Macroscopic spray characteristics of a gasohol fueled GDI injector and impact on engine combustion and particulate morphology

A comprehensive understanding of renewable fuels' spray behavior leads to superior combustion and emission characteristics from internal combustion (IC) engines. This study is aimed at investigating the influence of gasoline and gasohol (E15, M15, and Bu15; 85% v/v gasoline blended with 15% v/v ethanol, methanol, and butanol) on macroscopic spray characteristics, followed by IC engine combustion characterization. Macroscopic spray investigations were performed at four different fuel injection pressures (FIPs) in a constant volume spray chamber (CVSC) for oxygenated renewable fuels vis-à-vis conventional fuels. This study was followed by engine investigations, with a focus on comparative combustion characterization for the test fuels at different load points. The engine was then optimized to find the maximum brake torque (MBT) timing for all test fuels. Towards the end, field emission-scanning electron microscopy (FE-SEM) images of soot particles were also presented along with Energy-dispersive X-ray spectroscopy (EDS) analysis to find trace metals in soot particles. Numerous studies in the open literature are available wherein researchers have shown that the presence of oxygen in fuel helps meet stringent emission legislations; however, most studies didn't investigate the effect of fuel oxygen on spray characteristics. One of the research questions debated in this manuscript is “how important is macroscopic spray characteristics, when it comes to using renewable fuels in gasoline direct injection (GDI) engines?” The database from these experimental investigations of renewable fuels may be vital in simulations of spray and combustion in the near future for developing efficient and cleaner next-generation IC engines, which is in contrast with previous researches focused on engine emissions and fuel efficiency improvement alone.