Engine Fuel Systems Flashcards
What is meant by a compensated fuel pump?
It is a fuel pump that senses the ambient air pressure and maintains the fuel pressure a specific amount above this air pressure.
What would likely cause a reciprocating engine equipped with a float carburetor to hesitate momentarily when the throttle is rapidly advanced from idle to full power?
A malfunctioning accelerator pump.
What is the function of a float carburetor?
The float carburetor’s function is to measure airflow through the engine induction system and dispense the appropriate amount of gasoline into the airflow for all engine operating perimeters and conditions. It must also provide the fuel in a state that is as vaporized as possible by the time ignition occurs in the engine cylinders.
Why do aircraft fuel metering systems for reciprocating engines have mixture controls?
The air density decreases as the aircraft ascends, causing the mixture to become richer. The mixture control allows the fuel to be decreased to maintain a fuel-air mixture ratio that produces the desired power.
What are the two types of fuel injection systems used on modern reciprocating aircraft engines?
Teledyne Continental (TCM) system and Precision Airmotive (Bendix) system.
What is used in the TCM fuel injection system to control the amount of fuel sent to the nozzles?
The engine speed determines the injector pump output pressure. The relief valve determines the fuel for low-speed operation, and the adjustable orifice determines the fuel for high-speed operation.
What is used in the Precision Airmotive system to control the amount of fuel sent to the nozzles?
The mass of the air entering the engine acts on an air diaphragm that controls a servo ball valve in the line between the regulator and the flow divider.
Where are the fuel strainers normally located in an aircraft fuel system?
Finger strainers are located in the tank outlet, the main strainer, located at the lowest point in the fuel system, and strainers in the carburetor or fuel injection system.
What are two types of fuel heaters used in a jet transport aircraft?
Air-to-fuel and oil-to-fuel heat exchangers.
What kind of fuel boost pumps are normally installed inside the fuel tanks?
Centrifugal pumps.
What two things are adjusted when setting the idling conditions on a float carburetor?
a. Idling RPM by adjusting the throttle stop. b. Idling mixture by adjusting idle needle valve.
What are three functions of the boost pump in the tank of a jet transport aircraft?
a. To pressurize the fuel in the line between the tank and the engine-driven pump.
b. To transfer fuel from one tank to another to balance the fuel load.
c. To pump fuel from the tank into the dump chute when fuel is being dumped.
