Automotive terms Modern (S)
Automotive Technical terms and abbreviations overview used in the industry, Guide and explanations.
The following are examples of Mid Modern technical terms for the letter S recommended for general use worldwide. For in-depth specific terms also see terms for historic vintage and specific areas such as Paint.
SEALED BEAM:
A automotive headlight. The lens, reflector and filament from a single unit.
SEATBELT INTERLOCK:
A system whereby the car cannot be started unless the seatbelt is buckled.
SECONDARY CIRCUIT:
The high voltage side of the ignition system, usually above 20,000 volts. The secondary includes the ignition coil, coil wire, distributor cap and rotor, spark plug wires and spark plugs.
SELF-INDUCTION:
The generation of voltage in a current-carrying wire by changing the amount of current flowing within that wire.
SEMI-CONDUCTOR:
A material (silicon or germanium) that is neither a good conductor nor an insulator; used in diodes and transistors.
SEMI-FLOATING AXLE:
In this design, a wheel is attached to the axle shaft, which takes both drive and cornering loads. Almost all solid axle passenger cars and light trucks use this design.
SENDING UNIT:
A mechanical, electrical, hydraulic or electromagnetic device which transmits information to a gauge.
SENSOR:
Any device designed to measure engine operating conditions or ambient pressures and temperatures. Usually electronic in nature and designed to send a voltage signal to an on-board computer, some sensors may operate as a simple on/off switch or they may provide a variable voltage signal (like a potentiometer) as conditions or measured parameters change.
SERIES CIRCUIT:
(See circuit, series.)
SERPENTINE BELT:
An accessory drive belt, with small multiple v-ribs, routed around most or all of the engine-powered accessories such as the alternator and power steering pump. Usually both the front and the back side of the belt comes into contact with various pulleys,
SERVO:
In an automatic transmission, it is a piston in a cylinder assembly that converts hydraulic pressure into mechanical force and movement; used for the application of the bands and clutches.
SHIFT BUSYNESS:
When referring to a torque converter clutch, it is the frequent apply and release of the clutch plate due to uncommon driving conditions.
SHIFT VALVE:
Classified as a relay valve, it triggers the automatic shift in response to a governor and a throttle signal by directing fluid to the appropriate band and clutch apply combination to cause the shift to occur.
SHIM:
Spacers of precise, predetermined thickness used between parts to establish a proper working relationship.
SHIMMY:
Vibration (sometimes violent) in the front end caused by misaligned front end, out of balance tires or worn suspension components.
SHORT CIRCUIT:
An electrical malfunction where current takes the path of least resistance to ground (usually through damaged insulation). Current flow is excessive from low resistance resulting in a blown fuse.
SHUDDER:
Repeated jerking or stick-slip sensation, similar to chuggle but more severe and rapid in nature, that may be most noticeable during certain ranges of vehicle speed; also used to define condition after converter clutch engagement.
SIMPSON GEARSET:
A compound planetary gear train that integrates two simple planetary gearsets referred to as the front planetary and the rear planetary.
SIPPING
Tire process to improve traction across rubber surface by cutting thin slits to improve traction in wet .
SINGLE OVERHEAD CAMSHAFT:
see overhead camshaft.
SKIDPLATE:
A metal plate attached to the underside of the body to protect the fuel tank, transfer case or other vulnerable parts from damage.
SLAVE CYLINDER:
In automotive use, a device in the hydraulic clutch system which is activated by hydraulic force, disengaging the clutch.
SLIPPING:
Noticeable increase in engine rpm without vehicle speed increase; usually occurs during or after initial clutch or band engagement.
SLUDGE:
Thick, black deposits in engine formed from dirt, oil, water, etc. It is usually formed in engines when oil changes are neglected.
SNAP RING:
A circular retaining clip used inside or outside a shaft or part to secure a shaft, such as a floating wrist pin.
SOFT:
Slow, almost unnoticeable clutch apply with very little shift feel.
SOFTCODES:
DTCs that have been set into the PCM memory but are not present at the time of testing; often referred to as history or intermittent codes.
SOHC:
Single overhead camshaft.
SOLENOID:
An electrically operated, magnetic switching device.
SPALLING:
A wear pattern identified by metal chips flaking off the hardened surface. This condition is caused by foreign particles, overloading situations, and/or normal wear.
SPARE
Term for spare tire to replace a flat tire normally hidden under floor.
SPARK PLUG:
A device screwed into the combustion chamber of a spark ignition engine. The basic construction is a conductive core inside of a ceramic insulator, mounted in an outer conductive base. An electrical charge from the spark plug wire travels along the conductive core and jumps a preset air gap to a grounding point or points at the end of the conductive base. The resultant spark ignites the fuel/air mixture in the combustion chamber.
SPARK-IGNITION
Ignition system. where the combustion process of the air-fuel mixture is ignited from a spark plug.
SPECIFIC GRAVITY (BATTERY):
The relative weight of liquid (battery electrolyte) as compared to the weight of an equal volume of water.
