An Investigation of OME ₃ -Diesel Fuel Blend on a Multi-Cylinder Compression Ignition Engine

Oxygenated, low energy-density fuels have the potential to decouple the NOx-soot emissions trade-off in compression-ignition engines. Additionally, synthetic fuels can provide a pathway to reach carbon-neutral utilization of hydrocarbon-based fuels in IC engines. Oxymethylene Dimethyl Ether (OME) is one such synthetic, low energy-density fuel, derived from sustainable sources that in combination with conventional fossil fuels with higher energy content, has the potential to reduce CO₂ emissions below the US and EU VI legislative limits, while maintaining ultra-low soot emissions. The objective of this work is to investigate and compare the performance, emissions and efficiency of a modern multi-cylinder diesel engine under conventional high temperature combustion (HTC) with two different fuels; 1) OME₃10 - a blend of 10% OME₃ by volume, with conventional Ultra-Low Sulphur Diesel (ULSD), and 2) D100 - conventional ULSD in North America. EGR sweep tests at three speed-load points (with highest time residency on the US EPA Emission Test Cycles) have been carried out on a multi-cylinder compression ignition engine to allow a detailed comparison of the two fuels. The engine employs production-level hardware with no modifications, allowing for turbocharger-EGR trade-off and accessories friction loads to be accounted for. All results are reported on a brake-specific basis. The tests results indicate that OME₃10 is effective in reducing soot and HC emissions under low load operation by up to 50% while no discernible improvement is seen at higher loads. The lower soot can permit higher intake dilution levels to be applied with Exhaust Gas Recirculation (EGR) to reduce NOx emissions. The burning characteristics such as the combustion phasing and duration, with OME₃10 are similar or improved compared to that of D100 and the CO₂ emissions are reduced by up to 4% with improved brake thermal efficiency under all the tested speed/load conditions.