Engine Fuel Systems Flashcards
What type of pump can vary the amount of fuel discharge regardless of speed?
Variable displacement pump
What is used to keep water, sediment, and foreign matter out of the carburetor?
The main fuel strainer
What is the purpose of a pressure relief valve and a constant displacement pump?
It returns excess fuel that is not required by the engine to the inlet side of the pump
What type of engine driven fuel pump is widely used other than gear or piston pumps?
Rotary vane type
What function do fuel boost pumps perform?
They supply pressurized fuel to the pump, which helps prevent vapor lock and cavitation
What is a commonly used type of fuel boost pump?
Centrifugal type
What causes vapor lock and why is it a concern?
Insufficient fuel pressure, high fuel temperatures and excessive fuel turbulence, which may completely block any fuel flow resulting in engine failure
Why is vapor lock serious?
Fuel flow may be completely blocked
What does the use of fuel boost pumps help prevent?
Cavitation and vapor lock
What function does the engine driven pump on a turbine engine perform?
Provides a continuous supply of fuel at the proper pressure while the engine is running
Name two categories of turbine engine fuel pumps
Constant and variable displacement
What category is a gear type pump classified?
Constant displacement
When performing an external inspection of an engine driven fuel pump, what should you look for?
Leaks and the security of mounting
What is the purpose of a shear section of the driveshaft in a dual element constant displacement pump?
If one fails the other one continues working
Where in a turbine engine fuel system is ice formation likely to occur and how is it prevented?
Fuel filter is most susceptible to ice formation and the heat exchanger using either engine oil or bleed air to warm the fuel
