Automobiles are a major part of everyday life for most people. They enable us to travel long distances quickly and easily, getting to work, school or other activities. Cars also allow us to go on vacations, visit friends and relatives, and shop. Automobile technology and safety features have advanced significantly throughout history. With more than 1.4 billion cars in operation around the world, automobiles have become essential to modern civilization.
Unlike trains and buses, which carry cargo, automobiles are designed to transport people. The word “automobile” is derived from the Greek words for self and move, because they do not need horses or other external power to make them run. The term is also sometimes used to refer to the chassis and other parts that support the engine, or to the vehicle as a whole.
The earliest automobiles had three wheels and were powered by steam, an internal combustion engine, or electric motors. By the late 1800s, manufacturers were producing gas-powered vehicles that could run at high speeds. They had a much greater appeal than vehicles that were dependent on steam or electric power because of their ability to travel long distances without stopping for fuel.
During the 1920s, American automakers introduced mass-production techniques. These methods allowed them to produce more vehicles and sell them at affordable prices. By 1940, the United States dominated world automotive production, with Ford, General Motors, and Chrysler being the big three. With the end of World War II, demand for automobiles soared in both the United States and abroad. The industry expanded rapidly, and by 1980, a majority of Americans owned at least one motor vehicle.
The design of an automobile is a complex balance of many factors. Engineers consider safety, comfort, fuel efficiency, ease of operation and maintenance, cost, and appearance. In order to achieve these goals, they must consider the design of the body, chassis, and engine; the choice and layout of the controls; the suspension system; and the electrical and mechanical systems. The final product is a vehicle that varies widely in style and size, from small compacts to large trucks.
Almost all automobiles use an internal combustion engine to create the energy that drives the wheels. Most burn gasoline, although diesel and other fuels are common in some countries. The engine’s power is transferred to the wheels through a transmission, which has several gears that change the ratio of the crankshaft’s speed to the output shaft’s speed. Different gears give the vehicle different speeds and torque, allowing it to climb hills or accelerate. The transmission also has a reverse gear.