SPEEDOMETER
The speedometer is a gauge that measures and displays the speed of a vehicle early vehicles analogue and more modern often electric.
SPLINES:
Ridges machined or cast onto the outer diameter of a shaft or inner diameter of a bore to enable parts to mate without rotation.
SPLIT TORQUE DRIVE:
In a torque converter, it refers to parallel paths of torque transmission, one of which is mechanical and the other hydraulic.
SPONGY PEDAL:
A soft or spongy feeling when the brake pedal is depressed. It is usually due to air in the brake lines.
SPOOLVALVE:
A precision-machined, cylindrically shaped valve made up of lands and grooves. Depending on its position in the valve bore, various interconnecting hydraulic circuit passages are either opened or closed.
SPRAG CLUTCH:
A type of one-way clutch design using cams or contoured-shaped sprags between inner and outer races. (See one-way clutch.)
SPRUNG WEIGHT:
The weight of a car supported by the springs.
SQUARE-CUT SEAL:
Molded synthetic rubber seal designed with a square- or rectangular-shaped cross-section. This type of seal is used for both dynamic and static applications.
SRS: Supplemental restraint system
STABILIZER (SWAY) BAR:
A bar linking both sides of the suspension. It resists sway on turns by taking some of added load from one wheel and putting it on the other.
STAGE:
The number of turbine sets separated by a stator. A turbine set may be made up of one or more turbine members. A three-element converter is classified as a single stage.
STALL:
In fluid drive transmission/transaxle applications, stall refers to engine rpm with the transmission/transaxle engaged and the vehicle stationary; throttle valve can be in any position between closed and wide open.
STALL SPEED:
In fluid drive transmission/transaxle applications, stall speed refers to the maximum engine rpm with the transmission/transaxle engaged and vehicle stationary, when the throttle valve is wide open. (See stall; stall test.)
STALL TEST:
A procedure recommended by many manufacturers to help determine the integrity of an engine, the torque converter stator, and certain clutch and band combinations. With the shift lever in each of the forward and reverse positions and with the brakes firmly applied, the accelerator pedal is momentarily pressed to the wide open throttle (WOT) position. The engine rpm reading at full throttle can provide clues for diagnosing the condition of the items listed above.
STALL TORQUE:
The maximum design or engineered torque ratio of a fluid torque converter, produced under stall speed conditions. (See stall speed.)
STARTER:
A high-torque electric motor used for the purpose of starting the engine, typically through a high ratio geared drive connected to the fly-wheel ring gear.
STATIC:
A Sealing application in which the parts being sealed do not
STATOR (REACTOR):
The reaction member Of a fluid torque converter that changes the direction of the fluid as it leaves the turbine to enter the impeller vanes. During the torque multiplication phase, this action assists the impeller's rotary force and results in an increase in torque.
STEERING COLUMN
The steering column also performs the following secondary functions: provide mounting switch locations, or in some vehicles the gear selector.
STEERING GEOMETRY:
Combination of various angles of suspension components (caster, camber, toe-in); roughly equivalent to front end align
STEERING LOCK
An anti-theft device. fitted to the steering column disengaged by the ignition key or in modern cars electronically.
STEERING WHEEL
Normally a hand-held wheel to control vehicles. Makes the steering system responds to the driver inputs.
STRAIGHT ENGINE
The straight engine has all the cylinders aligned in a row.(also called inline engine)
STRAIGHT WEIGHT:
Term designating motor oil as suitable for use within a narrow range of temperatures. Outside the narrow temperature range its flow characteristics will not adequately lubricate.
STROKE:
The distance the piston travels from bottom dead center to top dead center.
SUBFRAME:
The structural component of a vehicle, a separate structure within a larger frame or body to spread chassis loads.
SUBSTITUTION:
Replacing one part suspected of a defect with a like part of known quality.
SUMP:
The storage vessel or reservoir that provides a ready source of fluid to the pump. In an automatic transmission, the sump is the oil pan. All fluid eventually returns to the sump for recycling into the hydraulic system.
SUN GEAR:
In a planetary gearset, it is the center gear that meshes with a cluster of planet pinions.
SUN VISOR
To help shade from the glare of sunlight this interior component above the windshield often hinged and adjustable and option on early transport.
SUPERCHARGER:
An air pump driven mechanically by the engine through belts, chains, shafts or gears from the crankshaft. Two general types of supercharger are the positive displacement and centrifugal type, which pump air in direct relationship to the speed of the engine.
SUPPLEMENTAL RESTRAINT SYSTEM:
see air bag.
SURGE:
Repeating engine-related feeling of acceleration and deceleration that is less intense than chuggle.
SUSPENSION
General term for the complete suspension system including shock absorbers springs and all components.
SWITCH:
A device used to open, close, or redirect the current in an electrical circuit.
SYNCHROMESH:
A manual transmission/transaxle that is equipped with devices (synchronizers) that match the gear speeds so that the trans-
mission/transaxle can be downshifted without clashing gears.
SYNTHETIC OIL:
Non-petroleum based oil.
