Reciprocating aircraft engine piston cooling oil nozzle?
I am unsure what you are asking but:
The cooling oil nozzle is arraigned so the underside of the
piston is sprayed with oil to cool the piston crown.
This is done on high stress engines as the pistons could and
would overheat leading to detonation and other problems leading to
engine failure.
This system is also used on Cumin's diesel engines as used in
Dodge trucks, race cars, heavy trucks and so on.