Researchers at the Technical University of Munich (TUM) have tested how the synthetic fuel oxymethylene ether behaves in engines and have developed an optimised combustion process, which reduces emissions significantly.
A full-engine testbed in the engine laboratory of TUM's Institute for Internal Combustion Engines in Munich.
Moritz Ermert / TUM
In the XME Diesel project, scientists from the Institute of Internal Combustion Engines at the Technical University of Munich investigated the use of oxymethylene ether (OME) in diesel engines. To accomplish this, the researchers first did computer simulations and experiments on a single-cylinder engine testbed. This enabled them to determine the ideal parameters for the efficient combustion of the synthetic fuel, which has a lower calorific value than that of diesel. The fuel injectors therefore had to be adjusted to a higher flow rate. Furthermore, since OME does not produce soot, the exhaust gas recirculation could be designed for more capacity. The resulting lower combustion temperatures led to a reduction in nitrogen oxides.
The scientists checked their parameters on a full-engine testbed. The six-cylinder production engine was adapted specifically to run on synthetic fuel. These tests also confirmed previous results.
Synthetic fuel drastically reduces emissions
"We determined that using this fuel can significantly reduce pollutant emissions", explains project coordinator Dr. Martin Härtl, and adds, "The Euro 6 level, the currently applicable limit, is easily met when using the synthetic fuel. We are also convinced that high-performance exhaust aftertreatment can even reduce emissions to almost zero."
The use of OME could be particularly interesting for heavy commercial vehicles and industrial plants. Trucks, for example, could not so easily be converted to battery-powered drives due to the drives' limited range. The same applies to the aviation and shipping sectors. OME's production costs are still very high compared to those of diesel. If OME could be produced from CO2 generated in industry and from renewable energy, it would even be carbon neutral. The German Federal Ministry of Economic Affairs and Energy is funding the XME Diesel project.