Fuel Supply Pipe Structure Preventing Backflow Leakage
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Solution Overview
Problem
The capless type fuel supply portion structure has a reduced vertical height between the filler port and the automatic stop sensor, leading to potential fuel backflow and leakage during refueling, with fuel entering the space between the inner and outer caps and possibly being discharged through the drain hole.
Innovation Solution
A fuel supply portion structure with a tubular portion, a flap mechanism, a drain hole, an inner diameter member with an inclined surface, and a drain hole on-off valve, where the valve is positioned at the lowermost side of the vehicle, preventing fuel leakage by directing backflow fuel along the inclined surface and into the filler pipe.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the capless type fuel supply portion structure is adopted, then refueling convenience is improved, but the vertical height between the filler port and automatic stop sensor is reduced, causing fuel backflow and leakage
Solution Approach 1:
The drain hole on-off valve is activated in advance by the inserted nozzle to close the drain hole before fuel backflow occurs. This preliminary action prevents the harmful effect (fuel leakage) before it can manifest, resolving the contradiction between maintaining capless convenience and preventing fuel leakage during automatic stop operations.
Solution Approach 2:
The drain hole on-off valve acts as an intermediary component between the tubular portion and the external environment. It mediates the conflict by selectively controlling the drain hole opening/closing state, allowing water drainage during normal operation while preventing fuel leakage during backflow conditions, thus enabling both convenience and reliability.
2Ease of manufacture
If the drain hole is kept open for water drainage, then water and dust can be discharged, but fuel can leak through the drain hole during backflow
Solution Approach 1:
The drain hole on-off valve transforms the static drain hole into a dynamic opening/closing structure. The valve dynamically adjusts its state based on operational conditions - remaining open during normal refueling to drain water and dust, then closing automatically when the nozzle is inserted to prevent fuel discharge, thus resolving the contradiction between drainage functionality and fuel containment.
Solution Approach 2:
The drain hole on-off valve operates automatically based on the nozzle insertion itself, without requiring external control. The inserted nozzle directly actuates the valve to close the drain hole, and when the nozzle is removed, the valve automatically reopens for drainage. This self-service mechanism resolves the contradiction by autonomously switching between drainage mode and fuel containment mode.
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 fuel leakage to the outside during automatic stop operations by effectively managing backflow fuel through the inclined surface and drain hole on-off valve, ensuring efficient refueling without external fuel discharge.
Implementation Method 1
a placement surface located at the lowermost side of a vehicle on an inner wall of the inner diameter member, the placement surface is made of an inclined surface falling from the opening side toward the connection port
Data Source
AI summary
To prevent fuel from leaking to outside even when the fuel flows back at the time of an automatic stop operation during refueling. A fuel supply portion structure of a fuel supply pipe, including a tubular portion having a filler port and a connection port, a first flap mechanism which is provided on the filler port side of the tubular portion, a drain hole, and a drain hole on-off valve, wherein the drain hole on-off valve is disposed on a placement surface located at the lowermost side of a vehicle on an inner wall of a first inner diameter member, the placement surface is made of an inclined surface falling from the filler port side toward the connection port with respect to a horizontal plane of the vehicle, and a wall portion rising toward the filler port is provided on the filler port side of the inclined surface.