Automobiles are land vehicles that carry people and are powered by an internal combustion engine. Usually they have four wheels and use gasoline, but can also be run on diesel, natural gas, electric power, or any other volatile fuel. Automobiles are the most common form of motor transportation on the world’s roads and highways. They are the main way that people get to work, school, shopping centers and entertainment venues. They have helped shape a wide range of economic and social changes since their invention in the early 1900s. The automobile has become a symbol of both the promise and the pitfalls of modern civilization.
The modern automobile is a complex technical system with many subsystems that have specific design functions. These include body, chassis, electrical equipment, control systems, service devices and engine. The engine is the heart of the automobile, and it is driven by a transmission that transfers the engine’s output to the car’s driving wheels. The transmission is often designed to be as light and efficient as possible, but this must be balanced with the need for robustness to withstand the high loads and severe operating conditions that a vehicle normally experiences.
An automobile has many other systems that affect its operation, including brakes and suspension. The braking system can be mechanical (using friction between the tires and the road), hydraulic, or regenerative. Hydraulic systems use pressure to slow the vehicle and make it easy to stop, while mechanical systems require a large amount of force to overcome inertia and friction.
In addition to these systems, the design of an automobile depends upon its intended usage. For example, automobiles designed for off-road use need durable, simple systems that are able to resist heavy overloading and extreme operating conditions. Cars that are designed for high-speed, limited-access road systems, on the other hand, must be optimized for passenger comfort and performance, with improved stability at high speeds.
The development of the modern automobile began in the late 1800s, when European scientists began to understand the workings of the internal combustion engine. Karl Benz, an engineer from Germany, created the first successful automobile in 1885. Using a four-stroke, liquid-cooled, carburetor-fed internal combustion engine, his Benz Patent-Motorwagen was capable of traveling long distances and at relatively high speeds. It was not until after World War II that mass production of automobiles allowed a few large companies to dominate the market. The production of these “Big Three” cars was aided by Henry Ford’s innovations in mass-production techniques, which were copied by other manufacturers worldwide. Eventually the number of automakers dropped to 44, and now there are an estimated 59 million different types of cars in use around the world.
