Aircraft Engine Lubrication Circuit With Variable-Section Jet Pump

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Solution Overview

Problem

The existing lubrication systems for aeronautical engines and reduction gearboxes are complex and cumbersome, making it difficult to precisely meter and distribute lubricating oil effectively, leading to inefficient lubrication.

Innovation Solution

A system with a jet pump of variable section is introduced between the first and second supply pumps, allowing for modulation of the suction flow and recovery of hydraulic energy, with an electronic control unit to calculate and control oil flow rates to ensure precise lubrication needs are met.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a four-way valve is used to distribute oil to the aeronautical engine and reduction gearbox, then oil flow can be regulated to different enclosures, but the system becomes complex and cumbersome

Engineering Contradiction:
Improveoil flow distributionVSAvoidsystem complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent extracts the complex four-way valve distribution system and replaces it with two independent supply pumps, each dedicated to a specific lubrication circuit. This eliminates the need for complex valve mechanisms while maintaining the ability to regulate oil flow to different enclosures independently.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The lubrication system is segmented into two independent circuits with separate supply pumps (first supply pump for reduction gearbox, second supply pump for aeronautical engine). Each pump can be controlled independently, simplifying the overall system architecture while maintaining adaptability.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If separate lubrication circuits are implemented for the reduction gearbox and aeronautical engine, then each can be lubricated independently, but the system becomes more complex

Engineering Contradiction:
Improveindependent lubricationVSAvoidcircuit complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The system is divided into two independent lubrication circuits, each with its own supply pump. The first supply pump serves the reduction gearbox circuit, while the second supply pump serves the aeronautical engine circuit. This segmentation allows independent control and simplifies the overall system by eliminating the need for complex valve arrangements.

Inventive Principle:
Principle #1Segmentation

3Device complexity

If a single supply pump is used for both lubrication circuits, then the system is simpler, but precise metering of oil flow to each enclosure becomes difficult

Engineering Contradiction:
Improvesystem simplicityVSAvoidoil flow metering
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

Instead of using a single supply pump, the patent implements two separate supply pumps, each dedicated to a specific lubrication circuit. This segmentation enables precise metering of oil flow to each enclosure independently, as each pump can be controlled separately to deliver the exact flow rate required by its respective circuit.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces independent supply pumps as intermediary devices between the oil reservoir and each lubrication circuit. These pumps act as mediators that can precisely control and meter the oil flow to each enclosure, ensuring accurate lubrication while maintaining system simplicity.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 solution simplifies the lubrication system by allowing fairer oil distribution, reducing power consumption, and preventing cavitation, thereby extending pump lifespan and improving lubrication efficiency without modifying existing circuits.

Implementation Method 1

the second circuit comprises a jet pump of variable section powered at least by said first supply pump bypassing the first circuit

Methodology Applied
Scientific EffectJet pump: Jet

Implementation Method 2

allowing for modulation of the suction flow and recovery of hydraulic energy

Methodology Applied
Scientific EffectHydraulic energy recovery: Hydraulic Press

Implementation Method 3

jet pump of variable section allowing for modulation of the suction flow

Methodology Applied
Scientific EffectVariable section modulation: Venturi Effect

Data Source

PatentEP3976938B1Lubrication system of an aircraft engine
Publication Date: 2023.11.29 SAFRAN AIRCRAFT ENGINES SAS
  • EP3976938B1 patent drawingFigure 1
  • EP3976938B1 patent drawingFigure 2
  • EP3976938B1 patent drawingFigure 3

AI summary

The invention relates to a system (1) for lubricating an aeronautical engine (5) and a reduction gearbox (4) associated with the engine (5), the system (1) comprising an oil reservoir (2) feeding at least one first supply pump (3) supplying a first circuit (6) of the gearbox (4) opening into at least one chamber (4a) of the gearbox (4) and, in parallel, a second circuit (7) of the engine (5) opening into chambers (5a) of the engine (5). The second circuit (7) comprises a jet pump (9) of variable cross section supplied at least by the first supply pump (3), bypassing the first circuit (6), a second driven supply pump (10) being integrated into the second circuit (7) downstream of the jet pump (9), a portion of a flow (Qp) in the first circuit (6) being drawn off by the jet pump (9) to supply the second circuit (7).