中文摘要：

应用自行开发的柴油机瞬态工况测控系统,试验研究了燃料挥发性对直喷式柴油机恒转速增转矩瞬态工况下燃烧过程、消光烟度及NOx排放的影响规律。研究结果表明,在增负荷工况下,适当提高燃料挥发性,可有效改善燃油与空气的混合,缩短燃烧持续期及扩散燃烧期,增加预混合燃烧量,降低瞬态工况消光烟度排放。同时,适当的改善燃料挥发性、缸内平均压力峰值、放热率峰值和缸内平均温度峰值均有所降低,致使NOx排放有所降低。

英文摘要：

The effects of fuel volatility on the combustion process, smoke opacity and NOx emission of a direct-injection diesel engine under the fixed engine speed and increasing torque （FSIT） operations are studied based on the self-made transient operation controlling and measuring system. Results show that high fuel volatility can improve the quality of fuel-air mixture and results in short combustion duration and diffusion combustion duration, an increased premixed combustion fraction and low exhaust smoke opacity. Meanwhile, increasing fuel volatility decreases the NOx emission because of decreasing the peak cylinder pressure, peak heat release rate and mean temperature.