Fuel Tank Liquid Trap Emptying via Natural Negative Pressure
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Solution Overview
Problem
Existing fuel tank venting systems rely on suction jet pumps to empty liquid traps, which are energy-intensive, complex, and inefficient during pressure regulation, and do not effectively prevent fuel leakage.
Innovation Solution
The system utilizes natural pressure drops in the fuel tank, such as those caused by temperature changes or fuel consumption, to create a negative pressure difference between the gas space and the liquid trap, allowing liquid fuel to be sucked out through a suction line without the need for a suction jet pump, and includes a tank shut-off valve to enhance emptying when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a suction jet pump is used to empty the liquid trap, then the liquid fuel can be removed from the collection chamber, but the system becomes energy-intensive, complex, and prone to fuel leakage
Solution Approach 1:
The invention extracts the problematic suction jet pump from the system and replaces it with a passive suction line that utilizes natural pressure differences. The suction line is simply connected to the collection chamber, allowing liquid fuel to be removed without complex pumping equipment, thereby eliminating the associated complexity and energy consumption issues.
Solution Approach 2:
The liquid trap emptying process becomes self-service by utilizing the natural negative pressure that develops in the fuel tank during normal operation. The system automatically empties the collection chamber when pressure conditions are favorable, without requiring external energy input or complex control mechanisms, thus simplifying the overall system design.
2Productivity
If a suction jet pump is used to empty the liquid trap, then fuel can be removed, but permanent energy consumption increases
Solution Approach 1:
The system uses the natural pressure differences that occur during normal fuel tank operation to drive the emptying process. The negative pressure developed during fuel consumption or temperature changes is harnessed to remove liquid fuel from the collection chamber, eliminating the need for continuous energy input from a suction jet pump.
Solution Approach 2:
The invention converts the naturally occurring negative pressure in the fuel tank, which would otherwise be wasted, into a useful force for emptying the liquid trap. This transforms a passive pressure condition into an active emptying mechanism, reducing energy consumption while maintaining effective liquid fuel removal.
3Productivity
If a suction jet pump is used to empty the liquid trap, then fuel removal can be achieved, but the design becomes complex to prevent leakage
Solution Approach 1:
The invention removes the suction jet pump and its associated complex sealing and control systems from the design. By using a simple suction line that opens directly into the collection chamber, the system eliminates the sources of potential fuel leakage while maintaining effective emptying capability through passive pressure-driven flow.
Solution Approach 2:
Instead of using a pump to push fuel out under pressure (which requires complex sealing), the system inverts the approach by allowing negative pressure to pull fuel out through an open line. This reversal of the pressure application method simplifies the design and reduces leakage risks by eliminating the need for sealed moving parts and complex valve mechanisms.
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 method allows for efficient and energy-saving emptying of the liquid trap without complex equipment, using natural pressure variations to facilitate fuel removal and preventing fuel leakage, while also serving as a vent line during refueling.
Implementation Method 1
a negative pressure generated in a gas or head space (5) of the fuel tank (1) is applied to the liquid trap (7) through a suction line (10) and the liquid fuel in the collection chamber (9) is sucked out through the suction line (10) into the gas or head space (5)
Data Source
Figure 1~2
Figure 3~4
Figure 5a~5b
AI summary
The invention relates to a method for extracting liquid fuel from a liquid trap (7) in a fuel tank (1) of a motor vehicle, in which liquid fuel is separated during venting of the fuel tank (1) and collected in a collection chamber (9). The invention further relates to a fuel system for a motor vehicle with such a liquid trap (7). In order to enable the liquid trap (7) to be emptied using simple means without a suction jet pump, the invention proposes that a negative pressure generated in a gas or headspace of the fuel tank (1) be applied to the liquid trap (7) via a suction line (10), and that the liquid fuel located in the collection chamber (9) be at least partially extracted through the suction line (10) into the gas or headspace (5).that the gas or headspace (5) of the fuel tank (1) is connected to the liquid trap (7) by means of a suction line (10) communicating with the collection space (9).