摘要
在一台单级废气涡轮增压中冷柴油机的基础上,建立二级增压中冷柴油机仿真模型及调节EGR阀开度,使EGR率保持在45%,在验证了二级增压器匹配的合理性后,研究了标定转速2 200,r/min、50%负荷下柴油机二级增压耦合预喷射对燃烧特性参数的影响,最后在标定转速50%负荷工况、标定工况以及最大转矩工况进行了预喷对发动机机械负荷和热负荷影响的研究.结果表明,二级增压相比一级增压提高增压压力18%左右,但也同时增加最大压升率.预喷能够大幅度降低最大压升率,增加二级增压性能,缩短主喷滞燃期,推迟放热重心,增加燃烧持续期,降低机械负荷;但同时增加柴油机热负荷,小预喷量耦合较小的预喷间隔角,柴油机燃烧特性较好.
Numerical study was carried out to investigate the influences of two-stage turbo-charging cou- pled with pilot injection on combustion characteristic of a diesel engine at rated speed of 2 200 r/rain and 50% full load, with the EGR rate of 45%. The simulation model of two-stage turbo-charged inter-cooling system was added on the basis of one-stage turbo-charging diesel engine when rationality of two-stage turbo-charging matching was verified. The influence of points injection on mechanical and thermal loads at rated and maximum torque operating points and speed of 2 200 r/min and 50% full load was studied. Re- suits show that two-stage turbo-charging system can increase the inlet pressure by 18%, but the maximum rate of pressure rise is increased as well. Pilot injection can largely reduce the maximum rate of pressure rise, enhance the performances of the two-stage turbo-charging system, shorten the ignition delay of main injection, delay the center of heat release curve and lower the mechanical load and increase the thermal load. A small quantity of pilot injection fuel coupled with small pilot injection dwell timing show good combustion characteristic.
出处
《内燃机学报》
EI
CAS
CSCD
北大核心
2013年第6期513-518,共6页
Transactions of Csice
基金
国家"863"计划资助项目(2012AA111705)
国家自然科学基金资助项目(50676067)
关键词
柴油机
二级增压
预喷
燃烧特性
数值模拟
diesel engine
two-stage turbo-charging
pilot injection
combustion characteristic
numerical simulation
