The word automobile literally means self-moving. It is derived from the Greek wordautos，which means self, and the French world mobile, which means moving. Anautomobile is a wheeled motor or vehicle used for transporting passengers and cargoes anddesigned to run primarily on roads. Automobile is fine pieces of precision engineering,technology and design, with 15，000 individual parts and working units each.
Along with the development of science and technology, many engineeringimprovements have been done. However，the basic principles have remained the samesince the advent of automobile in the 1870s. It has an internal-combustion engine, fourrubber wheels and a protective body. To provide the energy required to make the carmove，the engine needs either petrol or diesel，air, and electric current. The enginetemperature is usually kept relatively low by water or air. The major moving parts of theenginearSthepistons. They move up and down very quickly inside cylinders. To reduceengine wear and prevent seizure the pistons are lubricated by oil. The clutch connects theengine to the gearbox by means of plates and the drive shafts are arranged to suit whetherthe car is front-or rear-wheel drive.
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