DEFINITION OF TERMS-CONTINUED
Dolly. A two-wheel trailer coupled to a semitrailer to
high-voltage sparks to the engine cylinders to fire
support and steer its front end when it is converted into a
compressed fuel-air charges, lights the lights, and
operates heater motor, radio, etc. Consists, in part, of
starter, wiring, battery, generator, generator regulator,
Drag Link. An intermediate link in the steering system
Ignition distributor, and ignition coil.
between the pitman arm and an intermediate arm, or
Electricity. A form of energy that involves the movement
of electrons from one place to another, or the gathering
Drive Shaft. A shaft used to transmit rotary motion.
of electrons in one area.
Drop Center Rim. A rim in which the center section is
Electrode. Either terminal of an electric source; either
closer to the center of the rim than the two outer edges.
conductor by which the current enters and leaves an
Drop Forged. A part that has been formed by heating
until red hot and pounding with a hammer.
The liquid in a battery or other
electrochemical device, in which the conduction of
Dry Sleeve. A cylinder sleeve that is supported its entire
electricity is accompanied by chemical decomposition.
length by the block; coolant does not contact the sleeve
in this configuration.
Electromagnet. A temporary magnet constructed by
winding a number of turns of insulated wire into a coil or
Dry Sump. An oiling system that uses a scavenger
around an iron core; it is energized by a flow of electric
pump to collect oil and transfer it to an auxiliary container
current through the coil.
Electron. A negative-charged particle that is a basic
Dual Ignition. An ignition system using two spark plugs
constituent of matter and electricity. Movement of
for each cylinder so that a dual spark effect takes place,
electrons is an electric current.
driving each power stroke.
Electron Theory. A theory stating that electron flow is
Dual-Ratio Axles. An axle in a truck that contains a
from one area to another.
mechanism for changing driving ratio of the wheels to
either high or low ratio. Two-speed differential.
EMF. Electromotive force.
Dynamometer. A device for measuring the power output
Emissions. Products of automotive engine combustion
of an engine.
that are released into the atmosphere.
Energy. The capacity for performing work.
Eddy Currents. Currents that are induced in an iron core
Engine. An assembly that burns fuel to produce power;
and circulate in the core.
sometimes referred to as the powerplant.
Efficiency. The ratio between the effect produced and
Ethylene Glycol. A solution added to antifreeze to help
the power expended to produce the effect.
Electric Brakes. A brake system that uses electric
Evaporation. The action that takes place when a liquid
current for energizatlon.
changes to a vapor or gas.
Electrical System. In the automotive vehicle, the system
Evaporator. A unit in an air conditioning system used to
that electrically cranks the engine for starting, furnishes
absorb heat from a passing airstream.