Fuel Tank Venting Layout With Fewer Valves and Lower Vapor Loading
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Solution Overview
Problem
Existing fuel tank venting systems for automotive vehicles are complex, expensive, and space-consuming, particularly due to the use of multiple valves like Roll-Over Valves and Fill Limit Vent Valves, which compromise tank capacity and increase emissions.
Innovation Solution
A simplified fuel tank venting system featuring a permanently open orifice in the vapor dome of the fuel tank, connected to a fuel vapor trap via an inlet conduit, and a normally closed shutter device with an electrically-actuated valve that opens during refueling and closes at predetermined fill levels, reducing the need for additional valves and increasing tank pressure to minimize vapor trap loading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple valves (Roll-Over Valve, Fill Limit Vent Valve) are used in the fuel tank system, then the fuel tank can achieve reliable vapor recovery and safety functions, but the system becomes expensive, complicated, and space-consuming
Solution Approach 1:
The patent extracts and eliminates unnecessary valves from the fuel tank system. Specifically, it removes the Fill Limit Vent Valve by implementing a different approach using the existing vent valve in combination with a control system that monitors tank fill level and activates the vapor recovery system accordingly. This extraction of redundant components directly reduces system complexity while maintaining the required safety and vapor recovery functions.
Solution Approach 2:
The patent makes the vent valve multi-functional by enabling it to serve both as a pressure relief valve and as a controlled vent during refueling operations. By integrating control logic that activates the vapor recovery system based on tank fill level detection, the vent valve performs multiple functions that previously required separate dedicated valves, thereby reducing overall system complexity.
2Reliability
If multiple valves are installed in the fuel tank system, then safety and vapor recovery functions are ensured, but the fuel tank capacity is reduced due to space occupied by valves
Solution Approach 1:
The patent removes the Fill Limit Vent Valve from the fuel tank system, directly increasing the available fuel storage volume. By using an alternative approach that relies on control logic and the existing vent valve, the system eliminates the need for additional valve components that would occupy space within the fuel tank, thereby maximizing fuel tank capacity while maintaining safety functions.
3Object-generated harmful factors
If a closed fuel tank system is used during normal operation, then CO2 emissions are reduced by minimizing fuel vapor trap loading, but the system requires precise control to prevent overpressure
Solution Approach 1:
The patent implements a feedback control system that monitors tank pressure and fill level, and automatically activates the vapor recovery system when needed. The control unit receives signals from pressure sensors and fill level detectors, and accordingly controls the vent valve and vapor recovery system to maintain safe operating conditions. This feedback mechanism enables the closed system to operate safely without requiring complex manual intervention or additional safety valves.
Solution Approach 2:
The system is designed to automatically manage its own pressure control through integrated sensors and control logic. The fill level detector and pressure monitor work together with the vapor recovery system to self-regulate tank pressure, eliminating the need for external intervention or additional complex control mechanisms. The system serves itself by detecting conditions and automatically activating appropriate responses.
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 reduces CO2 emissions by minimizing fuel vapor trap loading, increases fuel tank capacity by eliminating unnecessary valves, and simplifies the production and assembly process, making it cheaper and more space-efficient.
Implementation Method 1
a normally closed shutter device that communicates with the atmosphere and that is connected to the fuel vapor trap by an outlet conduit, the normally closed shutter device comprising an electrically-actuated valve being closed when the electrically-actuated valve is de-energized
Implementation Method 2
The entire fuel system is thus closed after refueling and during normal operation of the vehicle which contributes to the increase of the pressure in the fuel tank under the closed environment. It is known that the volatility of the fuel decreases when the pressure in the fuel tank increases.
Data Source
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AI summary
The invention relates to a fuel tank venting system (10) for an automotive vehicle comprising: - a fuel tank (1) comprising a vapor dome, - a refueling pipe (2), - a fuel vapor trap (3) that is connected to the fuel tank (1) by an inlet conduit (4), wherein the inlet conduit (4) is connected with the fuel tank (1) through at least one orifice (5) which is permanently open, the orifice being arranged in the vapor dome of the fuel tank (1) in a static condition and - a normally closed shutter device (CVS) (6) that communicates with the atmosphere and that is connected to the fuel vapor trap (3) by an outlet conduit (7), the normally closed shutter device (6) comprising an electrically-actuated valve being closed when the electrically-actuated valve is de-energized, wherein the normally closed shutter device (6) is configured to be open during vehicle refueling process and to be closed when the fuel in the fuel tank (1) reaches a predetermined fill level and when the vehicle is in normal operation.