The ultimate goal of any city government is to create a sustainable and at the same time functional public transport system. The easiest way to do this is to have buses with very limited fuel consumption characteristics, which run regularly but do not contribute to urban air pollution.
An effective solution to this will be presented at the IAA International Motor Show in Frankfurt, by engineers from Karlsruhe Institute of Technology (KIT). Their invention is an e-city bus, which is a battery-based electric drive, highly suitable for frequent acceleration and slowing down in short-distance traffic.
The e-city bus prototype, or demonstrator, as the developers referred to, is the result of the Competence E project, conducted at KIT and funded by the Federal Ministry of Economics and Technology. The invention will be presented as an example to illustrate the potential of electric mobility in public transportation.
The e-city bus is fitted with a drive train which consists of a high-voltage network, a high-torque electric motor, and a battery management system, made from lithium-ion cells. One of the key advantages of the battery system is the flat modules, which allow stacking and adjusting of the dimensions, so that the desired size and characteristics are reached. In addition, the storage system can be fitted to pretty much all types of buses in various available spaces, and it takes into account the limitations of the system and current performance status.
The high driving torque is supplied by a low-torque engine, which is directly connected to the gear of the rear axle. This decreases the implementation of the gear reduction, making the torque transmission much more efficient.
According to the developers, the energy efficiency of any electric bus can be increased greatly using a selection of carefully picked components, and an anticipatory operation and recuperation strategy.