Emission regulations focus on the simultaneous reduction of NOx and particulate matter emissions, especially for heavy-duty engines. Oxygenated fuels offer significant advantages in reducing particulate emissions while having little effect on NOx emissions. In addition, renewable fuels present a GHG emission advantage to meet the zero-emission requirements of future hydrocarbon fuels. Among the leading contenders, oxymethylene dimethyl ether (OME) fuels have the potential to be used for direct injection applications. OME as a blend with diesel fuel offers a direct means of improving the emissions of current on-road diesel engines without modification.
In this paper, an empirical investigation into spray behavior and engine performance of diesel/OME fuel at 10% by mass has been performed under various fuel injection pressures. Neat diesel fuel was tested as a baseline case. The results are compared to tests under matching conditions using a diesel and OME fuel blend with a focus on spray characteristics, combustion behavior, and engine-out emissions. The physical properties of OME improve the volatility of diesel fuel and can tolerate shorter mixing times without promoting PM production. The PM emissions were found to be reduced by up to 50% and the combustion efficiency was improved at matching NOx levels with OME blending.