An experimental study of the hydraulic free piston engine

An experimental investigation into the starting process of free-piston engine generator

“…In recent years, modern applications of the free-piston concept have been proposed for the generation of electric and hydraulic power, typically in hybrid electric vehicles [8][9]. Different prototype designs have been reported using the FPEG concept.…”

Combustion characteristics analysis of hydraulic free piston diesel engine

“…Then the pump chamber pressure rises rapidly. However, there is a delay time before the check value falls down [22]. So the pump chamber sets up high pressure after Dt when the piston moves from TDC.…”

Precise piston trajectory control for a free piston engine

“…Among them is the pulse pause modulation (PPM) control which has been implemented by a number of researchers on single-piston and opposed-piston FPEs (Achten, Van Den Oever, Potma, & Vael, 2000;Hibi & Ito, 2004;Zhao, Zhang, Huang, Zhao, & Guo, 2012). The main idea is to utilize hydraulic circuits as a bounce chamber which holds the piston at its bottom dead center (BDC) to achieve identical piston motion of each engine cycle.…”