高原缺氧环境下柴油主喷正时对氢气/柴油双燃料发动机燃烧与排放的影响

Effects of Diesel Main Injection Timing on Combustion and Emission of Hydrogen/Diesel Dual-Fuel Engine under Highland Hypoxia Environment

为了研究高原缺氧环境下柴油主喷正时对氢气/柴油双燃料发动机燃烧与排放的影响,搭建了氢气/柴油双燃料发动机试验台架,在最大扭矩转速1600 r/min,30%、50%、70%负荷、海拔2000 m高原缺氧环境下进行了发动机燃烧与排放特性试验.研究结果表明:主预喷间隔固定,随着柴油主喷正时的推迟,缸压峰值下降,瞬时放热率峰值对应的相位后移,碳烟、CO排放上升,NO_(X)排放下降;在三种负荷下,双燃料NO_(X)排放最大下降幅度分别为53.9%、57.9%、40%.当三种负荷下氢气替代率分别为27.4%、21.2%、15.4%时,与纯柴油模式相比,NO_(X)排放上升,CO、CO_(2)排放下降.30%负荷下,当柴油主喷正时为-8°CA ATDC时,双燃料模式下CO排放与CO_(2)排放分别下降46.5%与17.3%;30%和50%负荷下,碳烟排放下降,平均降低幅度分别为21.55%和11.69%;70%负荷下,碳烟排放上升,平均上升幅度为32.62%.

To study the effect of diesel main injection timing on the combustion and emission of a hydrogen/diesel dual-fuel engine in a plateau oxygen-deficient environment,a hydrogen/diesel dual-fuel engine test rig was constructed,and the engine combustion and emission characterization tests were carried out in a plateau oxygen-deficient environment at an altitude of 2000 m at the maximum torque speed of 1600 r/min and under 30%,50%,and 70%loads.The results show that:the main pre-injection interval is fixed,with the postponement of the diesel main injection timing,the peak cylinder pressure decreases,the phase corresponding to the peak transient exothermic rate is shifted back,the carbon smoke,and CO emission rises,and the NO_(X)emission decreases;under the three loads.The maximum reductions in dual-fuel NO_(X)emissions were 53.9%,57.9%,and 40%,respectively.When the hydrogen substitution rate is 27.4%,21.2%,and 15.4%at the three loads,respectively,NO_(X)emission rises,CO,and CO_(2)emission decreases compared with the diesel-only mode,and at 30%load,when the diesel main injection timing is-8°CA ATDC,CO emission and CO_(2)emission decrease by 46.5%and 17.3%,respectively,in the dual-fuel mode,and at 30%and 50%loads,carbon soot emission decreases with an average reduction of 21.55%and 11.69%,respectively,and carbon soot emission increases with an average increase of 32.62%at 70%load.