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US6748744: Method and apparatus for the engine control of output shaft speed

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Filing Information

Inventor(s) Martin Adam Peplow · Ian McCormick ·
Assignee(s) Pratt & Whitney Canada Corp. ·
Attorney/Agent(s) Ogilvy Renault ·
Primary Examiner Justine R. Yu ·
Assistant Examiner William H. Rodriguez ·
Application Number US10038463
Filing date 11/21/2001
Issue date 06/15/2004
Prior Publication Data
Predicted expiration date 01/29/2022
Patent term adjustment 69
U.S. Classifications 607/73  · 60/392.81  · 602/43  ·
International Classifications --
Kind CodeB2
International Classifications 60773 · 60 39281 · 60243 ·
19 Claims, 5 Drawings


Abstract

In accordance with one aspect of the present invention, in a control system for controlling a gas turbine engine, there is provided a system and a method for determining an optimized output shaft speed for a required thrust and setting an appropriate engine power. The method comprises the steps of: providing a required thrust value at a particular flight condition; determining input values for each of a power, output shaft speed, airspeed, and altitude; determining whether the required thrust is a low power condition; if the required thrust is a low power condition, determining a reduced propeller speed value from the input values and the required thrust value; at least one of increasing and decreasing the optimized output shaft speed using the reduced propeller speed value.

Independent Claims | See all claims (19)

  1. 1. In a control system for controlling a gas turbine engine, a method for determining an optimized output shaft speed for a required thrust and setting an appropriate engine power, the method comprising the steps of: providing a required thrust value at a particular flight condition; determining input values for each of a power, output shaft speed, airspeed, and altitude; determining whether said required thrust is a low power condition; if said required thrust is a low power condition, determining a propeller speed value from said input values, said required thrust value and a performance map for a free power turbine; at least one of increasing and decreasing said optimized output shaft speed using said propeller speed value.
  2. 5. A system for determining an optimized output shaft speed in a gas turbine engine for a required thrust and setting an appropriate engine power in a gas turbine engine control system, the system comprising: a pilot command providing a required thrust value at a particular flight condition; a reduced power cruise condition determiner determining whether said required thrust is a low power condition; an output shaft speed determiner for determining a propeller speed value from a propeller performance map based on at least one of engine power, airspeed, and altitude, said required thrust value and a performance map for a free power turbine, when said required thrust is a low power condition; a fuel consumption determiner for at least one of increasing and decreasing said optimized output shaft speed using said propeller speed value.
  3. 8. A method for determining an optimized output shaft speed for a selected thrust setting in a gas turbine turbopropeller engine having at least one free turbine and an output shaft, the method comprising the steps of: acquiring a selected thrust setting; determining an engine power setting corresponding to the selected thrust setting; determining a current airspeed, altitude and air temperature; determining whether a low power condition exists, and if a low power condition exists then selecting an optimum shaft speed from a data store, the selection based on at least engine power setting, determined airspeed, altitude and temperature and data acquired from a performance map of a free power turbine.
  4. 13. A method of reducing fuel flow during low power operation of a turboprop engine having a free turbine, the method comprising the steps of: calculating an engine power required to achieve a pilot-selected thrust setting; providing a first fuel flow to the engine sufficient to achieve the calculated power; acquiring input data relating to airspeed, altitude, ambient air temperature and engine power; and determining if the selected thrust setting corresponds to a low power condition, and if so: using said input data and performance maps of a free power turbine to select an optimized propeller speed from a propeller performance map; and supplying a second fuel flow to the engine to achieve the optimized propeller speed.
  5. 17. A method of optimizing fuel consumption during low power operation of a turboprop engine having a free turbine, the method comprising the steps of: receiving a request for a desired thrust level; calculating an engine power setting based on the requested thrust level; and determining if the requested thrust level is within a low-power range, and if so then: determining an optimum propeller shaft speed from a data store, the steps of determining including using a stored map of free turbine speed and accounting for calculated power setting, current airspeed and current altitude; determining a corresponding fuel flow required to achieve the optimum propeller shaft speed; and sending a command to a fuel metering unit of the engine to achieve said corresponding fuel flow and thereby achieve the determined optimum propeller shaft speed.

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Patent Family

Document NumberAssigneeInventorsIssue/Pub Date
CA2466526 PRATT & WHITNEY CANADA MCCORMICK IAN et al. Jun 2003
US20030126862 Ian McCormick et al. Jul 2003
US6748744 Pratt & Whitney Canada Corp. Martin Adam Peplow et al. Jun 2004