Dual Float Valve Fuel Fill-Up Control Device
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Solution Overview
Problem
Existing fill-up control valve devices for fuel tanks fail to prevent additional refueling after the tank is filled, as the float valve closes and opens too quickly due to pressure changes, allowing fuel to overflow during initial refueling and allowing additional refueling despite the tank being full.
Innovation Solution
A dual float valve system where a first float valve closes the ventilation passage when the fuel surface reaches a predetermined level, and a second float valve with an air storage recess and air-discharge hole ensures the first float valve remains closed by maintaining air pressure balance, preventing fuel from entering the container during turns or initial refueling, and opening the passage to prevent overflow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a vent hole is provided on the casing above the second predetermined level to communicate the interior space of the fuel tank with the interior space of the casing, then pressure variations in the fuel tank are reduced, but the float valve opens too quickly allowing additional refueling
Solution Approach 1:
The vent hole is segmented into two parts: an upper vent hole above the second predetermined level for pressure balancing, and a lower vent hole at or below the second predetermined level for controlled fuel drainage. This segmentation allows independent control of pressure stability and refueling prevention functions.
Solution Approach 2:
The lower vent hole acts as an intermediary mechanism between the upper vent hole and the fuel surface. It controls the drainage of fuel from the casing, preventing direct communication between the upper vent hole and the fuel surface, thereby maintaining the float valve in a closed state.
2Reliability
If the float valve closes the ventilation passage when the fuel surface reaches the fill-up level, then additional refueling is prevented, but the float valve opens too quickly due to pressure changes
Solution Approach 1:
The ventilation passage is segmented into an upper passage and a lower passage, with the lower vent hole providing a separate drainage path. This allows the float valve to maintain closure in the upper passage while fuel drains through the lower vent hole, extending the closed state duration.
Solution Approach 2:
The lower vent hole is pre-positioned at or below the second predetermined level to enable preliminary fuel drainage before the float valve would normally open, ensuring the valve remains closed for an extended period.
3Stability of the object's composition
If the float valve opens quickly after closing, then pressure equalization occurs, but fuel overflow is allowed during initial refueling
Solution Approach 1:
The vent hole system is segmented into upper and lower components, allowing pressure equalization through the upper vent hole while preventing fuel overflow through the lower vent hole's controlled drainage capability.
Solution Approach 2:
Different locations of the vent hole system serve different functions: the upper vent hole provides pressure equalization, while the lower vent hole provides controlled fuel drainage. This local differentiation prevents fuel overflow while maintaining pressure stability.
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 system effectively prevents additional refueling after the tank is full by keeping the first float valve closed for an extended period and ensuring the fuel tank is not overfilled during initial refueling, even when the vehicle turns, thereby maintaining accurate fuel levels and preventing overflow.
Implementation Method 1
a first float valve that is provided vertically movably in an accommodation space formed in the casing, that floats on liquid fuel in the casing, and that opens and closes the ventilation passage with a vertical movement of a fuel surface in the casing
Implementation Method 2
a second float valve that is provided vertically movably in an accommodation space formed in an upstream portion of a location in the casing where the container is disposed in a discharge direction of the ventilation passage, and that opens and closes the ventilation passage with a vertical movement of a fuel surface in the casing
Data Source
AI summary
A casing includes a container in which a float valve is disposed. When the float valve is closed, the casing keeps the float valve in a closed state for a relatively long period of time. A sub-float valve is provided below the container in the casing, and is closed by floating on fuel at the time of a turn of a vehicle or an automatic stop of first refueling. When the first refueling is completed, air in the sub-float valve is discharged, and the sub-float valve loses its floating function.