柴油机瞬变过程烟度排放的劣变分析  

Analysis of Soot Deterioration in Diesel Transient Process

作　　者：田径[1] 刘忠长[1] 许允[1] 张龙平[1] 

机构地区：[1]吉林大学汽车仿真与控制国家重点实验室,吉林长春130025

出　　处：《内燃机学报》2016年第2期125-134,共10页Transactions of Csice

基　　金：国家重点基础研究发展计划(973计划)资助项目(2013CB228402);国家自然科学基金资助项目(51206060);吉林省科技发展计划资助项目(20150520113JH)

摘　　要：在一台增压中冷高压共轨柴油机上进行了恒转速增转矩典型瞬变工况下烟度劣变的成因分析,并确定了适用于瞬变工况劣变性能分析的评价参数.研究结果表明:瞬变过程烟度峰值较稳态工况恶化了17.5倍,供油量、转矩和进气量的滞后程度依次增大,而减小发动机加载率、增大加载起始点负荷或减小恒定转速均有助于改善发动机瞬变性能劣化程度;表观上供油和供气速率不匹配、低燃烧速率和燃烧相位滞后造成的燃烧劣变在缸内物理场中可以归因于缸内油气混合气驱动能量的不足;与稳态工况相比,瞬态工况的燃烧反应基团在φ-T图碳烟(soot)生成岛中更大的体积比例和更长的停留时间导致缸内局部浓混合气比例增大;缸内油气混合状态与soot生成量呈现出显著的相关性,是造成soot排放恶化的主要原因.Soot deterioration under typical transient load of constant speed and increasing torque（CSIT）was analyzed on a turbocharged and intercooled common-rail diesel engine.Evaluation parameters were defined for the transient performance analysis.Test results show 17.5 times of peak soot emissions in the transient process compared with the corresponding steady conditions.Dynamic response speeds of fuel-supply,torque and air-supply are decreased in turn,and engine performance is improved with low loading rates,high initial-load conditions or high constant engine-speeds.The deterioration caused by non-matching between air and fuel supply rate decreases in combustion rate delay in combustion phase,is attributed to the deficiency of driven capability of air-fuel mixture in physical computation fields.Combustion reactive group in transient conditions causes richer air-fuel mixture with large volume ratio and long dwelling time when entering into the soot generation zone in φ-T MAP.The decrease in fuel atomization,vaporization and air-fuel mixture rates brings high possibility of local rich mixture in cylinder,indicating that the airfuel mixture feature has strong correlativity with soot deterioration,and is a key reason for high soot emission.

关 键 词：柴油机 瞬变过程 油气混合 燃烧劣变 烟度 

分 类 号：TK421.2[动力工程及工程热物理—动力机械及工程]