Dual-Fuel Engine Control for Temperature-Limited Low-Carbon Operation

Solution Overview

Problem

Hydrogen and ammonia, due to their low effective specific energies, are not suitable for medium or long-range journeys in vehicles like aircraft, as they require excessive fuel mass flow and storage challenges, limiting their practicality.

Innovation Solution

A method and system that control the relative fractions of two fuel types (hydrocarbon and non-hydrocarbon fuels) to maintain engine temperature within thresholds, adjusting fuel flow rates based on temperature, power demand, and other factors to optimize engine performance and efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-generated harmful factors

If hydrogen or ammonia is used as fuel in gas turbine engines, then carbon dioxide emissions are reduced, but the effective specific energy is low requiring heavy storage tanks and excessive fuel mass flow

Engineering Contradiction:

Improvecarbon dioxide emissionsVSAvoideffective specific energy

Core Design Contradiction:

Object-generated harmful factorsVSUse of energy by moving object

Solution Approach 1:

The patent combines hydrogen or ammonia fuel with hydrocarbon fuel (kerosene or methane) in a dual-fuel gas turbine engine. This merging allows the engine to benefit from the low carbon dioxide emissions of hydrogen/ammonia while compensating for their low effective specific energy through the higher energy density of hydrocarbon fuels, achieving a balanced performance for medium and long-range journeys

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent changes the fuel composition parameter by using variable ratios of hydrogen/ammonia to hydrocarbon fuels. The control system adjusts the proportion of each fuel type based on operational requirements, allowing optimization of both emissions and effective specific energy for different flight conditions and ranges

Inventive Principle:

Principle #35Parameter changes

2Object-generated harmful factors

If hydrogen or ammonia is used as fuel, then carbon dioxide emissions are reduced, but storage requirements increase due to heavy tanks and thermal insulation needs

Engineering Contradiction:

Improvecarbon dioxide emissionsVSAvoidstorage tank requirements

Core Design Contradiction:

Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The patent combines hydrogen or ammonia fuel with hydrocarbon fuel (kerosene or methane) in a dual-fuel gas turbine engine. This merging allows the engine to benefit from the low carbon dioxide emissions of hydrogen/ammonia while compensating for their low effective specific energy through the higher energy density of hydrocarbon fuels, achieving a balanced performance for medium and long-range journeys

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent changes the fuel composition parameter by using variable ratios of hydrogen/ammonia to hydrocarbon fuels. The control system adjusts the proportion of each fuel type based on operational requirements, allowing optimization of both emissions and effective specific energy for different flight conditions and ranges

Inventive Principle:

Principle #35Parameter changes

3Ease of operation

If ammonia is used as fuel, then storage is easier than hydrogen, but the specific energy is lower requiring greater fuel mass flow

Engineering Contradiction:

Improvestorage easeVSAvoidspecific energy

Core Design Contradiction:

Ease of operationVSUse of energy by moving object

Solution Approach 1:

The patent combines hydrogen or ammonia fuel with hydrocarbon fuel (kerosene or methane) in a dual-fuel gas turbine engine. This merging allows the engine to benefit from the low carbon dioxide emissions of hydrogen/ammonia while compensating for their low effective specific energy through the higher energy density of hydrocarbon fuels, achieving a balanced performance for medium and long-range journeys

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent changes the fuel composition parameter by using variable ratios of hydrogen/ammonia to hydrocarbon fuels. The control system adjusts the proportion of each fuel type based on operational requirements, allowing optimization of both emissions and effective specific energy for different flight conditions and ranges

Inventive Principle:

Principle #35Parameter changes

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 approach enhances engine efficiency and temperature management, allowing for extended range and reduced weight, while minimizing the need for thermal insulation and high-pressure containment.

Implementation Method 1

mechanical power is generated by combustion or oxidation of a fuel in an engine

Methodology Applied

Scientific EffectCombustion: Combustion

Implementation Method 2

a portion of the air flow may be removed prior to combustion or oxidation, to provide cooling air for cooling parts of the engine

Methodology Applied

Scientific EffectConvection: Convection

Data Source

PatentUS12601303B2Engine system and method of operating the same

Publication Date: 2026.04.14 ROLLS ROYCE PLC

AI summary

An engine system comprises a first fuel store, a second fuel store, an engine arranged to produce mechanical power by combustion or oxidation of a fuel in an engine, a fuel distribution system arranged to deliver fuel from the first and second fuel stores to the engine, the first fuel delivered at a first mass flow rate, the second fuel delivered at a second mass flow rate, the first and second mass flow rates contributing to a total mass flow rate of fuel to the engine; and a control system arranged to control the relative fractions of the total mass flow rate of fuel to the engine represented by the first mass flow rate and the second mass flow rate, based on an engine temperature.