Abstract: Direct injection (DI) system has been commonly used in spark ignition engines for its good performance in fuel economy, combustion efficiency, emissions and cold-start. Currently,2-methylfuran (MF) has already been a more attractive biomass fuel because of its better performance than ethanol. However, there is little study on the DI spray characteristics of 2-MF-gasoline blends. In this paper, the spray characteristics of 2-methylfuran-gasoline blends M20 (20% volume fraction MF-gasoline blend fuel), M40 and pure gasoline from 6-hole DI injector are investigated under various ambient pressure and fuel temperature using high-speed schlieren photography. The spray parameters include spray penetration, spray cone angle and spray area. The results show that there are two different spray forms, flash boiling and non-flash boiling. When flash boiling occurs, the spray penetration increases with the increase of MF ratio. With the reduction of ambient pressure, the spray penetration decreases firstly and then increases. And the spray cone angle is greater than that without flash boiling. The spray area increases with the increase of MF ratio and the spray area is negatively correlated with the fuel temperature. When there is no flash boiling, with the increase of MF ratio, the spray penetration decreases

Key words: 2-methylfuran-gasoline blends, multi-hole DI injector, high-speed schlieren photography, flash boiling