Definition
A valve assembly built into a fuel manifold that controls the distribution of fuel from a single inlet to multiple outlet lines feeding individual cylinders or fuel nozzles. In a typical fuel-injection system, the manifold valve sits downstream of the fuel control unit and opens at a set fuel pressure to deliver metered fuel evenly to each cylinder's discharge nozzle, and closes positively when the engine is shut down to provide a clean fuel cutoff.
Plain English
A valve at the central fuel hub on the engine that opens to send fuel out to all the cylinders at once, and shuts cleanly when the engine is turned off so fuel doesn't keep dribbling into the cylinders.
Context Anchor
Seen in aircraft engine fuel-injection system descriptions, maintenance checks, and troubleshooting for hard starting, rough running, or uneven fuel flow.
Derivation
‘Manifold’ comes from Old English ‘manigfeald,’ meaning ‘many folds’ or ‘many parts’ — used in engineering for a pipe or chamber with one inlet and many outlets. So a manifold valve is the valve that controls flow into that branching distribution point.
Why Pilots Care
Even fuel delivery keeps the engine running smoothly and prevents power loss or cylinder damage from uneven combustion.
Intuition Check
Do not assume “manifold valve” means any valve on any manifold. In this powerplant context, it means the fuel-injection valve that distributes measured fuel to the engine’s fuel nozzles.
Example Sentence 1
After shutdown, the manifold valve closed and stopped fuel flow to all six cylinder nozzles at the same time.
Example Sentence 2
A clogged manifold valve caused the engine to run rough until the fuel lines were cleaned.