios while maintaining balanced pressure by allowing controlled vapor venting, ensuring efficient fuel management and safety.
Implementation Method 1
The membrane is configured to allow the passage of the vapor and prevent the passage of a liquid through the membrane
Data Source
AI summary
A valve assembly includes a housing. A membrane supported by the housing such that the membrane covers a vapor passage defined by the housing. The membrane allows the passage of vapor through the membrane and prevents the passage of liquid through the membrane. A flow control feature is supported by the housing and at least partially controls flow of a vapor to the vapor passage. The flow control feature enables variable flow of vapor to the vapor passage.