Hydrogen Fuel Tank Filling Control via Dynamic Flow Rate Adjustment

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Solution Overview

Problem

Filling fuel tanks with compressed hydrogen safely and efficiently over a reasonable time period is challenging due to the risk of overheating, as the gas heats up and increases pressure, limiting capacity and requiring multiple topping-off cycles.

Innovation Solution

A method and apparatus that measure instantaneous gas pressure, temperature, and ambient temperature to adjust the flow rate of the compressing means, controlling the mass flow rate to achieve a predetermined pressure rise rate, preventing overheating and ensuring safe, efficient filling of hydrogen fuel tanks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the tank is filled quickly with compressed hydrogen gas, then the filling time is reduced, but the gas temperature increases causing overheating and pressure buildup that prevents filling to capacity

Engineering Contradiction:
Improvefilling speedVSAvoidgas temperature
Core Design Contradiction:
ProductivityVSTemperature

Solution Approach 1:

The filling process dynamically adjusts the mass flow rate based on real-time temperature measurements. The controller continuously monitors gas temperature and modulates the compressor operation to maintain optimal filling speed while preventing overheating, transitioning from static to dynamic control

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the mass flow rate parameter during the filling process based on temperature conditions. By adjusting this critical parameter in response to temperature feedback, the system achieves both rapid filling and temperature control, resolving the contradiction between speed and heat generation

Inventive Principle:
Principle #35Parameter changes

2Productivity

If the mass flow rate is increased to reduce filling time, then productivity improves, but the gas heats up requiring multiple topping-off cycles

Engineering Contradiction:
Improvefilling timeVSAvoidtime for multiple filling cycles
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The system implements feedback control by continuously measuring gas temperature and using this information to adjust the mass flow rate. This closed-loop control prevents the need for multiple topping-off cycles by maintaining optimal filling conditions throughout the entire process, eliminating the time loss associated with repeated filling operations

Inventive Principle:
Principle #23Feedback

3Productivity

If the tank is filled to maximum working pressure quickly, then filling efficiency increases, but the increased pressure prevents the tank from being filled to capacity

Engineering Contradiction:
Improvefilling efficiencyVSAvoidgas capacity
Core Design Contradiction:
ProductivityVSQuantity of substance

Solution Approach 1:

The system performs preliminary cooling action by controlling the mass flow rate to prevent excessive temperature and pressure buildup in the first place. By anticipating the thermal effects of rapid compression, the system maintains lower pressures during filling, allowing the tank to be filled to full capacity in a single operation rather than requiring pressure reduction and subsequent topping-off

Inventive Principle:
Principle #10Preliminary action

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

Enables safe and efficient filling of hydrogen fuel tanks without overheating, allowing for complete filling in a shorter time frame compared to existing methods, by dynamically adjusting the flow rate based on real-time pressure and temperature measurements.

Implementation Method 1

a compressing means (20) having a variable mass flow rate and an inlet (18) and an outlet (26)

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 2

any charging of a tank with compressed gas will cause the gas within the tank to heat up, increasing its pressure, the volume being fixed

Methodology Applied
Scientific EffectAdiabatic heating: Adiabatic Heating

Data Source

PatentEP2093475B2Compressor fill method and apparatus
Publication Date: 2018.12.05 AIR PROD & CHEM INC
  • EP2093475B2 patent drawingFigure 1
  • EP2093475B2 patent drawingFigure 2
  • EP2093475B2 patent drawing

AI summary

A method an apparatus for filling a vessel with compressed gas is disclosed. Gas is compressed into the vessel at a predetermined flow rate using a variable speed pump or compressor. The flow rate is adjusted to increase the gas pressure at a predetermined rate of change. The flow rate is adjusted based upon the instantaneous value of a measured parameter such as gas temperature or pressure or ambient temperature. The parameter is measured by a transducer and the value is fed back to a controller which adjusts the speed of the compressor or pump to produce the flow rate needed to achieve the predetermined pressure rate of change.