An electric vehicle of a very different kind: EMPA-Trac

To design an electric vehicle, it is not enough to replace the combustion engine with an electric drive and the tank with batteries. "You have to rethink the entire vehicle," explains Christian Chimani, Head of Center for Low-Emission Transport at the AIT Austrian Institute of Technology. That means taking a close look at the overall system. Electrification opens up completely new possibilities - from the design of the structure and the construction of the body to energy management in the vehicle. Digitization also enables a completely new type of control of all components.

"This can be used to design vehicle concepts that are new from the ground up and challenge everything - perhaps except the driver's seat," Chimani says. This has been demonstrated in a vehicle called EMPA-Trac ("Electric Modular Platform Architecture Trac"), which was designed by an Austrian consortium over the past two years. This is an electric commercial vehicle in the weight class of up to ten tons, which has a modular design and can thus be adapted very easily to the respective requirements. Such vehicles are needed by municipalities or farmers to clear roads in winter, mow embankments, handle refuse collection or clear the undergrowth in the forest. Diesel vehicles currently dominate in all these areas, as they can deliver the high performance required - but accompanied by correspondingly high pollutant and CO2 emissions.

EMPA-Trac, on the other hand, relies entirely on electric power. "In the cooperation project, we can nicely demonstrate that electric is also possible without local CO2 emissions," Chimani emphasizes. In addition to AIT, TÜV Austria Automotive and the battery designer Hellpower are involved in the project, which is being led by the Lower Austrian agricultural technology specialist Adolf Tobias GmbH. The project is supported by the Climate and Energy Fund and the Austrian Research Promotion Agency (FFG).

The concept of EMPA-Trac is revolutionary in its own way: It is based on segmentation and modular construction according to the so-called same-part principle: At its core, the vehicle is assembled from completely identical modules. For example, drive modules have been developed, each containing identical electric motors, brakes, suspension joints, air springs, wheel suspensions, transmission gears, and so on. These can be strung together as required: Two-axle vehicles can be built from the same components just as easily as three- or four-axle ones. Moreover, the multipurpose vehicles can be expanded or downsized as needed with little effort. "If, for example, the local authority decides that it wants to do the forestry work itself again and buys a powerful front crane for it, then they bring the vehicle to us and we install a second front axle," says project manager Peter Kainz (Tobias GmbH), giving an example.

Common parts principle enables cost advantages

As few different parts as possible are used. For example, there is only one type of electric motor that is used for both the drives and the electric PTO. The same applies to suspension joints, control arms or side windows. "Consistent adherence to the principle of identical parts simplifies production and later facilitates maintenance and spare parts management," explains AIT expert Elisabeth Dörr, who played a key role in developing the EMPA-Trac project idea. As a result, EMPA-Trac should also be price-competitive with conventional diesel-powered commercial vehicles. During the design process, great attention was paid to the needs of municipal employees. For example, touch screens were not used for the controls - instead, large buttons were installed that can be easily operated even when wearing work gloves. The operator's cab can be very easily converted from left-hand to right-hand steering: To do this, the complete steering console is swiveled to the passenger side and the driving and brake pedals are plugged in on the other side. This makes it much easier to mow roadside slopes, for example. 

For most components, commercially available parts could be used for the EMPA-Trac. However, some things had to be specially developed. One major challenge in particular was the control electronics, the development and implementation of which was the responsibility of AIT researcher Hannes Lacher. "The task was to find a control unit that could operate eight drives at the same time. That was new territory for us as well," he recounts. Over the past few months, the EMPA-Trac prototype has been in the AIT laboratories, where the vehicle was equipped with all the necessary control units and software. Among other things, sensors and connections to the control unit, high-voltage and signal cabling for drives, current transformers, chargers, fan and heating control, etc. were installed. After commissioning and extensive tests on the test bench, extensive practical tests will subsequently take place. It will probably take another one to two years before the system is ready for series production. This will also require legal changes, because the type of modularity implemented in the EMPA-Trac is not yet adequately reflected in current legislation.

In addition to new concepts for electric vehicles, the Center for Low-Emission Transport is also working on other areas that are essential for vehicles of the future. An important thrust is the development of next-generation batteries, for which AIT researchers have access to a state-of-the-art battery research laboratory with its own pilot production facility for innovative batteries. Components for power electronics, new methods for energy management and simulation systems for electric vehicles are also being developed. A key aspect for increasing efficiency and reducing emissions is the development of new lightweight materials, including manufacturing processes, new joining technologies and design principles. The activities of the Center for Low-Emission Transport are completed by studies of the transport infrastructure (road, rail, buildings, bridges, etc.) in order to evaluate their performance and resilience and to ensure a highly resilient, resource-efficient and safe transport network.

Electromobility, however, is much more than just building electric cars: In order for them to be used optimally, many parts of the transport and energy system must also be adapted. This also requires a rethinking of the infrastructure. Researchers at the AIT Center for Energy are working on such issues. This begins with the design and operation of power grids: In order to integrate as much renewable energy as possible and provide a high-quality charging infrastructure, the grids must become more intelligent with the help of information and communication technologies ("smart grids"). In addition, there is a need for optimal spatial planning of the charging infrastructure, among other things. The Center for Energy is working on the development of tools for energy-efficient route planning, location planning of charging stations, and considerations for the size and mix of electric-powered vehicle fleets.