Research

Downsizing

Peter Eilts worked with large engines for power stations and ships for a number of years. Nowadays, as a professor at the TU Braunschweig, he devotes his time to all kinds of engines, including petrol and diesel engines in cars and commercial vehicles. Away from work, however, his real passion is reserved for the smallest engines of all – those found on motorbikes.

How small can an engine be designed?

When he sets off for work early in the morning, he generally eschews his ‘old treasures’, as he likes to call them. Even when it is freezing cold, he cycles the few kilometres to his office on the northern campus of the TU Braunschweig. ‘It wouldn’t be worth it,’ explains Peter Eilts. ‘In the time it took me to put on my motorbike clothing, I would already have cycled to work.’ His old treasures are a Zündapp KS 125, BMW R100S, Yamaha TDR 250 and KTM GS 350. At 43, the 125 cc Zündapp is the oldest in his collection and probably his favourite. An impressive store of spare parts in the basement provides the peace of mind of being equipped to deal with any uncertainty that time may bring. ‘I have built up the store over the dec-ades,’ reports the professor. ‘In theory I could build another two Zündapps out of all the parts.’

Whether in his own workshop or on the test stand at the university – Eilts loves the smell of machine oil

Peter Eilts has been head of the Institute of Combustion Engines at the TU Braunschweig since 2007. It has around 30 members of staff, 20 of whom are doctoral students. As 2014 turned into 2015, his institute moved into a new building in the north of the city, right by the airport, which primarily serves as a research airport nowadays. On 16 engine test beds for power classes ranging from 250 to 500 kilowatts, he and his colleagues conduct research on ‘everything that flows and combusts within the engine – or in one word: thermodynamics,’ as he succinctly puts it. As such, his remit is certainly broad and includes mixture formation and combustion, turbocharging and gas exchange as well as research on fuels, energy management and exhaust gas aftertreatment. ‘People in the industry generally work on large, medium-sized or small engines,’ says Eilts. ‘Here at the university we can do everything. That’s what I especially like about my job.’

Perhaps above all else, however, the focus is on small engines. In any case, Eilts, who has played an active role in the FVV since the beginning of the 1990s and whose first project involved chairing passionate discussions on tribological processes in the material layers of cylinder liners, talks enthusiastically about one of the latest FVV projects. ‘Statutory provisions relating to consumption and emissions mean that even smaller vehicles will be developed in future,’ he says. ‘This raises the question of exactly how small an engine can be designed and how far it is possible to go with downsizing.’ Under his guidance, three doctoral students are working on a project to develop a cylinder with a volume of just 200 cubic centimetres for a direct-injection petrol engine and have come to the conclusion that the mini cylinder works just as well as a large one, yet consumes and emits less. Among other things, a follow-up FVV project will look at locating the injector in a different position in order to refine the concept.

Before his calling to the university, however, Eilts spent 16 years working on much larger engines for power stations and ships at MAN B&W Diesel in Augsburg. Initially as a development engineer, then group leader and ultimately head of department, he worked on so-called medium-speed engines with less than 1,000 revolutions per minute and an output of up to two megawatts per cylinder. Emission limits are being tightened in certain coastal regions. ‘That is why we have been looking at ways of cutting nitrous gases since the beginning of the noughties,’ reports Eilts. ‘To this end, we introduced the so-called Miller process: by closing the inlet valves earlier, it was possible to reduce the combustion temperature and simultaneously cut the production of nitrous gases.’ Today he is working on an FVV project concerned with conducting research into variable valve timing in commercial vehicles to raise the exhaust gas temperature and thus provide more energy for aftertreatment.

The engineering career is clearly in his blood. He grew up in Hanover and after leaving school and completing his military service – the latter mostly in the engine room of a navy supply ship – he quickly enrolled on a mechanical engineering course at the university in his hometown. ‘I was never interested in anything else,’ he says. ‘As a two-year-old, I stood with my mother at the window, because she wanted to show me a beautiful sunset, but I was pointing at the cars driving past below – I didn’t have anything else in my mind.’ When he was five, he received a Lego set for Christmas, even though he had put a model of a VW 1500 on his list. There were tears, but the next day he built a car out of the Lego. At the age of twelve, he bought his first moped, an NSU Quickly, and as a teenager he became an expert in ‘making mopeds go faster,’ as he puts it.

First moped at the age of twelve – for three marks

His old treasures are fast enough for him these days as he embarks on weekend trips past fields, forests and meadows to the north of Braunschweig. He experiences his very own version of downsizing, however, when he is on the island of Langeoog, the homeland of his father, who built a holiday home there. No combustion engines can be heard here – the island is completely car-free. In the wild coastal landscape, between the dunes and the beach grass, Eilts finds total peace and quiet on his travels. This is where he gathers his strength before returning to the world of thermodynamics.

Photo Credit: FVV | Rui Camilo

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Prof. Dr. Peter Eilts

Born and raised in Hanover, Peter Eilts studied mechanical engineering at the University of Hanover and worked at the IFKM after graduating in 1984. After being awarded a doctorate in 1990, he moved into industry and worked at MAN B&W Diesel. As administrator, group leader and head of department, he spent 16 years working on the thermodynamics of large diesel engines for ships and power stations. In 2007 he followed a calling to teach at the TU Braunschweig. He has been head of the Institute of Combustion Engines ever since and, together with his colleagues, conducts research into the thermodynamics of engines of all sizes for a wide range of applications – from small 200cc research cylinders to large-scale engines in the megawatt class. Eilts is married and has two grown-up children.

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