摘要
基于一套经改造的汽柴油混合双燃料发动机系统,在柴油发动机进气道安装汽油喷射系统实现缸内均质的混合气制备,通过上止点直喷柴油控制燃烧相位,通过调整汽柴油比例及EGR比例研究双燃料发动机燃烧性能。研究显示:相比原机,汽柴油比例增大,排气温度降低,当汽柴油比例提高到65%时,呈现出低温燃烧效果,同时降低NOx和碳烟的排放,燃烧持续期缩短,最大压力升高率增大,但是整体燃烧效果更优;从EGR特性及其对缸内燃烧过程和发动机燃烧性能的影响来看,此款双燃料发动机在小负荷时宜采用热EGR,在大负荷时宜采用冷EGR;双燃料发动机进气温度提升对燃油消耗率和碳烟并没有明显影响,而对于NOx来说,进气温度会改善发动机燃烧性能提升缸内燃烧温度,进而NOx排放会出现恶化现象。
Based on a modified gasoline-diesel dual-fuel engine system,the gasoline-injection system is installed at the intake port of the diesel engine,in order to realize the preparation of the homogeneous mixture in the cylinder.The combustion phase is controlled by the direct-injection diesel at the top dead spot.Both the gasoline-diesel ratio and EGR rate are adjusted for analysis on the combustion performance of the dual-fuel engine.The result shows that compared with the original system,the gasoline-diesel ratio increases as the air-exhaust temperature lowers,and when the gasoline-diesel ratio increases to 65%,the low-temperature combustion is ensured.Besides,the emissions of NOx and soot are reduced,and the duration of combustion is shortened;the rising rate of the maximum pressure goes up,and the overall effect of combustion is better.From the characteristics of EGR and its influence on the in-cylinder combustion process and the engine’s combustion performance,hot EGR should be adopted when the dual-fuel engine is operating with the low load,and cold EGR should be adopted when the engine is operating with the high load.The rise of the air-intake temperature has no significant effect on the fuel-consumption rate and soot.For NOx,the air-intake temperature will improve the engine’s combustion performance and increase the in-cylinder combustion temperature,and thus the NOx emissions will deteriorate.
作者
戴春蓓
郭辉
仲崇智
张泰钰
李旭聪
康红格
DAI Chun-bei;GUO Hui;ZHONG Chong-zhi;ZHANG Tai-yu;LI Xu-cong;KANG Hong-ge(China Automotive Technology and Research Center Co.,Ltd.,Tianjin 300300;Borgward Automotive(China)Co.,Ltd.,Beijing 102206;Tibet Dialev New Energy Automobile Co.,Ltd.,Beijing 100076)
出处
《机械设计》
CSCD
北大核心
2019年第10期97-104,共8页
Journal of Machine Design
关键词
双燃料发动机
汽柴油比例
EGR
进气温度
dual-fuel engine
gasoline-diesel ratio
EGR
intake air temperature
