D-Pillar or D-Post
The vertical or sometimes diagonal roof supporting member located
at the extreme rear of the roof or greenhouse structure on station
wagons and some sedan models.
solid or hollow form used for shaping materials by stamping, pressing,
extruding, drawing or threading.
A diesel engine uses heavier weight components than gas engines
to handle higher compression ratios. Typically, diesel engines run
with greater efficiency and higher torque than similar size gas
engines. These attributes lead to better fuel economy and towing
performance. Diesel engines do not have spark plugs or carburetors.
Instead glow plugs are used to preheat air in the cylinders to ensure
easy starts. Once the engine is started, compression heats the fuel
in the cylinders for combustion.
A condition in which gasoline continues to fire after the ignition
has been shut off. In late-model engines, dieseling , or run-on,
is caused by heat and the unusually high manifold pressure that
result from retarding the spark at idle. In fuel-injected cars when
the engine is turned off, fuel is automatically shut off, eliminating
The gear assembly connected to the drive shaft that permits the
wheels to turn at different speeds when going around a corner, while
transmitting power from the drive shaft to the wheel axles.
The same attributes of a standard differential, except that when
one wheel is slipping, the most torque is supplied to the wheel
with best traction. A locking differential reduces the possibility
of a vehicle becoming immobile when one driving wheel loses traction.
A vehicle's ability to maintain a true course of travel despite
bumps, crosswinds, uneven road surfaces.
Properly called caliper disc brakes, a type of brake that consists
of a rotor that rotates at wheel speed, straddled by a caliper that
can squeeze the surfaces of the rotor with brake pads near its edge.
Disc brakes provide a more linear response and operate more efficiently
at high temperatures and during wet weather than drum brakes.
In an engine, the total volume of air or air-fuel mixture an engine
is theoretically capable of drawing into all cylinders during one
operating cycle. Generally expressed in liters or cubic inches.
Engine displacement is equal to (bore) x (bore) x (stroke) x (number
of pistons) x (.785).
A component of the ignition system, usually driven by the camshaft
that directs high-voltage surges to the spark plugs in the proper
Double Wishbone Suspension
("A" Arm Suspension)
A system of independent suspension in which each wheel is located
on a "knuckle" that is connected by ball joints to an
upper A arm and a lower A arm. Usually, the lower A arms are longer.
This system provides minimal changes in track and camber when the
suspension is under load, as when going over bumps or in hard cornering.
A measure of the aerodynamic sleekness of an object. Drag coefficient
is signified by "dc.: The lower the number, the greater the
aerodynamic efficiency. The higher the drag coefficient, the more
a car's engine must work to keep a given road speed. Also known
as "CD" for coefficient of drag."
The shaft that transmits power from the transmission to the differential
in a rear-drive power train.
The power-transmitting components in a car, including clutch, gearbox
(or automatic transmission), driveshaft, universal joints, differential
and axle shafts.
Dual Overhead Camshafts
A DOHC engine has two camshafts in each cylinder head; one camshaft
actuates intake valves and the other actuates exhaust valves. The
camshafts act directly on the valves, eliminating pushrods and rocker
arms. This reduced reciprocating mass of the valve train enables
the engine to build RPM more quickly. DOHC designs are typically
high-performance, four valve per cylinder engines. (A four valve
per cylinder two intake and two exhaust design helps the engine
"breathe" more freely for increased performance.)
A device which absorbs and measures the power derived by an internal