F-T柴油/乙醇混合燃料的燃烧及排放特性

在具有高十六烷值的F-T柴油中添加不同比例的乙醇燃料制得乙醇/F-T柴油混合燃料,通过与0#柴油和纯F-T柴油进行比较,研究其燃烧和排放特性。研究结果表明:与0#柴油相比,F-T柴油的滞燃期最短,混合燃料的滞燃期小于0#柴油、大于F-T柴油,且混合燃料乙醇比例越高,滞燃期越长;混合燃料燃烧始点提前,累计放热量达50%时的曲轴转角CA50增大,燃烧放热中心推迟,燃烧放热率第一峰值点下降,预混燃烧放热量降低,使燃烧温度降低,第二峰值点上升,扩散燃烧比重增大。在外特性2 000 r/min下,相比于0#柴油,混合燃料E10、E20的NO_x排放分别降低了24.9%和30.6%,碳烟排放分别降低了65.1%和76.2%,甲醛排放分别降低了67.7%和45.9%。

Combustion and emission performances of diesel engine burning F-T diesel/ethanol blended fuel

The combustion and emission characteristic effect was investigated for the F-T diesel, which have high cetane value, adding multitudinous proportions ethanol fuel on comparing with the F-T diesel. The results show that compared to the 0# diesel fuel, the ignition delay period decreased obviously, and with more ethanol addition, the ignition delay period increased, the ignition time advanced, the CA50 increased and the combustion heat release center was postponed. The first peak combustion heat release rate decreased, premixed combustion heat reduction, which decreased the combustion temperature. The other peak value increased and the diffusion combustion in proportion was increased. Under 2000r/min of external characteristic, E10 and E20 NOx emissions were reduced by 24.9%,30.6% respectively, carbon smoke emissions were reduced by 65.1%,76.2% respectively, formaldehyde emissions were reduced by 67.7%,45.9% respectively.