Automobiles are wheeled vehicles that are designed for passenger transportation. They are usually powered by an internal combustion engine using a volatile fuel. They may be equipped with various accessories for transporting cargo, such as trailers and caravans. Often, they are 4-wheel drive and can travel places where public transport is inconvenient or nonexistent.
The automobile first appeared in the early 20th century and quickly overtook trains, horses, and bicycles as the primary mode of transportation in most countries. During this time, the automotive industry became a major employer in many nations. This was due to the large number of jobs required to build and maintain the cars. In addition, the invention of the assembly line by U.S. carmaker Henry Ford revolutionized industrial manufacturing and made the cars more affordable for middle-class families.
Modern life would be nearly impossible without access to an automobile. Today, there are about 1.4 billion cars in use worldwide. In the United States alone, people drive more than three trillion miles (five trillion kilometers) each year on average. This makes the automobile one of the most significant technological achievements of all time.
An automobile is a complex technical system consisting of thousands of subsystems with specific design functions. The basic parts are the body, chassis, drivetrain, and engine. Research and development engineers have made great progress in improving the performance and safety of automobiles. This has led to the development of high-strength plastics, new alloys of steel and nonferrous metals, and electronic computer systems.
During the 1890s and early 1900s manufacturers produced several types of automobiles. These included cars powered by steam, electric power, or gasoline. Steam-powered cars moved slowly and were clumsy to operate. Electric cars were much more convenient to operate, but they could only travel short distances and required a long period of time to recharge their batteries. Gasoline-powered automobiles soon became the dominant model.
Most modern automobiles are powered by an internal combustion engine that uses gasoline, diesel, or kerosene to produce energy. This energy is transferred to the wheels by a crankshaft or rotor driven by pistons. The expanding gases create torque, or rotational force, which drives the wheels. The modern automobile also contains a variety of electrical and mechanical devices to keep the vehicle running smoothly, safely, and efficiently. It is important to note that the exhaust from automobiles contains a wide range of substances, some of which are harmful to human health and the environment. As a result, environmental regulations and the technology to control emissions from automobiles continue to evolve. Some of the most recent regulations require that automobiles reduce the amount of harmful pollutants they release into the air. This is accomplished through the use of emission-control systems. These systems may include catalytic converters, oxidation catalysts, and oxygen sensors. They can help to improve the fuel efficiency of a car, as well as its braking and acceleration. This can help to prevent air pollution, global warming, and climate change.