Automobiles are motor vehicles that carry people over long distances at a high speed. They have four wheels and are fueled by the internal combustion of a liquid product, typically gasoline (petrol in some European countries) and a battery-powered electrical system. They are among the most universal of modern technologies. More than 73 million automobiles were produced worldwide in 2017.
Modern automobiles use an engine that is driven by the internal combustion of gasoline or other fuel. This drives a crankshaft that turns the drive axles to propel the car forward. Most of the energy of the fuel is converted to heat and mechanical power by the engine, with the rest going to the wheels. The speed at which the wheels turn is controlled by a transmission system, with gears that shift the amount of power being sent to each wheel. The power is measured in kilowatts or horsepower.
There are many different types of automobiles, each designed for specific uses. For example, automobiles built for off-road use need durable systems that can withstand severe overload and extreme operating conditions. Cars built for highway travel need to have passenger comfort options, optimized high-speed handling and stability, and efficient power delivery.
The automobile industry requires large amounts of raw materials to build the cars and components that make them work. Economic, ecological and geopolitical factors influence the availability of these materials. In addition, a car’s design often dictates how much cargo can be carried.
Until the 20th century, most automobiles were expensive vehicles owned by the wealthy. However, the development of the mass production assembly line allowed Ford to produce enough Model T cars to put them within the reach of middle-class Americans. This was a revolutionary event that gave the automobile to most of the world’s population for the first time.
Today, there are more automobiles on the road than ever before. Many of them are manufactured in the United States, which is the largest automobile producer and consumer in the world. Other major car makers include Japan, Germany and China.
New technical developments constantly alter the automobile. Some of these changes are small, such as the replacement of physical linkages between pedals and the throttle and brake mechanisms by electronic controls. Some are larger, such as the introduction of hybrid electric vehicles that combine an internal combustion engine with electric motors and batteries.
A car is a useful device to have, because it saves time spent travelling. People can get to their workplaces and homes quicker and spend more time doing things they enjoy. This is particularly important for people who live in remote areas, where access to public transport is limited. Having an automobile also makes it easier to go on vacations and to visit friends and relatives.