Auxiliary Float Valve Assembly for Fuel Tank Roll-Over Sealing
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Solution Overview
Problem
Conventional float valves in vehicle fuel tanks face reduced effectiveness in preventing overfilling and spillage due to decreased net buoyancy force caused by condensation of fuel vapor at lower temperatures, leading to potential fuel leakage during roll-over or tilting conditions.
Innovation Solution
A float valve design incorporating an auxiliary float member with a lower density than the liquid medium, which provides a consistent upthrust force regardless of orientation, combined with a primary float member and spring element, ensures the valve remains closed to prevent overfilling and spillage by maintaining the required buoyancy force even when the primary float member is submerged in liquid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the float valve uses an open-bottom float member with fuel vapor for buoyancy, then the valve can effectively prevent overfilling during normal operation, but the net buoyancy force decreases significantly when fuel vapor condenses at lower temperatures
Solution Approach 1:
The float member is divided into two distinct parts: a primary float member that provides buoyancy during normal operation, and an auxiliary float member that provides additional buoyancy when the primary float member becomes submerged due to vapor condensation. This segmentation allows each component to address specific operational conditions independently.
Solution Approach 2:
The auxiliary float member acts as an intermediary element that compensates for the loss of buoyancy force when the primary float member is submerged. It provides the additional upward force needed to maintain valve operation effectiveness under adverse temperature conditions.
2Reliability
If the float valve relies on spring bias and float weight for roll-over protection, then the valve can prevent fuel leakage during inversion, but the effectiveness is reduced when the float chamber is filled with liquid fuel
Solution Approach 1:
The float system is segmented into primary and auxiliary float members, where the auxiliary member specifically addresses the roll-over condition by providing consistent buoyancy force regardless of the float chamber's fill level or orientation.
Solution Approach 2:
The auxiliary float member is designed with different physical parameters (density, volume, position) than the primary float member, enabling it to provide reliable buoyancy force under varying conditions including roll-over scenarios where the primary float member may be fully submerged.
3Ease of operation
If the float chamber is open at the bottom to allow fuel vapor entry, then the valve can respond to fuel level changes, but the open space fills with condensed fuel at low temperatures, reducing buoyancy
Solution Approach 1:
The float chamber is effectively segmented into two functional zones: the primary float member that interacts with fuel vapor for normal operation, and the auxiliary float member that provides backup buoyancy when the vapor space is compromised by condensation.
Solution Approach 2:
The auxiliary float member is pre-positioned within the float chamber to provide immediate compensatory buoyancy force when the primary float member becomes submerged, without requiring any system reconfiguration or response time.
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 float valve effectively prevents fuel leakage and overfilling across various environmental conditions, including temperature changes and roll-over scenarios, by ensuring the primary float member is maintained in a floating configuration through the auxiliary float member's upthrust, enhancing the valve's operational reliability.
Implementation Method 1
said auxiliary float member is configured for providing a net upthrust force with respect to the liquid medium under submerged conditions irrespective of whether the float valve is in said upright configuration or in said inverted configuration
Implementation Method 2
the spring element being configured for providing a biasing spring force to the primary floating member in a direction towards said at least one outlet port
Data Source
AI summary
A float valve (10) is provided for use with a liquid medium, the float valve having an upright configuration and an inverted configuration. The float valve includes: a housing (12), defining at least one inlet port (20) and at least one outlet port (24); a float assembly (60) movable within the housing; and an auxiliary float member (50) movable within said housing. The float assembly (60) comprises a primary float member (70; 70′), different from the auxiliary float member, and a spring element (80). The primary in float member is configured for closing the at least one outlet port when in abutment therewith, the spring element being configured for providing a biasing spring force to the primary float member in a direction towards said at least one outlet port. The auxiliary float member is configured for providing a net upthrust force with respect to the liquid medium under submerged conditions irrespective of whether the float valve is in said upright configuration or in said inverted configuration.