Fuel Tank Vent Valve With Flow Reducer for Leak-Limiting Venting

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Solution Overview

Problem

Existing vent valves for motorcycle tanks fail to prevent excessive fuel leakage during steep descents, sudden braking, or sharp turns, leading to fuel spills either into a canister or directly on the road, especially when the vehicle is not equipped with a canister.

Innovation Solution

A vent valve with a piston and pendulum mechanism, featuring an asymmetrical cam profile and a flow reducer, which limits fuel leakage by adjusting the pendulum's oscillation angle based on vehicle orientation and includes a pressure control device to manage overpressure, ensuring efficient ventilation while preventing fuel loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a vent valve with pendulum mechanism is provided to prevent fuel leakage during overturning, then safety during vehicle inclination is improved, but fuel leakage during steep descents and sudden braking remains excessive

Engineering Contradiction:

Improvesafety during vehicle inclinationVSAvoidfuel leakage during steep descents

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The vent valve is divided into two independent valve systems: a first valve (pendulum mechanism) that responds to vehicle inclination and a second valve (spring mechanism) that responds to pressure changes. Each valve handles specific conditions separately, allowing the first valve to prevent leakage during overturning while the second valve prevents excessive fuel leakage during steep descents and sudden braking through pressure-sensitive operation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The second valve employs a spring mechanism that dynamically responds to pressure changes within the tank. The spring force adjusts automatically based on internal pressure conditions, enabling the valve to open or close in response to steep descents, sudden braking, or acceleration without requiring external control systems.

Inventive Principle:

Principle #15Dynamics

2Productivity

If the vent valve opens to allow ventilation during normal operation, then tank oxygenation is maintained, but fuel can leak into the canister or on the road during aggressive driving

Engineering Contradiction:

Improvetank ventilation efficiencyVSAvoidfuel spill on road

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The second valve is pre-configured with a spring mechanism that applies closing force before pressure buildup occurs. During steep descents or sudden braking, the increasing internal pressure automatically overcomes the spring force and opens the second valve to release excess fuel vapor and liquid, preventing fuel from being forced out through the first valve or leaking into the canister.

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The spring mechanism acts as an intermediary between the tank's internal pressure and the second valve's opening/closing action. The spring translates pressure changes into mechanical movement of the valve, providing a passive yet effective control mechanism that responds to aggressive driving conditions without requiring electronic sensors or active control systems.

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

Significantly reduces fuel leakage during aggressive driving conditions and maintains efficient ventilation, preventing fuel spills and ensuring proper tank oxygenation.

Implementation Method 1

a vent valve with piston and pendulum mechanism, featuring an asymmetrical cam profile and a flow reducer, which limits fuel leakage by adjusting the pendulum's oscillation angle based on vehicle orientation

Methodology Applied

Scientific EffectGravitation: Gravitation

Implementation Method 2

Methodology Applied

Scientific EffectInertia: Inertia

Implementation Method 3

it is also known to provide a second valve, normally closed, which includes a spring pressing on a spherical cap, which opens in the event of overpressure

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 4

a flow reducer, which limits fuel leakage by adjusting the pendulum's oscillation angle based on vehicle orientation and includes a pressure control device to manage overpressure

Methodology Applied

Scientific EffectFlow resistance:

Data Source

PatentEP4091852B1New cap with valve system provided with flow reducer

Publication Date: 2023.12.27 CEV LAB S R L

Figure 1~2
Figure 3~4

AI summary

A fluid vent valve (1) for a fuel tank, comprising: a valve body (10) having an inlet opening connected or connectable to a tank, an outlet opening and a main chamber (13) interposed between said inlet opening and said outlet opening (12); a piston (20) inserted or insertable in the main chamber (13) and movable therein so as to define a closed configuration and an open configuration; a pendulum (30) hinged to the valve body (10) and coupled to the piston (20) so as to promote a movement of the piston (20) between the two configurations; a flow reducer (40) operatively interposed between the outlet opening (12) and the piston (20).