Dr. Hans Welfers (MAN Nutzfahrzeuge):

Development of a citybus with hybrid powertrain - requirements, experiences and results

In times of the financial crisis topics such as high prices for raw materials and fuels, CO2 reduction or dwindling energy resources seem to loose priority. These issues, however, are still the primary drivers for the development of drive-train concepts for the future. In addition - and in particular under today's economical boundary conditions – new technologies have to be economical too - and should not just provide show-cases to demonstrate a company's technological potential.

With these boundary conditions MAN Nutzfahrzeuge AG is currently running a development project for the implementation of a diesel-electric hybrid drive system in a city bus. The target is to launch the system into series production by autumn 2010. This paper reports on the general conditions for and experiences in the project in the fields of EE system development and modular integration of functions.

Beside numerous technical challenges, the project to date has clearly shown that there is a significant lack of standardisation and standard components for hybrid power-trains in heavy commercial vehicles – which provides yet another economical thread to the viability of such systems. Therefore with regard to total transport efficiency, both the commercial-vehicle industry and the suppliers should, wherever possible, join forces to further spur on the development of economical hybrid drive systems for commercial vehicles.