The final report demonstrates that a heavy‑duty diesel engine can be operated successfully on pure OME3‑5, an oxygenated oligomeric ether that offers markedly reduced particulate and NOx emissions. The project established a complete development chain, from the design of a high‑temperature, high‑pressure combustion chamber to the use of spray characteristics for constructing reaction mechanisms, and from detailed 3D CFD simulation to in‑engine validation. The engine tests confirmed that the combustion parameters derived from the simulations could be applied to the vehicle‑grade engine, yielding combustion quality comparable to conventional diesel while achieving near‑zero particulate formation.

Key technical achievements include the measurement of injection depth for OME3 and OME4 using three different injector designs. The data, obtained with pure OME reagents, revealed distinct penetration profiles under identical boundary conditions, providing essential input for the development of accurate spray models. The project also validated the charge‑exchange models and built sector‑based spray models for the combustion calculation. The reaction kinetics for OME were formulated by TU Darmstadt and incorporated into the combustion models, enabling realistic prediction of flame propagation and pollutant formation. The simulation framework was initially built in AVL Fire and later migrated to CONVERGE CFD, allowing for more detailed turbulence–chemistry interaction studies. The validated models were used to design an engine‑level simulation that matched the measured in‑engine data, confirming the reliability of the approach.

The study highlighted that OME’s particle‑free combustion permits the use of low‑emission engine strategies that would otherwise produce excessive soot when using diesel. Consequently, the combination of low raw emissions, optimized combustion, and a two‑stage selective catalytic reduction (SCR) system can bring NOx levels to the detection limit, meeting forthcoming stringent regulations. The report also discusses the need for advanced in‑engine measures and new after‑treatment components to cope with future NOx limits, emphasizing the role of OME as a renewable alternative to finite mineral fuels.

Collaboration was carried out within a consortium that included MAN Truck & Bus SE, the Technical University of Munich (TUM), and the Technical University of Darmstadt. MAN supplied the vehicle‑grade engine, provided operational data, and participated in regular steering meetings. TUM led the 3D simulation work, performed validation of the combustion models, and coordinated the exchange of data with the other partners. TU Darmstadt was responsible for developing the OME reaction‑kinetics database and integrating it into the simulation environment. The project ran over several years, with the third year affected by the COVID‑19 pandemic, which caused significant delays and capacity constraints at MAN. Despite these challenges, the partners maintained close coordination, and the project was completed within the agreed budget and timeframe, supported by a German federal research program.