AutoTram® High-Tech Demonstrator

Konzept

The AutoTram^®, a novel transport system, was developed at the Fraunhofer IVI in Dresden in cooperation with several industry and development partners.

It is an attractive, cost-efficient alternative to conventional buses and trams for local authorities, public transport providers and private operators. Moreover, it has the same passenger capacity as contemporary BRT systems, can be operated bidirectionally and decoupled to form two 12-m vehicles.

Its transport-related advantages are:

Simple route design on various levels,
Narrow clearance gauge,
Innovative vehicle design,
Adaptable passenger capacity,
High standards of safety and availability,
Environmentally friendly operation.

Key Development Topics

Demand-based public transport solution using a modular vehicle concept for both unidirectional and bidirectional operation,
Low fuel consumption, with partially emission-free hybrid propulsion technology,
Accident avoidance through assisted lane guidance,
Adherence to a given lane by electronic multi-axle steering system,
Flexibly configurable as either 12-m or 24-m using gangway modules for coupling and decoupling,
Significant market potential through 30 to 50 percent lower lifecycle costs compared to conventional tram systems

Technology

The AutoTram’s^® structure and passenger capacity are similar to those of a tram. However, the AutoTram^®does not make use of the common wheel/rail system, but has rubber tires that run on conventional concrete and asphalt roadways. Due to its axisymmetric coupling module, a 24-m bidirectional train operated on high-demand inner-city routes can be converted into two individual 12-m vehicles. These shorter vehicles are suitable for shuttle services in sparsely populated areas and are also a good option for periods of low demand.

The propulsion concept makes use of the advantages of trolley bus technology. However, it generates its required electric energy through an on-board diesel or liquid gas fueled engine combined with high-performance energy storage units for hybrid propulsion.

The AutoTram’s^®advantages over conventional trolley buses are:

Both unidirectional and bidirectional operation on convnetional bus lanes,
Adaptable vessel size,
Driver assistance systems for both lateral and longitudinal vehicle control (»Virtual Rail«),
High safety standards through multiple redundancy and mechanical fallback level,
Emission-free propulsion from high-performance on-board electric storage units
Recharging via docking stations during regular stops
High flexibility through catenary-free operation,
High economic efficiency and
Reliability.

Engineering

Retractable axisymmetric coupling and gangway module

Vehicle Structure

The 24-m bidirectional train consists of two 12-m low-floor vehicles that can be coupled in the rear. Its width is 2.55 meters. The three axles that are driven by asynchronous motors can be steered separately with the help of electro-hydraulics. Thus, the vehicle train’s swept path and its clearance gauge are kept at a minimum. The AutoTram^® is able to reach a maximum speed of 70 km/h. The dimensions and equipment of the basic vehicle comply largely to the approval regulations for buses in public transport.

Propulsion Concept

The partially emission-free hybrid propulsion system consists of a compact combustion engine and a storage module for electric energy (batteries and high-performance capacitors). Emission-free operation is possible for short distances of 2 to 3 kilometers. Depending on the route profile, up to 20 percent of the braking energy can be recuperated during fully electric operation.

Coupling and Gangway Module

All 12-m vehicles can be combined due to their axisymmetrical coupling module. If desired, middle segments can be inserted to form a 36-m train. The coupling procedure is automated. After decoupling, the joint is retracted into the vehicle floor.

Assisted Lane Guidance

Although the drivers are responsible for driving the vehicle, a lane guidance system offers support for lane adherence, precise approaching of the stops and bidirectional driving. This advanced driver assistance system is realized by combining DGPS and video images.

Cooperation

GÖPPEL Bus GmbH Nobiz / Ehrenhain
HÜBNER GmbH Kassel
DESIGNTEAM D Karlsruhe
IAV GmbH Chemnitz
DVB AG Dresden
SAD GmbH Dresden
M&P GmbH Dresden

Competencies

The Fraunhofer IVI is competent in the following areas:

Conception and pre-development of intermediary vehicles,
Implementation and testing of alternative propulsion systems and energy storage systems,
Energy management of hybrid vehicles,
Conception of advanced driver assistance systems.