【摘要】 应用自主开发的电控液压可变配气机构在一台经过改进的单缸发动机上实现了两种EGR策略下的可控自燃着火(CAI),并对两种策略下CAI燃烧的发动机运行参数以及燃烧特征参数进行了研究。研究结果表明:在相同转速1000r/min时,NVO策略下的CAI工作区域比EGRB策略下的工作区域宽广,相位可调整范围较大;EGRB策略下的最大平均有效压力略高于NVO策略;两种策略在整个CAI工作区域内,有效热效率较高,大部分区域内的效率超过了30%,而且NOx排放水平极低;NVO策略下的燃烧始点较提前,燃烧持续期较短。更多还原

【Abstract】 On the basis of self-developed electro-hydraulic variable valve train,controlled auto-ignition(CAI)was achieved under two different EGR strategies on a modified single cylinder engine.Stable CAI operating ranges of these two valve timing scenarios were obtained by plotting tested operating points.Within the operating range,engine performances and combustion features were analyzed.The experimental results indicate that operating range of NVO strategy,allowing more substantial adjustment of valve phase,is wider than that of EGRB strategy at fixed engine speed of 1000 r/min.The maximum BMEP of EGRB strategy slightly exceeds the NVO strategy.Moreover,brake thermal efficiency exceeds 30% in most of these two operating range,higher than conventional engine,with an extremely low NOx emission at the same time.Besides,start of combustion of CAI under NVO strategy is a little advanced and combustion duration is a little shorter compare with that of EGRB strategy.更多还原