Sébastien Cavedon is not getting much sleep at the moment. Free time is also in short supply, as he is working for the Bern Racing Team in parallel with his studies. But when the 23-year-old talks about his work with the team, there is no sign of fatigue. Cavedon is CEO of the Formula Student Team that the Bern Univer­sity of Applied Sciences is entering in the Formula Student compe­ti­tion. In the compe­ti­tion, students develop and build single-seater racing cars with elec­tric drives and compete against teams from all over the world. At the end, the jury not only judges the car, but also the sales concept in terms of design, cost plan­ning and sales presen­ta­tion.

A light­ning bolt from Bern

Cavedon is in his third year studying auto­mo­tive engi­neering in Bern, and is passionate about motor racing. So he has been part of the student Bern Racing Team since the start of his degree. “It’s all very time-consuming, but we learn a lot from it. For example, how we work together as a team and how we imple­ment a project from start to finish,” he says. His favorite phase is currently under way: vehicle parts that indus­trial part­ners have manu­fac­tured for the students are grad­u­ally arriving in the work­shop and the construc­tion of “Sajetta” is starting.

The exciting assembly phase begins in Bern: Will all the parts fit as planned? (Photo | Bern Racing Team)

The ETH racing car is also taking shape in Zurich. (Photo | AMZ Racing)

This is what the students have chris­tened the vehicle for the 2023/24 season – Sajetta means light­ning in the local Rhaeto-Romanic dialect. “The assembly is always a special moment for me. Until now, we’ve only seen the racing car on digital design draw­ings, but now we’re bringing it to life.” With Sajetta, the team is focusing on keeping the weight as low as possible. “With the last car, we paid atten­tion to reli­a­bility, this time we want to make it as light as possible on this basis.” As CEO, Cavedon is less involved in the design of the car this season and is concen­trating on spon­sor­ship instead. He is there­fore not only respon­sible of orga­nizing and managing the whole project, but also presenting the project to many compa­nies in order to obtain the neces­sary finan­cial and tech­nical support.

“The assembly is always a special moment for me. Until now, we’ve only seen the racing car on digital design draw­ings, but now we’re bringing it to life.”

Sébastien Cavedon, CEO Bern Racing Team

Strong partner

As a tech­nical sponsor, ebm-papst has been supporting the students with its prod­ucts for around ten years. In the current vehicle, 5 EC fans are respon­sible for cooling the high-voltage vehicle battery. The axial fans force air into the battery, which then flows through the entire system to cool the cells. “The fans are extremely impor­tant to us because the racing events take place in summer and – espe­cially in combi­na­tion with the high power – it can get really hot. They make sure that our battery doesn’t over­heat,” explains Cavedon. “We don’t have much instal­la­tion space in the vehicle and our battery is very small. The compact size of the fans is just perfect,” says the aspiring engi­neer. “We are very happy with the quality and reli­a­bility of ebm-papst’s prod­ucts and the air flow they deliver. They also work effi­ciently and, most impor­tantly, reli­ably.” When it came to selecting the compo­nents, the team quickly found what they were looking for in the data­base. “We didn’t need any tech­nical support from ebm-papst for this, but we know that we can always fall back on it, if neces­sary,” Cavedon explains.

Learning new skills

100 kilo­me­ters away, Sven Haug is also in the middle of the manu­fac­turing phase. The 23-year-old is in his fifth semester of mechan­ical engi­neering at ETH in Zurich. He chose Formula Student as his main project and has been part of the AMZ racing team since September 2023. He explains what moti­vates him: “We do rela­tively little program­ming in our studies and we don’t do much elec­trical engi­neering either. So being part of this team is a great add-on because I can learn a lot in these areas in partic­ular.”

This racing season, he is respon­sible for the vehicle control unit, or VCU for short. “This is the computer that connects the entire vehicle, i.e. it routes all the sensors and signals correctly, sends the instruc­tions for the fans, and regu­lates how much engine torque should be applied,” explains Haug. The coming weeks will show whether every­thing is working as planned. Like Cavedon, he says: “The assembly phase is actu­ally the most enjoy­able phase. On the elec­trical engi­neering side, I work with the people respon­sible for the circuit board to see whether their circuits work, whether our sensors can be set correctly and how we need to para­me­terize them. Then we can pre-cali­brate and install every­thing in the vehicle.”

“We partic­u­larly like the reli­a­bility of the fans. They are extremely robust and you need some­thing reli­able, espe­cially for a car that is assem­bled by students them­selves.”

Sven Haug, Vehicle Control Unit, AMZ Racing

Using nega­tive pres­sure to set the world record

The ETH team’s vehi­cles tradi­tion­ally bear the name of a Swiss moun­tain. This season, the students will be competing with “dufour”. A new feature is its hybrid suspen­sion, in other words a suspen­sion that works mechan­i­cally and pneu­mat­i­cally. This time too, the students are relying on what is known as the ‘power-to-ground’ effect. The racing team used this in their previous vehicle, “Mythen WR”, accel­er­ating the elec­tric vehicle from 0 to 100 km/h in less than a second: a world record.

To achieve this, two high-perfor­mance fans in the record-breaking vehicle suck the air out from under the vehicle, creating a vacuum that allows the vehicle to cling tightly to the ground and deliver the maximum trans­mit­table force to the road. The high intake pres­sure is gener­ated by two DiaForce compact fans from ebm-papst. The conical cover plate of the fan rotates in tandem, so that the outlet opening is larger than the intake opening and the air flows around the fan in a radial and axial direc­tion, enabling the high intake pres­sure.

Small power packs

Various ebm-papst fans are also used in “dufour”. “This year we have a driver­less team that has to control the racing car without a driver. They will be using a DC axial compact fan to cool their computer box,” explains Haug. He himself uses compact fans of different sizes to cool the voltage-controlled oscil­lator and the optical velocity sensor, which measures the speed of the vehicle. The budding engi­neer says: “We partic­u­larly like the reli­a­bility of the fans. They are extremely robust and you need some­thing reli­able, espe­cially for a car that is assem­bled by students them­selves.” Cooling plays an impor­tant role in the vehicle, after all. “Having fans that consume little energy is a clear advan­tage. Their compact design and light weight also help us to save on weight and install them in confined spaces. Finding such small fans that still have enough power is a real chal­lenge. That’s why we’re happy that we can use the ones from ebm-papst,” he adds.

The next few months will defi­nitely be busy for Sven Haug and Sébastien Cavedon. But both are already looking forward to the first events and races, which are sched­uled for summer 2024. Then we will see whether “Sajetta” or “dufour” has the edge and which team’s project is ulti­mately the most impres­sive.