Automobiles are a form of road vehicle that is usually propelled by an internal-combustion engine. They are used primarily for passenger transportation. They are often also employed as a means of transporting cargo or a load.
They are typically a vehicle with four wheels and can seat one to eight passengers, although larger vehicles are often designed to transport more than this number of people. Cars are designed to meet a variety of needs, including passenger capacity, luggage or cargo space, and styling features.
A modern automobile is a highly complex technical system employing subsystems with specific design functions. Some of these subsystems are based on existing technology, while others are derived from advances in other technologies such as electronic computers and high-strength plastics.
During its long history the automobile has changed dramatically in terms of its technology, its design, and its manufacturing processes. A common theme is the elimination of physical knobs and switches in favor of controls that are integrated into the control panel or touchscreen. In addition, new features, such as air conditioning and navigation systems, are added to the cars.
The most important component of any vehicle is the engine, which generates power. There are several different types of engines, with the most popular being those that use gasoline.
Some engines are water-cooled, while others are air-cooled. The type of fuel used in an automobile has an effect on its power output, efficiency, and emissions.
Another important feature of an automobile is its transmission system, which translates the power from the engine into motion on the wheels. There are many different types of transmissions, including planetary gears, double-clutch gears, and fluid couplings.
Depending on the intended use of an automobile, its design may need to be adjusted for safety or for stability in various operating conditions. For example, automobiles that are designed for off-road use need to be durable and easy to operate in adverse weather conditions.
When developing an automobile, designers must consider the size and shape of the engine as well as the distribution of weight between the front and rear wheels, the height of the centre of gravity and its position relative to the aerodynamic center of pressure, and suspension characteristics.
The type of tires, the brakes, and the steering system are also crucial to the performance and safety of an automobile. Wheels are primarily used to transmit power, but they also provide traction and suspension by deflecting the road surface.
Motorcars can be equipped with various safety devices such as automatic brakes, anti-lock braking, and traction control. The brakes are particularly useful in the event of a sudden stop or collision.
Some models of automobiles also have an electronic steering system that can automatically adjust the angle of the axels as the vehicle turns. This system improves handling, especially on wet and rough terrain.
During its development, the automobile has developed a large number of innovations that have made it more efficient and safer. Examples include electric ignition and the self-starter (both invented by Charles Kettering in 1910-1911), independent suspension, four-wheel brakes, and a variety of other engineering features.