Thermodynamic and energy saving benefits of hydraulic free-piston engines

Zhenfeng Zhao, Shan Wang, Shuanlu Zhang and Fujun Zhang

Energy, 2016, vol. 102, issue C, 650-659

Abstract: The hydraulic free-piston engine integrates the internal combustion engine with a hydraulic pump. The piston of an HFPE is not connected to the crankshaft and the piston movement is determined by the forces that act upon it. These features optimize combustion and make higher power density and efficiency increase. In this paper, a detailed thermodynamic and energy saving analysis is performed to demonstrate the fundamental efficiency advantage of an HFPE. The thermodynamic results show that the combustion process can be optimized to an ideal engine cycle. The experimental results show that the HFPE combustion process is a nearly constant-volume process; the efficiency is approximately 50%; the piston displacement and velocity curves for a cycle are the same at any frequency, even at a 1.25 Hz. The maximum velocities are of the same value at high or low frequencies. Similarly, pump output flow is not influenced by frequency. The independent cyclic characteristics of HFPE determine that it should work in higher frequencies when the vehicle runs in Japanese 10–15 road conditions. It indicates that a higher working frequency will lead to the starting frequency of HFPE, and a lower frequency will decrease the pressurized pressure of the hydraulic accumulator.

Keywords: Hydraulic free-piston engine; Thermodynamic benefits; Energy saving benefits; Experimental (search for similar items in EconPapers)
Date: 2016
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (3)

Downloads: (external link)
http://www.sciencedirect.com/science/article/pii/S0360544216300603
Full text for ScienceDirect subscribers only

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:eee:energy:v:102:y:2016:i:c:p:650-659

DOI: 10.1016/j.energy.2016.02.018

Access Statistics for this article

Energy is currently edited by Henrik Lund and Mark J. Kaiser

More articles in Energy from Elsevier
Bibliographic data for series maintained by Catherine Liu ().