Automobiles are a key part of modern life. They provide a means for people to work and play at different locations, travel to different regions and visit friends. They allow the movement of goods to market. And they are a vital part of the police, fire, and utility services. The automobile also revolutionized industrial production, enabling mass production and low prices.
Although the exact origin of the first automobile is a matter of debate, we know that by the early 1900s the car had replaced the horse-drawn carriage as the preferred mode of transport for many people. The gasoline-powered auto quickly overtook its steam and electric competitors, thanks in large part to the invention of the assembly line by U.S. automaker Henry Ford. This allowed the cars to be made cheaply and quickly, making them affordable to middle-class families.
Thousands of different systems are involved in the design and operation of an automobile. Unlike the human body, however, automobiles are not built in discrete components but rather are designed to be flexible enough to handle a wide range of needs and uses. The basic framework is the chassis, which supports and carries the engine, wheels, steering system, suspension and braking systems, and body. The chassis is like the skeletal structure of the automobile, and it must be strong enough to support the weight of the vehicle, yet somewhat flexible to absorb shocks and tension caused by road conditions and driving maneuvers.
A key part of the chassis is the tires, which make contact with the road surface. The tires must be strong and durable enough to withstand the constant friction of the road surface while providing sufficient traction and comfort for the driver and passengers. The tires must be able to move in any direction the chassis is steered, and they must be able to respond quickly to changes in terrain and road conditions.
Another major component of an automobile is the transmission, which provides a variety of power outputs to the wheels based on varying driving requirements. Most automobiles have at least three forward gears and a reverse gear, but some have four or even five. Each gear provides a different ratio of the number of crankshaft revolutions per minute (the input of power) to the number of wheels turning (the output of power).
The final key component is the fuel system, which must be able to supply the engine with enough gasoline or other fuel to propel the automobile. Many automobiles have fuel-injection systems that automatically adjust the amount of fuel to match engine demand, which helps to minimize pollution and improve gas mileage.
While automobiles enable individuals to live in different places and expand their social circles, they also encourage sprawl (i.e., sloppy, low-density urban development that degrades landscapes and causes traffic congestion). Nonetheless, most people agree that the freedom of long-distance transportation provided by automobiles has greatly improved their quality of life.