Effects of n-pentanol/biodiesel blend fuels on combustion and conventional and unconventional emission characteristics of diesel engine.

The use of n-pentanol/biodiesel as a diesel engine fuel is one of the important ways to reduce fossil fuel consumption and lower diesel engine emissions. The objective of this work was to investigate the mechanism of the effect of different n-pentanol blending ratios (0%, 10%, 20%, and 30%) on the combustion and emission performance of a common rail diesel engine. Tests were conducted on a four-cylinder supercharged intercooled diesel engine at 1540 r/min with brake mean effective pressures of 0.289, 0.578, and 0.867 MPa. The results showed that with the increase of the n-pentanol blending ratio, the ignition delay was prolonged, the combustion duration was shortened, and the heat release center was shifted forward. The combustion process at medium and high loads was improved. When the blending ratio of n-pentanol reached 20%, the blended fuel showed better combustion characteristics at all three loads, and the peak in-cylinder pressure of the blended fuel increased by 13.74%, 1.95%, and 5.26% at the three loads, respectively, compared with that of pure biodiesel. With the increase of the n-pentanol blending ratio, HC, CH2O, CH4, and CH3CHO emissions increased at all three loads. Soot emission was reduced by 25.86%, 19.71%, and 31.59% at three loads when the n-pentanol blending ratio was 30%. C2H4 emissions increased with the increase of n-pentanol blending ratio at the low-load condition and showed a decreasing tendency at the medium and high loads. At high load conditions, NOx emissions increased with increasing n-pentanol blending ratio, and CO emissions decreased with increasing n-pentanol blending ratio.