Multichamber Fuel Tank Level Equalization Pump Control
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Solution Overview
Problem
Multichamber fuel tanks in rear-wheel drive motor vehicles face challenges in level equalization during filling, as existing solutions either require multiple feed pump units or a sucking jet pump, which are inadequate for maintaining equal liquid flow rates between chambers, especially when the liquid level in one chamber is high, causing inefficiencies and installation difficulties.
Innovation Solution
A pump designed for level equalization, driven by an electric motor and controlled by level sensors in each chamber, is used to maintain equal filling speeds between the two chambers, allowing for a larger connecting line cross section and efficient delivery flow, with the pump only operating during filling and starting when the liquid level reaches specific thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a small cross section connecting line is used to maintain liquid level, then the siphon effect can equalize levels between chambers, but the level equalization cannot keep up with the liquid flow rate from the gas pump nozzle during filling-up
Solution Approach 1:
The patent changes the key parameter of the connecting line from a small cross-section (for siphon effect) to a large cross-section (for high flow rate). This parameter change allows the connecting line to handle liquid flow rates that match the gas pump nozzle capacity, enabling both reliable level equalization and high productivity during filling-up.
2Productivity
If a large cross section connecting line is used to increase filling speed, then level equalization can keep up with gas pump nozzle flow rate, but the siphon effect cannot be maintained and external liquid level control is required
Solution Approach 1:
The patent replaces the mechanical siphon effect system with an electrically controlled pump system. The pump can be precisely controlled by the control unit based on liquid level sensor signals, providing reliable automatic level equalization without depending on the siphon effect, which requires specific pressure and cross-section conditions.
Solution Approach 2:
The patent implements a feedback control system where liquid level sensors detect the liquid levels in both chambers and send signals to the control unit. The control unit adjusts the pump operation based on this feedback, ensuring automatic and precise level equalization during filling-up, regardless of the connecting line's large cross-section.
3Ease of operation
If multiple feed pump units are installed in each chamber, then fuel can be drawn and delivered to the engine, but the device complexity and cost increase significantly
Solution Approach 1:
The patent makes the pump unit multi-functional by equipping it with both a feed pump function (for fuel delivery to the engine) and a level equalization function (for balancing liquid levels during filling-up). The control unit manages these different functions based on operational conditions, reducing the total number of pump units needed while maintaining full functionality.
4Reliability
If a sucking jet pump is used in one chamber to keep the connecting line filled with liquid, then level equalization is maintained, but the sucking jet pump must be fed from the fuel pump which complicates the fuel pump design
Solution Approach 1:
The patent extracts the level equalization function from the fuel pump system by using a separate, dedicated pump unit. This separate pump is specifically responsible for maintaining liquid levels and filling the connecting line, while the fuel pump focuses solely on fuel delivery to the engine. This separation simplifies the fuel pump design and eliminates the complexity of integrating level control functions into it.
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 solution ensures both chambers are filled at approximately the same speed during filling, improving the efficiency of fuel tank filling processes and reducing installation complexities by utilizing a turbopump with a large mass flow and small delivery head, ensuring the pump operates effectively without drawing fuel.
Implementation Method 1
a pump designed for level equalization during filling-up and driven by an electric motor is provided in the line
Implementation Method 2
a level sensor is provided in each of the two chambers, the output signals of which sensors are available to a control unit
Data Source
AI summary
A multichamber tank for motor vehicles comprises two chambers (4, 5) connected via a constricted region (6) located high up in the chambers, a first chamber (4) having a filler neck (2), and a line (13) bridging the constriction forming the connection to a second chamber (5). In order that both chambers are filled at approximately the same speed during filling-up through the filler neck (2), a pump (11) designed for level equalization during filling-up and driven by an electric motor (12) is provided in the line (13), and a level sensor (17, 18) is provided in each of the two chambers (4, 5), the output signals of which sensors are available to a control unit (14) which controls the electric motor (12) of the pump (11).