Turbine Engine Oil Pump Control for Fire-Sustained Lubrication

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Solution Overview

Problem

Current oil systems for turbomachines are oversized to maintain oil supply during engine shutdowns, such as in the event of a fire, leading to increased mass, size, and cost, and fail to efficiently control oil flow according to the turbomachine's needs.

Innovation Solution

An oil system featuring a speed-controllable electrical drive pump and an electronic control unit with two distinct control logics, allowing the pump to decouple from engine speed and maintain sufficient oil flow during fires, and automatically stop the pump in case of a leak, reducing the need for thermal shields.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the oil system pumps are oversized to ensure sufficient flow during autorotation, then the oil supply reliability is improved, but the mass, size and cost of the oil system increase

Engineering Contradiction:
Improveoil supply reliabilityVSAvoidmass of oil system
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The patent applies dynamics by replacing the mechanically driven pump with an electrically driven pump whose speed can be dynamically adjusted. The electronic control unit modulates the pump speed according to real-time operational conditions, allowing the system to maintain adequate oil flow during autorotation without requiring an oversized pump. This dynamic control resolves the contradiction by enabling reliable oil supply with a properly sized pump.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the operating parameters of the pump by controlling its rotational speed through electronic means rather than mechanical coupling. The electronic control unit adjusts the pump speed parameter based on engine conditions, allowing the pump to deliver sufficient flow during autorotation without being permanently oversized. This parameter control resolves the contradiction between reliability and mass.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the oil system pumps are oversized to ensure sufficient flow during autorotation, then the oil supply reliability is improved, but the size and cost of the oil system increase

Engineering Contradiction:
Improveoil supply reliabilityVSAvoidsize and cost of oil system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical drive system (pump mechanically coupled to the engine) with an electrical drive system. The electrically driven pump is controlled by an electronic control unit that receives signals from sensors monitoring engine conditions. This substitution allows for precise control of oil flow without the complexity of oversized mechanical components, resolving the contradiction between reliability and device complexity.

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

3Object-affected harmful factors

If thermal blankets or shields are added to limit thermal radiation effects, then the protection of equipment is improved, but the mass, size and cost of the oil system increase

Engineering Contradiction:
Improvethermal radiation protectionVSAvoidmass of oil system
Core Design Contradiction:
Object-affected harmful factorsVSWeight of moving object

Solution Approach 1:

The patent converts the harmful effect of fire/overheating into a beneficial control signal. The fire detector senses thermal radiation and converts it into an electrical signal that triggers the electronic control unit to increase pump speed. This transforms the harmful thermal radiation into useful information that enables the system to respond appropriately, eliminating the need for passive thermal protection and reducing mass.

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

Solution Approach 2:

The patent implements a feedback control system where the fire detector continuously monitors thermal conditions and feeds this information to the electronic control unit. The control unit adjusts the pump speed in real-time based on the detected thermal radiation level. This active feedback mechanism replaces passive thermal protection, allowing the system to respond dynamically to thermal threats without adding mass through shields or blankets.

Inventive Principle:
Principle #23Feedback

4Device complexity

If the pump speed is coupled to turbomachine speed, then the system simplicity is improved, but the ability to maintain oil flow during shutdown is reduced

Engineering Contradiction:
Improvesystem simplicityVSAvoidoil supply capability during shutdown
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent replaces the direct mechanical coupling between the pump and turbomachine with an electrical drive system. The electrically driven pump is controlled by an electronic control unit that can independently regulate pump speed based on operational conditions. This substitution breaks the mechanical link while maintaining system functionality, allowing the pump to operate independently during shutdown and preserving oil supply capability.

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

Data Source

PatentEP3966434B1Oil system for a turbine engine
Publication Date: 2024.06.19 SAFRAN AIRCRAFT ENGINES SAS
  • EP3966434B1 patent drawingFigure 1~2
  • EP3966434B1 patent drawingFigure 3

AI summary

Oil system for a turbine engine, enabling oil to continue to be supplied to the devices of the turbine engine in the event of a fire within the turbine engine, the oil system comprising an oil circuit (2), at least one oil-consuming device (3a, 3b, 3c) which is supplied by the oil circuit (2), a pumping unit, comprising at least one speed-controllable electrically driven pump (22, 4) which supplies the oil circuit (2), and an electronic control unit (6) configured to control the electrically driven pump (22, 4), wherein the electronic control unit (6) comprises two separate logics for controlling the electrically driven pump (22, 4), and wherein the electronic control unit (6) is configured to control the electrically driven pump (22, 4) according to the first logic by default and to switch to the second logic if a signal that is representative of the presence of a fire or of overheating is received.