配气相位对天然气发动机燃烧和排放的影响  

Investigation of Effect of Cam Phase on Combustion and Exhaust Characteristics of CNG Engine

作　　者：焦运景[1] 张惠明[1] 杨志勇 张自立 司鹏 程辉 

机构地区：[1]天津大学内燃机燃烧学国家重点实验室,天津300072 [2]东风南充汽车有限公司,南充637000

出　　处：《农业机械学报》2009年第8期13-17,共5页Transactions of the Chinese Society for Agricultural Machinery

基　　金：国家“863”高技术研究发展计划资助项目(2006AA11A1B2)

摘　　要：对改装为火花点火式天然气发动机的柴油机配气机构的配气相位进行了优化设计,并在发动机台架上进行了对比试验,研究了配气相位对发动机燃烧及排放的影响。试验结果表明:随着气门重叠角的减小,HC和NOx排放量有所降低,但高转速时过小的气门重叠角,不利于HC排放量的降低;气门重叠角的减小使得缸内可燃气体浓度降低,在抑制NOx生成的同时,也损失了部分功率,因而在降低有害排放的同时,还要兼顾动力性;随着转速的升高,要适当增大点火提前角,以保证其动力性,避免后燃,降低排温。Two cam phases were designed basing on original diesel engine which was refitted into spark ignition CNG engine. The influence of cam phase on combustion and exhaust was studied by experiment on indoor test. The conclusions are showed as follows. With the smaller valve overlap, the exhaust of HC and NOx reduces; but too small valve overlap at high speed is adverse to the exhaust of HC. The density of burning mixture reduces with smaller overlap and the growth of NO~ is restricted. On the other hand, power of the engine also reduces. So, both the power and the exhaust should be considered at the same time. The crank angle of ignition advance should increase properly at high speed, in order to keep the power and avoid the post combustion and reduce the temperature of exhaust.

关 键 词：天然气发动机 配气相位 燃烧 排放 

分 类 号：TK464[动力工程及工程热物理—动力机械及工程]