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在一台四冲程六缸增压中冷的高压共轨柴油机上采用进气总管喷射无水甲醇的方式进行柴油/甲醇组合燃烧实验(DMCC).通过改变共轨柴油喷射的主喷射时刻以及甲醇的喷射量,对柴油机燃烧和尾气排放进行研究.试验发现,纯柴油模式下,压缩冲程缸压随着喷油提前角的减小而增大,推迟喷油,后燃期延长,排气压力增大.甲醇替代率为30%时,随着喷油提前角的增大,峰值缸压和峰值放热率均增大.在柴油/甲醇双燃料燃烧模式下主喷射时刻对减少柴油机氮氧化合物(NO_x)排放具有较好的作用,同一替代率情况下NO_x排放随着主喷射时刻的推后而减少;主喷射时刻对碳烟(Soot)排放的影响则比较复杂,纯柴油模式下碳烟的排放随着主喷射时刻的提前逐步减少,而柴油甲醇二元燃料燃烧(DMDF)模式下碳烟的排放则随着主喷射时刻的提前呈现出先上升后下降的趋势;DMDF模式下主喷射时刻提前CO、HC排放均降低,且替代率越大下降趋势越明显.
In a four-stroke six-cylinder supercharged intercooled high-pressure common-rail diesel engine, a diesel / methanol combustion experiment (DMCC) was carried out by injecting anhydrous methanol in the intake manifold. By changing the main injection timing of the common rail diesel injection and the methanol Of the amount of injection, the diesel engine combustion and exhaust emissions were studied.Experimental found that the pure diesel mode, the compression stroke cylinder pressure increases with the decrease of injection advance angle, postpone fuel injection, post-combustion period, exhaust pressure Increase.When the methanol substitution rate is 30%, the peak cylinder pressure and the peak heat release rate increase with the increase of injection advance angle.During the diesel / methanol dual-fuel combustion mode, (NO_x) emissions have a good effect, the same replacement rate of NO_x emissions with the main injection time to reduce and postpone; main injection timing of soot (Soot) emissions are more complex, pure diesel mode carbon The emission of smoke decreases with the advance of the main injection time, while the emission of soot in DMDF mode increases first and then decreases with the advance of main injection time. In DMDF mode, the main injection time Before the CO, HC emissions are reduced, and instead of the more obvious the greater the decrease trend.