Chapter 7 Section B - Engine Fuel Systems (Fuel Injection systems) Flashcards
What are the two limitations to carburetors?
- Because of the different length and shape of the intake manifold, there is a uneven fuel/air distribution
- They are susceptible to carburetor icing
When the fuel is injected directly into the combustion chamber, the injection system is referred to as what?
Direct fuel injection system
What is the most common type of fuel injection system used in reciprocating aircraft engines and it’s two types?
Continuous-flow fuel injection system
- Precision Airmotive RSA system
- Teledyne Continental Motors system
Name the four main components of the TCM continuous flow.
Engine driven fuel pump (the heart
F.C.U
Fuel Mianifold a.k.a Spider (ball valve)
fuel nozzle
Name two functions of a Direct Fuel Injection System.
- Pumps force metered fuel directly into the combustion chambers of the individual cylinder
- They are timed to the engine in high-pressure spurts
What are the two classifications of fuel injection systems?
Direct fuel
Continuous-flow
Fuel metering is accomplished by fuel flowing through both the _____and the ______.
Fuel metering is accomplished by fuel flowing through both the mixture control valve and the idle valve.
What is the procedure when starting a Lycoming engine equipped with a a fuel injection system?
- Boost pump on
- Throttle 1/2 inch open
- Mixture full rich for 3-5 seconds & watch fuel guage rise
- Mixture idle cut-off
- Crank engine, once started mixture goes full rich
What is the starting procedure when starting a Continental engine equipped with a fuel injection system?
- Boost pump on
- Throttle 1/2 inch open
- Mixture full rich
- Monitor fuel guage
- Crank engine
What is the difference between the RSA and the TCM systems when it comes to metering fuel?
RSA system uses both fuel and air metering forces to meter fuel.
The TCM system only uses fuel metering forces.
How do you adjust for unmetered fuel pressure low and high RPM?
Low unmetered fuel pressure - Adjust at the pump relief valve
High unmetered fuel pressure - Adjust at the variable oriface
Troubleshooting:
The fuel flow of a TCM system is reading higher than normal and the engine is running rough. What could be the problem?
A blockage in the fuel nozzle.
What will happen if the nozzle screen of a RSA system becomes clogged?
The fuel will become richer, the cylinder will become cooler, and there will be a change in the CHT guage.
Where does the nozzle dispense it’s fuel?
Intake valve
What are the names of the two halves of a cylinder?
Barrel and head
Foe TCM systems, what is the “spider” also known as?
The fuel manifold
Name two functions of the Fuel manifold.
Distributes fuel to the nozzles
Provides positive pressure for shut down
Where does the fuel pressure guage get it’s reading from?
The fuel manifold (Spider)
How would you know which of the cylinders held the CHT of EGT probe?
Check the Type certification data sheet
What are the five primary components of the RSA system?
Venturi housing
fuel metering unit
fuel regulator
flow divider
fuel nozzles
Fuel delivered to the nozzle in a Bendix system is a function of what?
Mass air flow
What is the function of the air metering forces in a Bendix?
To open the ball valve
When transitioning to off-idle, what keeps the engine from stumbling?
Constant effort spring
How does the AMC work in the bendix system
- Bellows expand as aircraft climbs
- Expansion pushes needle valve off its seat to open bleed port air
- reduction of air diaphram pressure partially closes ball valve, which leans mixture
