Development Trends in Bus Manufacturing 2001-01-3330
The vast majority of all buses built today are composed of a steel chassis containing the Diesel-engine, gearbox and the axles with a steel body attached to the chassis. One route of development is exploring the use of clean fuels and alternative engines. Among the clean fuels compressed natural gas, liquefied petroleum gas and methanol must be mentioned. Representatives of alternative engines are Diesel-electric systems and fuel cells. Another route is light weight design of the body. For more than 30 years some manufacturers offer aluminium structures to be mounted on a steel chassis. In order to overcome the impact of the high cost of aluminium against steel, innovative assembly techniques have been introduced to shorten the assembly work. In a following step so called hybrid concepts have been introduced, where big surfaces such as floor and roof are made as one piece sandwich panels. In advantageous configurations such buses can be built without chassis except axle modules. This means that the expensive components such as engine and gearbox can be brought to the bus at a very late stage of assembly and not at the beginning with the chassis. Finally, even more fiber reinforced elements are brought into the bus body such as rollbars, end modules etc. All these developments have cut the manufacturing hours for a bus in half, reducing simultaneously the mass of the bus by 10-20%.