Heated-Wire Thermal Coking Sensor for Fuel Heat Control

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Solution Overview

Problem

Existing gas turbine engines face limitations in utilizing fuel as a heat sink due to the risk of thermal coking, which occurs when fuel temperatures exceed 400°F, restricting the amount of heat that can be added to the fuel, thereby limiting engine efficiency improvements.

Innovation Solution

A thermal coking sensor using two heated wires measures real-time fuel temperature to determine the onset of coking, allowing the system to actively control fuel temperature by adjusting the heat transfer from heated oil to fuel, preventing coking and optimizing heat utilization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If fuel is used as a heat sink to remove heat from system components, then heat transfer capability is improved, but fuel temperature increases causing thermal coking

Engineering Contradiction:
Improveheat transfer capabilityVSAvoidthermal coking
Core Design Contradiction:
Loss of energyVSObject-affected harmful factors

Solution Approach 1:

The fuel temperature monitoring system continuously measures fuel temperature before it reaches coking conditions, enabling preemptive control actions. The system detects temperature trends and activates cooling measures before thermal coking occurs, preventing the harmful effect rather than responding after damage is done.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements closed-loop feedback control by continuously monitoring fuel temperature and adjusting heat transfer operations accordingly. When fuel temperature approaches the coking threshold, the system automatically reduces heat transfer intensity or activates cooling mechanisms, creating a self-regulating system that prevents thermal coking while maximizing heat utilization.

Inventive Principle:
Principle #23Feedback

2Reliability

If fuel temperature is limited to prevent coking, then fuel temperature is controlled, but heat sink potential is reduced

Engineering Contradiction:
Improvefuel temperature controlVSAvoidheat sink potential
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The system dynamically adjusts fuel temperature management based on real-time operating conditions. Rather than applying a static temperature limit, the system continuously adapts heat transfer rates, cooling intensity, and fuel flow management to maximize heat sink potential while maintaining fuel temperature below coking thresholds. This dynamic approach allows optimal heat utilization across varying engine loads and environmental conditions.

Inventive Principle:
Principle #15Dynamics

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 real-time control of fuel temperature to prevent coking, maximizing heat sink potential and fuel burn efficiency, particularly with Sustainable Aviation Fuels, enhancing engine performance and reducing emissions.

Implementation Method 1

a fuel/oil cooler that is in fluid communication with the fuel delivery subsystem to receive the fuel and is in fluid communication with the oil cooling subsystem to receive the heated oil, the fuel/oil cooler configured to transfer heat from the heated oil to the fuel

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 2

A thermal coking sensor is in fluid communication with the fuel and is configured to generate a signal in response to interacting with the fuel. A controller is configured to determine a coking temperature indicating an onset of coking in the fuel based on the signal

Methodology Applied
Scientific EffectHeat loss measurement: Joule Heating

Data Source

PatentEP4632205A1Real-time thermal coking sensor
Publication Date: 2025.10.15 RTX CORP
  • EP4632205A1 patent drawingFigure 1
  • EP4632205A1 patent drawingFigure 2
  • EP4632205A1 patent drawingFigure 3

AI summary

A gas turbine engine fuel system (100) includes a fuel delivery system (102), an oil cooling subsystem (120), and a fuel conditioning subsystem (110). The fuel delivery subsystem (102) delivers fuel (105) to a gas turbine engine (20), and the oil cooling subsystem (120) receives heated oil (121) from the gas turbine engine (20). The fuel conditioning subsystem (110) includes a fuel/oil cooler (112) that is in fluid communication with the fuel delivery subsystem (102) to receive the fuel (105) and is in fluid communication with the oil cooling subsystem (120) to receive the heated oil (121), the fuel/oil cooler (112) configured to transfer heat from the heated oil (121) to the fuel (105). A thermal coking sensor (150) is in fluid communication with the fuel (105) and is configured to generate a signal in response to interacting with the fuel (105). A controller (148) is configured to determine a coking temperature indicating an onset of coking in the fuel (105) based on the signal.