Fuel Tank Vent Lines with Arched Siphon and Bypass Valve

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Solution Overview

Problem

Existing fuel tank ventilation systems are costly and inefficient, particularly due to the need for roll-over valves that penetrate the tank wall and are prone to fuel leakage when the tank is tilted or rolled over, and they do not effectively prevent liquid fuel from entering the ventilation lines.

Innovation Solution

The implementation of a fuel tank with two vent lines routed to form arches in both the lower and upper wall sections, with ball valves at the open ends to prevent liquid escape when the tank is tilted, and a bypass connection to the inlet check valve to ensure reliable fuel vapor discharge without liquid contamination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If roll-over valves are used to prevent fuel leakage, then fuel safety is improved, but device complexity and cost increase due to penetrating container walls requiring sealed openings

Engineering Contradiction:
Improvefuel safetyVSAvoidcontainer wall penetration
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention extracts the valve function from the container wall structure by using internal vent lines that do not penetrate the wall. Instead of placing valves in the wall (roll-over valves), the system uses internal arch-shaped vent lines with check valves at their ends, separating the containment function from the ventilation function.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The arch-shaped vent lines act as intermediaries between the fuel tank interior and the external environment. These vent lines with integrated check valves provide a mediation path for vapor discharge that eliminates the need for direct wall penetrations, thereby maintaining safety without structural complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If roll-over valves are used for ventilation, then pressure equalization is achieved, but manufacturing complexity increases due to required container openings and sealing

Engineering Contradiction:
Improvepressure equalizationVSAvoidcontainer openings and sealing
Core Design Contradiction:
Ease of operationVSEase of manufacture

Solution Approach 1:

The ventilation function is extracted from the container wall structure and implemented through internal routing. The vent lines are integrated into the tank interior without requiring wall openings, eliminating the need for complex sealing operations while maintaining pressure equalization capability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The ventilation lines are merged with the tank interior structure, forming an integrated system where the vent lines follow the inner contour of the tank. This combination eliminates separate wall penetration components and simplifies manufacturing by using the existing tank structure as part of the ventilation pathway.

Inventive Principle:
Principle #5Merging (Combining)

3Device complexity

If a single vent line is used, then device complexity is reduced, but reliability decreases as the tank cannot be secured against flooding in overhead position

Engineering Contradiction:
Improvenumber of vent linesVSAvoidprotection against flooding
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The ventilation system is segmented into multiple independent arch-shaped vent lines instead of using a single line. Each vent line is equipped with its own check valve and is positioned to discharge above the liquid level. This segmentation ensures that if one line becomes flooded, others remain functional, thereby improving reliability without excessive complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The check valves are pre-positioned at the ends of the arch-shaped vent lines to close automatically when liquid reaches them. This preliminary positioning of the safety mechanism ensures that flooding is prevented before it can compromise the ventilation system, providing proactive protection rather than reactive response.

Inventive Principle:
Principle #10Preliminary action

4Productivity

If vent lines extend to upper wall area, then vapor discharge efficiency is improved, but risk of liquid fuel entering vent lines increases when tank is tilted

Engineering Contradiction:
Improvevapor discharge efficiencyVSAvoidliquid fuel contamination
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The vent lines are designed with arch-shaped curvature instead of straight paths. This curvature allows the lines to extend upward for efficient vapor discharge while naturally preventing liquid fuel from reaching the discharge ends when the tank is tilted. The arched geometry creates a physical barrier against liquid contamination while maintaining vapor access.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The arched vent lines with check valves serve as intermediaries that selectively allow vapor passage while blocking liquid fuel. The check valve mechanism acts as a mediator that opens for vapor flow but closes automatically when liquid approaches, preventing contamination of the ventilation system while maintaining discharge efficiency.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

This configuration enhances pressure tightness and prevents unintentional fuel escape in any tank position, allowing for efficient refueling and optimal use of tank volume while maintaining the integrity of the ventilation system.

Implementation Method 1

the at least one vent line is routed in such a way that it forms a siphon in the area of a lower wall section

Methodology Applied
Scientific EffectSiphon: Syphon

Implementation Method 2

arranging a valve, in particular a ball valve, at the open end of the at least one venting line, which is open when the fuel tank is in a normal position and is closed when the fuel tank is in an overhead position

Methodology Applied
Scientific EffectGravity: Gravitation

Implementation Method 3

a filler pipe (22) that opens into the fuel tank (10) via an inlet check valve (28)

Methodology Applied
Scientific EffectCheck valve mechanism: Valve

Data Source

PatentEP3368366B1Fuel container with inlet check valve
Publication Date: 2021.04.07 TI AUTOMOTIVE TECHNOLOGY CENTER GMBH
  • EP3368366B1 patent drawingFigure 1
  • EP3368366B1 patent drawingFigure 2
  • EP3368366B1 patent drawingFigure 3

AI summary

The invention relates to a fuel container (10) with a filler tube (22) which opens into the fuel container (10) via an inlet check valve (34), and with a venting device for discharging fuel vapours from the fuel container (10). According to the invention, the venting device has at least one venting line (32; 38, 40; 50, 52) which runs in the interior of the fuel container (10) and opens with an open end into a gas volume in the region of an upper wall part of the fuel container (10), wherein the at least one venting line (32; 38, 40; 50, 52) is routed in such a way that it forms a siphon in the region of a lower wall part, and wherein the inlet check valve (34) has a bypass connector (68), to which the at least one venting line (32; 38, 40; 50, 52) is connected.