Dual-Spool Gas Turbine Starter Transmission

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Solution Overview

Problem

Gas turbine engines, particularly turboshaft engines, face challenges with complexity, weight, and manufacturing simplicity due to the need for an additional starter motor and its drive train, which increases part count and physical space requirements.

Innovation Solution

A dual-spool gas turbine engine with a selective starter transmission arrangement using a sprag clutch that engages and disengages the spools for starting, allowing a single e-machine to function as both a generator and starter, reducing complexity and weight while maintaining reliability and ease of assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an additional starter motor and its drive train are added to the gas turbine engine, then the engine can be started reliably, but the system complexity increases and part count increases

Engineering Contradiction:
Improvestarting reliabilityVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the starter motor and generator into a single integrated e-machine assembly. The e-machine includes a motor generator assembly with a stator and rotor that can function as either a motor (for starting) or a generator (for power generation), eliminating the need for separate starter motor and generator components. This merging reduces system complexity while maintaining starting reliability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The e-machine is designed with multi-functionality, serving as both a starter motor and a generator within a single unit. The motor generator assembly can operate in motor mode to crank the engine during starting, and in generator mode to produce electrical power once the engine is running. This universal design eliminates the need for separate dedicated starter and generator systems.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If an additional starter motor and its drive train are added to the gas turbine engine, then the engine can be started reliably, but the weight increases

Engineering Contradiction:
Improvestarting reliabilityVSAvoidsystem weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The patent combines the starter motor and generator into a single integrated e-machine assembly. The e-machine includes a motor generator assembly with a stator and rotor that can function as either a motor (for starting) or a generator (for power generation), eliminating the need for separate starter motor and generator components. This merging reduces system complexity while maintaining starting reliability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The e-machine is designed with multi-functionality, serving as both a starter motor and a generator within a single unit. The motor generator assembly can operate in motor mode to crank the engine during starting, and in generator mode to produce electrical power once the engine is running. This universal design eliminates the need for separate dedicated starter and generator systems.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Reliability

If an additional starter motor and its drive train are added to the gas turbine engine, then the engine can be started reliably, but the physical space requirements increase

Engineering Contradiction:
Improvestarting reliabilityVSAvoidphysical space
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The patent combines the starter motor and generator into a single integrated e-machine assembly. The e-machine includes a motor generator assembly with a stator and rotor that can function as either a motor (for starting) or a generator (for power generation), eliminating the need for separate starter motor and generator components. This merging reduces system complexity while maintaining starting reliability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The e-machine is designed with multi-functionality, serving as both a starter motor and a generator within a single unit. The motor generator assembly can operate in motor mode to crank the engine during starting, and in generator mode to produce electrical power once the engine is running. This universal design eliminates the need for separate dedicated starter and generator systems.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Reliability

If an additional starter motor and its drive train are added to the gas turbine engine, then the engine can be started reliably, but the manufacturing complexity increases

Engineering Contradiction:
Improvestarting reliabilityVSAvoidmanufacturing simplicity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent combines the starter motor and generator into a single integrated e-machine assembly. The e-machine includes a motor generator assembly with a stator and rotor that can function as either a motor (for starting) or a generator (for power generation), eliminating the need for separate starter motor and generator components. This merging reduces system complexity while maintaining starting reliability.

Inventive Principle:
Principle #5Merging (Combining)

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 solution results in a compact, lightweight, and robust gas turbine engine with a low part count, simplifying manufacturing and maintenance, while achieving high efficiency and reliability by eliminating the need for a separate starter motor and reducing physical space requirements.

Implementation Method 1

a sprag clutch that selectively engages and disengages the spools for starting

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3715601B1Auxiliary power unit with plural spool assembly and starter transmission arrangement
Publication Date: 2024.05.08 HONEYWELL INTERNATIONAL INC
  • EP3715601B1 patent drawingFigure 1
  • EP3715601B1 patent drawingFigure 2

AI summary

A gas turbine engine includes a plural spool assembly including a first spool and a second spool. The engine also includes an accessory configured to change between a motor mode and a generator mode and a transmission configured to transmit mechanical power between the accessory and at least one of the first spool and the second spool. The transmission, when the accessory is in the generator mode, is configured to transmit mechanical power from the first spool to the accessory for generating electric power at the accessory. The transmission, when the accessory is in the motor mode, is configured to transmit mechanical power from the accessory to the second spool.