Automotive Technical Terms |
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Throughout this site we use
many technical terms, and given the breadth of readership
our site enjoys, sometimes we are remiss and incorrectly
assume everyone knows what we are referring to. For those
that do not, here are some explanations of the technical
terms use. |
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Shock Absorber:
Alternatively 'damper', generally a hydraulic device
that minimises unnecessary road spring oscillations.
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Solenoid:
An electrical device that consists of a sliding iron
bar within an electrical coil. Used to transfer electrical
energy into mechanical motion. Main automotive application
is in starter motors.
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Spark Plugs:
Screwed into the combustion chamber and used to ignite
the compressed air-fuel mixture.
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Steering Ratio:
Steering systems are geared down, usually in the ratio
3:1 to 5:1 to reduce the steering effort. The ratio indicates
how many times the wheel is turned to move the road wheels
from one lock to the other, and so a ratio of 3:1 would
require three complete rotations of the steering wheel
to complete a lock to lock transition.
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Stroke:
The piston stroke from top dead centre to bottom dead
centre.
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Swing Axle:
Independent rear suspension favored by the European
manufacturers through the 1950's to late 1960's, typically
found in the Volkswagen Beetle, some Mercedes models
and rear-wheel drive Renault's. It consists of independently
sprung shafts that are attached directly to the gearbox.
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Synchromesh:
A function of a gearbox that allows gears to engage without
noise.
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Tachometer:
An instrument that measures engine speed in revolutions
per minute.
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Tappet:
Part of a rocker assembly that actuates both inlet and
exhaust valves and has a facility for valve clearance
adjustment.
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Torque Tube:
A tube that fully encloses a propeller or drive shaft
that helps relieve the rear springs of driving and braking
forces. A superior but older design, most commonly
found on the Peugeot 404. |
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Torsion Bar:
A type of spring commonly used in automotive suspension
that consists of a high tensile steel bar that is fixed
solidly at one end while the other end is attached to the
suspension arm or wishbone. The springing effect is created
by twisting the bar around its own axis.
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Track:
The lateral distance between the wheels of a vehicle. Most
cars have different front and rear tracks.
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Trailing Arms:
A type of indepoendent suspension found on the rear of
many front-wheel-drive vehicles. Consists of a single
arm per wheel that moves parallel to the longitudinal
axis of the car.
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Trans-Axle:
A mechanical component that consists of the gearbox, clutch, differential and
final drive gears combined in one unit. Originally found in the VW Beetle and
rear-wheel-drive Renault's, then in the Porsche 924 and Alfa Romeo Alfetta's.
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Transistorised Ignition:
An ignition system that utilises magnetic induction or other electronic means
to make and break the low-tension ignition circuit, it has today replaced the
use of control breaker points.
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Tuned Length:
Refers to an exhaust or inlet system that has a specific length designed to optimise
performance in a specific rev range, usually at higher revs.
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Twin Choke:
A type of carburetor that has two chokes or throats instead of the usual single
throat. Several types are found including those whose throats open simultaneously
and progressive types where the second throat opens after the first throat is
approximately two-thirds open.
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