Cryogenic Fuel Delivery Using Phase-Change Pressure Pumping

Solution Overview

Problem

Mechanical pumps are unreliable for handling cryogenic fuels like liquid hydrogen due to low temperatures, and storing gaseous hydrogen at high pressure requires large and heavy vessels, while liquid hydrogen at low pressure is insufficient for engine fuel delivery.

Innovation Solution

A liquid delivery system utilizing a source tank, transition tank, and pumping tank with valves and heat exchangers to convert liquid hydrogen to a pressurized gaseous state without mechanical pumps, using pressure differentials and heat to achieve high-pressure delivery.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stress or pressure

If gaseous hydrogen is stored at high pressure (200 bar) to enable engine fuel delivery, then the fuel can be routed to the engine, but large and heavy pressure vessels are required

Engineering Contradiction:

Improvehydrogen pressureVSAvoidpressure vessel weight

Core Design Contradiction:

Stress or pressureVSWeight of stationary object

Solution Approach 1:

The system changes the physical state of hydrogen from gaseous to liquid form, allowing storage at low pressure (2 bar) instead of high pressure (200 bar). This parameter change from gas to liquid phase enables the same mass of hydrogen to be stored in a much smaller and lighter tank while still providing sufficient fuel for engine operation.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention replaces mechanical pumps with a thermal field-based system. Instead of using mechanical pumping equipment to pressurize and deliver liquid hydrogen, the system uses controlled heating to vaporize liquid hydrogen and generate pressure differentials that drive fuel delivery through the engine, eliminating the need for heavy mechanical pumping components.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Weight of stationary object

If liquid hydrogen is stored at low pressure (2 bar) for easier storage, then storage is more feasible, but the pressure is insufficient to route liquid hydrogen into the engine

Engineering Contradiction:

Improvestorage tank weightVSAvoidfuel delivery pressure

Core Design Contradiction:

Weight of stationary objectVSStress or pressure

Solution Approach 1:

The system utilizes phase transition of hydrogen from liquid to gaseous state to generate the necessary pressure for fuel delivery. By controlling the vaporization process through heating, the system creates pressure differentials that automatically drive liquid hydrogen from the storage tank through the fuel delivery system to the engine without requiring mechanical pumps.

Inventive Principle:

Principle #36Phase transitions

Solution Approach 2:

The invention replaces mechanical pumps with a thermal field-based system. Instead of using mechanical pumping equipment to pressurize and deliver liquid hydrogen, the system uses controlled heating to vaporize liquid hydrogen and generate pressure differentials that drive fuel delivery through the engine, eliminating the need for heavy mechanical pumping components.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Stress or pressure

If mechanical pumps are used to pump liquid hydrogen, then fuel delivery pressure can be achieved, but the pumps are unreliable at cryogenic temperatures (20 Kelvin)

Engineering Contradiction:

Improvefuel delivery pressureVSAvoidpump reliability

Core Design Contradiction:

Stress or pressureVSReliability

Solution Approach 1:

The invention replaces mechanical pumps with a thermal field-based system. Instead of using mechanical pumping equipment to pressurize and deliver liquid hydrogen, the system uses controlled heating to vaporize liquid hydrogen and generate pressure differentials that drive fuel delivery through the engine, eliminating the need for heavy mechanical pumping components.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system uses the inherent physical properties of liquid hydrogen and controlled thermal input to self-generate the pressure needed for fuel delivery. The vaporization process naturally creates pressure differentials that drive fuel flow without requiring external mechanical pumping, making the system self-regulating and eliminating mechanical failure points.

Inventive Principle:

Principle #25Self-service

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 efficient and reliable delivery of liquid hydrogen to engines without mechanical pumps, reducing emissions and system weight, and maintaining consistent fuel supply.

Implementation Method 1

The transition tank may heat the cryogenic liquid to convert it to a pressurized gaseous state

Methodology Applied

Scientific EffectPhase change (liquid to gas): Phase Change

Implementation Method 2

The transition tank heats the liquid hydrogen using ambient air flow, combustion, or a heating element

Methodology Applied

Scientific EffectHeating: Heating

Implementation Method 3

The pressurized gas from the transition tank is routed to the pumping tank to exert pressure on the cryogenic liquid therein. The pressurized gas pushes the cryogenic liquid in the pumping tank through an outlet and towards the engine at the higher pressure

Methodology Applied

Scientific EffectPressure differential: Pressure Gradient

Data Source

PatentUS20260078875A1Liquid delivery system

Publication Date: 2026.03.19 EATON INTELLIGENT POWER LTD

AI summary

A liquid delivery system is configured to pump a liquid (e.g., a cryogenic liquid) without a mechanical pump. The system includes a storage tank to store the liquid at low pressure; a transition tank configured to transition the low pressure liquid to a high pressure gas; and a pumping tank configured to first receive part of the low pressure liquid from the source tank and then to receive the pressurized gas from the transition tank to expel the low pressure liquid from the pumping tank. The liquid delivery system can be used to deliver fuel to an engine (e.g., on an aircraft).