Study on a Novel Variable Valve Timing and Lift Mechanism for a Miller Cycle Diesel Engine

Fanshuo Liu, Bolan Liu (), Junwei Zhang, Peng Wan and Ben Li
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Fanshuo Liu: School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China
Bolan Liu: School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China
Junwei Zhang: School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China
Peng Wan: School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China
Ben Li: School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China

Energies, 2022, vol. 15, issue 22, 1-11

Abstract: Thermal efficiency and power density improvement are the main research foci of the literature on diesel engines. The Miller cycle is considered to be one of the most promising methods of diesel engine operation. In this study, a fully variable valve timing and lift mechanism (CD-HFVVS) was studied to determine the possibility of a Miller operation. Firstly, the valve seat impact buffer in the mechanism was tested, which proved that the buffer can effectively eliminate the valve seat impact. Then the influences of different speeds and oil temperatures were studied. The results show that the valve opening duration is prolonged when engine speed increases, and the valve lift and duration are reduced while the oil temperature increased. The valve timing and lift can be fully adjusted by changing the oil discharge position and the initial plunger position, which further proves that CD-HFVVS can achieve the performance optimization of the Miller cycle. By using the mechanism, a single cylinder test was performed. By using variable inlet valve timing, the fuel efficiency can be effectively improved and the peak pressure and in-cylinder average temperature can both be suppressed.

Keywords: Miller cycle; diesel engine; CD-HFVVS; valve seating jerk buffer; performance optimizing (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2022
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (1)

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