自由活塞汽油直线发电机燃烧过程特性  

Combustion characteristics of free-piston gasoline engine for linear alternator

作　　者：袁晨恒[1] 冯慧华[1] 王梦秋[1] 左正兴[1] 

机构地区：[1]北京理工大学机械与车辆学院,北京100081

出　　处：《吉林大学学报（工学版）》2015年第1期127-132,共6页Journal of Jilin University:Engineering and Technology Edition

基　　金：国家自然科学基金项目(51006010);高等学校学科创新引智计划项目(B12022)

摘　　要：为了获得自由活塞汽油直线发电机工作过程中的燃烧特性,根据试验测得的活塞运动曲线对其燃烧过程进行了CFD仿真研究,并对比传统发动机分析了两种发动机活塞运动规律差异对燃烧过程的影响规律。研究发现:与传统发动机相比,自由活塞汽油发电机缸内最高燃烧压力和平均温度均较小,且最高燃烧压力保持时间较短,这有助于减少NO污染物;自由活塞直线发电机燃烧放热率呈现'缓和长'的特点,燃烧放热过程等容度较低;自由活塞直线发电机较少的混合气在上止点前完成燃烧,压缩行程负功较小,但由于后燃较严重,其指示效率较传统发动机低。In order to analyze the combustion performance of a spark ignited free-piston gasoline engine for linear alternator, according to the piston motion characteristics, a coupled multidimensional computational fluid dynamics model is used to simulate the combustion process. The effect of free- piston motion on the combustion process is analyzed in comparison with a conventional crankshaft- driven gasoline engine. The results show that, compared with the conventional engine, the peak in- cylinder pressure and the mean temperature of the free-piston linear alternator are lower, and the period of the peak in-cylinder pressure is shorter, which benefits the reduction of emission of NO exhaust. The heat release rate of the free-piston linear alternator has the characteristics of slow heat release at prophase, gentle heat release at metaphase and long combustion at anaphase. Less gas mixture burns before the piston reaches the top dead centre. The loss work in compression stroke is also less than that of the conventional engine. However, the indicated efficiency of the free-piston linear alternator is lower because of its serious after-combustion period.

关 键 词：动力机械工程 自由活塞汽油机 燃烧特性 活塞运动特性 点火时刻 

分 类 号：TK441[动力工程及工程热物理—动力机械及工程]