缸内直喷参数对复合均质压燃发动机排放特性的影响  

Impact of the direct injection parameters of the compound homogeneous charge compressed ignition engine on the exhaust emission characteristics

作　　者：张超[1] 张春化[1] 薛乐[1] 李阳阳[1] 

机构地区：[1]长安大学汽车学院,交通新能源应用与汽车节能陕西省重点实验室,西安710064

出　　处：《安全与环境学报》2016年第4期270-276,共7页Journal of Safety and Environment

基　　金：陕西省工业科技攻关项目(2016GY-002);中央高校科研业务费项目(310822151029,2014G1502035)

摘　　要：为了提高内燃机的热效率、降低排放,在一台由柴油机改造的均质压燃发动机上开展了正丁醇/正庚烷复合均质压燃试验。分别研究了缸内直喷时刻、直喷压力、直喷量及进气温度对发动机排放的影响,并对复合均质压燃模式下发动机的运行范围进行了对比分析。结果表明:随缸内直喷时刻推迟,CO和HC的排放先增加后减小再增加;随缸内直喷压力升高,CO的排放先升高后降低,HC的排放略有升高趋势;随总体混合气逐渐变浓CO的排放总体上有所降低,HC呈现先增后减的趋势;随进气温度不断升高HC与CO的排放均呈明显的下降趋势;NOx的排放总体处于较低水平。存在最优的直喷参数值,即φin=340°CA,pinject=6 MPa,λt=1.15,使得排放与热效率相对平衡且均获得优化。在复合均质压燃燃烧模式下,发动机运行范围得到了较为明显的拓展。The article is to introduce an experimental exploration of the impact of the direct injection parameters of the compound homogeneous charge compressed ignition（ HCCI） engine on the exhaust emission characteristics so as to heighten the thermal efficiency and reduce the exhaust emission pollution of the internal combustion engine. For the above purpose,we have done an experimental study for the port injected n-butanol homogeneous charge compression ignition（ HCCI） in combination with the incylinder n-heptane direct injection,so as to find the effects of the direct injection timing,the direct injection pressure,the direct injection quantity and the intake temperature on the emission characteristics and the operation range of the HCCI engine in the compound mode. Furthermore,we have also modified cylinder 2#of the test engine so that it can operate as HCCI combustion mode by adding a PI injector in the intake pipe,on the condition that its cylinder 1# is used in the diesel mode. In addition,a DI injector has been mounted on the head of cylinder 2# to realize the fuel direct injection. Since the fuel pressure is driven by the highpressure nitrogen that can be adjusted as is expected,it has to be noticed that each cylinder has its own intake and exhaust system with its own independent fuel supply system,which makes the HCCI cylinder easy to be controlled and tested respectively. The results show that,with the retard of the direct injection timing,the CO and HC emissions tend to increase first,then decrease,and finally tend to rise again. When the direct injection pressure is increased,the CO emission would first increase and then decrease,conducing to a slight increase of HC emission. At the same time,with the gradual increase of the overall mixture concentration,CO emission tends to decrease a bit. And,then,the HC emission tends to increase first and then decrease. A significant downward trend will be followed with the rise of the intake of the air temperature,HC and CO emissions. The NOxemission would be tot

关 键 词：环境工程学 排放特性 缸内直喷 复合均质压燃 正庚烷 正丁醇 

分 类 号：X51[环境科学与工程—环境工程]