Control device for an engine

Patent metadata

Field	Value
Publication number	US-9745051-B2
Application number	US-201314648051-A
Country	US
Kind code	B2
Filing date	Nov 15, 2013
Priority date	Nov 30, 2012
Publication date	Aug 29, 2017
Grant date	Aug 29, 2017

Abstract

An engine control device having a calculator for calculating a pitch setpoint for at least one propeller of the engine, the calculator taking account at least of a flight speed.

First claim

The invention claimed is:

1. An engine control device, comprising:
a full authority digital engine control computer configured to calculate a pitch setpoint for at least one propeller of the engine using a propeller performance model that takes account at least of a flight speed in order to adapt a pitch setpoint while taking account of a shaft power setpoint, said propeller performance model being based on predicting losses associated with the operation of the propeller and an absorbed power coefficient.

2. A control device according to claim 1 , wherein a magnitude representative of a behavior of the propeller is determined using at least one polynomial of second or higher order.

3. A control device according to claim 1 , wherein a magnitude representative of a behavior of the propeller is determined as a function of a relative Mach number for a blade of the propeller and an assumed pitch for the propeller.

4. A control device according to claim 1 , wherein a speed of rotation of the propeller is input into the propeller performance model.

5. A control device according to claim 1 , wherein an assumption for a blade pitch is input into the propeller performance model.

6. A control device according to claim 1 , wherein the propeller performance model is implemented using an iteration loop having a stop criterion that is a calculated value for shaft power converging on a shaft power setpoint.

7. A turboprop including a control device according to claim 1 .

8. An unducted fan engine including a control device according to claim 1 .

9. A control device according to claim 1 , wherein the losses associated with the operation of the propeller is established using

{

Loss
=

Loss
ml

+

{

A
⁢

⁢

2
loss

⁢
choke

A
⁢

⁢

2
loss

⁢
stall

}

·

GH
2

GH
=

Jml
-
J

,

in which J is an advance ratio, Jml is an advance ratio for minimum loss, Loss ml is a minimum loss, A2 loss choke is a parabolic curve of loss for negative angles of incidence, and A2 loss stall is a parabolic curve of loss for positive angles of incidence,
Jml, Loss ml , A2 loss choke, and A2 loss stall are coefficients determined based on a blade pitch, the flight speed, and a speed of rotation of the propeller.

10. A control device according to claim 9 , wherein the absorbed power coefficient is established using

Cp
=

Cp
ml

+

A
⁢

⁢

1
·
GH

+

{

A2
Cp

⁢
choke

A
⁢

⁢

2
Cp

⁢
stall

}

·

GH
2

,

in which Cp is the absorbed power coefficient, Cp ml is an absorbed power coefficient on a minimum loss line, A1 is a first order coefficient of the model for the absorbed power coefficient, A2 cp choke is a parabolic curve of the absorbed power coefficient for negative angles of incidence, and A2 cp stall is a parabolic curve of the absorbed power coefficient for positive angles of incidence, and
Cp ml , A1, A2 cp choke, and A2 cp stall are coefficients determined based on the blade pitch, the flight speed, and the speed of rotation of the propeller.

Assignees

• Snecma

Inventors

• Tantot Nicolas Jerome Jean
• Brichler Thierry

Classifications

• B64C11/44 Primary

  electric · CPC title

• B64C11/305 Primary

  characterised by being influenced by other control systems, e.g. fuel supply · CPC title

• B64D31/06

  actuated automatically · CPC title

• Y02T50/66

  Cross-Sectional Technologies · mapped topic

• Y02T50/60

  Efficient propulsion technologies, e.g. for aircraft · CPC title