AUTOMOBILE

byname auto, also called motorcar, or car a usually four-wheeled vehicle designed primarily for passenger transportation and commonly propelled by an internal-combustion engine using a volatile fuel. The modern automobile is a complex technical system employing subsystems with specific design functions. Some of these consist of thousands of component parts that have evolved from breakthroughs in existing technology or from new discoveries such as electronic computers, high-strength plastics, and new alloys of steel and nonferrous metals, as well as from factors such as air pollution, safety legislation, and foreign competition. Passenger cars have emerged as the primary means of family transportation, with the total number in use worldwide expected to reach half a billion in the 1990s. One-third of these are in the United States, where more than 1.5 trillion miles are traveled each year. Approximately 500 different models have been offered annually to U.S. car buyers, about half domestic and half foreign in origin. New designs have been brought into the market more quickly in recent years than in the past to permit manufacturers to capitalize on their proprietary technological advances. With more than 30 million new units built each year worldwide, manufacturers have been able to split up the total into many very small segments that nonetheless remained economical to market. New technical developments are recognized to be the key to successful competition. Research and development engineers and scientists have been employed by all automobile manufacturers and suppliers to improve the car body, chassis, engine, drivetrain, vehicle control systems, occupant safety, and environmental emissions, and further work by the industry is necessary to meet the needs of the 21st century. Vehicle design depends to a large extent on its intended use. Automobiles for off-road use in countries that lack service facilities must be durable, simple systems with high resistance to severe overloads and extremes in operating conditions. Conversely, the customers for products that are intended for the high-speed, limited-access road systems in Europe and North America expect more passenger comfort options, increased engine performance, and optimized high-speed handling and vehicle stability. Stability depends principally on the distribution of weight between the front and rear wheels, the height of the centre of gravity and its position relative to the aerodynamic centre of pressure of the vehicle, suspension characteristics, and whether front or rear wheels are used for propulsion. Weight distribution depends principally on the location and size of the engine. The common practice of front-mounted engines exploits the stability that is more readily achieved with this layout. The development of aluminum engines and new manufacturing processes have, however, made it possible to locate the engine at the rear without necessarily compromising stability. byname Auto, also called Motorcar, or Car, a usually four-wheeled automotive vehicle designed primarily for passenger transportation and commonly propelled by an internal-combustion engine using a volatile fuel. Although by the mid-15th century the idea of a self-propelled vehicle had been put into practice (with the development of experimental vehicles powered by means of springs, clockworks, and the wind), Nicolas-Joseph Cugnot of France is considered to have built the first true automobile in 1769. The vehicle, which was designed as an artillery carriage, was a steam-powered tricycle capable of carrying four passengers for 20 minutes at 2.25 miles (3.6 kilometres) per hour. In Britain, during the first half of the 19th century, steam-powered vehicles, although noisy, smelly, and dangerous because of the possibility of boiler explosions, were used on several routes for public transportation. Despite the development of the four-stroke gasoline-powered engine in 1876 by the German engineer Niklaus August Otto, steam and electricity remained the most widespread forms of automotive power until the beginning of the 20th century. Gasoline-powered engines eventually prevailed, however, because they allowed vehicles to travel at higher speeds and for longer distances than steam- or electric-powered engines and were safer and less troublesome than steam-powered ones. The pioneers of automobile manufacturing in Europe were Gottlieb Daimler and Carl Benz of Germany, who began, separately, to make cars in the 1880s (their companies were later merged). In the United States, Ramson Eli Olds and Alexander and James Packard were among the first builders of automobiles. In 1898 there were 50 automobile-manufacturing companies in the United States, a number that rose to 241 by 1908. In that year Henry Ford revolutionized the manufacture of automobiles with his assembly-line style of production and brought out the Model T, a car that was inexpensive, versatile, and easy to maintain. The introduction of the Model T transformed the automobile from a plaything of the rich to an item that even people of modest income could afford; by the late 1920s the car was commonplace in modern industrial nations. Automobile manufacturers in the 1930s and 1940s refined and improved on the principles of Ford and other pioneers. Cars were generally large, and many were still extremely expensive and luxurious; many of the most collectible cars date from this time. The increased affluence of the United States after World War II led to the development of large, gas-consuming vehicles, while most companies in Europe made smaller, more fuel-efficient cars. Since the mid-1970s the rising cost of fuel has increased