Balancing Conduit for Pressurized Fuel Tanks

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Solution Overview

Problem

The use of multiple pressurized fuel tanks in vehicles leads to pressure imbalances due to temperature differences, causing uneven fuel distribution and inefficient pumping, as one tank may become over-filled while another is emptied, resulting in excessive energy expenditure and potential system inefficiencies.

Innovation Solution

The implementation of a pressurized liquid fuel system with symmetrical tank arrangements, liquid balancing conduits, and vapor balancing conduits to equalize pressure across multiple fuel tanks, ensuring balanced fuel distribution and efficient pumping by controlling pressure drops across return and feed lines, and using liquid and vapor balancing valves to manage pressure and flow.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If multiple pressurized fuel tanks are used to provide equivalent energy storage, then the energy capacity is improved, but pressure imbalance occurs due to temperature differences causing uneven fuel distribution

Engineering Contradiction:
Improvefuel energy capacityVSAvoidpressure balance
Core Design Contradiction:
Quantity of substanceVSStability of the object's composition

Solution Approach 1:

A balancing conduit is introduced as an intermediary element connecting the first and second fuel tanks. This conduit includes a balancing valve that mediates fuel flow between tanks, allowing pressure equalization while maintaining the benefit of multiple tanks for increased fuel capacity.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system incorporates pressure sensors in each fuel tank that provide feedback to a control unit. The control unit monitors pressure differences and automatically adjusts the balancing valve to maintain pressure equilibrium, creating a closed-loop control system that responds to actual tank conditions.

Inventive Principle:
Principle #23Feedback

2Quantity of substance

If multiple fuel tanks are used, then the fuel energy storage is improved, but fuel distribution becomes uneven with one tank over-filled and another emptied

Engineering Contradiction:
Improvefuel energy storageVSAvoidfuel level distribution
Core Design Contradiction:
Quantity of substanceVSManufacturing precision

Solution Approach 1:

The balancing conduit acts as an intermediary that automatically equalizes fuel levels between tanks. When one tank becomes over-filled and another emptied, the balancing valve opens to transfer fuel from the higher level tank to the lower level tank, maintaining uniform fuel distribution.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system changes the operational parameters of fuel transfer by using pressure differential as the driving force for balancing. The balancing valve responds to pressure differences caused by level imbalances, automatically adjusting fuel flow to maintain equal distribution without manual intervention.

Inventive Principle:
Principle #35Parameter changes

3Quantity of substance

If multiple fuel tanks are used, then the energy capacity is improved, but energy expenditure increases due to inefficient pumping against pressure imbalances

Engineering Contradiction:
Improvefuel energy capacityVSAvoidpumping energy
Core Design Contradiction:
Quantity of substanceVSUse of energy by moving object

Solution Approach 1:

The balancing conduit creates equipotential conditions between the two fuel tanks by equalizing their pressure levels. This eliminates pressure differentials that would otherwise cause inefficient pumping, as fuel can now be drawn from either tank without the pump working against significant pressure imbalances.

Inventive Principle:
Principle #12Equipotentiality

Solution Approach 2:

The balancing system is self-regulating, automatically equalizing pressure between tanks without requiring external energy input. The pressure differential itself drives the balancing process through the balancing valve, making the system self-service and eliminating the need for additional energy-consuming balancing mechanisms.

Inventive Principle:
Principle #25Self-service

4Quantity of substance

If larger tanks are used to accommodate DME fuel volume, then the energy equivalent storage is improved, but the tank volume and packaging space requirements increase

Engineering Contradiction:
ImproveDME fuel storageVSAvoidtank volume
Core Design Contradiction:
Quantity of substanceVSVolume of stationary object

Solution Approach 1:

The fuel storage system is segmented into multiple separate tanks rather than using a single large tank. This segmentation allows the fuel to be distributed across several smaller volume containers, achieving the same total energy capacity while improving packaging efficiency and reducing the volume of any single stationary object.

Inventive Principle:
Principle #1Segmentation

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 balanced fuel levels and pressures in multiple fuel tanks, preventing over-filling or over-emptying, optimizing fuel distribution, and reducing energy expenditure by maintaining equal pressure and flow rates across all tanks, thus enhancing the efficiency and reliability of the fuel system.

Implementation Method 1

pressure in the first fuel tank and the second fuel tank can be balanced by equalizing a pressure drop across a return line from a circulation system to each of the fuel tanks

Methodology Applied
Scientific EffectPressure gradient: Pressure Gradient

Implementation Method 2

pressure in the first fuel tank and the second fuel tank can be balanced by equalizing a pressure drop across a return line from a circulation system to each of the fuel tanks

Methodology Applied
Scientific EffectVapor pressure: Vapour Pressure

Data Source

PatentEP3334921B1Vehicle comprising an engine and a pressurized liquid fuel system and method for operating a vehicle comprising an engine and a pressurized liquid fuel system
Publication Date: 2021.05.26 VOLVO TRUCK CORP
  • EP3334921B1 patent drawingFigure 1
  • EP3334921B1 patent drawingFigure 2
  • EP3334921B1 patent drawingFigure 3

AI summary

A vehicle including a pressurized liquid fuel system includes a first pressurized liquid fuel tank arrangement, a second pressurized liquid feel tank arrangement, and a balancing conduit open to a first fuel tank and to a second fuel tank at least one of above a maximum liquid level of the first fuel tank and a maximum liquid level of the second fuel tank and below a minimum liquid level of the first fuel tank and a minimum liquid level of the second fuel tank. A first return line and a second return Sine to the first and second fuel tanks are configured such that a pressure drop across the first, return line from a pressurized liquid fuel circulation system to the first fuel tank is adapted to be the same as a pressure drop across the second return line from the pressurized liquid fuel circulation system to the second fuel tank. Methods for operating a pressurized liquid fuel system are also disclosed.