摘要
以一台混合动力专用发动机为样机,研究了其采用常规循环(压缩比11.5)和米勒循环(压缩比分别为11.5、12.5、15)的燃烧排放特性。结果表明:低负荷工况压缩比均为11.5时,与常规循环相比,采用米勒循环后,节气门开度增大,泵气损失减小,热效率提升;增加米勒循环压缩比至15时,其较常规循环热效率提升1.62%。高负荷工况压缩比均为11.5时,与常规循环相比,采用米勒循环后,爆震倾向减弱,燃烧相位得到优化,经济性略有改善;增加压缩比至12.5时,此时由于米勒循环抑制爆震能力占据主导地位,其油耗仍有改善,但将压缩比增至15,压缩比影响占据主导,此时爆震倾向严重,热效率降低。排放方面,采用米勒循环后,燃烧温度降低,NO_(x)排放下降,HC、CO排放有所上升,颗粒排放有所改善;增大压缩比后,燃烧温度上升,NO_(x)、CO排放增加,HC排放略有上升,颗粒排放增多。
Taking a special hybrid engine as the prototype, the conventional cycle(compression ratio 11.5) and Miller cycle are studied the results show that when the compression ratio is 11.5,12.5 and 15 under low load conditions, compared with the conventional cycle, the throttle opening increases, the pump loss decreases and the thermal efficiency increases;when the compression ratio of Miller cycle is 15, the thermal efficiency increases by 1.62% compared with the conventional cycle.When the compression ratio of Miller cycle is 11.5 under high load conditions, compared with the conventional cycle, the knock tendency is weakened, the combustion phase is optimized and the economy is slightly improved;When the compression ratio is increased to 12.5, the fuel consumption is still improved due to the dominant knock suppression ability of Miller cycle. However, when the compression ratio is increased to 15, the influence of compression ratio is dominant. At this time,the knock tendency is serious and the thermal efficiency is reduced. In terms of emission, after Miller cycle, the combustion temperature decreases, NO_(x)emission decreases, HC and CO emissions increase, and particle emission improves;After increasing the compression ratio, the combustion temperature increases, NO_(x)and CO emissions increase, HC emissions increase slightly, and particle emissions increase.
作者
谭丕强
王梓桐
楼狄明
胡志远
房亮
TAN Piqiang;WANG Zitong;LOU Diming;HU Zhiyuan;FANG Liang(School of Automobile,Tongji University,Shanghai 201804,China)
出处
《工程热物理学报》
EI
CAS
CSCD
北大核心
2022年第8期2152-2162,共11页
Journal of Engineering Thermophysics
基金
国家重点研发计划资助项目(No.2018YFB0105802)。
关键词
混合动力
汽油机
压缩比
米勒循环
燃烧
排放
hybrid
gasoline engine
compression ratio
miller cycle
combustion
emission
