Experimental study on combustion and emission characteristics of a diesel engine fueled with diesel-gasoline-iso-butanol blends

In order to improve combustion behavior and farther decrease pollutant emissions of diesel engines fueled with diesel/gasoline blends, the effects of ternary diesel/gasoline/iso-butanol blends on the combustion performance and pollutant emissions in a diesel engine were experimentally investigated in this work. The test fuels were pure diesel fuel (D100), 70% diesel fuel and 30% gasoline (DG), 70% diesel fuel and 15% gasoline and 15% iso-butanol (DGB), 70% diesel fuel and 30% iso-butanol (DB). Experimental results indicated that the ignition timing periods were delayed, CA50 was advanced, the combustion durations were shortened and the maximum pressure rise rates were increased when engine fueling the three blends in contrast with D100. Meanwhile, DGB and DB increased the brake specific fuel consumption. It was also found that a decrease in CO emissions and an obvious increase in the emissions of HC and NOx by adding gasoline and iso-butanol. DB shows the highest sub-20 nm particles number concentration, followed by DGB, DG, and D100 shows the lowest value. In contrast, the super-20 nm particles number concentration and particulate geometric mean diameters (GMDs) of all fuels in ascending order is sequenced as DB < DGB < DG < D100. Furthermore, adding iso-butanol can further improve PM-NOx trade-off than gasoline addition.