| S.A.E. |
|
| Society of Automotive Engineers. The professional association of transportation-industry engineers. A group known for publishing research papers and defining various standards of measurement. The SAE |
|
| Safety Restraint Systems |
|
| Devices that reduce injury in the event of a accident. Typical examples include safety belts and airbags. |
|
| Sealed Beam |
|
| A one-piece, hermetically sealed headlight in which the filament is an integral part of the unit, and the lens itself is the bulb. |
|
| Sedan |
|
| A closed, fixed-roof car for four or more passengers with either two or four doors. (Called saloon in U.K.) |
|
| Selective Transmission |
|
| The conventional manual transmission of today in which any gear may be selected at will as opposed to the very early progressive transmission in which the gears had to be selected in order. |
|
| Semi-elliptic leaf spring |
|
| A slightly curved leaf spring that is attached to a car`s body at its ends and to a suspension component near its middle. One of the two body attachments is a shackle, which allows for changes in the spring`s length as it flexes up and down. |
|
| Semi-trailing-arm suspension |
|
| An independent rear-suspension system in which each wheel hub is located only by a large, roughly triangular arm that pivots at two points. Viewed from the top, the line formed by the two pivots is somewhere between parallel and perpendicular to the car`s longitudinal axis. |
|
| Series (tire) |
|
| The numerical representation of a tire`s aspect ratio. A 50-series tire has an aspect ratio of 0.50. |
|
| Shift Gate |
|
| The mechanism in a transmission linkage that controls the motion of the gearshift lever. The shift gate is usually an internal mechanism; however, in some transmissions: including Ferrari five-speeds and Mercedes-Benz automatics : the shift gate is an exposed guide around the shift lever. |
|
| Single-rate spring |
|
| A spring with a constant spring rate. For example, if a 100-pound force deflects the spring by one inch, an additional 100 pounds will deflect it one more inch, and so on until the spring either bottoms or fails. |
|
| Sleeve Valve |
|
| Consists of metal sleeves located between the piston and cylinder wall. When moved up and down, holes in the sleeves coincide with inlet and exhaust parts to provide passage for the gases at the right time. |
|
| Slip angle |
|
| The angular difference between the direction in which a tire is rolling and the plane of its wheel. Slip angle is caused by deflections in the tire`s sidewall and tread during cornering. A linear relationship between slip angles and cornering forces indicates an easily controllable tire. |
|
| Slushbox |
|
| A slang for an automatic transmission.
|
|
| SOHC |
|
| Acronym for single overhead cam (see Overhead Cam). An SOHC engine uses one camshaft in each cylinder head to operate both the exhaust valves and the intake valves. |
|
| Space frame |
|
| A particular kind of tube frame that consists exclusively of relatively short, small-diameter tubes. The tubes are welded together in a configuration that loads them primarily in tension and compression. |
|
| Spark Plug |
|
| The spark plug converts high voltage energy into an arc that passes between its electrodes. The arc causes the gasoline-air mixture in the cylinder to ignite and expand, providing power by pushing down the piston. |
|
| Sports Car |
|
| An agile vehicle that is easily maneuverable, accelerates briskly, brakes positively, handles well and steers precisely. It is tightly sprung and does not wallow and heave as does a conventional passenger car and is therefore not as comfortable. |
|
| Spyder or Spider |
|
| In the early 1900s, a light two-seater car. In the 1950s the word was revived by some Italian manufacturers for an open two seater sports car.
|
|
| Squat |
|
| The opposite of dive, squat is the dipping of a car`s rear end that occurs during hard acceleration. Squat is caused by a load transfer from the front to the rear suspension. |
|
| Stamping |
|
| A process technology which manufactures automotive parts by shaping rolled sheet metal or by bending or stretching it in a sequence of purpose-built tools fitted to a general purpose press. |
|
| Standard Industrial Classification (1980) |
|
| Catalogue No. 12-E Standard Industrial Classification (SIC) industry class that represents a level of organization of production by type of specialization. Currently the 1980 Standard Industrial Classification is in effect identifying each industry at the 4 digit level.
|
|
| Starter |
|
| A motor powered by the battery that rotates the crankshaft before the engine is started. |
|
| Steering Axis |
|
| The line that intersects the upper and lower steering pivots on a steered wheel. On a car with a strut suspension, the steering axis is defined by the line through the strut mount on top and the ball joint on the bottom. |
|
| Steering feel |
|
| The general relationship between forces at the steering wheel and handling. Ideally, the steering effort should increase smoothly as the wheel is rotated away from center. In addition, the steering effort should build as the cornering forces at the steered wheels increase. Finally, the friction built into the steering mechanism should be small in comparison with the handling-related steering forces.
|
|
| Steering gain |
|
| The relationship between yaw and the steering wheel`s position and effort. All three should be proportional and should build up smoothly. |
|
| Steering Geometry |
|
| The group of design variables outside the steering mechanism that affect steering behavior, including camber, caster, linkage arrangement, ride steer, scrub radius, toe-in, and trail. |
|
| Steering Response |
|
| A subjective term that combines steering feel and steering gain. |
|
| Steering, Power |
|
| Assist provided by the engine to reduce steering effort. Power steering is essential to make large, heavy vehicles manageable. Small vehicles often do not require power steering.
|
|
| Steering, Rack and Pinion |
|
| A common steering type. The steering wheel is connected to a pinion gear that meshes with a rack, or linear gear. As the pinion rotates, the rack moves side to side, this moves the steering linkage, causing the wheels to pivot left or right.
|
|
| Straight-line Tracking |
|
| The ability of a car to resist road irregularities and run in a straight line without steering corrections. |
|
| Stroke |
|
| The back-and-forth motion of the piston. The length of the motion of the piston from top dead center to bottom dead center. |
|
| Strut |
|
| A suspension element in which a reinforced shock absorber is used as one of the wheel`s locating members, typically by solidly bolting the wheel hub to the bottom end of the strut.
|
|
| Sump |
|
| The space in the engine block under the crankshaft into which the oil drains from its various applications.
|
|
| Supercharger (Blower) |
|
| An air compressor used to force more air into an engine than it can inhale on its own. The term is frequently applied only to mechanically driven compressors, but it actually encompasses all varieties of compressors-including turbochargers. |
|
| Supplier Cost Reduction Effort (SCORE) |
|
| a United States program that urges suppliers to develop processes to cut costs. Suppliers are allowed to keep half the savings and pass on the other half to the automakers.
|
|
| Suspension |
|
| The assembly of springs, shock absorbers, torsion bars, joints, arms, etc., that cushions the shock of bumps on the road and serves to keep the wheels in constant contact with the road, thereby improving control and traction. |
|
| SUV |
|
| Sport Utility Vehicle.
|
|
| Swing Axle |
|
| Type of independent rear suspension using half shafts that have universal joints only at their inboard ends on both sides of the differential. This causes a camber angle change of the wheel with up-and-down wheel movements. |
|