Numerical Assessment of Polyoxymethylene Dimethyl Ether (OME3) Injection Timing in Compression Ignition Engine

Abstract This research encompasses the numerical analysis of trioxymethylene dimethyl ether (OME-3) e-fuel on an industrial compression ignition engine, as a viable replacement for diesel fuel. The performed simulations examined single injection and multi injection operating conditions of OME-3, varying injection rates and timing. The combustion process is modelled employing two approaches: three-dimensional Extended Coherent Flame Model (ECFM-3Z) and General Gas Phase Reactions (GGPR) with the reduced chemical kinetic mechanism. ECFM-3Z gives a faster convergence, where pretabulated autoignition and laminar flame speed databases are integrated into the model to decrease computational time. GGPR approach is validated on the experimental values for mean pressure, temperature, and rate of released heat in the same engine with diesel fuel and then again on an OME-3. Both approaches confirmed that a higher amount of OME-3 and a longer injection time is needed to achieve equivalent output power as diesel fuel since OME-3 has a lower net calorific value. It is established that multi injection case with an adapted injection timing is the optimal choice for OME-3 combustion since it achieves a 15% higher mean pressure peak compared to the diesel case. Nitrogen oxides emissions for OME-3 are also compared to the diesel case for both combustion modelling approaches.