DEFINITION OF TERMS-CONTINUED
Antifreeze. A substance added to the coolant system In
Axial. In a direction parallel to the axis. Axial movement
a liquid-cooled engine to prevent freezing.
is movement parallel to the axis.
Antifriction Bearing. A bearing of the type that supports
Axis. A centerline. The line about which something
the imposed load on rolling surfaces (balls, rollers,
rotates or about which something is evenly divided.
needles), minimizing friction.
Axle. A cross support on a vehicle on which supporting
Antiknock. Refers to substances that are added to
wheel, or wheels, turn. There are two general types: live
automotive fuel to decrease the tendency to knock when
axles that also transmit power to the wheels, and dead
fuel-air mixture is compressed and Ignited In the engine
axles that transmit no power.
Backfiring. Preexplosion of fuel-air mixture so that
Armature. The rotating assembly in a direct current
explosion passes back around the opened Intake valve
generator or motor. Also, the iron piece In certain
and flashes back through the intake manifold.
electrical apparatus that completes a magnetic, and in
many cases, an electric, circuit.
Backlash. The backward rotation of a driven gear that is
permitted by clearance between meshing teeth of two
A fibrous material that resists heat and
Back Pressure. The resistance of gases to flow through
ATDC. After top dead center.
Atmosphere. The mass of air that surrounds the earth.
Baffle. A plate or shield to divert the flow of liquid or gas.
Atmospheric Pressure. The weight of the atmosphere
A resistor that changes voltage In direct
per unit area.
proportion to heat of wire.
Atom. The smallest particle, or part, of an element,
Ball Bearing. A type of bearing that contains steel balls
composed of electrons and protons and also of neutrons
that roll between inner and outer races.
(with the exception of hydrogen).
Battery. A device consisting of two or more cells for
Atomization. The spraying of a liquid through a nozzle so
converting chemical energy into electrical energy.
that the liquid is broken into tiny globules or particles.
Battery Capacity. Rating of a battery's current output.
Automatic Choke. A choke that operates automatically
in accordance with certain engine conditions, usually
Battery Charging. The process of supplying a battery
temperature and intake manifold vacuum (also
with a flow of electric current to produce chemical actions
in the battery; these actions reactivate the chemicals in
the battery so they can produce electrical energy again.
Automatic Leveling Control. A system designed to
maintain proper riding height, regardless of changes In
Battery, Maintenance-Free. A battery that does not
require addition of water during its normal life.
Automatic Transmission. A transmission that reduces or
Battery Rating. A standardized measurement of a
eliminates the necessity of hand shifting of gears to
battery's ability to deliver electrical power under certain
secure different gear ratios in the transmission.