缸径对微型内燃机微燃烧性能影响和极小化分析  

Effect Analysis of Cylinder Bore on Micro Combustion and Miniature in Micro IC Engine

作　　者：唐刚志[1] 张力[1] 尚会超[1] 

机构地区：[1]重庆大学机械传动国家重点实验室,重庆400044

出　　处：《内燃机工程》2016年第3期23-30,共8页Chinese Internal Combustion Engine Engineering

基　　金：国家自然科学基金项目(51175530);博士点基金项目(20130191110001)

摘　　要：为研究缸径对微型内燃机微燃烧特性的影响机理及探索实现燃烧的临界缸径,采用层流有限速率模型和甲醇燃烧化学反应机理及动态网格技术,对其闭口热力系的瞬态预混层流燃烧过程进行动态多维仿真。并运用微观化学反应机理对不同缸径和压缩比时的微型内燃机燃烧和排放性能进行分析。研究结果表明:仿真与试验结果比较吻合,当缸径从10.8mm减至3.38mm时,缸内平均温度和压力及NO、CO、CH_2O排放浓度呈先增大后减小的趋势,最高压力值增加了约1.5MPa。在文中参数下,实现燃气完全燃烧的临界缸径约为4.5mm,完全不燃烧的缸径约为3.38mm。通过进一步分析,揭示了缸径对燃烧性能的影响主要取决于缸内未燃低温燃气总量和对环境散热量占燃烧释放总热量比值两个因素。分析还表明,随着缸径变化,缸内自由活性基团浓度和基元反应速率都将变化,并影响整个燃烧过程。随着压缩比提高,缸内温度和压力及NO、CO和CH_2O排放浓度增大。In order to research the influence of the cylinder bore on the micro combustion performances and miniaturization limitations in IC engine, the laminar flow finite rate model and methanol chemical reaction mechanism were adopted for a series of multidimensional numerical simulations of transient stratified charge combustion process. The combustion and emission performances under different cylinder bore and compression ratio were analyzed. The results show that the simulation results agree well with the experimental results. When the cylinder bore decreases from 10.8 mm to 3.38 ram, the average temperature, pressure and concentrations of NO, CO, CH20 will increase first and then decrease and the highest pressure will increase by 1.5 MPa. Under these conditions, the critical cylinder bore for complete combustion is about 4.5 mm, and for completely unburned combustion is about 3.38 mm. The influence of the cylinder bore on the combustion performance mainly depends on the following factors; the first factor is the ratio of the environmental heat loss to the total combustion heat release, and the second factor is the total amount of unburned gas in combustion chamber. With the increase of the compression ratio, the temperature, pressure and concentrations of NO, CO, CH20 will increase.

关 键 词：内燃机 微型内燃机 微燃烧 化学反应机理 极小化 

分 类 号：TK422[动力工程及工程热物理—动力机械及工程]