缸内直喷天然气/氢气混合燃料配合废气再循环的性能与排放  

Performance and Emission Characteristics of a Direct-Injection Spark Ignition Hydrogen Enriched Natural Gas Engine Diluted with EGR

作　　者：刘亦夫[1] 刘兵[1] 曾科[1] 周磊[1] 孙璐[1] 

机构地区：[1]西安交通大学能源与动力工程学院,西安710049

出　　处：《西安交通大学学报》2011年第7期5-8,69,共5页Journal of Xi'an Jiaotong University

基　　金：国家自然科学基金资助项目(50636064;50776070)

摘　　要：在一台天然气/氢气混合燃料的缸内直喷火花点火发动机上通过引入废气再循环(EGR)实验研究了EGR率、掺氢比及喷射时刻对发动机性能和排放的影响.结果表明:掺入氢气,在小EGR率时可以减小平均有效压力(BMEP)和有效热效率,在大EGR率时可以增加BMEP和有效热效率;BMEP随EGR率的增大而减小,有效热效率随EGR率的增大先减后增.NOx排放随EGR率的增大而下降,随掺氢比的增大而上升;HC排放随EGR的增大而上升,随掺氢比的增大而下降;CO排放与EGR率变化基本无关,随掺氢比的增大而上升.平均指示压力变动系数Cimep随EGR率的增加而增大,相比于早喷射,晚喷射时Cimep的增大趋势更为明显,此时掺氢可以有效降低Cimep.An experimental study was conducted on a direct-injection spark-ignition（DISI） engine fuelled with hydrogen-natural gas blends with the introduction of EGR（exhaust gas recirculation）.The effects of the EGR rate,the hydrogen fraction and the injection timing on the engine performance and emission characteristics were investigated.The results show that the hydrogen addition reduced the brake mean effective pressure（BMEP） and the brake thermal efficiency at the lower EGR rate but increased the BMEP and the brake thermal efficiency at the higher EGR rate.The BMEP decreased with an increase in the EGR rate,and the brake thermal efficiency increased at first and then decreased with an increase in the EGR rate.The NOx concentration decreased with an increase in the EGR rate and increased with the hydrogen fraction.The HC emission increased with the EGR rate and decreased with an increase in the hydrogen fraction.The CO emission changed slightly with the EGR rate and decreased with an increase in the hydrogen fraction.In addition,the variation coefficient of indicated mean effective pressure Cimep increased with the EGR rate,and the hydrogen addition could reduce the Cimep more effectively for late injection..

关 键 词：缸内直喷火花点火 天然气 氢气 废气再循环装置 

分 类 号：TK431.2[动力工程及工程热物理—动力机械及工程]