船用高替代率双燃料宽域喷射系统开发

Development of Marine Dual Fuel Wide Field Injection System with High Substitution Ratio

针对内河船用高天然气替代率和柴油模式满功率输出的应用需求,开发一款新型的双燃料喷射系统。该系统主要由歧管燃气喷射阀、智能化控制系统、含宽域喷油器的共轨系统等组成。喷油器仿真结果表明:缩短喷油持续期和减小喷孔直径有利于降低油耗和soot排放,但会增加NO_(x)排放。平台试验结果表明:宽域喷油器在全油量区域内具有优异的喷射重复性。整机匹配试验结果表明柴油模式下动力不损耗,额定点油耗相较原机改善了4.9%;微喷燃气模式下最高替代率出现在50%工况,为96.1%。推进工况下最高替代率相较原机平均提高8.2%,最大提高20.5%。各工况下最高替代率时的平均指示压力和爆压的循环变动系数均低于5%,且25%工况下除爆压循环波动系数外,微喷模式的其他循环变动系数均低于纯柴模式。

A new dual-fuel injection system is developed to meet the application of the high natural gas substitution ratio(SR)and the full-power output in diesel mode for inland river ships.The system is mainly composed of the gas valve in the inlet manifold,the intelligent control system and the common rail system included wide field injectors.The simulation results show that shortening the injection duration and reducing the nozzle diameter can reduce the fuel consumption and soot emissions,but can increase NO_(x) emissions.The platform test results show that the wide field injectors have the excellent injection repeatability in the full load range.The matching test results show that there is no power loss in diesel mode.The fuel economy is improved by 4.9%compared to the original engine.The maximum SR(96.1%)can be realized at the load of 50%in micro-injection natural gas mode.The maximum SR is increased by an average of 8.2%compared to the original engine,and the maximum increase is 20.5%.The cyclic variation coefficients of the indicated mean effective pressure and detonation pressure at the highest SR under each condition are less than 5%.Except for the cyclic variation coefficients of detonation pressure at the 25%load,the other cyclic variation coefficients in the micro-injection mode are lower than those in the pure diesel mode.