Cold starting characteristics analysis of hydraulic free piston engine

Shuanlu Zhang, Zhenfeng Zhao*, Changlu Zhao, Fujun Zhang, Shan Wang

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

13 Citations (Scopus)

Abstract

The cold start characteristic of hydraulic free piston diesel engine may affect its stable operation. Therefore the specific cold start characteristics, such as BDC or TDC positions, pressure in-cylinder, heat release rate, should be investigated in detail. These parameters fluctuate in some regularity in the cod start process. With the development of the free piston engine prototype and the establishment of test bench, the results are obtained. For the dynamic results, the fluctuation range of TDC and BDC positions is 8 mm and decreases with time. The thermodynamic results show that the combustion process is not stable and the pressure in-cylinder fluctuates largely in the cold start process. In addition, the combustion is rapid and knock happens inevitably. In order to investigate the reasons, a CFD model is established for temperature analysis in-cylinder and heat transfer conditions. It is found that higher start wall temperature will lead to more uniform temperature distribution. The delay period may decreases and heat release will move forward. This reason is analyzed by thermodynamic derivation based on the first law of thermodynamics. Finally, the improvement suggestions of cold start strategy are proposed.

Original languageEnglish
Pages (from-to)879-886
Number of pages8
JournalEnergy
Volume119
DOIs
Publication statusPublished - 2017

Keywords

  • Cold start
  • Energy
  • Free piston engine
  • Heat release
  • Heat transfer
  • Scavenging

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Zhang, S., Zhao, Z., Zhao, C., Zhang, F., & Wang, S. (2017). Cold starting characteristics analysis of hydraulic free piston engine. Energy, 119, 879-886. https://doi.org/10.1016/j.energy.2016.11.052