巴士的历史
说说巴士的历史，用英文，什么时候发明的，谁，在哪里？…………
参考答案:Any of a class of large, self-propelled, wheeled vehicles designed to carry passengers, generally on a fixed route can be termed a bus. Developed at the beginning of the 20th century, to provide greater route flexibility, it was the natural outgrowth of the horse-driven coach. In the present moment, buses are defined as vehicles that accommodate more than 10 passengers.
In 1830, Sir Goldworthy Gurney of Great Britain designed a large stagecoach driven by a steam engine that may have been the first motor-driven bus. It was Germany's turn next to design an eight-passenger omnibus, driven by a four-horsepower single-cylinder engine in 1895. Sight seeing companies were the firs to introduce buses in the United States. One type of these open vehicles built by Mack Trucks, Inc., in 1904 had a nominal seating capacity of 15 with a four-cylinder gasoline engine developing 36 horsepower at street speeds of up to 20 miles per hour (32 kilometres per hour).
Technically, the early bus resembled the motor truck. Until the 1920s the bus consisted of a bus body mounted on a truck chassis. 1921 saw the development of a chassis specifically meant for a bus. This was manufactured in the United States and was made by the Fageol Safety Coach Company of Oakland, Calif. This new frame was one foot lower than a truck frame. In 1926 Fageol developed the first integral-frame bus, with twin engines mounted amidships under the floor. The integral frame utilized the roof, floor, and sides of the bus as structural members.
Mack and Yellow Truck & Coach of the United States were among the other early bus manufacturers in the United States, both of which built gasoline-electric models. In these buses a gasoline engine drove a direct-current generator, and the output of the generator provided electrical power for the driving motors on the rear wheels. This electrical system performed the functions of a transmission by multiplying driving torque and providing a means of connecting and disconnecting the engine from the drive wheels.
Transcontinental bus service was introduced in the United States in 1928. The first rear engine in an integral-frame bus was introduced in 1931. Two-stroke-cycle diesel engines were first used in buses in 1938 and were found in most city and intercity models for the next 40 years.
Introduced in 1953, air suspensions continue to be employed on integral-frame bus models. They consist of multiple heavy rubber bellows, air springs, mounted at each axle. The air springs are supplied with air from a reservoir in which pressure at about 100 pounds per square inch (690 kilopascals) is maintained. An advantage gained from this type of suspension is that as the load increases or decreases, the level and height of the vehicle remain constant.