The automobile, one of the most significant inventions in modern times, has had a profound impact on our economy and society. From public services like police, fire and utility vehicles to private uses such as vacation travel and grocery shopping, automobiles are an integral part of our daily lives. Automobiles are also a major driver of industry and the economy, providing jobs in manufacturing, engineering, design, and many other areas. Mass production techniques, developed for automobiles in the early twentieth century, have since been applied to nearly every industry.
The first automobiles were essentially horse-drawn carriages with engines added. They ran on steam, electric power or gasoline. Steam cars could go fast, but were noisy and inconvenient to operate. Electric cars had a limited range, and recharging stations were difficult to find. Gasoline cars, however, proved to be the most popular because they were more versatile and easier to use than either the steam or electric cars.
Exactly who invented the automobile is a matter of some controversy. Many people, including Karl Benz of Germany, claimed to have done so in the late 1880s. Later, Henry Ford revolutionized automobile manufacturing by creating the assembly line and making automobiles affordable for middle-class families.
Today’s automobiles are sophisticated systems of mechanical, electrical and computer technologies. Depending on their intended use, automobiles must be durable and simple enough to withstand severe overloads and extreme operating conditions, while at the same time offering passengers comfort options and optimized high-speed handling. Despite these complexities, the basic elements of automobile design remain relatively unchanged.
Most automobiles have a four-cylinder engine, although some have two-, six- or eight-cylinder engines. The number of cylinders in the engine determines how much power it has, and how smoothly the automobile drives. The cylinders are arranged in pairs, with one pair working together during the intake and compression strokes to turn the crankshaft, while the other pair works during the exhaust and expulsion strokes.
The engine’s output is directed to the wheels through a transmission system. Most automobiles have a standard four-speed manual transmission, although some have five or even more gears. The gears in the transmission vary the ratio of the engine’s rotational speed to the wheel speed, thereby changing how much power is transferred from the crankshaft to the drive wheels.
The body of an automobile, analogous to the skeleton in the human body, supports the other components and systems of the car, while protecting the occupants from the elements. The chassis is a rigid structure that supports the weight of the car and provides a stable platform for steering, braking, and suspension. The suspension system includes springs that support the vehicle above the wheels, and shock absorbers that dampen or quiet the movements of the springs using tubes and chambers filled with hydraulic fluid. Several other important systems are connected to the chassis, such as the brakes and the wheels and axles.