Dictionary of Automotive Terms Abbreviations

DICTIONARY OF AUTOMOTIVE TERMS - "Sy"

Sylphon seal: Corrugated metal tubing used to hold seal ring and provide leakproof connection between seal ring and compressor body or shaft.

Symmetrical: Symmetrical tread is the most common tread design. Both halves of the tread face are the same design. It does not matter which side faces out.

Also See
asymmetrical Tread
directional tire.

Symmetric rim: A rim type in which the rim well is located symmetrically on the wheel centerline. Opposite to asymmetric rim

Synchromesh: Click image to supersize
Synchromesh transmission

A device in a manual transmission that allows two gears to mesh more smoothly. When a synchronizer gear matches the speed of the transmission main shaft to the speed of the gear being selected, they mesh smoothly and prevent grinding and clashing of gears. It was first introduced by Cadillac in 1928.

Also See
locking synchromesh
porsche-type synchromesh
proportional load synchromesh

Synchromesh transmission: A transmission using a device ( synchromesh) that synchronizes the speeds of gears that are being shifted together. This prevents "gear grinding." Some transmissions use a synchromesh on all shifts while others synchronize second and high gearshifts.

Synchronize: To bring about a timing that will cause two or more events to occur simultaneously; plug firing when the piston is in the correct position, the speed of two shafts being the same, a valve opening when the piston is in the correct position, etc. Also see synchronizer.

Synchronized Transmission: A transmission with built-in mechanisms to automatically "equalize" the speed of its gears to allow smooth shifting without the need to double-clutch

Synchronizer: A cone or sleeve that slides to and fro on the transmission main shaft and makes the gears rotate at the same speed to prevent clash when the gears are about to mesh. Whenever a vehicle is rolling, the transmission main shaft is turning and the clutch gear is spinning. Even though the clutch is disengaged, the clutch gear continues to spin until friction slows it down or stops it. Thus when the driver shifts into another gear he is trying to mesh gears that may be moving at different speeds. By using synchronizers, the possibility of broken or damaged teeth is reduced and shifting effort is lowered. A transmission using synchronizers is called a synchromesh transmission.

Synchronous motor: An alternating-current motor that runs at a speed that is equal to or is a multiple of the frequency of the supply (e.g., the drive motor of electric powered vehicles)

Synchronous speed: The speed of the rotating magnetic field set up by an energized stator winding. In synchronous electric motors, the rotor locks into synchronism with the field, and is said to run at synchronous speed

Synergetic effect: A protective effect occurring as a result of the combination of a metallic and an additional organic coating

Synergistic effect: A protective effect occurring as a result of the combination of a metallic and an additional organic coating

Synthesizer: A device which generates quartz-controlled frequency steps in a PLL circuit. Also see speech synthesizer

Synthetic dust weight arrestance: Measurement of filter's ability to remove synthetic dust from test air.

Synthetic engine oil: A non-petroleum based oil; more expensive than mineral oil but more resistant to breakdown at high temperatures and less viscous at low temperatures

Synthetic lining: Non-asbestos, non-metallic brake linings reinforced with fiberglass and/or aramid fiber.

Synthetic natural gas: (SNG) (Also referred to as substitute natural gas) A manufactured product, chemically similar in most respects to natural gas, resulting from the conversion or reforming of hydrocarbons that may easily be substituted for or interchanged with pipeline-quality natural gas.

Synthetic rubber

A man-made elastomer. The raw materials are generally derived from oil by-products. Produced by the polymerization or copolymerization of petroleum-derived olefins or other unsaturated compounds. Also see natural rubber.
Any rubber which is manufactured by a chemical process as distinguished from natural rubber obtained from trees. Typical examples of chemical rubbers are GR-S, butyl, neoprene, nitrile, and polysulfide rubbers.

Synthetic rubber, neoprene: Soft resilient material made of a synthetic chemical compound.

System: An orderly, interconnected, complex arrangement of parts.

Also See
accumulator system
air filtration system
air injection reaction system
air system
alarm system
anti-dive system
anti-lock brake system
anti-noise system
anti-squat system
anti-theft system
bleeding a system
brake system
braking system
bumper system
C-4 system
charging system
clear system
closed loop system
closing system
controlled combustion system
coolant recovery system
cooling system
diagonally split system
electrical system
electronic ignition system
engine-control system
exhaust system
flushing the cooling system
fuel system
fuel vapor recirculation system
ignition system
induction system
linear wiper system
lubrication system
microprocessor spark timing system
oil-combination splash and pressure system
oil-full pressure system
oil-splash system
open loop system
PCV system
performance handling system
positive crankcase ventilation system
pulse air system
starting system
steering system
supplemental restraint inflatable air-bag system
suspension system
triangle-split system
vapor recovery system
voice alert system

System pressure: Fuel pressure in the CIS fuel distributor controlled by the pressure reguklator

System pressure regulator: A pressure relief valve located on the fuel distributor. In a continuous injection system, it holds system fuel pressure constant. See K-jetronic

System with electronic: See
high energy ignition system with electronic spark timing

System with electronic spark: See
high energy ignition system with electronic spark timing

System with electronic spark timing: See
high energy ignition system with electronic spark timing