燃烧室内积聚燃料在柴油机冷起动过程中的蒸发方式初探  

Research on evaporation mode of accumulated fuel in combustion chamber during diesel engine cold start

作　　者：周乃君[1] 裴海灵[1] 陈秋亮[1] 王本亮[1] 陈宏德[1] 

机构地区：[1]中南大学能源科学与工程学院,湖南长沙410083

出　　处：《热科学与技术》2007年第2期156-161,共6页Journal of Thermal Science and Technology

摘　　要：针对燃烧室内积聚燃料作用机理未明的现状,在分析了积聚燃料蒸发特点的基础上,提出了液滴蒸发模型和液膜蒸发模型;并对一台单缸自然吸气式直喷柴油机在0℃冷起动时的积聚燃料蒸发情况进行了仿真模拟计算。结果表明:对于相同量的燃料,液膜厚度从25μm到20μm导致缸内的燃空比减少了2%,而从25μm到30μm却增加了3%的燃空比,说明油膜较厚时能够较快蒸发;且油膜蒸发是燃烧室内积聚燃料冷起动时蒸发主要方式。为进一步改善柴油机冷起动性能提供了依据。The effect of accumulated fuel in combustion chamber is not clear yet. Based on the analyses of accumulated fuel evaporation characteristic, liquid drops and liquid film models were put forward to research the fuel evaporation during cold start. By the models, the simulation was applied on a single-cylinder naturally aspirated direct injection diesel engine, when the engine cold start at the ambient temperature 0℃. The results show that for the same amount of fuel, the change of fuel film thickness from 25 μm to 20μm results in 2% fuel air ratio reduction; from 25μm to 30 μm results in 3% fuel air ratio increase. It can be concluded that thicker fuel film （the same amount of fuel） evaporates more fuel vapor and the fuel film mode is the driving force for accumulated fuel evaporation during cold start. This conclusion may provide a theory foundation for improving cold start performance of diesel engine.

关 键 词：柴油机 冷起动 积聚燃料 液滴模型 液膜模型 

分 类 号：TK421.2[动力工程及工程热物理—动力机械及工程]