DOC与SCR系统在轻型柴油机中的应用研究  

Applied research of DOC and SCR on light-duty vehicle diesel engine

作　　者：游靖[1] 朱浩[1] 邓红喜 罗福强[1] 

机构地区：[1]江苏大学汽车与交通工程学院,江苏镇江212013 [2]无锡四达动力机械集团有限公司,江苏无锡214187

出　　处：《广西大学学报（自然科学版）》2016年第5期1386-1393,共8页Journal of Guangxi University（Natural Science Edition）

基　　金：国家自然科学基金资助项目(51476072);江苏省高校优势学科建设工程资助项目(苏政办发[2011]6号)

摘　　要：针对单独的选择性催化还原器(SCR)不能使轻型柴油机排放达到标准,提出氧化催化转化器(DOC)与SCR组合应用。基于台架试验,在一台四缸共轨增压中冷柴油机的排气管上匹配DOC和SCR并进行欧洲稳态循环(ESC)测试研究,探究了DOC对SCR入口处进气的温度影响和对SCR中结晶物进行热重分析,研究了DOC+SCR对柴油机的经济性的影响、尾气排放性能的影响。试验结果表明:DOC对提高SCR入口温度的作用不大,在转速2 400 r/min,扭矩126 N·m时达到最大10℃;DOC主要改变SCR入口NO2与NOx的体积比,怠速状态下提高比例达到64%,其余工况达到30%;对尿素沉积物进行了分析,得出排气管壁与喷嘴处附近的结晶组分含量不相同;柴油机采用DOC与SCR后处理装置后,燃油消耗率在高负荷情况下增大1.5%;CO和HC排放在各个负荷下都大幅下降,排放值分别为0.007 g/(k W·h)、0.005 g/(k W·h);NOx的排放在SCR作用下达到1.209 g/(k W·h),转化率达到79%。研究结果可为轻型柴油机满足排放标准、优化排放提供参考。Because the individual selective catalytic reduction （ SCR） can not make light diesel en-gine reaches emission standards, Coupling diesel oxidation catalyst （ DOC） with SCR is proposed. An experimental research was carried out to explore the effects of coupling DOC and SCR on per-formance and emission of a 4-cylinder, common rail, inter-cooling diesel engine to follow European steady state cycle （ ESC） role. Results showed that DOC had little effects on the temperature of SCR entrance especially. The temperature increased about 10℃ when speed was 2 400 r/min and torque was 126 N·m and it mainly changed the ratio of NO2 to NOx to 64% on the idling condition while other conditions were about 30%;By the analysis of the urea sediment, it is found that the compo-nents of urea sediment on the surface of the exhaust pipe and near the injector were different. With the coupling use of DOC and SCR, the fuel consumption rate slightly increased about 1. 5% at high load conditions. The CO and HC emission were decreased obviously, the results showed that emission were 0. 007 g/（ kW·h ） and 0. 005 g/（ kW·h ） . Moreover, the NOx emission was 1. 209 g/（ kW·h） with the use of SCR and its conversion efficiency reaches 79%. The results can provide reference to meet emission standards and to optimize emission for light diesel engine.

关 键 词：柴油机 排放 氧化催化转化器(DOC) 选择性催化还原器(SCR) 

分 类 号：TK421.5[动力工程及工程热物理—动力机械及工程]