FAA Aviation Mechanic Powerplant (AMP)Reciprocating EnginesMedium
A mechanic is troubleshooting a continuous-flow fuel injection system on a horizontally opposed engine. Fuel is metered by the fuel control unit based on airflow and then distributed to each cylinder through a component mounted at the top of the engine that divides the flow equally to all injector lines. What is this component called?
- AVapor separator
- BEconomizer valve
- CFlow divider
- DAccelerator pump
Show answer & explanationAnswer & explanation
Correct answer: C. Flow divider
The flow divider (also called the fuel manifold valve) receives metered fuel from the fuel control unit and distributes it equally to each cylinder's injector nozzle. It also contains a spring-loaded valve that shuts off fuel flow uniformly when the engine is stopped, preventing after-fire drips.
Why the other options are wrong
- A. A vapor separator removes vapor bubbles from fuel before it reaches the metering unit, unrelated to distribution.
- B. An economizer valve enriches mixture at high power in some carburetors, not a distribution component.
- D. An accelerator pump provides extra fuel during rapid throttle changes in float carburetors, not injection systems.
Flow Divider (Fuel Manifold Valve)
A component in continuous-flow fuel injection systems that equally distributes metered fuel from the fuel control unit to each cylinder's injector line.
- Mounted centrally, typically atop the engine
- Contains a diaphragm/spring valve for equal distribution
- Shuts off fuel uniformly to all cylinders when engine stops
Memory trick: The flow DIVIDER splits fuel like slicing a pie equally for every cylinder.