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 promising gasoline alternative regarding its positive effect on engine performance and emissions. Before using pure MF in spark ignition engines, it is more likely to be used in a low-level blended form in gasoline.

An experimental research study was carried out to investigate the impacts of low-level MF content in gasoline (volumetric 10% MF in blend) on direct-injection spark-ignition (DISI) engine combustion behavior and emissions. The tests were conducted on a single-cylinder spray-guided DISI research engine at an engine speed of 1500 rpm under stoichiometric conditions. The engine loads of 3.5 ~ 8.5 bar IMEP were tested and gasoline-optimized spark timing was used. Furthermore, the effects of spark timing, exhaust gas recirculation (EGR) and valve overlap on NO_x emissions were tested. The results showed that by adding 10% MF to gasoline, the combustion behavior was not changed significantly however the combustion stability has been improved. The HC emissions were reduced and the NO_x emissions were comparable. At low engine load (3.5 bar IMEP), retarded spark timing, EGR and increased valve timing all tended to reduce NO_x emissions. However adding EGR or retarding the spark timing resulted in reduced indicated efficiency. The increased valve overlap is an ideal strategy to reduce NO_x emissions for its less negative effect on combustion stability and improved indicated efficiency, compared to the effect of retarded spark timing and EGR.