Abstract：Based on a dual fuel engine, the effects of premixed nbutanol/air mixture concentrations on nbutanol/diesel compound combustion process and emission characteristics were investigated for the injection timing at top dead center. The results show that the selfignition happens in premixed nbutanol/air mixture before the diesel injection timing when the cylinder temperature reaches between 1 150 K and 1 200 K, and the start of selfignition keeps constant for different load and injection quantity of nbutanol. As the injection quantity of nbutanol is increased, the combustion duration is greatly shortened with increased heat release rate. When the break mean effective pressure pB is less than or equal to 0.50 MPa, the soot and NOx emissions are lightly reduced simultaneously with the increasing of nbutanol injection quantity, while the HC and CO emissions are linearly increased. When pB is greater than 0.78 MPa, the soot emission is greatly reduced with the increasing of nbutanol injection quantity，while the NOx, CO and HC emissions are maintained equal to that of pure diesel mode.
2019, Vol. 40 
