Overall efficiency optimization of controllable mechanical turbo-compounding system for heavy duty diesel engines

作     者：HE GuanZhang XIE Hui HE ShiJie HE GuanZhang XIE Hui HE ShiJie

作者机构：State Key Laboratory of Engines Tianjin University Tianjin 300072 China School of Mechanical Engineering Tianjin University Tianjin 300072 China 

出 版 物：《Science China(Technological Sciences)》 (中国科学（技术科学英文版）)

年 卷 期：2017年第60卷第1期

页      面：36-50页

核心收录：

学科分类：0810[工学-信息与通信工程] 080703[工学-动力机械及工程] 08[工学] 0807[工学-动力工程及工程热物理] 0805[工学-材料科学与工程（可授工学、理学学位）] 0702[理学-物理学] 0812[工学-计算机科学与技术（可授工学、理学学位）] 

基　　金：supported by the National Basic Research Program of China(Grant No.2011CB707206) 

主　　题：heavy duty diesel engine waste heat recovery controllable mechanical turbo-compounding continuously variabletransmission device driving cycle transient response 

摘      要：A controllable mechanical turbo-compounding(CMTC) system including continuously variable transmission(CVT) and power turbine bypass valve is proposed to recover waste heat from engine exhaust. The combined matching principle considering swallowing capacity of both charging turbine and power turbine, main gear ratio is investigated at first based on the analysis of individual influence. Then the effects and strategies of CVT and power turbine bypass valve are studied for better performance under off-design conditions. At last, the transient response of intake pressure of engine with CMTC system is researched and the fuel saving potential is tested under driving cycle conditions. The results indicate that the overall fuel efficiency elevates at the off-design conditions if CVT is adopted due to the improvement of power turbine operating efficiency by speed modulation. The diversion of exhaust through power turbine bypass valve under the low load condition is necessary. The back pressure of the charging turbine infuences the transient response of intake pressure for a fixed CMTC configuration. A method featured by the assistance of power turbine bypass valve is tested to improve the transient response of the intake pressure. The fuel consumption reduces by 2% and 3.4% under highway fuel economy test(HWFET) and Tianjin 503(TJ503) driving cycles respectively.