Back-up control method and apparatus for turbo machine

• US 20020078692A1
• Filed: 12/22/2000
• Published: 06/27/2002
• Est. Priority Date: 12/22/2000
• Status: Active Grant

• Current Assignee: Pratt & Whitney Canada Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Original Assignee: Pratt & Whitney Canada Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: Jarvo, Jim Robert, Gratton, Daniel Claude, Jay, Alexandre
• Granted Patent: US 6,568,166 B2
• Time in Patent Office: Days
• US Class Current: 60/773
• CPC Class Codes: F02C 9/46 Emergency fuel control

Abstract

A method and apparatus for controlling a turbo-machine in case of failure of the main burn fuel flow calculator. The apparatus receives at least information from various sensors as well as from the main burn fuel flow calculator. The method and apparatus, herein disclosed, provides a smooth and secure transition between the last burn fuel flow value before the failure of the main burn fuel flow calculator and the future burn fuel flow values.

Claims

1. A back-up system for controlling a turbo-machine via a fuel metering unit when the electronic engine control of the turbo-machine fails and which comprises:

a back-up burn fuel flow calculator, said back-up fuel flow calculator receiving at least the amount of fuel requested by the operator signal of the turbo-machine and the actual spool speed of the turbo-machine and computing an amount of fuel to provide to said turbo-machine in order to adjust its speed to obtain a spool speed equivalent to said amount of fuel requested by the operator signal;

a last burn fuel flow storage, said last burn fuel flow storage storing the last burn fuel flow value provided by said electronic engine control before its failure; and

a transitional burn fuel flow manager, said transitional burn fuel flow manager receiving the amount of fuel computed by said back-up burn fuel flow calculator and said last burn fuel flow value stored in said storage and providing an amount of fuel to provide to said fuel metering unit.

2. The apparatus as claimed in claim 1, further comprising a non-volatile memory connected to said back-up burn fuel flow calculator.

3. The apparatus as claimed in claim 2, wherein said back-up burn fuel flow calculator receives also the ambient temperature and the ambient pressure.

4. The apparatus as claimed in claim 3, wherein said non-volatile memory comprises a look-up table which provides a relation between a fuel consumption of the turbo-machine and the speed of the turbo-machine, using said ambient temperature and said ambient pressure.

5. The apparatus as claimed in claim 1, wherein said backup system is integrated within an over-speed detection system.

6. The apparatus as claimed in claim 1, wherein said transitional burn fuel flow manager receives an enabling signal from said electronic engine control of the turbo-machine, said enabling signal being responsible for beginning said computing of the amount of fuel to provide to said fuel metering unit.

7. A method for determining a burn fuel flow value, comprising the steps of:

receiving a current fuel flow value provided to a fuel metering unit of a turbo-machine from a main burn fuel flow calculator;

storing said current fuel flow value in a memory upon detection of a malfunction of said main burn fuel flow calculator;

calculating a transitional value using said stored fuel flow value and a back-up burn fuel flow value received from a back-up burn fuel flow calculator; and

outputting said transitional value to said fuel metering unit.

8. The method as claimed in claim 7, wherein said calculating is done by operating a tracking from said current fuel flow value to a fuel flow value necessary to provide to said turbo-machine in order to obtain a desired speed.

9. A method for determining a burn fuel flow value for an aircraft turbo-machine in case of a malfunction, said method comprising the steps of:

receiving a current fuel flow value from a main burn fuel flow calculator;

storing said current fuel flow value prior to said malfunction;

calculating a back-up burn fuel flow value using sensor readings from said aircraft and initially said stored current fuel flow value, wherein said calculating using an algorithm which is different from an algorithm used for calculating said main burn fuel value, said back-up burn fuel flow value having a smooth transition between said current fuel flow value prior to said malfunction and future burn fuel flow values; and

outputting said back-up burn fuel flow value to a fuel metering unit.