Vehicle Fuel Tank Valve Assembly with Dynamic Float Sealing
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Solution Overview
Problem
Fuel tank valves fail to effectively prevent liquid fuel from entering the vapor control structure during vehicle roll-overs or when parked on a grade, leading to potential vapor control structure saturation.
Innovation Solution
A valve assembly with a float mechanism and sealing member that moves between positions to seal the vapor outlet, using a biasing member to maintain the float in a position that prevents liquid fuel from entering the vapor control structure, even when the vehicle is rolled over or on an incline, and a flexible sealing member that deforms to seal the outlet.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional fuel tank valve is used to vent vapors, then vapor venting function is provided, but liquid fuel enters the vapor control structure during roll-overs or when parked on a grade
Solution Approach 1:
The float is made movable relative to the valve body, allowing it to dynamically adjust its position based on liquid fuel level and vehicle orientation. This dynamic adjustment enables the sealing member to automatically engage with the first seat during roll-overs or graded parking, preventing liquid fuel from entering the vapor control structure while maintaining normal vapor venting operation during standard driving conditions
Solution Approach 2:
The sealing member acts as an intermediary element between the float mechanism and the vapor outlet. It is attached to the float and selectively engages with the first seat to seal the vapor outlet, providing a mechanical mediation that prevents liquid fuel from reaching the vapor control structure while allowing vapor to pass through when the sealing member is disengaged
2Reliability
If the float is positioned to prevent liquid fuel entry, then liquid fuel is blocked from entering vapor control structure, but vapor venting may be restricted
Solution Approach 1:
The float mechanism dynamically positions the sealing member based on real-time conditions. When liquid fuel approaches the vapor outlet or during roll-overs, the float moves to engage the sealing member with the first seat, blocking liquid fuel entry. During normal operation with sufficient liquid level and proper orientation, the float positions the sealing member away from the first seat, maintaining open vapor venting pathways and ensuring vapor can be efficiently vented to the vapor control structure
Solution Approach 2:
The sealing member provides localized sealing at the vapor outlet (first seat) rather than blocking the entire vapor pathway. This localized approach allows vapor to flow through other pathways in the valve body while preventing liquid fuel from entering the vapor control structure, thus maintaining vapor venting productivity while achieving reliable liquid fuel blocking at the critical interface
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 liquid fuel and vapor from entering the vapor control structure, ensuring efficient vapor venting and minimizing the risk of vapor control structure saturation during vehicle roll-overs or when parked on a grade.
Implementation Method 1
a float movable between a first position and a second position in response to a liquid fluid level in the tank
Implementation Method 2
a biasing member engaging the float to continuously bias the float toward the first seat
Implementation Method 3
a flexible sealing member that deforms to seal the outlet
Data Source
Figure 1~2
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AI summary
A valve assembly (10) for a tank (12) of a vehicle is disclosed. A valve body (16) is adapted to be attached to the tank (12). A seat (22) is disposed inside the valve body (16) and defines an outlet (28) for venting the tank (12). A float (38) is disposed inside the valve body (16) and is movable between a first position and a second position relative to the valve body (16) in response to a liquid fluid level (40) inside the tank (12). A support (54) is coupled to the float (38) and is movable with the float (38) between the first and second positions. A sealing member (60) is attached to the support (54) and has an engagement portion (64) supported by a base (62) to define a space (66) between the engagement portion (64) and the support (54) to allow movement of the engagement portion (64) between an initial position when in the first position and a displaced position when in the second position. The sealing member (60) includes an outer periphery, and a plurality of extensions spaced from each other and each of the extensions have a portion extending non-tangentially from the outer periphery to respective distal ends.