柴油机可控机械复合涡轮系统总能效率优化研究  

Optimization of Overall Efficiency of Heavy Duty Diesel Engines Equipped with Controllable Mechanical Turbo-Compounding System

作　　者：谢辉[1] 何诗洁 

机构地区：[1]天津大学内燃机燃烧学国家重点实验室,天津300072

出　　处：《内燃机工程》2016年第6期31-36,共6页Chinese Internal Combustion Engine Engineering

基　　金：国家"九七三"重点基础研究发展计划项目(2011CB707206)

摘　　要：针对重型柴油机余热和余压能回收利用,提出了一种可控机械复合涡轮系统。该系统采用废气旁通阀和无级变速器,根据发动机运行工况动态调节增压涡轮和动力涡轮的运行状态,以获得最大的总能效率。在基于GT-SUITE的发动机及整车仿真平台上,从设计域层面研究了动力涡轮通流面积与传动速比对柴油机总能效率的影响规律,提出了增压涡轮、动力涡轮与发动机的匹配策略;针对发动机在驾驶循环下的全工况运行特征,从控制域层面研究了无级变速器传动速比和动力涡轮旁通阀开度对动力涡轮运行效率及系统总能效率的调节规律;根据所提出的无级变速器和旁通阀的控制策略,对总能效率改进效果进行了评估。研究结果表明:增压涡轮与动力涡轮的匹配关系对总能效率的提升效果有显著影响。标定工况下总能效率提高了4.3%,FTP75市郊驾驶循环工况下节油率为1.28%。A controllable mechanical turbo-compounding system with an exhaust bypass valve and a continuously variable transmission（CVT） was proposed to recover waste heat of heavy duty diesel engines so that overall engine efficiency would be raised. A model covering engine and vehicle, as well as the proposed system was set up using the GT-SUITE software. Based on this model, an optimization of the overall engine efficiency was conducted from two aspects. From the perspective of design, power turbine flow area and transmission ratio were two major characteristic parameters. Their effects on turbocharged diesel engines-- mainly the effects of turbocharger operating area and back pressure on the overall engine efficiency--were investigated first. Then, a matching strategy of turbocharger, power turbine and engine was proposed, pursuing the maximum overall engine efficiency under design condition. From the perspective of control, the effects of speed ratio of CVT and opening of the exhaust bypass valve on the power turbine performance and overall engine efficiency were discussed throughout the whole engine operation range. And then a corresponding control strategy was put forward, with which the overall engine efficiency was improved and assessed. The results show the matching of turboeharger and power turbine has great effect on the overall engine efficiency. The results indicate that the fuel consumption could be reduced by 4.3% and 1.28%0 under rated operating point and FTP75 suburb driving cycle respectively.

关 键 词：内燃机 重型柴油机 可控机械复合涡轮系统 总能效率 

分 类 号：TK421[动力工程及工程热物理—动力机械及工程]