Automotive Dictionary

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.

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

Synchromesh

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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.

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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.

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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.

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Automatic Synchronizer

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.

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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 oil: A non-petroleum based oil.

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.
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.

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