COMMUTATOR--A mechanical device that reverses
CHASSIS--An assembly of mechanisms, attached to
armature connections in a motor or generator at the
a frame, that make up the major operating parts of
proper instant so that current continues to flow in
an automotive vehicle (less the body).
one direction only.
CHEMICAL CHANGE--A change that alters the
COMPENSATING PORT--A small hole in the brake
composition of the molecules of a substance.
master cylinder to permit fluid to return to the
CHOKE--A device in a carburetor that blocks off, or
reservoir.
reduces, the flow of air into the intake manifold.
COMPRESSIBILITY--The change in volume of a
This produces a partial vacuum in the intake
unit volume of a fluid when it is subjected to a unit
manifold and a consequent richer fuel-air mixture.
change of pressure.
CHOKE STOVE--A device used to draw heat from
COMPRESSION--The act of pressing into a smaller
around the exhaust manifold into the carburetor
space or reducing in size or volume by pressure.
during engine warmup.
COMPRESSION RATIO--The ratio between the
CID--Cubic inch displacement.
volume in a cylinder with the piston at bottom dead
CIRCUIT--A closed path or combination of paths
center and with the piston at top dead center.
through which passage of the medium (electric
COMPRESSION RINGS--The upper rings on a
current, air, liquid, etc) is possible.
piston. They are designed to hold the compression
CIRCUIT BREAKER--In electric circuits, a device
in the cylinder and prevent blowby.
designed to break or open the circuit when certain
COMPRESSION STROKE--The piston stroke from
conditions exist.
bottom dead center to top dead center during which
CLEARANCE--A given amount of space between
both valves are closed and the gases in the cylinder
two parts.
are compressed.
CLOCKWISE--The direction of movement, usually
COMPRESSOR--A device that converts mechanical
rotary, which is the same as movement of hands on
force and motion into pneumatic fluid power.
the face of a clock.
COMPUTER--A device capable of accepting in-
CLUTCH--The mechanism in an automotive vehicle,
formation, applying prescribed processes to the
located in the power train, that connects the engine
information, and supplying the results of these
to, or disconnects the engine from, the remainder of
processes.
the power train.
CONCENTRIC--Having a common center, as circles
COIL--In electrical circuits, turns of wire, usually on
or spheres, one within the other.
a core and enclosed in a case, through which
CONDENSE--To transform a vapor into a liquid.
electric current passes.
CONDENSATION--The change from a gaseous (or
COIL SPRING--A type of spring made of an elastic
vapor) state to a liquid state.
metal such as steel, formed into a wire or bar and
wound into a coil.
CONDENSER--(1) A unit used in air-conditioning
and refrigeration systems that removes heat of
COMBUSTION--A chemical action, or burning; in
compression from a gas to return it to a liquid state.
an engine, the burning of a fuel-air mixture in the
(2) See also CAPACITOR.
combustion chamber.
CONDUCTOR--A material through which electricity
COMBUSTION CHAMBER--The space at the top
will flow readily.
of the cylinder and in the head in which combustion
of the fuel-air mixture takes place.
CONNECTING ROD--The linkage between the
crankshaft and piston, usually attached to the
COMMUTATION--The process of converting
piston by a piston pin and to the journal on the
alternating current that flows in the armature
crankshaft by a split bearing and bearing cap.
windings of direct current generators into direct
current.
CONTAMINANT--Detrimental matter in a fluid.
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