F-T柴油/甲醇双燃料发动机燃烧循环波动分析

通过在四缸增压中冷柴油机上进行的甲醇能量替代比分别为5%、10%、15%的甲醇均质混合气F-T柴油引燃燃烧试验,与0#柴油的传统燃烧对比,研究了的发动机转速、负荷、甲醇替代比对预混合引燃燃烧的循环波动的影响。结果表明:转速的增加对发动机输出动力的波动影响较小,但对预混合引燃具体燃烧过程的循环波动影响较大,瞬时放热率峰值波动率高达25%;中等负荷下,预混合引燃的循环波动较小,但在起动、怠速等小负荷工况时发动机的循环波动率较大,其中放热率峰值的循环波动率达到30%,且在大、小负荷时燃烧始点的循环波动均大于10%;甲醇替代比低时,预混合引燃燃烧模式的循环波动稍大,但当甲醇替代比增加到一定比例后循环波动率逐渐降低到与0#柴油相当的水平,甚至更低。

The Combustion Cycle Fluctuation Analysis of Premixed Methanol Charge Induced by F-T Diesel

Effects of engine speed, load and energy substitution ratio of methanol on combustion cycle-to-cycle fluctuation were studied experimentally in a premixed charge induced ignition combustion diesel engine. In the research, the combustion modes, in which the energy substitution ratio of methanol were 5%, 10% and 15% respectively, were compared with the original combustion mode of 0# diesel. Results show that when increasing the engine speed the engine output power fluctuation change little, while the specific the combustion process change a lot with the speed increasing, whose peak value of heat release rate (HRR) fluctuation rate reach as high as 25%; the cyclic fluctuation of the engine is small under moderate load, but large when the engine running at small load conditions like starting and idling, the max HRR peak value fluctuation rate reached 30%, the start of combustion fluctuation rates are always greater than 10% both at very large and small load; the cyclic fluctuation of the combustion mode is slightly large when methanol energy alternative in the low proportion, however, when methanol ratio increases to a certain value the cyclic fluctuation gradually reduced to the level of 0# diesel engine, or even lower.