DRY SLEEVE--A cylinder sleeve that is supported its
DIAGRAM, SCHEMATIC--(See DIAGRAM,
entire length by the block and coolant does not
GRAPHICAL.)
contact the sleeve.
DIAPHRAGM--A flexible membrane, usually made
DRY SUMP--A lubricating system that uses a
of fabric and rubber, in hydraulic and pneumatic
scavenger pump to collect oil and transfer it to an
components.
auxiliary container or sump.
DIESEL ENGINE--An engine using the diesel cycle
DUAL IGNITION--An ignition system using two
of operation. Air alone is compressed in the
spark plugs for each cylinder so that a dual spark
cylinder and diesel fuel is injected at the end of the
effect takes place, driving each power stroke.
compression stroke. Heat of compression produces
ignition.
DYNAMOMETER--A device for measuring the
power output of an engine.
DIESELING--A condition in which an engine con-
tinues to run after the ignition is turned off. Also
ECCENTRIC--Offcenter; as in the eccentrics (lobes)
referred to as engine run-on.
on a camshaft.
DIFFERENTIAL--A mechanism between the axles
EDDY CURRENTS--Currents that are induced in a
that permits one axle to turn at a different speed
conducting material that are caused by a varying
than the other and, at the same time, transmits
magnetic field.
power from the driving shaft to the axles.
EFFICIENCY--The ratio between the effect
DIFFUSER--A duct of varying cross section designed
produced and the power expended to produce the
to convert a high-speed gas flow into low-speed at
effect.
an increased pressure.
ELECTRIC BRAKES--A brake system that uses
DIODE--A device that permits current flow in one
electric current for energization.
direction and resists flow in the other.
ELECTRICAL SYSTEM--The system that pro-
DISC BRAKE--A braking network that uses a
vides the necessary input power to operate such
rotating disk called a rotor and stationary brake
components. In an automotive vehicle, the system
pads such that when forced together perform a
that electrically cranks the engine for starting,
retarding action.
furnishes high-voltage sparks to the engine
cylinders to fire compressed fuel-air charges, lights
DISPLACEMENT--The total amount of air or liquid
the lights, and operates heater motor, radio, etc. It
an object consumes or moves while moving from
consists, in part, of the starter, wiring, battery,
one location to another.
alternator, alternator regulator, ignition distributor,
DISTRIBUTION TUBES--Tubes in the cooling
and ignition coil.
system used to direct coolant flow to vital areas.
ELECTRICITY--A form of energy that involves the
DISTRIBUTOR--See IGNITION DISTRIBUTOR.
movement of electrons from one place to another,
DIVERGENT--Moving away from each other, as the
or the gathering of electrons in one area.
inner wall of a tube that flares outward.
ELECTRODE--Either terminal of an electric source;
DOHC--Double overhead camshaft.
either conductor by which the current enters and
leaves an electrolyte.
DRAG LINK--An intermediate link in the steering
system between the pitman arm and an inter-
ELECTROLYTE--A solution that is capable of
mediate arm, or drag-link arm.
conducting electricity. It may be in the form of
either a liquid or paste.
DRIVE SHAFT--A shaft used to transmit rotary
motion. In an automotive drive train, the drive shaft
ELECTROMAGNET --A t e m p o r a r y m a g n e t
transmits power from the transmission to the dif-
constructed by winding a number of turns of
ferential. Also called the propeller shaft.
insulated wire into a coil or around an iron core. It
is energized by a flow of electric current through
DROP FORGED--A part that has been formed by
the coil.
heating until red hot and pounding with a hammer.
AI-8
