Impacts of Low-Level 2-Methylfuran Content in Gasoline on DISI Engine Combustion Behavior and Emissions

Research studies show that 2-methylfuran (MF) is a promisinggasoline alternative regarding its positive effect on engineperformance and emissions. Before using pure MF in spark ignitionengines, it is more likely to be used in a low-level blended formin gasoline.An experimental research study was carried out to investigatethe impacts of low-level MF content in gasoline (volumetric 10% MFin blend) on direct-injection spark-ignition (DISI) enginecombustion behavior and emissions. The tests were conducted on asingle-cylinder spray-guided DISI research engine at an enginespeed of 1500 rpm under stoichiometric conditions. The engine loadsof 3.5 ~ 8.5 bar IMEP were tested and gasoline-optimized sparktiming was used. Furthermore, the effects of spark timing, exhaustgas recirculation (EGR) and valve overlap on NOxemissions were tested. The results showed that by adding 10% MF togasoline, the combustion behavior was not changed significantlyhowever the combustion stability has been improved. The HCemissions were reduced and the NOx emissions werecomparable. At low engine load (3.5 bar IMEP), retarded sparktiming, EGR and increased valve timing all tended to reduceNOx emissions. However adding EGR or retarding the sparktiming resulted in reduced indicated efficiency. The increasedvalve overlap is an ideal strategy to reduce NOxemissions for its less negative effect on combustion stability andimproved indicated efficiency, compared to the effect of retardedspark timing and EGR.