Research On Control Method Of Starting Process Of Hydraulic Free Piston Engine

Hydraulic Free Piston Engine is a new engine, which has no crank-link mechanism. Instead, the piston is connected to the hydraulic components, so that the chemical energy stored in fuel can be converted to hydraulic energy directly. The simplicity and high overall efficiency are the advantages of Hydraulic Free Piston Engine. But these advantages also increase the design difficulty in control system and restrict the development of Hydraulic Free Piston Engine. Especially, the control in the starting process has become one of the technical difficulties in the research field of Hydraulic Free Piston Engine. In this paper, based on the existing prototype, the research on the control methods in starting process of a Hydraulic Free Piston Engine has been conducted.By studying the structure and working principle of Hydraulic Free Piston Engine, the selection of sensors, actuators and their layout work on the prototype engine were done and completed. Then, based on the actual parameters of the prototype engine, established a one-dimensional simulation model in AMESim to analyze the operating characteristics of Hydraulic Free Piston Engine. According to the operating characteristics obtained, found out the control methods in starting process, and used the simulation model to verify the control methods. These control methods include: position-based PPM frequency control, the fuel injection quantity based BDC(Bottom Dead Center) position control, the piston displacement based misfire control.Furthermore, Using Infineon XC2785 MCU to fabricate ECU(Electronic Control Unit) in kind. Using Tasking development kit to write the code, which was converted from the previous designed control methods. Meanwhile, in order to facilitate the debug and calibration of the ECU, a supporting PC program has been made by Lab View.Finally, according to the existing test bench, an engine operating monitoring system was developed. Connected the self-designed ECU with the prototype engine and carried out the starting test. The starting of the Hydraulic Free Piston Engine was implemented. Its results showed that the ECU was in good working order, and competent in the starting process of the Hydraulic Piston Engine.