Automobiles are a major part of the modern world. They have become a symbol of the promise and the perils of the industrial age. Automobiles are driven by internal combustion engines powered mostly by gasoline, a liquid petroleum product. Modern automobiles are complex technical systems involving thousands of component parts. These are grouped into a number of semi-independent subsystems with specific design functions. These have evolved from breakthroughs in existing technology as well as from the development of new materials such as high-strength plastics and nonferrous metals.
Several inventors contributed to the evolution of the automobile, but Karl Benz is credited with inventing the first true automobil. His design was based on a converted horse-drawn carriage. Other early automakers developed automobiles fueled by other volatile fuels. The first two-stroke petrol-powered engine was built in 1885. Siegfried Marcus, a German working in Vienna, Austria, also worked on a gasoline-powered automobile around this time. His vehicle, however, did not advance past the prototype stage.
The modern car has become a major consumer of energy and is responsible for releasing significant quantities of greenhouse gases into the atmosphere. The United States Environmental Protection Agency estimates that transportation is the source of 27 percent of the country’s greenhouse emissions. The automobile is also a source of noise and air pollution, which has resulted in health problems for many people.
In the United States, Henry Ford pioneered mass production in the automotive industry, using an assembly line to lower the cost of his Model T automobiles. This revolutionized manufacturing and dramatically reduced the price of personal transportation. The automobile gave people greater freedom of movement, and whole economies developed around the manufacture of car parts and fuel and around the distribution of goods to serve the needs of motorists. These changes were not without cost, however. Automobiles encourage sprawl (sprawling, low-density urban development) that degrades landscapes and contributes to traffic congestion. They also cause pollution, especially of airborne pollutants such as carbon dioxide and volatile organic compounds.
The most important part of an automobile is the engine, which uses a four-stroke cycle to burn gasoline or another fuel and produce heat. The cylinders, which are lined with ceramic tiles, fire up and down to drive the crankshaft, turning the wheels of the automobile. Most cars have from four to eight cylinders. The more cylinders, the more power the engine has.
Other important automotive systems include the transmission, which converts the engine’s rotational speed into linear motion, and the steering and brakes, which help control the direction and velocity of the automobile. The suspension system, which allows the automobile to move over rough road surfaces without losing stability, consists of springs and shock absorbers, which work together to reduce vibration and noise.
The interior of the automobile includes a passenger compartment, driver’s seat and controls, trunk, hood, roof and other components. Its exterior is designed to make a statement about its owner’s style and taste.