增压重型柴油机米勒循环应用的潜力研究  

Research on the potential application of the Miller cycle in supercharged heavy duty diesel engines

作　　者：王菁 班智博[1] 赵茗卓 官维 潘明章 WANG Jing;BAN Zhibo;ZHAO Mingzhuo;GUAN Wei;PAN Mingzhang(Technical Research Institute,Guangxi Yuchai Machinery Co.,Ltd.,Nanning 530004,China;Mechanical and Electrical Engineering College,Wenzhou University,Wenzhou 325035,China;School of Mechanical Engineering,Guangxi University,Nanning 530004,China)

机构地区：[1]广西玉柴机器股份有限公司技术研究院,南宁530004 [2]温州大学机电工程学院,浙江温州325035 [3]广西大学机械工程学院,南宁530004

出　　处：《重庆理工大学学报（自然科学）》2022年第12期223-230,共8页Journal of Chongqing University of Technology：Natural Science

基　　金：国家自然科学基金项目(51865002)。

摘　　要：米勒循环具有提高发动机热效率、降低NO x排放等优势,但同时也减少了缸内新鲜空气总质量,从而对燃烧过程产生不利影响。因此,通过试验研究,探索了柴油机在不同进气压力下从低负荷到高负荷区域应用米勒循环的应用潜力。通过计算总液体燃料消耗量(包括燃油消耗量和氮氧化物后处理系统中估算的尿素消耗量),对发动机总体运行效率进行综合分析。在装有高压共轨燃油喷射系统和可变气门驱动系统的单缸重型柴油机上进行指示平均压力分别为0.6、1.2和1.7 MPa三个工况的试验。结果表明,采用通过进气门晚关角的米勒循环技术,有效地降低了压缩冲程终了时的缸内气体压力和温度,从而降低了燃烧温度峰值,有助于降低氮氧化物的排放水平。同时,排气温度也明显高于非米勒循环时发动机排气温度。特别是在低负荷0.6 MPa的IMEP下,排气温度提高了约80℃,能显著提高NO x后处理转化效率。The Miller cycle has advantages of improving thermal efficiency and reducing NO x emissions in diesel engines.However,the use of the Miller cycle decreases the trapped in-cylinder fresh air,which deteriorates the combustion process.Therefore,experiments are carried out to explore the potential of the Miller cycle under different intake pressures from low to high loads.An overall engine efficiency analysis is performed by calculating the total liquid fuel consumption,which includes fuel consumption as well as estimated urea consumption in the NO x post-treatment system.The experiments are conducted at engine loads of 0.6,1.2,and 1.7 MPa indicated mean effective pressure(IMEP)on a single-cylinder heavy duty(HD)diesel engine equipped with a high-pressure common rail fuel injection system and a variable valve actuation(VVA)system.The results show that the application of the Miller cycle with late intake valve closing(LIVC)effectively reduces gas pressure and temperature at the end of compression stroke,which results in a lower peak combustion temperature and a lower level of NO x emissions.Meanwhile,exhaust gas temperature(EGT)significantly increases,compared with an engine operation without using the Miller cycle.It is worthy of mentioning that an increase of EGT by approximately 80℃is obtained at a low load of 0.6 MPa IMEP,which can substantially improve the NO x post-treatment conversion efficiency.

关 键 词：米勒循环 柴油机 排放 发动机总体运行效率 排气温度 

分 类 号：TK427[动力工程及工程热物理—动力机械及工程]