Florian Kock brings new drive to electromobility

While some may find it a tongue twister, for Florian Kock it remains a source of fascination and the object of his daily work – the Free-Piston Linear Generator (FPLG). Kock works at the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR) To the Institute's website in Stuttgart, where his task is to develop this new type of engine. His team is conducting research into a sustainable and innovative source of power for hybrid vehicles that might well become commonplace in as little as 10 years.

Kock was made project manager while still writing his doctoral thesis. Despite his very particular form of modesty, a touch of pride nevertheless shows through: “It seems unlikely that the majority of doctoral theses will produce an innovative engine principle unlike anything the world has seen before,” says Kock with a smile. The concept of a free-piston linear generator was first described around 1928. However, since then no one has pursued the idea of putting the theoretical principle into practice with such determination and skill as DLR for the last 10 years. Kock’s involvement began in 2010, and since then he has become responsible for four researchers and approximately the same number of student trainees. At the start of 2013, after several years of painstaking teamwork, they succeeded in demonstrating that the principle of an FPLG would work – referred to as ‘proof of concept’. “We succeeded because, luckily, we had defined the right priorities when we set about the design and construction,” says Kock, looking back.

A love of speed

The researcher likes going places fast, and not just at DLR. He spends his summers and free time out and about on his racing bike or motorcycle. A native of Hamburg, he is fascinated by speed. Working towards his doctorate at the Institute of Vehicle Concepts prompted his move to Stuttgart. Although initially homesick for North Germany, he has since settled well in the south. Kock quickly realised that the Alps are not far away – and discovered his passion for snowboarding.

Between the test rig and the computer

His frequent sporting activities are a welcome relief from working in front of a computer. A normal working day will consist of 90 percent computer work and meetings, and maybe 10 percent of practical work on the test rig. “I spent a lot more time at the test rig during the final ‘proof of concept’ phase,” he explains while opening the door leading to the approximately 30-square-metre room housing the rig in the basement of the Institute. “We built the hardware entirely by ourselves.” His gaze wanders across the metal cover of the FPLG. “It’s clear that once in a while things will go wrong. But that’s what makes our small team special. When things get hectic, we all lend a hand.”

The device itself is a monster made of steel, cables and wires, around the size of a coffin. Kock knows it like the back of his hand. “I’ve probably had every single screw in my hand at least once.” And there are a lot of screws. The test rig is an inhospitable place. Equipment buzzes, and a metallic chill hangs in the air. But Florian Kock gazes almost lovingly at the jungle of cables, hoses, control electronics, round and rectangular containers, steel drums and tools. Then his gaze hardens: “There shouldn’t really be tools lying around here,” he says firmly. There is a small workbench here, where small, customised units can be completed, pre-fitted or soldered. “But sometimes it’s misused as shelf space,” says Kock. “I’m not very keen on that.”

Travel broadens the mind

Kock discovered his love of travel back in 2013, just after the 'proof of concept' had demonstrated that the FPLG principle works. It was a good time; a milestone in FPLG project management had just recently been brought to a successful conclusion, his thesis was finished, and the institute management was enthusiastic about his decision to travel. So off he went, first to the University of Buenos Aires, where he acquired a keener understanding of different standards in practical research: “Seeing how they conduct research there was a fascinating experience. Resources that we take for granted when working at DLR simply do not exist over there. Naturally, that has to do with the circumstances in the country. But since then I have acquired an entirely different perspective of the research opportunities available at home here in Germany.”

FPLG operating principle

The amount of work on the FPLG project had not grown any smaller by the time he returned. The name says it all – the piston in the linear generator does indeed move freely, meaning it is not compelled to travel between two mechanically defined endpoints (see information box). “That was one of the biggest challenges right from the start,” explains Kock. After all, plenty can go wrong in that particular area. The piston only needs to move a fraction too far for it to impact the cylinder head at the end of the apparatus, which would cause horrendous damage. Not only would it be costly, it might also be dangerous. This is why the scientists observe the tests conducted on the FPLG from the safety of a separate control room – behind three centimetres of armoured glass. During the test cycles, at least two DLR employees keep their eyes trained keenly on the five monitors. Besides the tension of waiting to see whether the tests run as planned, the FPLG also makes a great deal of noise. “At the moment, it still sounds like you’re standing right next to a pneumatic drill. That’s one of the points we’re currently working on,” explains Kock.

The mechanical assembly was not the only daunting challenge. Florian Kock is also responsible for programming the electronics and control technology. “What we did – more or less – was develop an electronic crankshaft. We succeeded in creating a software model of what is usually a mechanical system.” It has been shown for over two years that the system works. The database software – developed in-house and used to catalogue all components – made a significant contribution to the success. “This tool is extremely important. When minor malfunctions occur, it helps us understand what it was that we installed incorrectly, when we did it, and where,” the project manager emphasises.

Kock shares a small flat in the city centre of Stuttgart with friends. “It wouldn’t be a problem to move to another city again. I haven’t put down any firm roots, and still feel relatively free,” he says with a smile. What he finds particularly enjoyable now is the task of developing an innovative drive system in a managerial position. Kock was entrusted with leading the project when his predecessor left the DLR Institute after finishing his doctoral thesis. “The initial period truly was a baptism of fire, but I am thankful for the huge opportunity.”