天然气混氢发动机稀燃极限影响因素试验研究

为了研究点火提前角、掺氢比、节气门开度、发动机转速、机油和冷却水温度对天然气混氢发动机稀燃极限的影响，在一台点燃式发动机上开展了台架试验。试验转速1 500～3 000 r/min，节气门开度10%～40%，机油温度75 ℃～95 ℃，冷却水温度65 ℃～85 ℃. 试验用燃料掺氢比0～40%，点火提前角条件为稀燃最佳角。结果表明：过大和过小的点火提前角都使发动机的稀燃极限减小；稀燃极限随燃料中掺氢比增加而显著提高；随节气门开度增加略有上升；随发动机转速增加而减小；随机油温度升高先减小后增大；随冷却水温度升高而略有上升。

Experimental Study on the Factors Affecting Lean Combustion Limit of S.I. Hydrogen-Natural Gas Engine

An experimental study was conducted on a spark ignition engine to investigate the factors that affect the lean combustion limit of hydrogen-natural gas engine.The effects of ignition timing,hydrogen mixing ratio,engine speed,throttle opening,lubricant oil and coolant temperature were examined.The engine speed was 1 500-3 000 r/min,the throttle opening was 10%-40%,the lubricant temperature was 75 ℃-95 ℃,and the coolant temperature was 65 ℃-85 ℃ during experience.The hydrogen mixing ratio varied from 0 to 40%,and the lean-combustion limit ignition timing was defined and adopted.The result shows that both over-retarded and over-advanced ignition timing would baffle the extension of lean-combustion limit.The lean-combustion limit increases with hydrogen mixing ratio,slightly increases with throttle opening,and decreases when the engine speed is raised.Besides,it decreases with the increase in lubricant temperature.Warming-up coolant is positively related to enlarge the lean-combustion limit.