两级增压米勒循环柴油机的热力学性能及(火用)分析  

Thermodynamic performance and exergy analysis of a two-stage turbocharged Miller-cycle diesel engine

作　　者：王毅[1] 何冠璋 林铁坚 黄豪中[1] 郭晓宇 邢孔钊 Wang Yi;He Guanzhang;Lin Tiejian;Huang Haozhong;Guo Xiaoyu;Xing Kongzhao(School of Mechanical Engineering,Guangxi University,Nanning 530004,China;Guangxi Yuchai Machinery Group Company Limited,Yulin 537000,China)

机构地区：[1]广西大学机械工程学院,南宁530004 [2]广西玉柴机器集团有限公司,玉林537000

出　　处：《内燃机学报》2025年第2期127-135,共9页Transactions of CSICE

基　　金：国家自然科学基金资助项目(52366007);广西科技重大专项资助项目(桂科AA23062012,桂科AA23062090).

摘　　要：四阶段《重型商用车辆燃料消耗量限值》对柴油机有效热效率(BTE)提出了更高的要求.基于一台7.7 L柴油机进行了一维仿真和试验验证,并通过(火用)分析探讨了米勒循环耦合压缩比对有效热效率的影响机制.结果表明:随着米勒度的增加,不可逆燃烧损失和排出损失降低.在等转矩条件下,压缩比的提高可以减小排出损失.两级增压器的使用提高了进气流量,缸内总热容增大,有利于降低传热损失和排出损失.在高爆压目标下,相比晚关策略,进气门早关方案的传热损失和排出损失增加.根据计算结果完成了实际方案开发,在转速为1200 r/min、转矩为1200 N·m工况下,当进气门关闭角延后40°CA、压缩比由17.2提高至20.5且爆压由16.5 MPa提升至25.0 MPa时,有效热效率提升了4.0%,燃油消耗率(BSFC)降低了16 g/(kW·h).The fourth stage of China’s fuel consumption limits for heavy-duty commercial vehicles has set higher requirements for the brake thermal efficiency(BTE).Based on a 7.7 L diesel engine,a one-dimensional simulation was firstly conducted with experimental verification,and the mechanism of the influence of Miller-cycle coupling compression ratio on the BTE was explored through exergy analysis.The results indicate that the irreversible combustion loss and exhaust loss decrease with the increase of Miller degree.Under the equal torque conditions,an increase in the compression ratio can reduce the exhaust loss.The use of two-stage turbochargers increases the intake flow rate and total heat capacity in the cylinder,which helps to reduce the heat transfer loss and the exhaust loss.Under high combustion pressure targets,compared to the late intake valve closing strategy,the early intake valve closing scheme increases the heat transfer loss and exhaust loss.Then,an actual engine development plan was completed based on the above calculation results.Engine test was run under the speed of 1200r/min and the torque of 1200N·m.The BTE increases by 4.0%and the brake specific fuel consumption rate(BSFC)decreases by 16 g/(kW·h),when the intake valve closing angle is delayed by 40°CA,the compression ratio is increased from 17.2 to 20.5 and the peak combustion pressure is increased from 16.5 MPa to 25.0MPa.

关 键 词：柴油机 两级增压 米勒循环 压缩比 (火用)分析 

分 类 号：TK421[动力工程及工程热物理—动力机械及工程]