Engine Fuel And Fuel Metering Flashcards
What are some of the sources used to heat the fuel in a turbine engine fuel system?
Bleed air.
Engine lubricating oil.
What are the most common types of fuel metering systems used on small reciprocating engines?
Float type carburetors.
Pressure injection carburetors.
Direct fuel injection systems.
What function does the mixture control perform? 
Controls the fuel air mixture.
What generally causes spark plug fouling?
Operating the engine with excessively rich mixture at idle.
What is the purpose of an accelerating system?
It provides an immediate but brief increase in fuel flow in the Venturi to enrich the mixture.
What is a carburetor economizer system?
It is a power enrichment system that provides a richer mixture at high power settings, where the excess fuel aids in engine cooling. And its functions at throttle settings above cruise.
When the mixture is placed in the idle cut off position, a slight rise in rpm is noted prior to the engine decelerating. What does this indicate?
The idle mixture is set correctly.
Why should engine rpm be accelerated periodically when making carburetor adjustments?
To clear the engine.
What maintains the fuel pressure in a pressure injection carburetor?
An engine driven fuel pump.
What happens if the manual mixture control of a pressure injection carburetor is moved the idle cut off position?
The engine stops. 
How does an automatic mixture control or AMC work?
A sealed brass bellows connected to the fuel metering system, expands and contracts with changes in pressure and temperature, adjusting the mixture accordingly. 
What are some of the advantages of fuel injection systems over carburetor systems?
Less danger of induction icing.
Better acceleration.
Better fuel distribution.
Better fuel economy.
Reduced overheating of individual cylinders.
What purpose do turbine engine fuel control units serve?
They automatically meter fuel to the engine.
What are the two basic types of turbine engine fuel control units?
Hydromechanical.
Electronic.
What are the engine variables detected by the fuel control unit?
Power level position.
RPMs.
Compressor inlet temperature.
Compressor inlet pressure.
Compressor discharge pressure.
Burner pressure.