the demand for these smaller cars, many of which have been produced in Japan as well as in Europe and the United States. An average automobile is made of roughly 14,000 parts, which can be divided into several structural and mechanical subsystems. The most basic of these is the body of the automobile, which contains the passenger and storage space as well as the engine compartment. It is usually classified according to the number of doors and the type of roof it has (e.g., two-door hardtop) and is made of molded steel, which is painted and treated to retard corrosion. The body sits upon the chassis, a steel frame that also supports the engine, wheels, axle assemblies, transmission, steering mechanism, brakes, and suspension members. The internal-combustion gasoline engine, with reciprocating pistons and a four-stroke cycle, is the most widely used power plant. In the United States in the 1940s engines were developed in size and design from four cylinders to the more powerful configuration of eight cylinders in a V shape. Since the 1970s, however, the trend has been toward smaller, less powerful, and more efficient engines. A transmissioncomprised of shafts, gears, and a clutchis installed between the engine and the driving wheels to allow the engine to be disconnected when the engine is started and idling and to make the most efficient use of the engine's power under varying loads. Transmissions are of two types: those in which the gears are shifted manually by the driver and those where the gears are shifted automatically by such a device as a hydraulic torque converter. To control it once it is in motion, a car is equipped with steering and braking systems. The steering system consists of a series of linkages and gears that transmit the movement of the steering wheel to the front wheels. One braking system employs two semicircular shoes at each wheel that when activated press outward against the inner surfaces of drums attached to each wheel. More recently disk brakes, in which a clamp squeezes a disk attached to the wheel, have been used. Automobiles have complex electrical systems that consist of a storage battery, alternator (alternating-current generator), devices for starting the engine and for vehicle operation (e.g., headlights and windshield wipers), and such accessories as heaters and radios. The battery provides enough power to engage the starting motor and to activate the ignition system. Once the engine is started, the alternator continually recharges the battery and supplies power to the other electrical equipment. There are several other important subsystems. The fuel system provides storage space for the fuel, transports it to the engine, and mixes it with air for combustion in the engine. The exhaust system vents exhaust gases by way of a muffler, which helps reduce engine noise. The lubrication system keeps friction from wearing out moving parts. Relatively lightweight motor oils are used in the engine, and heavier weight oils and greases are used in such parts as transmissions and wheel bearings. The cooling system keeps the engine from overheating, generally by means of liquid coolant, although many engines are air cooled. The suspension system, comprised of coil or leaf springs and shock absorbers, is combined with the tires to cushion the vehicle from the shock caused by driving over irregular surfaces. In addition, tires come in a variety of tread designs to provide traction in all driving conditions. Manufacturing an automobile is a complex process involving a number of subassembly stepssuch as the manufacturing of engines and transmissions, the stamping of body parts, and the procurement of batteries and tiresand culminating in the assembly of the vehicle on a production line. Generally there are two lines, body and chassis. The stamped body parts are first welded together and painted, and such items as windows and the instrument panel are installed. Meanwhile, on the chassis line, the suspension, brake, and exhaust systems, the power train (engine, transmission, drive shaft, and differential), and tires are installed. The body is then joined with the chassis, and the finish work, including seat and wiring installation, is performed. After a series of adjustments and tests, the completed car is ready to be shipped. Additional reading For reference surveys of the modern automobile, see David Burgess Wise (ed.), The Illustrated Encyclopedia of the World's Automobiles (1979); and G.N. Georgano (ed.), The New Encyclopedia of Motorcars, 1885 to the Present, 3rd ed. (1982). Philip G. Gott, Changing Gears: The Development of the Automotive Transmission (1991), is an in-depth interpretation of the development of automobile technology. Technical information is offered in Don Goodsell, Dictionary of Automotive Engineering (1989); and U. Adler (ed.), Automotive Handbook, 2nd English ed., trans. from German (1986). James P. Womack, Daniel T. Jones, and Daniel Roos, The Machine That Changed the World (1990), combines a history of technology with industrial forecasting. Ulrich Seiffert and Peter Walzer, Automobile Technology of the Future (1991; originally published in German, 1989), takes a closer look at newly emerging technologies. Technical standards for ground vehicles used by specialists in the design, manufacturing, and testing of automobiles are presented in a publication of the Society of Automotive Engineers, S.A.E. Handbook (annual). The Society also publishes compendiums of highly authoritative technical papers, such as Vehicle Aerodynamics: Recent Progress (1991); Frontal Crash Safety Technologies for the 90s (1991); and New Engine and Advanced Component Design (1990). George C. Cromer