预喷策略耦合EGR对DN双燃料发动机工作过程的影响  

Influence of Pilot Injection Strategy Coupled with EGR on the Working Process of DN Dual Fuel Engine

作　　者：陈贵升[1] 魏峰 肖仁鑫[1] 张敬贤 王震江 张涵[1] Chen Guisheng;Wei Feng;Xiao Renxin;Zhang Jingxian;Wang Zhenjiang;Zhang Han(Kunming University of Science and Technology,Yunnan Key Laboratory of Internal Combustion Engine,Kunming 650500)

机构地区：[1]昆明理工大学,云南省内燃机重点实验室,昆明650500

出　　处：《汽车工程》2021年第8期1143-1151,共9页Automotive Engineering

基　　金：国家自然科学基金(51866004)资助。

摘　　要：基于三维流体力学软件,模拟研究了不同预喷策略耦合EGR对柴油/天然气(DN)双燃料发动机燃烧和排放特性的影响,研究表明:柴油预喷射量(FDIR)固定,预喷时刻(FDIT)提前至-10(°)CA ATDC以前时,燃烧质心(CA 50)更加靠近上止点,有利于降低CH_(4)、HC、CO和Soot排放,但NO_(x)排放大于单次喷射且在-20(°)CA ATDC时达到峰值;FDIT提前至-10(°)CA ATDC时,FDIR的增加对排放影响不大,FDIT提前至-10(°)CA ATDC以前时,较大的FDIR使CH_(4)、HC、CO和Soot排放保持在较低水平;随EGR率增加,不同预喷策略下CH_(4)、HC、Soot、CO排放总体呈上升趋势;当EGR率达到15%、FDIT提前至-20(°)CA ATDC、FDIR为30%时各项排放值均低于单次喷射;当EGR率达到25%时,缸内燃烧变差,不同预喷策略下NOx排放均降至最低,CO、Soot排放都超过了单次喷射。The influence of different pilot⁃injection strategies coupled with EGR on the combustion and emis⁃sion characteristics of diesel/natural gas(DN)dual fuel engine are studied based on the three⁃dimensional fluid dy⁃namics software.The results show that when the pilot diesel injection ratio(FDIR)is fixed and the pilot diesel injec⁃tion timing(FDIT)is advanced beyond-10(°)CA ATDC,the burning center of gravity(CA 50)is closer to the top dead center.It is beneficial to reduce CH_(4),HC,CO and Soot emissions.But the NO_(x)emission is higher than that of sin⁃gle injection and reaches the peak when the FDIT is advanced to-20(°)CA ATDC.When FDIT is advanced to-10(°)CA ATDC,the increase of FDIR has little influence on emission.When FDIT is advanced beyond-10(°)CA ATDC,larger FDIR can keep CH_(4),HC,CO and Soot emissions at a low level.As the EGR rate increases,the emissions of CH_(4),HC,CO,and Soot of different pilot⁃injection strategies are generally increased.When the EGR rate reaches 15%,the FDIT is advanced to-20(°)CA ATDC,and the FDIR is 30%,the emission value of each gas is generally lower than that of the single injection.When the EGR rate reaches 25%,the NO_(x)emission of different pilot⁃injection strategies is re⁃duced to the lowest level while the CO and Soot emissions exceed that of the single injection.

关 键 词：柴油 天然气 预喷策略 EGR 排放特性 

分 类 号：TK46[动力工程及工程热物理—动力机械及工程]