Section 4 power management

© International Aero Engines Inc 2000

Power ManagementPower Management



© International Aero Engines Inc 2000© International Aero Engines Inc 2000



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Power ManagementPower ManagementThrust Control Lever MechanismThrust Control Lever Mechanism

The thrust control mechanism is based upon the ‘fixed thrust lever’ concept, There is no motorised movement of the thrust levers.

Each thrust control lever drives ‘dual resolvers’, each resolver output is dedicated to one EEC channel.



The Thrust Lever Angle (TLA) is the ‘input’ to the resolver.

The resolver ‘output’ which is supplied to the EEC is known as the Thrust Resolver Angle (TRA).

The relationship between the TLA and the TRA is linear.





The control system consists of:

Thrust Control Lever. Mechanical Box. Thrust Control Unit.





Thrust control lever movement is transmitted through a rod to a mechanical box.

The mechanical box incorporates ‘soft’ detents which provide selected engine ratings, it also provides artificial ‘feel’ for the thrust control system.


Output from the ‘mechanical box’ is transmitted by a second rod to the thrust control unit.

The thrust control unit houses 2 resolvers and 6 potentiometers.

The output from the potentiometers provides TLA information to the aircraft's flight management computers.






The EEC incorporates resolver fault logic, allowing engine operation after failure or loss of the TRA.

A rigging pin position is provided on the Thrust Control Unit in order to rig the resolvers and potentiometers.


Bump Rating Push Button. As an ‘option’ some aircraft (A1) are fitted

with ‘Bump’ rating guarded push buttons on the thrust levers (one per engine).

Enables the EEC to be ‘Re-rated’ to provide additional thrust capability for use during certain aircraft operations.



Bump Rating Button (A1 Aircraft only)





Power ManagementPower ManagementEEC/Fuel System InterfaceEEC/Fuel System Interface

Movement of thrust lever is sensed by the dual resolvers, which supply the resolver angle signal to the EEC.

The EEC ‘computes’ the fuel flow which will produce the required thrust.

The ‘computed ‘ fuel flow request is converted into an electrical current, which drives the torque motor in the Fuel Metering Unit (FMU)


Power ManagementPower ManagementEEC/Fuel System InterfaceEEC/Fuel System Interface

The FMU modulates the fuel servo pressure to move the Fuel Metering Valve (FMV) and set the fuel flow.

Movement of the FMV is sensed by a dual position resolver, which translates the FMV movement into an electrical ‘feedback’ signal which is supplied back to the EEC.



Channel A

Channel B

Fuel Fuel DemandDemand

Feedback signalFeedback signal

FMUFMU

EEC

Fuel Metering Valve

Dual Torque

Motor

nozzlesFuel in

Dual

Resolver

TRATRA

TRATRA

Education

Section 4 power management