APPENDIX I
GLOSSARY
(gasoline and diesel), it is mounted on or in-line
ABDC--After bottom dead center.
with the air inlet housing. A filtering device in the
ABSOLUTE--The temperature measured using ab-
air cleaner removes dust and dirt particles from the
solute zero as a reference. Absolute zero is
air.
-273.16C or -459.69F.
AIR CONDITIONING--A system designed to pro-
ACCELERATION--Time rate of change of veloc-
vide control over air temperature, movement, and
ity.
humidity.
ACCELERATION PUMP--A device in the car-
AIR-COOLED ENGINE--An engine cooled by air
buretor that supplies an additional amount of fuel,
circulating between the cylinders and around the
temporarily enriching the fuel-air mixture when the
cylinder heads, as opposed to the liquid-cooled
throttle is suddenly opened.
engine that is cooled by a liquid passing through
jackets surrounding the cylinders.
ACCELERATOR--Pedal and linkage used to control
engine speed.
AIR FILTER--A filter through which air passes, and
which removes dust and dirt particles from the air.
ACCUMULATOR--A device for storing liquid under
Air filters are placed in passages through which air
pressure. It usually consists of a chamber separated
must pass, as in the crankcase breather, air cleaner,
into a gas compartment and a liquid compartment
etc.
by a piston or diaphragm. An accumulator also
serves to smooth out pressure surges in a hydraulic
AIR-FUEL RATIO--The ratio between the volume
system.
of air and the volume of fuel used to establish
the combustible mixture in the cylinder of an
AC--Alternating current or current that reverses its
internal-combustion engine.
direction at regular intervals.
AIR HORN--That part of the air passage in the
ACTUATOR--A device that converts fluid power into
carburetor of a gasoline engine that is on the
mechanical force and motion.
atmospheric side of the venturi. The choke valve is
ADDITIVE--A chemical compound or compounds
located in the air horn.
added to a fluid to change its properties.
ALLOY--A mixture of two or more metals.
AFFF (AQUEOUS FILM FORMING FOAM)--(A
ALTERNATOR--An electrical system device that
fire fighting agent.) A liquid concentrate, which
converts mechanical energy into electrical energy
consists primarily of synthetic fluorocarbon
for charging the battery. Also known as an ac
surfactant materials.
generator, the alternator produces alternating
AIR, COMPRESSED--Air at any pressure greater
current (ac) which must be changed (rectified) to
than atmospheric pressure.
direct current for use in an automotive electrical
system.
AIR BLEED--A passage in the carburetor through
which air can seep or bleed into fuel moving
AMBIENT--Surrounding, such as ambient air, mean-
through a fuel passage.
ing surrounding air.
AIR BRAKES--Vehicle brakes actuated by air pres-
AMBIENT TEMPERATURE--The temperature of
sure.
the environment surrounding an object.
AIR CLEANER--A device through which air must
AMMETER--An electric meter that measures cur-
pass before entering the cylinders of an
rent, in amperes, in an electric circuit.
internal-combustion engine. On gasoline engines
AMPERE--Unit of measurement of electric current
equipped with carburetors, it is mounted on the
flow. The current that will flow through a 1-ohm of
carburetor air horn. On engines with fuel injection
AI-1