Engine performance and emissions from the combustion of low-temperature Fischer-Tropsch synthetic diesel fuel and biodiesel (RME) blends

The combustion of oxygenated biodiesel (rapeseed methyl ester (RME)) improves the engine-out particulate matter, hydrocarbon and carbon monoxide (CO) emissions, while the low-temperature Fischer-Tropsch synthetic paraffinic diesel fuel improves engine-out NOx, CO, hydrocarbon and particulate matter emissions. Blending synthetic diesel (SD) fuel with oxygenated biodiesel could unlock potential performance synergies in the fuel properties (e.g. O-2 content in RME and high cetane number of the synthetic fuels) of such blends and benefit engine performance and emissions. The combustion of synthetic diesel fuel/RME blend, named synthetic diesel B50, has shown similar combustion characteristics to diesel fuel, while simultaneous improvements in engine efficiency and smoke-NOx trade-off were achieved by taking advantage of the fuel's properties. The engine thermal efficiency was dependent on the fuel type, and followed the general trend: synthetic diesel > SDB50 > diesel > RME. Therefore, it has been shown that the design of a synthetic fuel with properties similar to the fuel blends presented in this work could improve engine-out NQ(x), smoke and hydrocarbon emissions and maintain or improve engine performance.