Abstract: To study the effect of ignition advance angle (〖θ 〗_i) on idle performance of a hydrogen fueled CNG engine, an idle performance test was conducted on a hydrogen fueled CNG engine. The engine speed was fixed at 800r/min; the excess air ratio was set at λ= 2 and 〖θ 〗_i was adjusted from 20℃ A BTDC to 0℃ ABTDC. The results demonstrated that as 〖θ 〗_i was reduced, the flame development angle decreased and the rapid combustion period increased. When > 16℃ A, most of the fuel was combusted before TDC; the negative power increased and the indicated thermal efficiency was rather low. When 〖θ 〗_i was around 10℃ A, the indicated thermal efficiency reached its top value and the exhaust emissions were rather low. To a hydrogen fueled engine, the combustion conditions were not enough to produce certain amount of CO and HC under conditions o f idle and lean burning; 〖θ 〗_i should be reduced properly to reduce NOx emissions

Key words: CNG engine, hydrogen, ignition advance angle, idle performance

摘要： 为了研究点火提前角i对CNG发动机燃氢怠速性能的影响,在一台天然气发动机上进行了燃氢怠速性能试 验。固定转速800r/min,过量空气系数??=2,i从上止点前20??A到0??A变化。结果表明:随着i减小,火焰发展 期减小而快速燃烧期增加。当i>16??A,大部分燃料在上止点前燃烧,负功增加,指示热效率低；i=10??A左右, 指示热效率最高,且排放指标较小。对于燃氢发动机,怠速稀燃工况下,不具备产一定量CO和HC的条件。为了降 低燃氢发动机的NOx排放,满足稀燃条件的同时,需要适当减小点火提前角。

关键词: CNG发动机, 氢气, 点火提前角, 怠速性能