废气再循环对高比例甲醇双燃料柴油机燃烧过程的影响.pdf

汽 车 工 程 2014年(第36卷)第11期 Automotive Engineering 2014(Vol.36)No.11 2014254 废气再循环对高比例甲醇双燃料 柴油机燃烧过程的影响* 李仁春,王 忠,张登攀,李铭迪 (江苏大学汽车与交通工程学院,镇江 212013) [摘要] 在4B26增压柴油机上,以进气管电控喷射的方式掺入甲醇,实现甲醇/ 柴油双燃料的燃烧。 采用废 气再循环技术拓宽高比例甲醇双燃料柴油机的工况范围,研究 EGR对燃烧过程的影响规律。 结果表明:适当的 EGR率可以显著降低燃烧初期时的燃烧反应速度和加速度,缸内燃烧压力振荡明显减弱。 随着EGR率的增加,甲 醇/ 柴油预混合燃烧量减少,滞燃期缩短,燃烧持续期延长,燃烧最高温度降低;原甲醇/ 柴油双燃料燃烧放热以预混 放热为主;引入EGR后,预混放热量减少,扩散放热量增加。 随着EGR率的增加,放热率峰值降低;在相同工况下, 保持掺混48%甲醇不变时,甲醇/ 柴油双燃料发动机的指示热效率随EGR率的增加而降低。 关键词:双燃料柴油机;EGR;甲醇;燃烧 Influence of EGR on Combustion Process in High Methanol Proportion Dual Fuel Diesel Engine Li Renchun,Wang Zhong,Zhang Dengpan Li Mingdi School of Automobile and Traffic Engineering,Jiangsu Univerisity,Zhenjiang 212013 [Abstract] Methanol/ diesel dual fuel combustion is realized on a turbocharged diesel engine 4B26 with methanol blended in by electronically controlled intake port injection. Exhaust gasrecirculation (EGR)technology is adopted to extend theworkingrange of dualfuel diesel enginewith high proportion of methanolwith itseffectson combustion process studied. The results show that an appropriate EGR rate can significantly reduce the speed and acceleration of combustion reaction at initial stage and weaken the oscillation of in-cylinder combustion pressure. With the increaseinEGRrate,thevolumeofpremixedcombustionofmethanol/ dieselblendreduces,ignitiondelay period shortens,combustion duration prolongs and the combustion temperature peak lowers. The main partsof heat release is premixed one for methanol/ diesel dual fuel combustion in nature,but with EGR introduced,