点火参数对二冲程点燃式煤油机爆震影响研究

Study on the effect of ignition parameters on knock of two-stroke spark ignition kerosene engine

为了研究点火参数对L275E二冲程点燃式煤油机爆震的影响,利用试验和数值模拟相结合的方法研究了点火提前角与点火能量对煤油发动机在爆震燃烧时性能的影响,以及点火提前角为30°BTDC~36°BTDC时,缸内爆震燃烧反应速率与点火提前角为34°BTDC时,不同曲轴转角缸内压力的变化情况。结果表明:当点火提前角为34°BTDC,点火能量为39.49 mJ时,出现轻微爆震,发动机功率为7.3 kW,燃油消耗率为611.5 g/(kW·h),动力性与经济性较好,增大点火能量对爆震强度的增幅不大,适当增大点火能量有利于煤油机的稳定运行。通过数值模拟得到在发生爆震燃烧的时刻,爆震燃烧出现在远离火花塞的壁面位置,且其位置随着曲轴转角变化而改变,进而导致爆震时压力振荡。

In order to study the effect of ignition parameters on the detonation of a two-stroke spark ignition kerosene engine,the effects of ignition advance angle and ignition energy on the performance of the engine are studied by means of experiment and numerical simulation,and the reaction rate of detonation combustion in cylinder between ignition advance angle of 34°and 36°BTDC and the change of cylinder pressure at different crankshaft angles when ignition advance angle is 34°BTDC was analyzed.The results show that when the ignition advance angle is 34°BTDC,ignition energy is 39.49 mJ,there is slight detonation,engine power is 7.3 kW,fuel consumption rate is 611.5 g/(kW·h),the power and economy are the best,increasing ignition energy does not increase detonation intensity,and proper increase of ignition energy is conducive to the stable operation of kerosene engine.The numerical simulation shows that at the time of detonation combustion,the detonation combustion occurs on the wall away from the spark plug,and its position changes with the change of crankshaft angle,which leads to the pressure oscillation during detonation.