In cooperation with Krone, the start-up Trailer Dynamics is developing an electric axle that acts independently of the tractor unit. Trailer Dynamics CEO Abdullah Jaber reports on the concept, which is intended to contribute to the decarbonization of the economy.

If you want to drive a 40-ton truck electrically – why not put the battery in the trailer instead of the tractor unit? This idea gave rise to the eTrailer, which was jointly developed by the Aachen-based start-up Trailer Dynamics and Krone: a powerful electric axle that works independently of the tractor unit. Abdullah Jaber is one of the smart minds behind the system: as managing director of Trailer Dynamics, he is the technical director. “If you really want to drive emission-free in heavy-duty transport, the tractor unit has a very limited capacity and volume to carry the battery. But the trailer has it all: it can carry and stow the battery without exceeding the permitted axle loads.”

In combination with diesel vehicle, an electric plug-in hybrid is created

The electrified axle replaces one of the conventional axles in the trailer. Via a sensory kingpin, the electric driveline can be reliably tracked in real time even without control inputs from the tractor unit. The system can be combined with all common tractor units. These are supported with the additional eAxle power in the drive and can also be dimensioned smaller – thus reducing both the ongoing operating costs and the total cost of ownership. The combination of eTrailer and diesel vehicle creates an electric plug-in hybrid. Diesel trucks thus become CO2 -lower, and electric tractor units enable the eTrailer to achieve a noticeable increase in range.

Technically, Jaber compares the eTrailer to an e-bike: The tractor unit and the eTrailer are mutually interchangeable and communicate with each other, but not much – just as is the case with a cyclist and his e-bike. The cyclist operates the pedals and brakes, but not much else is needed beyond that to move forward. In the same way, he says, the eTrailer has to anticipate a bit independently what the driver in the tractor is doing: “When he goes into a turn or stops at a light, the trailer may not give thrust on its own.” The eTrailer, just like an e-bike, makes driving resistance lower and helps the tractor unit to come up against it more easily. The trailer accounts for up to 70 percent of the driving resistance anyway – so the control system is in exactly the right place there.

Discrepancy between emission specifications and efficiency

As a physicist by training, Abdullah Jaber actually spent a long time studying topics such as the nature of gravity. But in his diploma thesis, he had explored the question of how commercial vehicles could become more efficient. At the time, he recognized the discrepancy between NOX emission targets and diesel engine efficiency “The cleaner a vehicle is, the harder it is to reach maximum efficiency. In addition, of course, the needs of carriers play an important role. They want to transport as much volume and payload from A to B as possible. Taking into account the previous specifications regarding the length, width and height of vehicles, we have therefore suggested that legislators should give more space, for example, to improve aerodynamics.” After all, the customer naturally wants a cargo area with maximum payload and the largest possible useful volume.

More payload would also be desirable because the batteries add weight: “Of course, there were no solutions in those directions at that moment.” With a designer and several engineers, Jaber later developed a so-called inflatable aerodynamic application for commercial vehicles that improved aerodynamics. They got into discussions with Krone about it at the time, too: “But we were maybe a little ahead of our time – there weren’t yet the necessary guidelines that would have allowed such an attachment.”

The vision of the electrically driven trailer

In 2018, Jaber and a small team jumped in at the deep end and founded Trailer Dynamics with the help of investor Michael Nimtsch. The vision: to develop an electrically powered trailer that could contribute to the decarbonization of the economy and to sustainable, environmentally friendly logistics for long-haul trucks. And: the trailer should receive the appreciation it deserves. “It was not easy to get our ideas heard. We talked to many large vehicle manufacturers – they didn’t take us seriously or didn’t find the idea tangible,” says Jaber. “In 2020, however, we got back in touch with Krone, and COO Dr. Stefan Binnewies called me right back the day our documents were on his desk.”

Although Trailer Dynamics was also negotiating with another potential partner at the time, the choice fell deliberately on Krone, because: “You can’t handle a project like this with money alone. You also need enthusiasm, technical support, experience, a production line, and a shared vision: We were able to put a big check mark behind all of that with Krone.” Both partners complement each other with their strengths: “Krone knows how to build trailers, knows the market, all the technical guidelines and has the experience in communication. And we as Trailer Dynamics come along with our crazy ideas.”

Learning from every no

With every no to its approaches that the Trailer Dynamics team has had to digest, it has learned something new, according to Abdullah Jaber. “Whenever someone says something doesn’t work or doesn’t make sense, you question yourself and your product and continue to develop.” Within just six months, the first working prototype was finally created with Krone. “This also means that we were not only able to prove technically that our device works, but also that it is an economical solution.” Many other players in the industry are now also very interested in it.

“During the development of the eTrailer, we were always faced with real challenges. We basically had to reinvent everything and were often pioneers,” explains the technology expert. A digital twin was used to test how the drive system should be designed, how large the battery should be and how strong the drive power of the axle should be: “We learned a lot from this digital model.” Currently, there are field test vehicles, with a total of around 20 to follow for technical validation. “We are well on track,” says Abdullah Jaber. To solve the problem of insufficient range and long charging times, Trailer Dynamics is considering a concept where batteries can be easily swapped on the road. In addition, automated driving also offers a lot of potential, according to Jaber: “We need the tractor unit, but do we need a cab without a driver? – but that is still further away”

Abdullah Jaber feels it is a privilege to be able to deal with all these issues and help shape climate protection. “We don’t just talk about climate change and problems, we do something.” With friends around Prof Achim Kampker, Trailer Dynamics has joined the association “Engineers Save the World”: “That might sound a bit out of touch, but behind it there really is the idea of making a contribution. I think we have to offer technical services that make a better world possible – for us and our children.”