Fuel System Vapour Trail Detection Sensor

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Solution Overview

Problem

Existing methods to suppress vapour trail formation from aircraft and ship engines incur weight, fuel-burn, or environmental penalties, and are not effective in optimizing the use of more expensive biofuels, which are needed to reduce climate-warming impacts.

Innovation Solution

A fuel system with a vapour trail detection sensor and control unit that selectively blends conventional and biofuels to achieve a desired soot emission index, reducing vapour trail optical depth and climate warming impact, while minimizing weight and power requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If heat exchanger and condenser arrangement are used to suppress vapour trail formation, then vapour trail formation is reduced, but significant weight is introduced into the engine

Engineering Contradiction:
Improvevapour trail formationVSAvoidengine weight
Core Design Contradiction:
Object-affected harmful factorsVSWeight of moving object

Solution Approach 1:

The harmful function of the exhaust system (vapour trail formation) is extracted and addressed separately from the main engine through a dedicated exhaust gas treatment system. The heat exchanger and condenser are integrated into the exhaust pathway rather than the core engine, allowing weight to be added only where necessary for vapour trail suppression without compromising engine performance.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The exhaust gas treatment system operates dynamically based on flight conditions. The heat exchanger and condenser are activated only when vapour trail suppression is required, rather than being continuously operational, thereby reducing the effective weight penalty during portions of flight when contrail suppression is not needed.

Inventive Principle:
Principle #15Dynamics

2Object-affected harmful factors

If directed electromagnetic energy is used to suppress vapour trail formation, then vapour trail formation is reduced, but weight penalty and significant fuel-burn penalty are incurred

Engineering Contradiction:
Improvevapour trail formationVSAvoidfuel burn
Core Design Contradiction:
Object-affected harmful factorsVSUse of energy by moving object

Solution Approach 1:

The patent replaces electromagnetic energy systems with a thermodynamic approach using heat exchangers and condensers. This mechanical/thermal system achieves vapour trail suppression through phase change and heat transfer rather than electromagnetic radiation, resulting in lower energy consumption and reduced fuel burn penalty.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Object-affected harmful factors

If ultrasound is directed into the engine exhaust plume to suppress vapour trail formation, then vapour trail formation is reduced, but material weight penalty is incurred

Engineering Contradiction:
Improvevapour trail formationVSAvoidequipment weight
Core Design Contradiction:
Object-affected harmful factorsVSWeight of moving object

Solution Approach 1:

The ultrasound generation equipment and its associated weight are extracted from the aircraft system and replaced with a passive thermal management system using heat exchangers and condensers. This eliminates the need for heavy active ultrasound generation equipment while achieving the same vapour trail suppression effect through thermodynamic processes.

Inventive Principle:
Principle #2Taking out (Extraction)

4Object-affected harmful factors

If chemicals are injected into the engine or exhaust plume to modify vapour trails, then vapour trail formation is suppressed, but additional pollution and weight penalty are incurred

Engineering Contradiction:
Improvevapour trail formationVSAvoidadditional pollution
Core Design Contradiction:
Object-affected harmful factorsVSObject-generated harmful factors

Solution Approach 1:

The system converts the naturally occurring exhaust water vapour, which causes vapour trails, into a beneficial effect by condensing it into liquid form. This phase change process removes the harmful vapour trail formation without introducing additional pollutants, as the water is simply changed from gas to liquid phase and condensed out of the exhaust plume.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

5Object-affected harmful factors

If black carbon is introduced into the aircraft engine effluent to hide vapour trails, then vapour trail visibility is reduced, but additional environmental warming impact is created

Engineering Contradiction:
Improvevapour trail visibilityVSAvoidenvironmental warming impact
Core Design Contradiction:
Object-affected harmful factorsVSObject-generated harmful factors

Solution Approach 1:

Instead of adding black carbon particles to hide vapour trails (which increases warming impact), the system inverts the approach by condensing and removing water vapour itself. This eliminates the vapour trail through phase change rather than obscuration, achieving the same visibility reduction without the harmful environmental side effects of black carbon emissions.

Inventive Principle:
Principle #13The other way round (Inversion)

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

The system effectively controls vapour trail optical depth, reducing climate warming impact and optimizing biofuel use, with minimal weight and power penalties, allowing aircraft to maintain optimal flight trajectories and reduce environmental impact.

Implementation Method 1

a vapour trail detection sensor configured to generate a first signal which indicates an optical depth of a vapour trail

Methodology Applied
Scientific EffectOptical depth detection: Absorption (EM radiation)

Implementation Method 2

products of combustion from at least one engine of the aircraft

Methodology Applied
Scientific EffectCombustion: Combustion

Implementation Method 3

arise from the precipitation of microscopic water droplets or, if the air is cold enough, tiny ice crystals

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 4

an aircraft vapour trail, once formed, will persist in ambient air which is supersaturated with respect to ice

Methodology Applied
Scientific EffectPhase change: Phase Change

Data Source

PatentEP2685280B1Fuel system
Publication Date: 2019.07.10 ROLLS ROYCE PLC
  • EP2685280B1 patent drawingFigure 1
  • EP2685280B1 patent drawingFigure 2
  • EP2685280B1 patent drawingFigure 3

AI summary

A fuel system (12) comprising a vapour trail detection sensor (20) configured to generate a first signal (28) which indicates the optical depth of a vapour trail (35). A control unit (40) is provided responsive to the first signal (28) and configured to generate a second signal (80) in dependence upon the first signal (28). The second signal (80) defines a percentage of at least one of a first fuel composition and second fuel composition required to produce a resultant fuel composition. At least one regulator (42) is provided configured to receive and be responsive to the second signal (80) and regulate the percentage of first and second fuel composition required to produce the resultant fuel composition.