Two young entrepreneurs are developing virtual testbeds designed to optimise the performance of marine diesel engines in the hope of selling their product to global shipping companies.
Author: Peter Rüegg, Science Editor -ETH Zurich
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During the course of a research period that spanned over eight years, two mechanical engineers; Christophe Barro and Panagiotis Kyrtatos, developed combustion and emission models that can be used as virtual sensors in a physical engine.
Their plan is to use these sensors in a commercial environment to simulate the performance of large ship engines. These models are then used for continuous re-tuning of the engines for specific emission limits and minimisation of fuel consumption independently from current environmental and operating conditions. This becomes increasingly important when taking into account different fuel qualities, which can change the engine combustion behaviour and emissions significantly.
Depending on the price of fuel and transport volumes, ships can change their nominal speed in order to save fuel and reduce emissions. In some cases, ship owners swap out individual components to make the engine run more efficiently at lower speeds. This task is generally performed mostly on the basis of empirical values.
“Tuning an engine can be a little hit and miss; it can require significant time which cannot be used to transport goods and can result in high fuel and other operating costs – a model-based approach produces a far more efficient result”, says Barro.
With the help of their virtual testbed, Barro and Kyrtatos are able to calculate in advance on the computer how a motor will run with certain settings and which of its components need to be modified – and how – in order to achieve the necessary savings.
The researchers use virtual sensors to “measure” the engine’s emissions, among other things. These sensors have a big advantage over their physical counterparts: they can be placed anywhere in the engine. Physical sensors, on the other hand, can only be placed in a limited number of positions.
“If you want to monitor the engine of a giant cargo ship, for example, you can’t simply stick a sensor in the exhaust pipe in order to measure emissions”, Barro stated.
The physical environment in the exhaust system of a marine engine is very harsh, and physical sensors have to be replaced sometimes after less than 100 hours of operation. The average deep-sea vessel travels around 8,000 hours a year, however. On top of that, the sensors have to be recalibrated after a short period, which is time-consuming and expensive.
The virtual test environment and its sensors therefore not only save shipping companies the task of continuously recalibrating sensors, but also having to repeatedly replace them. This saves them a lot of money, because the simulation also produces a real drop in fuel consumption. “Even a saving in the low single-digit percentage range can make a big difference in the shipping business”, Barro emphasised.
This leaves him fairly confident that the estimated price of their product will not put off potential customers: “We reckon that one of our simulation units will cost between 20,000 and 30,000 Swiss francs per ship.” Although that sounds like a lot of money, it’s still a good investment, as the amount is recouped in savings within a year.
The researchers want to concentrate on commercial shipping because the size of the industry is more manageable than, say, the automobile sector – even though virtual sensors can be used in automotive applications as well.
“In principle we can apply our system to all engines in any sector, in other words for cars, construction machinery or trucks”, said Kyrtatos.
However, it would be more difficult to break into the automobile industry. “Many carmakers prefer to solve the optimisation problem themselves using their own R&D departments”, he adds. Another factor to consider is that the firms who make marine diesel engines are much smaller than the big carmakers, but the range of models can be far more diversified.
Barro and Kyrtatos are currently still working as senior assistants and lecturers at the Aerothermochemistry and Combustion Systems Laboratory (LAV) under Professor Konstantinos Boulouchos.
In the future they plan to still collaborate closely with the group for the development of new products directed towards the automotive, heavy duty and marine markets.
Vir2sense is one of the newest members of the ETH family of spin-offs. Barro studied mechanical engineering at ETH, then went on to become a doctoral student and postdoc. He is now a senior assistant at the LAV, where he is head of a research group. Kyrtatos also completed his doctorate at ETH Zurich and currently leads a research group in the same laboratory. The company was legally founded in March 2016, making it one of the most recent recipients of the official label “ETH Spin-off”.
Image: The founders of Vir2sense: Panagiotis Kyrtatos (l.) and Christophe Barro (r.). (Credits: Peter Rueegg / ETH Zurich)
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