An investigation of mixture formation characteristics of a free-piston gasoline engine with direct-injection

Chenheng Yuan, Yang Liu, Cuijie Han and Yituan He

Energy, 2019, vol. 173, issue C, 626-636

Abstract: The free-piston engine generator (FPEG) is regarded as a substitute of conventional combustion engine (CCE) because of special operation mechanism and potential advantages. This article presents an investigation to analyze the fuel spray and mixture formation characteristics of a direct injection gasoline FPEG by comparing a corresponding CCE. A full-cycle multi-dimensional fuel spray model is established by coupling with dynamic, and then it is validated experimentally to predict fuel diffusion and mixture formation in the FPEG. Results indicate that compared with the CCE, the FPEG operates with lower in-cylinder gas turbulence, pressure and temperature during injection stage, so the fuel spray in FPEG receives a smaller gas resistance and behaves more impingement, longer penetration, slower evaporation, larger sauter mean diameter (SMD), and lower mixture uniformity in this stage than the CCE. However, the slower compression process of FPEG not only makes that the fuel droplets evaporates earlier, but also provides a longer duration for fuel-air mixing and diffusion. Therefore, at the moment of spark ignition, a more homogeneous mixture is formed in the FPEG, and it shows smaller SMD and higher concentration around spark plug than the CCE. This phenomenon may facilitate the spark ignition and high efficiency combustion.

Keywords: Free-piston gasoline engine; Fuel spray; Mixture formation; Motion; Comparison (search for similar items in EconPapers)
Date: 2019
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (4)

Downloads: (external link)
http://www.sciencedirect.com/science/article/pii/S0360544219302580
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:173:y:2019:i:c:p:626-636

DOI: 10.1016/j.energy.2019.02.063

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 ().