Relighting a turbofan engine

Patent metadata

Field	Value
Publication number	US-9347379-B2
Application number	US-201414503541-A
Country	US
Kind code	B2
Filing date	Oct 1, 2014
Priority date	Apr 21, 2006
Publication date	May 24, 2016
Grant date	May 24, 2016

Abstract

The method and apparatus for in-flight relighting of a turbofan engine involve in one aspect selectively controlling an accessory drag load on one or more windmilling rotors to permit control of the windmill speed to an optimum value for relight conditions.

First claim

What is claimed is:

1. A method for in-flight relighting an aircraft accessory gearboxless turbofan engine, the engine having at least two shafts, one of which is a high-pressure shaft mounted to a high-pressure compressor, a high-pressure turbine and a concentrically-mounted electrical generator, the generator electrically driving an accessory load, the method comprising:
using exclusively ram air through the engine to rotate the high-pressure shaft;
limiting the maximum speed at which the high-pressure shaft is rotating by applying a drag force to the high-pressure shaft; and then
relighting the engine.

2. The method of claim 1 further comprising adjusting a high-pressure shaft speed solely by altering an in-flight attitude of the aircraft.

3. The method of claim 1 wherein the generator is a starter-generator.

4. The method of claim 1 wherein the electrical generator is mounted to the high-pressure shaft and is used to apply said drag force.

Assignees

• Pratt & Whitney Canada

Inventors

• Dooley Kevin Allan

Classifications

• F02C7/262 Primary

  Restarting after flame-out · CPC title

• F02C7/32

  Arrangement, mounting, or driving, of auxiliaries · CPC title