Turbine Engine Power Transfer for Low-Idle Accessory Drive

Solution Overview

Problem

Existing turbine engines face inefficiencies in bleed air supply and increased idle thrust levels, leading to higher fuel consumption and maintenance costs due to the need for increased idle speeds to meet accessory power demands.

Innovation Solution

A system with a transmission and clutch that selectively transfers power between the low and high pressure spools of a turbine engine, allowing for efficient operation by modulating power distribution and reducing idle thrust and fuel flow.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If shaft power is extracted from the high spool during ground operation, then accessory power requirements are met, but ground idle fuel flow increases and thrust increases

Engineering Contradiction:

Improveaccessory powerVSAvoidfuel flow

Core Design Contradiction:

PowerVSUse of energy by moving object

Solution Approach 1:

The power transmission system is segmented into multiple independent pathways: a first transmission pathway for transferring power from the high spool to accessories, and a second transmission pathway for transferring power from the low spool to the high spool. This segmentation allows selective engagement of power sources based on operational requirements, enabling accessory power to be supplied without necessarily increasing high spool power extraction and associated fuel consumption.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The low spool acts as an intermediary power source that can transfer power to the high spool through the second transmission pathway. This intermediary mechanism provides an alternative route for meeting accessory power demands, reducing the need to increase high spool power extraction directly, thereby reducing fuel flow and thrust during ground idle operations.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Power

If shaft power is extracted from the high spool during ground operation, then accessory power requirements are met, but high pressure compressor stability margin decreases

Engineering Contradiction:

Improveaccessory powerVSAvoidcompressor stability margin

Core Design Contradiction:

PowerVSStability of the object's composition

Solution Approach 1:

The power transmission system is segmented into multiple independent pathways: a first transmission pathway for transferring power from the high spool to accessories, and a second transmission pathway for transferring power from the low spool to the high spool. This segmentation allows selective engagement of power sources based on operational requirements, enabling accessory power to be supplied without necessarily increasing high spool power extraction and associated fuel consumption.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The low spool acts as an intermediary power source that can transfer power to the high spool through the second transmission pathway. This intermediary mechanism provides an alternative route for meeting accessory power demands, reducing the need to increase high spool power extraction directly, thereby reducing fuel flow and thrust during ground idle operations.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Quantity of substance

If bleed air is extracted from the high pressure compressor, then pneumatic bleed air is provided to aircraft systems, but compressor performance is reduced

Engineering Contradiction:

Improvebleed air supplyVSAvoidcompressor performance

Core Design Contradiction:

Quantity of substanceVSProductivity

Solution Approach 1:

The auxiliary compressor is powered by shaft power from the engine to compress air from a lower stage of the engine compressor, allowing the system to serve its own pneumatic needs without external assistance. This self-service capability enables bleed air to be provided to aircraft systems while maintaining optimal high pressure compressor performance by reducing reliance on high-stage bleed air extraction.

Inventive Principle:

Principle #25Self-service

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 reduces unwanted thrust and fuel consumption while maintaining accessory power requirements, improving operational efficiency and reducing maintenance costs.

Implementation Method 1

a transmission with a speed changing transmission and a clutch

Methodology Applied

Scientific EffectSpeed changing transmission: Gear

Data Source

PatentEP4692526A1System to selectively transfer power of a turbine engine

Publication Date: 2026.02.11 THE BOEING CO

Figure 1
Figure 2
Figure 3

AI summary

A system configured to be operatively connected to a turbine engine of an aircraft and to an accessory of an aircraft. The system is configured to selectively transfer power between a first pressure spool of the turbine engine and a second pressure spool of the turbine engine and to power the accessory to deliver air to an aircraft system of the aircraft.