Fuel control unit

Fuel control unit

Fuel control unit is the generic term given to any of several types of control systems for gas turbine engines.

Fundamentals of turbine engine control

Gas turbine engines are primarily controlled by the amount of fuel supplied to the combustion chambers. With this in mind, the very simplest fuel control for a turbine engine is a fuel valve operated by the pilot. Many pre-production models of early turbojet engines featured just that, but it was soon found that this kind of control was difficult and dangerous in actual use. Closing the valve too quickly while trying to reduce power output could cause a "lean die-out", where the airflow through the engine blows the flame out of the combustion chamber and extinguishes it. Adding fuel too quickly to increase power can damage the turbines due to excessive heat, or the sudden rise in combustion chamber pressure may cause a compressor stall. Another danger of too much fuel is a "rich blow-out", where soaking the fire with fuel displaces the oxygen and lowers the temperature enough to extinguish the flame. The excess fuel may then be heated on the hot tailpipe and explode, possibly causing damage to the aircraft. [cite book
last = Kroes
first = Michael J.
authorlink =
coauthors = Wild, Thomas W.
title = Aircraft Powerplants
publisher = McGraw-Hill
date = 1995
location =
pages = 319-320
url =
doi =
id =
isbn = 0-02-801874-5
] For an aircraft engine, changes in airspeed or altitude cause changes in air speed and density through the engine, which would then have to be manually adjusted for by the pilot.

A fuel control unit attempts to solve those problems by acting as an intermediary between the operator's controls and the fuel valve. The operator has a "power lever" which only controls the engine's potential, not the actual fuel flow. The fuel control unit acts as a computer to determine the amount of fuel needed to deliver the power requested by the operator.

Types of fuel control units

*Hydromechanical: A combination of a flyweight governor and a several sensors including compressor discharge pressure, burner can pressure, and exhaust pipe pressure. In most cases the engine's fuel pump is integrated in to the fuel control.
*Electronic engine control (EEC): An EEC is essentially a hydromechanical fuel control but with added electrical components to prevent overheating or overspeeding the engine. If the electrical part of the control should fail, an EEC will revert to a standard hydromechanical fuel control.
*Full-authority digital engine control (FADEC): A digital computer which controls a servo-operated fuel valve. In this case the power lever is only electrically connected to the fuel control.

ee also

*Aircraft engine
*Jet engine


Wikimedia Foundation. 2010.

Игры ⚽ Нужна курсовая?

Look at other dictionaries:

  • fuel control unit — A fuel metering device that regulates the fuel flow to the engine in accordance with the pilot’s demand, ambient environmental conditions, aircraft speed, and other related factors …   Aviation dictionary

  • acceleration control unit — A component in the fuel control unit of a gas turbine engine that regulates the rate of increase of fuel to the nozzles when the engine control calls for acceleration. The ACU ensures that the engine does not stall during rapid engine… …   Aviation dictionary

  • Engine control unit — An engine control unit (ECU) is an electronic control unit which controls various aspects of an internal combustion engine s operation. The simplest ECUs control only the quantity of fuel injected into each cylinder each engine cycle. More… …   Wikipedia

  • Transmission control unit — A transmission control unit or TCU is a device that controls modern electronic automatic transmissions. A TCU generally uses sensors from the vehicle as well as data provided by the Engine Control Unit to calculate how and when to change gears in …   Wikipedia

  • electronic control unit — (ECU) [1] A microprocessor and memory with electronic maps, forming the central part of an engine management system or of subsystems such as a fuel injection or ignition system. [2] The brain of an ABS system. The ECU reads impulses from the… …   Dictionary of automotive terms

  • combined acceleration and speed control unit — A system designed to prevent engine surge. The acceleration control unit regulates the amount of fuel flowing into the engine during acceleration either by mechanical or hydromechanical devices. Most modern engines, however, use electronic… …   Aviation dictionary

  • mixture control unit — [1] A unit in the K jetronic fuel injection system which combines the fuel distributor and the airflow sensor; it monitors the rate of airflow and meters the fuel supplied to the injectors. [2] In Bosch CIS, the collective term for the airflow… …   Dictionary of automotive terms

  • microprocessor control unit — (MCU) an integral part of an electronically controlled feedback carburetor using a TWC catalyst. Various sensors monitor conditions. MCU is widely used on Ford vehicle for the control of air fuel ratios …   Dictionary of automotive terms

  • fuel filter — A filter in the fuel system of aircraft to prevent minute contaminants from affecting adversely the engine driven fuel pump and fuel control components. There is a low pressure filter between the supply tank and the engine fuel system and a high… …   Aviation dictionary

  • Fuel pump — should not be confused with fuel dispenser, a device that dispenses fuel into an automobile. A high pressure fuel pump on a Yanmar 2GM20 marine diesel engine. A fuel pump is a frequently (but not always) essential component on a car or other… …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”