VALVE, HYDRAULIC--A valve for controlling
TURNING RADIUS--The diameter of the circle
liquid.
made by a vehicle during operation with front
wheels turned fully in either direction.
VALVE, ISOLATION--A valve used to isolate a
system or components.
TURRET NOZZLE--A hose nozzle that pivots and
revolves on the A/S32P-25 fire fighting vehicle.
VALVE, PILOT--A valve used to operate another
valve or control.
TWO-STROKE-CYCLE ENGINE--An
internal-combustion engine requiring only two
VALVE, PNEUMATIC--A valve for controlling gas.
piston strokes to complete the cycle of events that
VALVE, PRESSURE REDUCING--A pressure
produce power.
control valve whose primary function is to limit
UNIVERSAL JOINT--A device that transmits power
outlet pressure.
through an angle.
VALVE, PRIORITY--A valve that directs flow to one
UNSPRUNG WEIGHT--Weight of a vehicle that is
operating circuit at a fixed rate and directs excess
not supported by springs.
flow to another operating circuit.
UPDRAFT CARBURETOR--A carburetor in which
VALVE, RELIEF--A pressure control valve whose
air passes through it in an upward direction.
primary function is to limit system pressure.
V-TYPE ENGINE--An engine with two banks of
VALVE SEAT--The surface, normally curved, against
cylinders set at an angle to each other in the shape
which the valve operating face comes to rest, to
of a V.
provide a seal against leakage.
VACUUM--A space entirely devoid of matter.
VALVE SEAT INSERT--A metal ring inserted into
the valve seat; made of special metal that can
VACUUM ADVANCE--The mechanism on an
withstand operating temperature satisfactorily.
ignition distributor that advances the spark in
accordance with vacuum in the intake manifold.
VALVE, SELECTOR--A directional control valve
whose primary function is to selectively
VACUUM BRAKE--Vehicle brakes that are actuated
interconnect two or more ports.
by vacuum under the control of the driver.
VALVE, SEQUENCE--A valve whose primary
VACUUM PUMP--A pump, used in a vacuum brake
function is to direct flow in a predetermined
system (for example), that produces a vacuum in a
sequence.
designated chamber.
VALVE, SERVO--A directional control valve that
VACUUM SWITCH--In the starting system, an
modulates flow or pressure as a function of its input
electric switch that is actuated by vacuum (in the
signal.
intake manifold) to open the starting system control
circuit after the engine starts.
VALVE, SHUTOFF--A valve that operates fully open
or fully closed.
VALVE--A device that controls fluid flow direction,
pressure, or flow rate.
VALVE SPRING--The compression-type spring that
closes the valve when the valve-operating cam
VALVE, CHECK--A directional control valve that
assumes a closed-valve position.
permits flow of fluid in only one direction.
VALVE TAPPET--The part that rides on the
VALVE, COUNTERBALANCE--A pressure control
valve-operating cam and transmits motion from the
valve that maintains back pressure to prevent a load
cam to the valve stem or push rod.
from falling.
VALVE TIMING--Refers to the timing of valve
VALVE, DIRECTIONAL CONTROL--A valve
closing and opening in relation to piston position in
whose primary function is to direct or prevent flow
the cylinder.
through selected passages.
VALVE TRAIN--The train of moving parts that
VALVE, FLOW CONTROL--A valve whose
causes valve movement.
primary function is to control flow rate.
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