Recirculation Check Valve Using Buoyant Ball to Block Fuel Backflow
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Liquid fuel backflow into the recirculation line remains a persistent problem in vehicle evaporative emission systems, especially during overfilling, leading to costly repairs.
Innovation Solution
A recirculation check valve with a hollow cylindrical insert and a ball valve member having a density less than that of liquid fuel, which moves between open and closed positions to allow vapor flow while preventing liquid fuel from entering the recirculation line.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional fuel connector is used to connect the filler tube to the recirculation line, then vapor flow is facilitated, but liquid fuel backflow into the recirculation line cannot be prevented
Solution Approach 1:
A ball valve member is introduced as an intermediary element within the fuel connector. This ball member responds to liquid fuel by floating upward to block the recirculation line passage, while allowing vapor flow through gaps when in the lower position. The ball acts as a mediator that automatically distinguishes between vapor and liquid fuel phases.
Solution Approach 2:
The system exploits the density parameter difference between vapor and liquid fuel. The ball valve member is designed with a density less than liquid fuel but greater than vapor, causing it to automatically change position based on the phase of fuel present. This parameter-based differentiation enables automatic protection without complex control systems.
2Strength
If the valve member density is greater than liquid fuel, then the valve can be anchored securely, but it cannot float to close the valve during liquid fuel backflow
Solution Approach 1:
The ball member density is precisely controlled to fall between the density of liquid fuel and vapor. This intermediate density parameter enables the ball to float on liquid fuel (closing the valve) while remaining anchorable in the vapor phase. The density parameter is the key differentiator that enables automatic phase-responsive operation.
3Reliability
If the recirculation line passage is completely blocked, then liquid fuel backflow is prevented, but vapor flow is also obstructed
Solution Approach 1:
The recirculation passage is segmented into multiple regions: an upper region for vapor flow, a middle region where the ball member operates, and a lower region for liquid fuel blockage. The hollow cylindrical insert further segments the passage to create defined flow paths. This segmentation allows simultaneous vapor passage and liquid blockage capability.
Solution Approach 2:
Different regions of the recirculation passage have different functional qualities. The upper portion allows free vapor flow, the middle portion contains the ball member for phase detection, and the lower portion is designed for liquid blockage. The hollow cylindrical insert creates localized flow characteristics that enhance both vapor permeability and liquid sealing.
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
Effectively prevents liquid fuel from entering the recirculation line, thereby avoiding potential vehicular damage and repairs by utilizing a valve member that floats on liquid fuel to close the check valve.
Implementation Method 1
a valve member provided in the channel between the hollow cylindrical insert and the outlet end of the housing, and configured to move between an open position where the valve member is seated against the plurality of radially inwardly extending projections and a closed position where the valve member is seated against a valve seat formed in the channel
Data Source
AI summary
A recirculation check valve positioned between a fuel system filler tube and a fuel system recirculation line. The check valve includes a hollow cylindrical insert having a plurality of radially inwardly extending projections provided around an inner circumference of the hollow cylindrical insert that are separated by a plurality of gaps therebetween. A valve member provided between the hollow cylindrical insert and an outlet of a housing of the check valve that is configured to move between an open position where the valve member is seated against the plurality of radially inwardly extending projections and a closed position where the valve member is seated against a valve seat formed in a channel of the housing.